Hypoxic severity

Abstract

A sleep test system for measuring hypoxic severity in a patient during sleep includes a patient sleep device configured to be coupled to the patient during sleep. The patient sleep device includes an arterial tone sensor configured to generate arterial tone data associated with the patient for monitoring arterial tone events in the patient and an oxygen saturation sensor configured to generate oxygen saturation data associated with the patient. The system further includes at least one controller configured to communicate with the patient sleep device. The at least one controller is configured to detect at least one arterial tone event in the arterial tone data, determine hypoxic desaturation information from the oxygen saturation data based on the at least one arterial tone event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

Description

HYPOXIC SEVERITYCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to United States Provisional Patent Application No. 63 / 569,412, filed on March 25, 2024, the disclosure of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to a sleep test system for monitoring and evaluating hypoxic severity based on data obtained from a sleeping patient.BACKGROUND

[0003] Medical devices can be used for monitoring a variety of physiological signals or parameters of a patient, including, for example, signals relating to breathing or respiratory parameters (e.g., blood oxygen levels, oxygen saturation, or oxygen uptake), as well as parameters for blood flow (e.g., heart rate or blood pressure) and blood composition (e.g., glucose concentration). Such medical devices can be used in connection with monitoring patients for certain sleep disordered breathing (SDB) conditions. For example, certain clinical applications use such devices for detecting and / or monitoring the patient’s physiological signals or parameters during sleep. The physiological signals and parameters detected by the medical devices can be processed and analyzed to provide quantitative assessments of patient condition including various physiological indexes, scores, ratios, and other calculated values providing information about conditions experienced by the patient during sleep. The information about the patient determined by the analysis can be provided to the patient, the patient’s health care provider (e.g., a physician), and / or other authorized individuals, as a patient sleep report.

[0004] It is desirable to improve the design and implementation of reporting from such sleep medical devices, including how data collected by the medical devices is analyzed and reported, to enhance the variety, accuracy, and probative value of information about the patient.SUMMARY

[0005] According to an aspect of the disclosure, a sleep test system for measuring hypoxic severityin a patient during sleep includes a patient sleep device configured to be coupled to the patient during sleep. The patient sleep device includes an arterial tone sensor (e.g., a peripheral arterial tone sensor and / or an arterial tone sensor configured to be positioned elsewhere on the patient for measuring arterial tone signals) configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient, and an oxygen saturation sensor configured to generate oxygen saturation data associated with the patient. The system further includes at least one controller (e.g., a portable computing device, remote computer-based server, a computer, or a microprocessor-based device) that is in communication with or, in some examples, is configured to communicate with, the patient sleep device. The at least one controller is configured to detect at least one arterial tone change or arterial tone event in the arterial tone data (e.g., peripheral arterial tone data), determine hypoxic desaturation information (e.g., an hypoxic deficiency value for an individual hypoxic desaturation event) from the oxygen saturation data, using information that is based at least in part on the at least one arterial tone change, and determine a hypoxic deficiency for the patient for a particular desaturation event based on the hypoxic desaturation information. For example, the hypoxic desaturation information can be determined from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart rate data. Depending on implementation and available sensor types, the pulse or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data.

[0006] Furthermore, in some examples, the hypoxic desaturation information can be determined from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart rate data, and / or patient movement or motion data during sleep. Depending on implementation and available sensor types, the patient movement or motion data during sleep can, for example, be based on motion sensors, including accelerometers, such as tri- axial accelerometers, gyroscopes, and / or other types of motion sensing devices. Such motion sensors can be disposed within a wrist worn portion of the patient sleep device, a digit probe portion of the patient sleep device, or any other predetermined location on the patient’s body.

[0007] The hypoxic desaturation information can also be determined from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart rate data, and / or patient movement or motion data during sleep, and / or snoring data during sleep. Depending on implementation and available sensor types, the patient snoring data during sleepcan, for example, be based on microphones or vibrational sensors, including audio sensors, vibrational sensors such as tri-axial accelerometers, and / or other types of audio capture devices. Such audio sensors can be disposed below a neck region of the patient, on an upper torso portion of the patient, a throat region of the patient, a face region of the patient, or any other predetermined location on the patient’s body.

[0008] According to another aspect of the disclosure, a computer-implemented method for measuring hypoxic severity in a patient during sleep (e.g., a computer implemented method that can be implemented by at least one of a remote computer-based server, a portable computing device, a computer, or a microprocessor-based device) includes: detecting, with at least one computer processor, at least one arterial tone change or event (e.g., a peripheral arterial tone change or event) in arterial tone data generated by at least one arterial tone sensor configured for monitoring arterial tone changes in the patient; determining, with the at least one computer processor, hypoxic desaturation information (e.g., a hypoxic deficiency value for an individual hypoxic desaturation event) from oxygen saturation data based on the at least one arterial tone change; and determining, with the at least one computer processor, a hypoxic deficiency for a desaturation event or hypoxic burden for multiple desaturation events for the patient based on the hypoxic desaturation information. For example, the hypoxic desaturation information can be determined from the oxygen saturation data using information from at least one arterial tone change and / or pulse or heart rate data. Depending on implementation and available sensor types, the pulse or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data.

[0009] The hypoxic desaturation information can also be determined from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart rata data, and / or patient movement or motion data during sleep. Depending on implementation and available sensor types, the patient movement or motion data during sleep can, for example, be based on motion sensors, including accelerometers, such as tri-axial accelerometers, gyroscopes, and / or other types of motion sensing devices. Such motion sensors can be disposed within a wrist worn portion of the patient sleep device, a digit probe portion of the patient sleep device, or any other predetermined location on the patient’s body.

[0010] The hypoxic desaturation information can also be determined from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart ratedata, and / or patient movement or motion data during sleep, and / or snoring data during sleep. Depending on implementation and available sensor types, the patient snoring data during sleep can, for example, be based on microphones or vibrational sensors, including audio sensors, vibrational sensors such as tri-axial accelerometers, and / or other types of audio capture devices. Such audio sensors can be disposed below a neck region of the patient, on an upper torso portion of the patient, a throat region of the patient, a face region of the patient, or any other predetermined location on the patient’s body.

[0011] According to another aspect of the disclosure, a patient sleep device for measuring hypoxic severity in a patient during sleep includes: a device housing comprising a proximal end adapted for facilitating insertion of a digit of the patient into the device housing; an arterial tone sensor (e.g., a peripheral arterial tone sensor) disposed in the device (e.g., in some implementations, within an interior of the device housing) configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient; an oxygen saturation sensor disposed in the interior of the device housing configured to generate oxygen saturation data associated with the patient; and a controller disposed in the interior of the device housing or mounted to an exterior surface of the device housing and in communication with the arterial tone sensor and the oxygen saturation sensor. The controller is configured to detect an arterial tone change or event in the arterial tone data, determine hypoxic desaturation information from the oxygen saturation data based on the arterial tone change, and determine a hypoxic deficiency for a desaturation event or hypoxic burden for multiple desaturation events for the patient based on the hypoxic desaturation information. For example, the hypoxic desaturation information can be determined from the oxygen saturation data using information from at least one arterial tone change and / or pulse or heart rata data. Depending on implementation and available sensor types, the pulse or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data. The hypoxic desaturation information can also be determined from the oxygen saturation data and using patient movement or motion data during sleep and / or patient snoring data during sleep.

[0012] According to an aspect of the disclosure, a sleep test system for measuring hypoxic severity in a patient during sleep includes at least one sensor configured to be coupled to the patient during sleep and to detect signals representative of oxygen saturation of the patient and a pulse rate or heart rate of the patient and at least one controller configured to communicate with the at least onesensor. The at least one controller is configured to: receive and process the signals from the at least one sensor to determine oxygen saturation data and pulse rate or heart rate data for the patient; detect at least one desaturation event in the oxygen saturation data; detect at least one pulse or heart rate event in the pulse rate or heart rate data; determine hypoxic desaturation information from the oxygen saturation data for the at least one desaturation event when there is a corresponding at least one pulse rate or heart rate event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

[0013] Preferred and non-limiting examples of the present disclosure will now be described in the following numbered clauses:

[0014] Clause 1 : A sleep test system for measuring hypoxic severity in a patient during sleep, comprising: a patient sleep device configured to be coupled to the patient during sleep, the patient sleep device comprising an arterial tone sensor configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient, and an oxygen saturation sensor configured to generate oxygen saturation data associated with the patient; and at least one controller configured to communicate with the patient sleep device, the at least one controller configured to detect at least one arterial tone event in the arterial tone data, determine hypoxic desaturation information from the oxygen saturation data based on the at least one arterial tone event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

[0015] Clause 2: The sleep test system of clause 1, wherein the patient sleep device comprises a digit housing comprising an external device housing surface, an internal device housing surface, and a proximal end adapted for facilitating insertion of a digit of the patient into the digit housing, and wherein the arterial tone sensor and the oxygen saturation sensor are disposed in the housing and configured to be positioned proximate to the digit of the patient.

[0016] Clause 3: The sleep test system of clause 2, wherein the digit of the patient comprises at least one of an index finger, middle finger, ring finger, pinky finger, or toes of the patient.

[0017] Clause 4: The sleep test system of clause 2 or clause 3, wherein the digit housing comprises a pressure device configured to apply a uniform or substantially uniform sub-diastolic pressure field to the digit of the patient.

[0018] Clause 5: The sleep test system of any of clauses 2-4, wherein the digit housing is configured to apply the uniform or substantially uniform sub-diastolic pressure field to at least a volar surface, a dorsal surface, and a distal tip of the digit of the patient.

[0019] Clause 6: The sleep test system of clause 4 or clause 5, wherein the pressure device comprises at least one membrane configured to apply pressure to the digit due to elastic deformation of the at least one membrane by the digit.

[0020] Clause 7: The sleep test system of any of clauses 4-6, wherein the pressure device is configured to apply the uniform or substantially uniform pressure of from about 40 mmHg to about 80 mmHg to surfaces of the digit.

[0021] Clause 8: The sleep test system of any of clauses 1-7, wherein the patient sleep device further comprises: a first clip member comprising a first surface configured to receive a first portion of a digit of the patient; and a second clip member coupled to the first clip member and comprising a second surface configured to receive a second portion of the digit, wherein the first clip member and the second clip member define a digit space with the arterial tone sensor and the oxygen saturation sensor disposed within the digit space.

[0022] Clause 9: The sleep test system of clause 8, wherein the first clip member and the second clip member are configured to receive the digit of the patient in the digit space, and wherein one of the first clip member or the second clip member is movable toward the other of the first clip member or the second clip member to generate pressure within the digit space.

[0023] Clause 10: The sleep test system of clause 9, wherein the patient sleep device further comprises a uniform pressure applicator configured to uniformly or substantially uniformly distribute the pressure generated within the digit space to a dorsal portion of the digit and a volar portion of the digit.

[0024] Clause 11: The sleep test system of any of clauses 1-10, wherein the patient sleep device is configured to be worn on the patient at a location where arterial tone is detectable.

[0025] Clause 12: The sleep test system of any of clauses 1-11, wherein the patient sleep device is configured to be mounted to at least one of a toe, an ear, forehead, an arm, a torso, abdomen, or a leg of the patient.

[0026] Clause 13: The sleep test system of any of clauses 1-12, wherein the patient sleep device is configured to be coupled to the patient during at least one of a home and / or remote sleep apnea test, a home and / or remote sleep disordered breathing test, and / or for sleep stage identification.

[0027] Clause 14: The sleep test system of any of clauses 1-13, further comprising a wrist-worn monitor in wired or wireless communication with the patient sleep device comprising processing circuitry for receiving and processing signals provided by the arterial tone sensor or the oxygen saturation sensor.

[0028] Clause 15: The sleep test system of any of clauses 1-14, wherein the arterial tone sensor is configured to detect signals representative of an arterial tone waveform of the patient and the oxygen saturation sensor is configured to detect signals representative of a saturation waveform that is correlated in time with the arterial tone waveform.

[0029] Clause 16: The sleep test system of any of clauses 1-15, wherein the arterial tone sensor comprises at least one emitter configured to emit light towards the patient and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the patient.

[0030] Clause 17: The sleep test system of clause 16, wherein the at least one emitter of the arterial tone sensor is configured to emit light within a wavelength of about 200 nm to about 600 nm.

[0031] Clause 18: The sleep test system of clause 16 or clause 17, wherein the arterial tone sensor is a transmissive sensor, in which light from the at least one emitter passes through the patient and is detected by the at least one detector.

[0032] Clause 19: The sleep test system of any of clauses 16-18, wherein the arterial tone sensor is a reflective-type sensor, in which light from the at least one emitter reflects from the patient and is detected by the at least one photodetector.

[0033] Clause 20: The sleep test system of any of clauses 1-19, wherein the oxygen saturation sensor comprises at least one emitter configured to emit light towards the digit and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the digit.

[0034] Clause 21: The sleep test system of clause 20, wherein the oxygen saturation sensor comprises a first emitter configured to emit light at a first wavelength configured to be absorbed by oxygenated hemoglobin of the patient and a second wavelength configured to be absorbed by deoxygenated hemoglobin of the patient.

[0035] Clause 22: The sleep test system of any of clauses 1-21, further comprising an attachment device comprising a fastening portion connected to an external surface of the patient sleep deviceand a securement portion configured to be worn on a wrist, forearm, and / or arm of the patient for releasably coupling the attachment device to the patient.

[0036] Clause 23 : The sleep test system of any of clauses 1 -22, wherein to determine the hypoxic desaturation information, the at least one controller is configured to identify portions of the oxygen saturation data that correspond in time with the detected at least one arterial tone event.

[0037] Clause 24: The sleep test system of any of clauses 1-23, wherein the determination of the hypoxic desaturation information is based on a baseline saturation level for the patient and the at least one arterial tone event.

[0038] Clause 25: The sleep test system of clause 24, wherein the baseline saturation level is a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

[0039] Clause 26: The sleep test system of clause 25, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

[0040] Clause 27: The sleep test system of any of clauses 24-26, wherein the baseline saturation level is at least one of 20%, 15%, 10%, 5%, or 1% of a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

[0041] Clause 28: The sleep test system of any of clauses 24-27, wherein the baseline saturation level is an average of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one arterial tone event.

[0042] Clause 29: The sleep test system of any of clauses 1-28, wherein to determine the hypoxic desaturation information, the at least one controller is configured to: identify a first fiducial point in the oxygen saturation data based on a baseline saturation level for the patient and the at least one arterial tone event, identify a second fiducial point in the oxygen saturation data, and determine the hypoxic desaturation information based on an area under curve between the first fiducial point and the second fiducial point.

[0043] Clause 30: The sleep test system of clause 29, wherein the at least one controller is configured to identify the second fiducial point in the oxygen saturation data as being subsequent to the at least one arterial tone event and substantially equal in value to the baseline saturation level.

[0044] Clause 31: The sleep test system of clause 29 or clause 30, wherein the at least one controller is configured to identify the second fiducial point in the oxygen saturation data as being subsequent to a desaturation start time and having a value within a predetermined percentage of the baseline saturation level.

[0045] Clause 32: The sleep test system of any of clauses 29-31, wherein the at least one controller is configured to determine the second fiducial point in the oxygen saturation data as being subsequent to the at least one arterial tone event and a maximum value of the oxygen saturation data within a predetermined post-event duration.

[0046] Clause 33: The sleep test system of any of clauses 1-32, wherein the arterial tone event comprises an arterial tone change that is representative of sympathetic activity of the patient.

[0047] Clause 34: The sleep test system of any of clauses 1-33, wherein the at least one controller is configured to detect the at least one arterial tone event based on a change in amplitude of an arterial tone signal of the arterial tone data.

[0048] Clause 35: The sleep test system of clause 34, wherein the arterial tone event detected by the at least one controller comprises attenuation of the arterial tone signal.

[0049] Clause 36: The sleep test system of clause 34 or clause 35, wherein the attenuation of the arterial tone signal comprises a decrease in an amplitude range in the arterial tone signal relative to a predetermined baseline value for arterial tone signal range.

[0050] Clause 37: The sleep test system of any of clauses 1-36, wherein the at least one controller is configured to determine a pulse rate for the patient based on at least one of the arterial tone data or the oxygen saturation data.

[0051] Clause 38: The sleep test system of any of clauses 1-37, further comprising a heart rate sensor configured to determine a heart rate for the patient, and wherein the at least one controller is configured to determine the hypoxic desaturation information based on the at least one arterial tone event and on identified changes in the determined heart rate of the patient.

[0052] Clause 39: The sleep test system of any of clauses 1-38, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient.

[0053] Clause 40: The sleep test system of any of clauses 1-39, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the atleast one hypoxic deficiency values determined for the patient and an actual sleep duration for the patient.

[0054] Clause 41: The sleep test system of any of clauses 1-40, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values and a nominal sleep duration for the patient.

[0055] Clause 42: The sleep test system of clause 41, further comprising a user interface element, and wherein the nominal sleep duration for the patient is input via the user interface element.

[0056] Clause 43: The sleep test system of any of clauses 1-42, further comprising at least one movement or motion sensor to generate movement information for the patient, and wherein the at least one controller is configured to determine the hypoxic burden desaturation information based on the at least one arterial tone event and the movement information.

[0057] Clause 44: The sleep test system of any of clauses 1-43, further comprising at least one snoring sensor for generating snoring information for the patient, and wherein the at least one controller is configured to determine the hypoxic burden desaturation information based on the at least one arterial tone event and the snoring information.

[0058] Clause 45: A computer-implemented method for measuring hypoxic severity in a patient during sleep, the method comprising: detecting, with at least one computer processor, at least one arterial tone event in arterial tone data generated by at least one arterial tone sensor configured for monitoring arterial tone events in the patient; determining, with the at least one computer processor, hypoxic desaturation information from oxygen saturation data based on the detected at least one arterial tone event; and determining, with the at least one computer processor, at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

[0059] Clause 46: The computer-implemented method of clause 45, wherein the arterial tone data is representative of an arterial tone waveform of the patient and the oxygen saturation data is representative of a saturation waveform that is correlated in time with the arterial tone waveform.

[0060] Clause 47: The computer- implemented method of clause 45 or clause 46, wherein determining the hypoxic desaturation information comprises, with the at least one computer processor, identifying portions of the oxygen saturation data that correspond in time with the detected at least one arterial tone event.

[0061] Clause 48: The computer- implemented method of any of clauses 45-47, wherein the determination of the hypoxic desaturation information is based on a baseline saturation level for the patient and the at least one arterial tone event.

[0062] Clause 49: The computer-implemented method of clause 48, wherein the baseline saturation level is a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

[0063] Clause 50: The computer-implemented method of clause 49, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

[0064] Clause 51: The computer-implemented method of any of clauses 48-50, wherein the baseline saturation level is at least one of 20%, 15%, 10%, 5%, or 1% of a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

[0065] Clause 52: The computer- implemented method of any of clauses 48-51, wherein the baseline saturation level is an average of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one arterial tone event.

[0066] Clause 53: The computer-implemented method of any of clauses 45-52, wherein determining the hypoxic desaturation information comprises: identifying a first fiducial point in the oxygen saturation data based on a baseline saturation level for the patient and the at least one arterial tone event, identifying a second fiducial point in the oxygen saturation data, and determining the hypoxic desaturation information based on an area under curve between the first fiducial point and the second fiducial point.

[0067] Clause 54: The computer-implemented method of clause 53, wherein the second fiducial point in the oxygen saturation data is identified as being subsequent to the at least one arterial tone event and substantially equal in value to the baseline saturation level.

[0068] Clause 55: The computer-implemented method of clause 54, wherein the second fiducial point in the oxygen saturation data is identified as being subsequent to a desaturation start time and having a value within a predetermined percentage of the baseline saturation level.

[0069] Clause 56: The computer-implemented method of clause 54 or clause 55, wherein the second fiducial point in the oxygen saturation data is identified as being subsequent to the at leastone arterial tone event and a maximum value of the oxygen saturation data within a predetermined post-event duration.

[0070] Clause 57: The computer-implemented method of any of clauses 45-56, wherein the at least one arterial tone event comprises an arterial tone change that is representative of sympathetic activity of the patient.

[0071] Clause 58: The computer-implemented method of any of clauses 45-57, wherein the detecting the at least one arterial tone event is based on a change in amplitude of an arterial tone signal of the arterial tone data.

[0072] Clause 59: The computer-implemented method of clause 58, wherein the detected at least one arterial tone event comprises attenuation of the arterial tone signal.

[0073] Clause 60: The computer-implemented method of clause 59, wherein the attenuation of the arterial tone signal comprises a decrease in an amplitude range in the arterial tone signal relative to a predetermined baseline value for arterial tone signal range.

[0074] Clause 61: The computer-implemented method of any of clauses 45-60, further comprising determining a pulse rate for the patient based on at least one of the arterial tone data or the oxygen saturation data, and wherein the hypoxic desaturation information is based on the pulse rate.

[0075] Clause 62: The computer-implemented method of any of clauses 45-61, further comprising, with the at least one processor, determining an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient.

[0076] Clause 63: The computer-implemented method of any of clauses 45-62, further comprising determining an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient and an actual sleep duration for the patient.

[0077] Clause 64: The computer-implemented method of any of clauses 45-63, further comprising determining an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values and a nominal sleep duration for the patient.

[0078] Clause 65: The computer-implemented method of any of clauses 45-64, further comprising receiving movement information for the patient, wherein the determination the hypoxic burden desaturation information for the patient is based on the at least one arterial tone event and the movement information.

[0079] Clause 66: The computer-implemented method of any of clauses 45-65, further comprising determining snoring information for the patient, wherein the determination of the hypoxic burden desaturation information is based on the at least one arterial tone event and the snoring information.

[0080] Clause 67 : A patient sleep device for measuring hypoxic severity in a patient during sleep, comprising: a device housing comprising a proximal end adapted for facilitating insertion of a digit of the patient into the device housing; an arterial tone sensor disposed in an interior of the device housing configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient; an oxygen saturation sensor disposed in the interior of the device housing configured to generate oxygen saturation data associated with the patient; and a controller disposed in the interior of the device housing or mounted to an exterior surface of the device housing and in communication with the arterial tone sensor and the oxygen saturation sensor, wherein the controller is configured to: identify at least one arterial tone event in the arterial tone data, determine hypoxic desaturation information from the oxygen saturation data based on the at least one arterial tone event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

[0081] Clause 68: The patient sleep device of clause 67, wherein the digit of the patient comprises at least one of an index finger, middle finger, ring finger, pinky finger, or toes of the patient.

[0082] Clause 69: The patient sleep device of clause 67 or clause 68, wherein the device housing comprises a pressure device configured to apply a uniform or substantially uniform sub-diastolic pressure field to the digit of the patient.

[0083] Clause 70: The patient sleep device of any of clauses 67-69, wherein the device housing is configured to apply the uniform or substantially uniform sub-diastolic pressure field to at least a volar surface, a dorsal surface, and a distal tip of the digit of the patient.

[0084] Clause 71 : The patient sleep device of clause 70, wherein the pressure device comprises at least one membrane configured to apply pressure to the digit due to elastic deformation of the at least one membrane by the digit.

[0085] Clause 72: The patient sleep device of clause 70 or clause 71, wherein the pressure device is configured to apply the uniform or substantially uniform pressure of from about 40 mmHg to about 80 mmHg to surfaces of the digit.

[0086] Clause 73: The patient sleep device of any of clauses 67-72, wherein the device housing comprises: a first clip member comprising a first surface configured to receive a first portion of adigit of the patient; and a second clip member coupled to the first clip member and comprising a second surface configured to receive a second portion of the digit, wherein the first clip member and the second clip member define a digit space with the arterial tone sensor and the oxygen saturation sensor disposed within the digit space.

[0087] Clause 74: The patient sleep device of clause 73, wherein the first clip member and the second clip member are configured to receive the digit of the patient in the digit space, and wherein one of the first clip member or the second clip member is movable toward the other of the first clip member or the second clip member to generate pressure within the digit space.

[0088] Clause 75: The patient sleep device of clause 74, further comprises a uniform pressure applicator configured to uniformly or substantially uniformly distribute the pressure generated within the digit space to a dorsal portion of the digit and a volar portion of the digit.

[0089] Clause 76: The patient sleep device of any of clauses 67-75, wherein the patient sleep device is configured to be worn on the patient at a location where arterial tone is detectable.

[0090] Clause 77: The patient sleep device of any of clauses 67-76, wherein the patient sleep device is configured to be mounted to at least one of a toe, an ear, forehead, an arm, a torso, abdomen, or a leg of the patient.

[0091] Clause 78: The patient sleep device of any of clauses 67-77, wherein the patient sleep device is configured to be coupled to the patient during at least one of a home and / or remote sleep apnea test, a home and / or remote sleep disordered breathing test, and / or for sleep stage identification.

[0092] Clause 79: The patient sleep device of any of clauses 67-78, wherein the arterial tone sensor is configured to detect signals representative of an arterial tone waveform of the patient and the oxygen saturation sensor is configured to detect signals representative of a saturation waveform that is correlated in time with the arterial tone waveform.

[0093] Clause 80: The patient sleep device of any of clauses 67-79, wherein the arterial tone sensor comprises at least one emitter configured to emit light towards the patient and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the patient.

[0094] Clause 81: The patient sleep device of clause 80, wherein the at least one emitter of the arterial tone sensor is configured to emit light within a wavelength of about 200 nm to about 600 nm.

[0095] Clause 82: The patient sleep device of clause 80 or clause 81, wherein the arterial tone sensor is a transmissive sensor, in which light from the at least one emitter passes through the patient and is detected by the at least one detector.

[0096] Clause 83: The patient sleep device of any of clauses 80-82, wherein the arterial tone sensor is a reflective-type sensor, in which light from the at least one emitter reflects from the patient and is detected by the at least one photodetector.

[0097] Clause 84: The patient sleep device of any of clauses 67-83, wherein the oxygen saturation sensor comprises at least one emitter configured to emit light towards the digit and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the digit.

[0098] Clause 85: The patient sleep device of clause 84, wherein the oxygen saturation sensor comprises a first emitter configured to emit light at a first wavelength configured to be absorbed by oxygenated hemoglobin of the patient and a second wavelength configured to be absorbed by deoxygenated hemoglobin of the patient.

[0099] Clause 86: The patient sleep device of any of clauses 67-85, further comprising an attachment device comprising a fastening portion connected to an external surface of the patient sleep device and a securement portion configured to be worn on a wrist, forearm, and / or arm of the patient for releasably coupling the attachment device to the patient.

[0100] Clause 87: A sleep test system for measuring hypoxic severity in a patient during sleep, comprising: at least one sensor configured to be coupled to the patient during sleep and to detect signals representative of oxygen saturation of the patient and a pulse rate or heart rate of the patient; and at least one controller configured to communicate with the at least one sensor, the at least one controller configured to receive and process the signals from the at least one sensor to determine oxygen saturation data and pulse rate or heart rate data for the patient; detect at least one desaturation event in the oxygen saturation data; detect at least one pulse or heart rate event in the pulse rate or heart rate data; determine hypoxic desaturation information from the oxygen saturation data for the at least one desaturation event when there is a corresponding at least one pulse rate or heart rate event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

[0101] Clause 88: The sleep test system of clause 87, wherein the at least one sensor comprises an oxygen saturation sensor.

[0102] Clause 89: The sleep test system of clause 88, wherein the oxygen saturation sensor comprises at least one emitter configured to emit light towards a digit and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the digit.

[0103] Clause 90: The sleep test system of clause 88 or clause 89, wherein the oxygen saturation sensor comprises a first emitter configured to emit light at a first wavelength configured to be absorbed by oxygenated hemoglobin of the patient and a second wavelength configured to be absorbed by deoxygenated hemoglobin of the patient.

[0104] Clause 91 : The sleep test system of any of clauses 88-90, wherein the at least one controller is configured to determine the pulse rate data based on the signals detected by the oxygen saturation sensor.

[0105] Clause 92: The sleep test system of any of clauses 87-91, wherein the at least one sensor comprises an oxygen saturation sensor and a heart rate sensor, and wherein the at least one controller is configured to determine the oxygen saturation data based on signals detected by the oxygen saturation sensor and determine the heart rate data based on signals detected by the heart rate sensor.

[0106] Clause 93: The sleep test system of clause 92, wherein the heart rate sensor comprises at least one of an electrocardiogram (ECG) electrode, ECG sensor, or ECG monitoring device.

[0107] Clause 94: The sleep test system of clause 87, wherein to determine the hypoxic desaturation information, the at least one controller is configured to identify portions of the oxygen saturation data that correspond in time with the at least one pulse rate or heart rate event.

[0108] Clause 95: The sleep test system of any of clauses 87-94, wherein the determination of the hypoxic desaturation information is based on a baseline saturation level for the patient and the at least one pulse rate or heart rate event.

[0109] Clause 96: The sleep test system of clause 95, wherein the baseline saturation level is a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one pulse rate or heart rate event.

[0110] Clause 97: The sleep test system of clause 96, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

[0111] Clause 98: The sleep test system of any of clauses 95-97, wherein the baseline saturation level is at least one of 20%, 15%, 10%, 5%, or 1% of a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one pulse rate or heart rate event.

[0112] Clause 99: The sleep test system of any of clauses 95-99, wherein the baseline saturation level is an average of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one pulse rate or heart rate event.

[0113] Clause 100: The sleep test system of any of clauses 87-99, wherein the at least one pulse rate or heart rate event comprises a change in pulse rate or heart rate compared to a baseline pulse or heart rate value of the patient.

[0114] Clause 101: The sleep test system of clause 100, wherein the baseline pulse or heart rate value is a maximum or average value in the pulse rate or heart rate data detected within a predetermined period of time preceding the at least one pulse rate or heart rate event.

[0115] Clause 102: The sleep test system of clause 101, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

[0116] Clause 103: The sleep test system of any of clauses 100-102, wherein the at least one pulse rate or heart rate event comprises an increase in pulse rate or heart rate compared to a baseline pulse or heart rate value.

[0117] Clause 104: The sleep test system of any of clauses 87-103, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient.

[0118] Clause 105: The sleep test system of any of clauses 87-104, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient and an actual sleep duration for the patient.

[0119] Clause 106: The sleep test system of any of clauses 87-105, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values and a nominal sleep duration for the patient.BRIEF DESCRIPTION OF THE DRAWINGS

[0120] Various aspects of the disclosure are discussed below with reference to the accompanying figures, which are not intended to be drawn to scale. The figures are included to provide an illustration and a further understanding of various examples, and are incorporated in and constitute a part of this specification, but are not intended to limit the scope of the disclosure. The drawings, together with the remainder of the specification, serve to explain principles and operations of the described and claimed aspects and examples. In the figures, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every figure. A quantity of each component in a particular figure is an example only and other quantities of each, or any, component could be used.

[0121] FIG. 1A is a schematic drawing of a medical system, according to an aspect of the disclosure;

[0122] FIG. IB is a schematic drawing of devices of the medical system connected to a patient, according to an aspect of the present disclosure;

[0123] FIG. 1C is a schematic drawing of a wearable medical device including a digit clip and a wearable monitor, according to an aspect of the present disclosure;

[0124] FIG. ID is a schematic drawing of components of the wearable medical device of FIG. 1C;

[0125] FIG. IE is a schematic drawing showing the wearable medical device worn by a patient;

[0126] FIG. 2 is a graph showing a relationship between pressure and volume for digit clip, according to an aspect of the present disclosure;

[0127] FIG. 3A is a flow chart showing a method for determining hypoxic deficiency for the patient based on arterial tone data and oxygen saturation data, according to an aspect of the present disclosure;

[0128] FIG. 3B is a graph of arterial tone data and oxygen saturation data for a patient showing arterial tone changes in the arterial tone data, according to an aspect of the present disclosure;

[0129] FIG. 3C is another graph of arterial tone data and oxygen saturation data for a patient showing additional examples of arterial tone changes in arterial tone data, according to aspects of the present disclosure;

[0130] FIG. 4A-4C are graphs of oxygen saturation data showing additional examples of methods for determining baseline saturation values for a patient, according to aspects of the present disclosure;

[0131] FIGS. 5A-5C are graphs of arterial tone data and oxygen saturation data showing timing issues between the end of desaturation and arterial change time, according to aspects of the present disclosure;

[0132] FIG. 6A is a flow chart showing a method for identifying hypoxic desaturation information, according to an aspect of the present disclosure;

[0133] FIG. 6B is a graph of arterial tone data and oxygen saturation data for a patient showing a baseline saturation level for the patient, according to an aspect of the present disclosure;

[0134] FIG. 7A is a flow chart showing another method for determining hypoxic burden for a patient based on multiple hypoxic deficiencies, according to an aspect of the present disclosure;

[0135] FIG. 7B is another graph of arterial tone data and oxygen saturation data for the patient showing the multiple hypoxic deficiencies, according to an aspect of the present disclosure;

[0136] FIG. 8A is a flow chart showing another example of a method for determining hypoxic deficiency for the patient based on arterial tone data, oxygen saturation data, and pulse rate data, according to an aspect of the present disclosure;

[0137] FIG. 8B is a flow chart showing another example of a method for determining hypoxic deficiency for the patient based on arterial tone data, oxygen saturation data, and motion sensor data for the patient, according to an aspect of the present disclosure;

[0138] FIG. 8C is a graph showing arterial tone data, oxygen saturation data, pulse rate data, motion data, and audio data for the patient, according to an aspect of the present disclosure;

[0139] FIG. 8D is a flow chart showing another example of a method for determining hypoxic deficiency for the patient based on oxygen saturation data and pulse rate or heart rate data for the patient, according to an aspect of the disclosure;

[0140] FIG. 8E is a graph showing oxygen saturation data and pulse rate data, according to an aspect of the disclosure;

[0141] FIG. 9A is a perspective view of a patient sleep device comprising a digit probe according to an aspect of the present disclosure;

[0142] FIG. 9B is a cross-sectional view of the digit probe of FIG. 9A;

[0143] FIG. 10A is a perspective view of a patient sleep device comprising a digit clip according to an aspect of the present disclosure;

[0144] FIGS. 10B and 10C are cross-sectional views of the digit clip of FIG. 10A;

[0145] FIG. 11 is a cross-sectional view of another example of a wearable medical device comprising a digit clip and an optical -based physiological sensors, according to an aspect of the present disclosure;

[0146] FIG. 12 is a cross-sectional view of another example of a wearable medical device comprising a digit clip and optical-based physiological sensors, according to an aspect of the present disclosure;

[0147] FIG. 13 is a perspective view of a patient sleep device comprising a digit probe and an attachment device, according to another aspect of the present disclosure;

[0148] FIG. 14 is a perspective view of a patient sleep device comprising another example of an attachment device and a digit clip, according to another aspect of the present disclosure;

[0149] FIGS. 15A-15C are schematic drawings of a physiological monitoring system including a wearable medical device comprising a digit clip, according to aspects of the present disclosure; and

[0150] FIGS. 16A-16F are user interface screens that can be displayed on a mobile or computer device guiding a patient in performing at at-home medical test, according to aspects of the present disclosure.DETAILED DESCRIPTION

[0151] This disclosure relates to systems, methods, and devices for detecting physiological information from a patient, such as for detecting physiological information from a patient during sleep to identify and / or assess severity of SDB events, and / or for analyzing patient data for the sleeping patient to provide a quantitative assessment of patient condition. In examples, the devices, systems, and methods disclosed herein provide measurements for hypoxic severity (e.g., a hypoxic deficiency value and / or hypoxic burden value) in the patient based, for example, on physiological parameters for the patient detected by a patient sleep device.

[0152] In examples, the systems, methods, and devices for detecting physiological information can comprise an oxygen saturation sensor or sensing device configured to generate oxygen saturation data for the patient and an arterial tone sensor or sensing device configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient. The sensors or sensing devices can be connected at various body locations of the patient including,for example, to a digit (toe or finger), ear, forehead, wrist, or any other convenient location of a patient).

[0153] In examples, an arterial tone sensor can be positioned in a body location different than or separate from a body location where the oxygen saturation sensor is located. Signals from oxygen saturation sensors can have a certain latency relative to onset of actual blood desaturation within the body. In examples, a sleep disorder event, e.g., a desaturation event, can initiate several seconds, e.g., 10 seconds, 20 seconds, or 30 seconds, in certain scenarios, prior to being detected by an oxygen saturation sensor located on, e.g., a peripheral location such as a patient digit location. In implementations in this regard, an oxygen saturation sensor is located in a body location where the sensor signal has faster detection of desaturation and resaturation events (e.g., beginning of a desaturation event or the end of a desaturation event) when compared to, for example, digit sensors. For example, the faster detection can be on the order of a few seconds, e.g., 2 seconds faster, 5 seconds faster, 10 seconds faster, relative to the latency described above. For example, such body locations include ear or forehead locations. In examples, the oxygen saturation sensor location can be an ear location, such as being securely positioned on the cavum conchae. Advantageously, such ear or forehead oxygen saturation sensors can permit easy access to a location on the patient’s body for a sleep study as described herein in situations where a patient may be undergoing or recovering from a surgical procedure or other similar scenario. Other scenarios can include, for example, following a resuscitation event or where a patient may have been in an accident or recovering from an accident. Other scenarios can include for patients with finger deformities or when digit access is otherwise not available or uncomfortable to the patient.

[0154] In examples, the systems, methods, and devices can be configured to calculate or determine hypoxic severity for a patient. For example, hypoxic severity can be based on determining hypoxic desaturation information from oxygen saturation data based on at least one arterial tone event in arterial tone data. In examples, the hypoxic desaturation information can be used to provide a hypoxic deficiency value for one or more desaturation events for a patient during sleep. In examples, an overall hypoxic burden for the patient during sleep can be determined from multiple hypoxic deficiency values. The hypoxic deficiencies or the hypoxic burden can be reported as alpha and / or numeric values or scores representing a frequency and / or severity of desaturation events present in oxygen saturation data for the patient over a predetermined duration. In examples, as described in detail below, a hypoxic deficiency value can be calculated for anindividual desaturation event. In this regard, hypoxic deficiency values for multiple individual desaturation events can be combined (e.g., mathematically added together, averaged, or a processed through a predetermined mathematical function) to provide a single representative overall hypoxic burden value for the patient corresponding to the predetermined period of time. For example, the predetermined period of time can be an entire night, a specified duration of a sleep study, actual sleep period as determined based on sensed physiological data (e.g., data representative of a sleep position or sleep stage), or a user specified duration. In examples, the calculated overall hypoxic burden can also be normalized based on a total time that the patient is asleep.

[0155] In implementations, the hypoxic deficiency value can be based on hypoxic desaturation information determined from both patient oxygen saturation data and arterial tone data for the patient. In some examples, the hypoxic deficiency value can be based on hypoxic desaturation information determined from oxygen saturation data and only arterial tone data for the patient. In some other examples, the hypoxic deficiency value can be based on hypoxic desaturation information determined from oxygen saturation data, arterial tone data, and pulse rate or heart rate data for the patient. In some other examples, the hypoxic deficiency value can be based on hypoxic desaturation information determined from oxygen saturation data, arterial tone data, pulse or heart rate data, and patient sleep movement data. In some other examples, the hypoxic deficiency value can be based on hypoxic desaturation information determined from oxygen saturation data, arterial tone data, pulse or heart rate data, and patient snore data detected, for example, by an acoustic sensor or microphone. In some examples, the hypoxic desaturation information includes details from arterial tone data that can be used to identify desaturation events in the oxygen saturation data, which are correlated with and / or related to sympathetic activity in the patient. For example, the hypoxic desaturation information can be used to determine such sympathetic activity in the patient based on analysis of arterial tone data (e.g., peripheral arterial tone data), pulse or heart rate data, patient sleep movement data, and / or patient snoring data included within the hypoxic desaturation information. In some examples, hypoxic desaturation information can be used to determine desaturation events in the oxygen saturation data that have corresponding changes in arterial tone (e.g., peripheral arterial tone which, in some cases, can be correlated to changes in pulse or heart rate and / or patient sleep movement data) can be considered in determining hypoxic deficiency for the patient. In some cases, desaturation events in the oxygen saturation data that donot appear to be correlated with an arterial tone change may not be considered in determining hypoxic deficiency or burden for the patient. Thus, in the present disclosure, the hypoxic desaturation information includes the oxygen saturation data and the arterial tone data (including, in implementations, when combined with pulse or heart rate data, patient sleep movement data, and / or patient snore data), which can advantageously be analyzed together to provide insight about certain desaturation events experienced by the patient during sleep. This analysis can aid in determining which desaturation events are of particular relevance for assessing hypoxic severity in the patient during sleep.

[0156] In examples, a wearable device for detecting patient physiological information can be a patient sleep device comprising, for example, an optical digit probe and / or digit clip, as disclosed herein. The patient sleep device can include optical sensors comprising light emitters and photodetectors for detecting the patient physiological signals. In examples, the patient sleep device can include an optical probe configured to be positioned at a predetermined location on the patient’s body, including a peripheral location. For example, the predetermined location on the patient’s body can be a digit, such as a finger, a toe, an ear (e.g., an ear lobe), or another peripheral portion of the patient’s body. The predetermined location can also be a location on, for example, an upper torso, chest, back, shoulder, upper limb, lower limb, neck, or head region, such as a forehead, of the patient.

[0157] The testing and patient monitoring performed by the systems and devices disclosed herein may be for sleep studies (e.g., in a sleep lab or a remote home -based sleep study) that can last for an overnight or a long study duration (e.g., between about 3-4 hours, about 6-8 hours, or about 9- 12 hours). While examples described herein are in the context of long, continuous duration studies, it is understood that the systems, devices, and methods can also be used for shorter duration applications or over several different nights. For example, the testing or monitoring activity may be an oxygen saturation measurement during a clinical visit (e.g. an induced sleep session lasting for a short duration such as about 10 seconds to about 5 minutes, more particularly about 10 seconds to about 1 minute). The testing or monitoring activity may also be a longer clinical study for e.g., arterial pressure pulse changes, blood pressure monitoring, oxygen saturation changes, etc., during a clinical visit lasting, e.g., for 5 minutes to about an hour.

[0158] The present disclosure is also directed to features of patient sleep devices, such as sensors, electronic circuitry, and processors. In particular, the present disclosure provides examples ofpatient sleep devices with different configurations of probes, clips, sensors, light emitters, photodetectors, and circuitry for detecting physiological signals for the patient. The patient sleep devices can be configured to measure arterial tone and oxygen saturation of the patient. The patient sleep devices and / or other sensors and devices associated with the patient can also be configured to measure or detect pulse rate, patient movement, snoring, and other parameters related to patient sleep.

[0159] These and other features and characteristics of the present disclosure, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limit of the disclosure.

[0160] As used herein, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0161] As used herein, the terms “right”, “left”, “top”, and derivatives thereof shall relate to aspects of the present disclosure as it is oriented in the drawing figures. However, it is to be understood that embodiments of the present disclosure can assume various alternative orientations and, accordingly, such terms are not to be considered as limiting. Also, it is to be understood that embodiments of the present disclosure can assume various alternative variations and stage sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are provided as examples. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

[0162] As used herein, including in the claims, unless otherwise stated, a statement that a function or operation is “based on” an item or condition means that the function or operation is based on the stated item or condition and may be based on one or more items and / or conditions in addition to the stated item or condition.

[0163] As used herein, the terms “communication” and “communicate” refer to the receipt or transfer of one or more signals, messages, commands, or other type of data. For one unit orcomponent to be in communication with another unit or component means that the one unit or component is able to directly or indirectly receive data from and / or transmit data to the other unit or component. This includes a direct or indirect connection that can be wired and / or wireless in nature. Additionally, two units or components can be in communication with each other even though the data transmitted can be modified, processed, routed, and the like, between the first and second unit or component. For example, a first unit can be in communication with a second unit even though the first unit passively receives data, and does not actively transmit data to the second unit. As another example, a first unit can be in communication with a second unit if an intermediary unit processes data from one unit and transmits processed data to the second unit. It will be appreciated that numerous other arrangements are possible.

[0164] The features described herein can be implemented within a variety of wearable systems, devices, sleep monitors, or sleep medical devices intended for either attended or unattended sleep studies. For example, systems, methods, computer readable media as described herein can be used in any of type I, type II, type III, or type IV devices, as currently described by the United States Center for Medicare and Medicaid Services (CMS). For example, such type I sleep monitors, as described herein, can be used for attended studies (e.g., sleep studies that are performed with the oversight of a sleep technologist) with sleep staging, e.g., monitoring transition through different sleep stages, such as with the use of electroencephalogram (EEG) electrodes that monitor the brain. Type I devices can include the following channels / sensors: one or more EEG channels / sensors, one or more electrooculography (EOG), one or more electrocardiogram (ECG) channels / sensors, one or more chin electromyography (EMG) channels / sensors, one or more limb EMG channels / sensors, one or more 3D accelerometer channels / sensors (e.g., positioned at thorax and abdomen) to sense respiratory effort, one or more air flow from nasal cannula (NSF) channels / sensors (e.g. thermistors), one or more pulse oximetry channels / sensors for oxygen saturation information, and one or more arterial tone channels / sensors for arterial tone information. For example, the arterial tone information can include peripheral arterial tone information as described in further detail herein. In examples, CMS guideline based type I devices can include additional channels for CPAP / BiPap levels, CO2, pH, pressure, among other channels.

[0165] In examples, systems, methods, computer readable media as described herein can be used in certain types of home sleep test (HST) devices. In certain cases, such home sleep test (HST) devices include home sleep apnea test (HSAT) devices. For example, such HST devices can betype II portable sleep monitors configured for unattended sleep studies that are performed without oversight of a sleep technologist. Such devices are considered to be type II portable sleep monitors according to current CMS guidelines. For example, current CMS guidelines based type II devices can include at least 7 channels. In this regard, current CMS guidelines based type II devices can include the following channels / sensors. EEG, EOG, ECG / heart rate, EMG, airflow, respiratory effort, oxygen saturation channels / sensors for oxygen saturation information, and one or more arterial tone channels / sensors for arterial tone information. For example, the arterial tone information can include peripheral arterial tone information as described in further detail herein.

[0166] Additionally or alternatively, systems, methods, computer readable media as described herein can be used in current CMS guidelines based type III HST portable sleep monitors configured for unattended sleep studies with at least 4 channels. Current CMS guidelines based type III devices include the following channels / sensors: at least 2 respiratory movement / airflow channels / sensors, one ECG / heart rate channel / sensor, one oxygen saturation channel / sensor for oxygen saturation information, and one or more arterial tone channels / sensors for arterial tone information. For example, the arterial tone information can include peripheral arterial tone information as described in further detail herein.

[0167] Additionally or alternatively, systems, methods, computer readable media as described herein can be used in current CMS guidelines based type IV HST portable sleep monitor configured for unattended sleep studies with at least 3 channels, including at least one oxygen saturation channel / sensor for oxygen saturation information, and one or more arterial tone channels / sensors for arterial tone information. For example, the arterial tone information can include peripheral arterial tone information as described in further detail herein. Current CMS guideline based type IV devices include channels that allow direct calculation of an Apnea- Hypopnea Index (AHI) or respiratory disturbance index (RD I) as the result of measuring airflow or thoracoabdominal movement.

[0168] Additionally or alternatively, the American Academy of Sleep Medicine (AASM) also classifies sleep devices / systems based on their features as types I-IV devices. AASM based type I devices include comprehensive portable devices that perform in-laboratory, technician-attended, overnight polysomnography (PSG). AASM based type II monitoring devices can perform full PSG outside of the laboratory. AASM based type III devices are devices that typically detect / monitor for at least four physiologic variables including: two respiratory variables (e.g., respiratorymovement and airflow), a cardiac variable (e.g., heart rate or an ECG), and arterial oxygen saturation for oxygen saturation information, and one or more arterial tone channels / sensors for arterial tone information. For example, the arterial tone information can include peripheral arterial tone information as described in further detail herein. Some AASM based type III devices may detect / monitor other signals including snoring sounds, or accelerometers and / or gyroscopes for detecting / monitoring body position. AASM based type IV devices include called continuous single or dual bioparameter devices. Such AASM based type IV devices can detect, process, and record one or two signals and can be used without a technician. Typically channels / sensors include: arterial oxygen saturation and airflow channels / sensors.

[0169] Additionally or alternatively, sleep test devices in other configurations can implement the details of the disclosure herein. For example, a sleep test device can include a system for monitoring one or more sleep parameters of a patient includes a portable electronic device, and one or more patches affixed to the patient’s torso in predetermined locations. A first patch can be adhesively affixed to an upper portion of the patient’s torso and include a first patch sensor. A second patch can be adhesively affixed to a lower portion of the patient’s torso and include a second patch sensor. In examples, the first patch can include a first adhesive pad configured to conform to the surface of the patient, and a first electrical circuit disposed on the first patch. In examples, the second patch can include a second adhesive pad configured to conform to the surface of the patient, and a second electrical circuit disposed on the second patch. Each of the first and second electrical circuits can be configured to transmit electrical data to the portable electronic device for determination of one or more sleep parameters. One or both of the patches can include ECG electrodes, optical sensors, motion sensors, and / or microphones / vibrational sensors.

[0170] Additionally or alternatively, a sleep test device can include systems for characterizing sleep disorders in a patient using a head and mandible based system. For example, such a head and mandible based system can include a physiological sensing device (e.g., including, ECG electrodes, EEG electrodes, EMG electrodes, accelerometers and / or gyroscopes) and a data processing device coupled to the physiological sensing device for sensing and measuring electrical and / or motion signals associated with the heart, the brain, and movements and positions of the head and mandible of the patient during a sleep study. For example, the physiological sensing device can sense disturbances that can occur during the patient’s sleep of a subject based on agyroscope adapted to measure movements of the patient’s mandible. In such devices, mandibular spin can be sensed and measured to assess the brain activity in the patient during sleep.

[0171] Additionally or alternatively, a sleep test device can include a head worn or head cap- integrated sleep test device. For example, such a head worn or head cap-integrated sleep test device can include a physiological sensing device (e.g., including, ECG electrodes, EEG electrodes, EMG electrodes, accelerometers and / or gyroscopes) and a data processing device coupled to the physiological sensing device for sensing and measuring electrical and / or motion signals associated with the heart, the brain, and movements and positions of the head and mandible of the patient during a sleep study.

[0172] Examples of wearable devices and systems for implementing the disclosure herein are described in further detail below. As noted above, the hardware features described in detail as follows include HST device features. As such, the features, techniques, methods, systems, apparatuses, and devices described herein are shown as being implemented in using an HST device as an illustration. It is appreciated, however, that features, techniques, methods, systems, apparatuses, and devices as described in this disclosure can be implemented in other type of sleep devices, systems, monitors, or configurations. In this regard, FIGS. 1A and IB show examples of a sleep measurement medical system 100. FIGS. 1C-1E show an exemplary system 100 comprising a sleep measurement medical device 110 comprising a patient sleep device or sleep probe 112 (e.g., shown here as a digit probe or a digit clip configuration), which can be used for patient sleep physiological detection, measurement, and / or monitoring to detect, record, and process physiological data for one or more patient physiological parameters for a sleeping patient. The medical system 100 can be configured for an attended, unattended, or at-home use, such as for use during a home or remote sleep study. Home or remote sleep studies beneficially allow for systematic screening of more patients than could be tested at specialized sleep centers or facilities. More specifically, the medical systems 100 and devices 110 disclosed herein can be used for home and / or remote sleep apnea tests (e.g., HSTs) and / or home and / or remote sleep disordered breathing (SDB) tests for diagnosing sleep apnea and / or for sleep stage (e.g., Rapid Eye Movement (REM), Light Sleep, Deep Sleep and Wake) identification for a patient or subject. Beneficially, such tests do not need to be performed at a sleep study center or facility. Instead, the tests can be performed at a patient’s home allowing the patient to sleep in his or her own bed, meaning that falling asleep can be easier and more convenient. Also, the sleep itself can be more natural and representativeof the patient’s typical nightly sleep, compared to sleep during studies performed at specialized centers or facilities.

[0173] In other examples, the medical systems 100 can be configured to be used by a patient in a medical facility. For example, the medical systems 100 and wearable medical devices 110 can be configured for short-term use (e.g., inducted sleep lasting for a few minutes to about an hour) and / or long-term and / or continuous use (e.g., during an inpatient or outpatient sleep study). The patient can be inpatient, e.g., a patient admitted to a medical facility, such as a hospital, rehabilitation center, a long term care center, a nursing facility, an assisted living facility, a long term memory care center, or other inpatient clinical facility. Additionally or alternatively, the patient can be outpatient, e.g., a patient that is visiting a healthcare facility, a caregiver, or other medical professional for a short duration, or remotely visiting via telemedicine facilities with the facility.

[0174] Information collected by the medical system 100, devices 110, or patient sleep probe 112 can be used for providing various types of medical feedback and information for clinicians, caregivers, and for the patient. For example, the medical device 110 can be configured to generate indices representative of respiratory function and / or breathing quality of the patient based on signals detected by sensors of the medical device 110 or patient sleep probe 112. The generated indices may include one or more of: a Respiratory Disturbance Index (RD I); an Apnea-Hypopnea Index (AHI); a central Apnea-Hypopnea Index (cAHI); and / or a percentage of total sleep time with Cheyne-Stokes Respiration pattern (%CSR). Information detected by the sensors of the medical device 110 or patient sleep probe 112 can also be analyzed to provide information representative of sleep staging identification. In examples, the respiratory indices and sleep staging information can be estimates determined from values produced by polysomnography (PSG) sensors / channels. The medical device 110 can also generate data representative of detected acoustic signals (e.g., acoustic decibel detection) used for monitoring snoring level and body position information representative of discrete states from motion signals from an accelerometer of a chest sensor of the medical device 110. In implementations, the hypoxic deficiency or hypoxic burden information as described in this disclosure can be provided to supplement, augment, enhance, or improve the reporting and diagnostic value of the foregoing indices and / or other signals or channels that are being used to aid sleep apnea diagnosis and treatment.

[0175] FIGS. 1A and IB show an exemplary system 100 for obtaining -1C, the patient sleep probe 112 (e.g., shown here as a digit probe or a digit clip configuration) can be configured to obtain physiological data for a patient 10 (shown in FIG. IB), which can be used for determining hypoxic desaturation information and hypoxic deficiency, including an arterial tone sensing device 136 (e.g., a peripheral arterial tone device or sensor) and a photoplethysmography (PPG) or oxygen saturation sensing device 130. The system 100 also includes a controller 138 in wired or wireless communication with the sensing devices 130, 136 for obtaining data from and determining the hypoxic desaturation information for the patient based on the received data. In implementations, the oxygen saturation sensing device 130 hardware can be incorporated within a different housing than the arterial tone sensing device 136 hardware and / or controller 138. In other examples, as described below in connection with the sleep probe 112, hardware of an oxygen saturation sensor 130 and arterial tone sensor 136 (e.g., a peripheral arterial tone sensor) can be provided in a single device and / or housing.

[0176] In some examples, the arterial tone sensing device 136 can comprise one or more lightemitting diodes (LED) and one or more photodetectors, which work together to measure pulsatile blood flow by shining a beam of light through the tissue and detecting the amount of light that is absorbed or by shining light to the tissue and measuring the amount of light reflected by the tissue. Specifically, in some examples, the arterial tone sensing device 136 and / or controller 138 can be configured to calculate the arterial tone signal by comparing ratios of absorbed to unabsorbed light emitted by the LEDs and detected by the photodetector(s).

[0177] In a similar manner, the PPG or oxygen saturation sensing device 130 can comprise one or more light-emitting diodes (LED) and one or more photodetectors, which work together to measure a level of oxygen saturation in the patient’s blood by shining a beam of light through the tissue and detecting the amount of light that is absorbed or by shining light to the tissue and measuring the amount of light reflected by the tissue. Specifically, in some examples, the PPG or oxygen saturation sensing device 130 and / or controller 138 can be configured to calculate oxygen saturation level by comparing ratios of absorbed to unabsorbed light emitted by the LEDs and detected by the photodetector(s).

[0178] In some examples, the sensing devices 130, 136 are wearable medical devices configured to be connected to various body locations of the patient 10. In some examples, the sensing devices 130, 136 can be connected to a same body location and / or in close proximity to each other on thepatient. In other examples, the oxygen saturation sensing device 130 can be configured to be positioned in a first location on the patient’s body, e.g., on a digit such as a finger, a toe, an ear (e.g. an ear lobe), or other peripheral portion of the patient’s body, or an upper torso, chest, back, shoulder, upper limb, lower limb, neck, or head region, such as a forehead, of the patient. The arterial tone sensing device 136 can be configured to be positioned in a second, different location on the patient’s body, e.g., on a different digit, such as a different finger, a different toe, a different ear, or another portion of the patient’ s body, such as an upper torso, chest, back, shoulder, upper limb, lower limb, neck, or head region, such as a forehead, of the patient, which is different than the region selected for the first location. For example, as shown in FIG. IB, the arterial tone sensing device 136 is attached to an ear of the patient 10. The PPG or oxygen saturation sensing device 130 is attached to a finger (e.g., an index finger, middle finger, ring finger, or pinky finger) of the patient 10. As discussed above, the sensing devices 130, 136 can be in wired or wireless communication with the controller 138, as shown in FIG. IB.

[0179] In some examples, physiological signals measured by the system 100 can include, for example, signals representative of cardiovascular and / or hemodynamic function of the patient. In particular, the system 100 can be configured to obtain the arterial tone data and the oxygen saturation data for the patient. More generally, physiological parameters that can be determined from data collected by the system 100 can include parameters representative of respiratory function, such as parameter values for oxygen blood levels or oxygen update (e.g., SpO2 metrics). Physiological parameters that can be determined from data collected by the system 100 can also include cardiac or blood flow parameters, such as arterial pulse parameters, blood pressure parameters, or heart rate parameters. Physiological parameters can also include certain blood metrics that can aid sleep disorder diagnostics and / or treatment, including blood glucose level, non-invasive or transcutaneous end-tidal carbon dioxide (ETCO2) metrics (e.g., amount of carbon dioxide (CO2) exhaled at the end of a breath), other blood gas levels, blood acidity, and / or naturally-produced chemical compound level (e.g., lactic acid).

[0180] Some signal(s), such as arterial tone signals, measured by the arterial tone sensing device 136 are representative of pulsatile volume changes in arteries of a digit (e.g., in a distal tip or fingertip of the patient). The pulsatile volume changes can reflect a relative state of the arterial vasomotor activity, which may relate indirectly to a level of sympathetic activation, such as sympathetic activity or activation that can occur due to a stress response of the patient’s body toincreasing CO2 and decreasing saturation. Arterial vasoconstriction, which can mirror sympathetic activation, can be shown as attenuation of arterial tone signal amplitude for signals detected by the arterial tone sensing device 136. Furthermore, in some examples, an arterial tone signal may rise and fall with changes in the patient’s sympathetic nervous system and may be linked to an oxygen saturation signal, actigraphy, and patient snoring, which can be detected by microphone associated with the patient. Attenuation of the arterial tone signal may reflect digital vasoconstriction and increased sympathetic activity and can serve as a marker for arousal from sleep. The arterial tone signal may also detect the peripheral vasoconstriction associated with REM sleep.

[0181] As described in further detail herein, the system 100 can be configured to identify relationships between and / or changes in parameters including arterial tone signals, actigraphy signals, pulse rate, heart rate, and / or snoring (e.g., audible breathing disturbances), which may be representative of sympathetic activity of the patient. Identified events representative of sympathetic activity can be used to determine which desaturation events in patient oxygen saturation data are most relevant for measuring hypoxic disturbances, burden, and / or severity for the patient during sleep.

[0182] In examples, hardware for sensing oxygen saturation and arterial tone can be incorporated within a same wearable medical device or housing, such as within a sleep probe or digit clip. FIGS. 1C-1E show a system 100 comprising wearable medical devices 110 including a patient sleep probe 112 for obtaining physiological data for and / or monitoring a variety of patient physiological signals and parameters during a study period (e.g., a sleep study period). As shown in FIGS. 1C- 1E, the sleep probe 112 comprises an arterial tone sensor 136 (e.g., a peripheral arterial tone sensor) and a photoplethysmography (PPG) or oxygen saturation sensor 130 (shown in FIG. ID), which can include similar components to the arterial tone and oxygen saturation sensing devices described above. In examples, the arterial tone sensor 136 and the PPG or oxygen saturation sensor 130 can comprise one or more light-emitting diodes (FED) and one or more photodetectors enclosed within a device housing, which work together to measure pulsatile blood flow and a level of oxygen saturation in the patient’s blood by shining a beam of light through the tissue and detecting the amount of light that is absorbed or by shining light to the tissue and measuring the amount of light reflected by the tissue. Specifically, in some examples, the sleep probe 112 and / or medical device 110 can be configured to calculate the arterial tone signal and / or oxygen saturationlevel by comparing ratios of absorbed to unabsorbed light emitted by the LEDs and detected by the photodetector(s).

[0183] In some examples, the patient sleep probe 112 can include mechanical features for improving signal quality of the arterial tone signal, such as features for applying pressure to portions of a digit being monitoring. For example, noise reduction (e.g., improved signal to noise ratio) in the arterial tone signal or measurement may be achieved by applying sufficient pressure to partially unload, but not occlude, the wall tension of the arteries in the digit (e.g., the finger or toe), when the digit is near heart level. In this regard, the arterial tone signal being captured by the patient sleep probe 112 from a peripheral region of the patient (e.g., a digit of the patient) includes a peripheral arterial tone signal. This may allow the arterial wall to move freely to accommodate the pulsatile blood delivery of the heart. The applied pressure may be slightly above a predetermined maximum pressure in the veins when the hand is fully lowered (e.g., 5% higher or the like). In order to provide such noise reduction and / or signal quality improvements, in some examples, the patient sleep probe 112 can include pressure applicator structure(s) configured, for example, to provide a uniform or substantially uniform pressure to the digit inserted into the patient sleep probe 112. In examples, the pressure applicator structure(s) can be preconfigured to implement a predetermined range of pressures so as to not adversely affect tissue perfusion. For example, such range can be determined based on clinical analysis indicating that while arterial pressure exceeds a counter-pressure permitting inflow of arterial blood, for blood to return via the veins, venous pressure overcomes the applied external pressure. In examples, the induced elevation of venous pressure can cause the upstream microcirculation to be pressurized to a pressure level intermediately between the outgoing venous blood and the incoming arterial blood. As such, the transmural pressure of the microcirculation within the applied pressure field can be greater than zero and can minimize potential collapse of microcirculation.

[0184] In some examples, the pressure applied to particular portions of the digit can be configured to be a static and uniform or substantially uniform (e.g., within 10%, 5%, or 1% of uniform) across surfaces of the digit, including the volar surface, dorsal surface, and distal tip of the digit. The target range for the uniform or substantially uniform pressure can be selected in order to provide a relatively large operating zone in which pressure remains substantially constant with changes in digit volume. Changes in digit volume can be due to changes in instantaneous blood volume related to arterial blood volume of the digit. The relationship between pressure and digit volumeis shown in the graph of FIG. 2, which shows an operating zone of about 60 mmHg to about 64 mmHg, where the pressure remains substantially constant with the changes in volume. However, an actual pressure value for a particular digit can be based on a function of the thickness and mechanical characteristics of the distensible material. For example, the pressure range or operating zone for the patient sleep probe 112 can be about 40 mmHg to about 70 mmHg.

[0185] In implementations, a temperature of the digit or patient region to which the arterial tone sensor 136 is applied may be detected, monitored, and / or controlled during arterial tone signal measurement. For examples, a patient sleep probe 112 can be configured to maintain temperature at a digit or fingertip surface within a range of, for example, around 30°C-40°C, or around 32°C - 38° C, or around 34°C -36°C.

[0186] With continued reference to FIGS. 1C-1E, in some examples, the medical systems 100 and wearable medical devices 110 can also include monitoring or sensing devices separate from the patient sleep probe 112, which can be coupled to other portions of a patient’s body than the patient sleep probe 112. For example, the medical systems 100 and devices 110 disclosed herein can further comprise a wrist-worn monitor 118 or device in wired or wireless communication with the patient sleep probe 112. The wrist-worn monitor 118 can include processing circuitry for receiving and processing data from the patient sleep probe 112. In addition, the wrist-worn monitor 118 can include wireless communications circuitry and a processor coupled to the memory for storing recorded data and for wirelessly transmitting data from the patient sleep probe 112 and / or wrist- worn monitor 118 to remote servers or computer devices.

[0187] In some examples, the wrist-worn monitor 118 can be a battery-powered monitoring device, which can be worn on a wrist, forearm, arm, or another convenient location of the wearer. The wrist-worn monitor 118 can be electrically connected to the patient sleep probe 112 by the connecting cable 134. The wrist-worn monitor 118 can comprise electronical circuitry of the wearable medical device 110 including the controller 138. The wrist-worn monitor 118 can also include a wireless transceiver 140 or communications module for wireless transmission of captured and / or processed data from the medical device 110 to a remote computer device or computer server.

[0188] In some examples, the wrist-worn monitor 118 comprises one or more physiological sensors 148, which can be the same or different than the physiological sensors of the patient sleep probe 112, for detecting additional physiological information for the patient. For example, thephysiological sensor 148 can include a wrist-based PPG sensor comprising, for example, at least one light emitting device (e.g., a photoemitter) and at least one light detecting device (e.g., a photodetector). In some examples, the wrist-worn monitor 118 comprises multiple physiological sensors 148, such as multiple PPG sensors 148. For example, the wrist-worn monitor 118 can comprise a plurality of light emitting devices (e.g., three light emitting devices having different wavelengths) and a light detecting device (e.g., configured to detect light of each wavelength of the light emitting devices). The wrist-worn monitor 118 can also include other sensors 150, such as position or motion sensors (e.g., a sensor for detecting body position or a sensor for detecting the patient’s arm position). In other examples, the other or additional sensor 150 can be an electrode, heart rate sensor, pulse rate sensor, or blood flow sensor for measuring physiological parameters including pulse rate, ECG, blood pressure, and / or cardiac physiological parameters.

[0189] The medical system 100 and wearable medical device 110 can also include a chest motion sensor device 120 configured to be disposed on an upper chest area of the patient. The chest motion sensor device 120 can include an acoustic sensor (e.g., a snoring microphone) and an accelerometer. In some examples, the chest motion sensor device 120 can also include other physiological sensors, such as a heart rate sensor, electrocardiogram (ECG) electrodes or sensors, and / or body impedance (e.g., transthoracic impedance) sensors.

[0190] As shown in FIGS. 1C-1E, the chest motion sensor device 120 can be connected to the wrist-worn monitor 118 by a second connecting cable 152 and can be configured to provide sensed data to the controller 138 of the wrist-worn monitor 118 for processing and / or to the wireless transceiver 140 of the wrist-worn monitor 118 for transmission to the remote computer device or server. The chest motion sensor device 120 can comprise a housing 142 (shown in FIG. 1C), such as a rigid plastic housing, enclosing circuitry for detecting movement and acoustic signals in proximity to the wearer. Signals detected by sensors of the chest motion sensor device 120 can be related to snoring, body position, and / or the wearer’s chest movement. The housing 142 can comprise an adhesive surface or adhesive layer on a bottom portion of the housing 142, which can be configured to be adhered to the chest of the patient to maintaining positioning of the chest motion sensor device 120 on the wearer’s chest for obtaining sensor data from sensors of the chest motion sensor device 120.

[0191] In some examples, the medical system 100 can also include additional wearable sensor devices positioned elsewhere on the patient and in wired or wireless communication with otherelectronic devices of the system 100, such as the chest motion sensor device 120 and / or wrist-worn monitor 118. For example, the medical system 100 can include devices, such as effort belts, comprising abdominal sensors for measuring, for example, expansion of the abdomen during breathing. The medical system 100 can also include electromyography (EMG) devices comprising, for example, sensors or electrodes for detecting activation of intercostal muscles during breathing.

[0192] With specific reference to FIG. ID, in some examples, the chest motion sensor device 120 comprises an acoustic snore sensor 144 and a chest movement sensor 146. The acoustic snore sensor 144 can be an acoustic decibel detector comprising, for example, a highly sensitive microphone that responds to snoring and other sounds in a preselected or determined audio range. The acoustic snore sensor 144 can be configured to convert detected sounds to signals that provide reliable indications that snoring has been detected. The chest movement sensor 146 can be an accelerometer, such as a 3 -axis accelerometer, which provides a signal that reflects the movement of the chest, which can be translated, for example, both to the patient’s sleeping posture (supine, prone, right, left and sit) and to the chest movement signal resulted by the subject’s breathing during the night.

[0193] In some examples, as previously described, the wearable medical device 110 can be configured to transmit, such as via the wireless transceiver 140 of the wrist-worn monitor 118, medical data, such as medical information based on signals detected on sensors 130, 136 of the patient sleep probe 112 and / or signals detected by sensors 144, 146 of the chest motion sensor device 120. In such an example, the wireless connection may include at least one of the following: a cellular connection, a short-range wireless technology such as a Bluetooth® protocol connection, Advanced Message Queuing Protocol (AMQP) connection, Constrained Application Protocol (CoAP) connection, a wireless network protocol based on the IEEE 802.11 standard (e.g., Wi-Fi® protocol connection), a wireless protocol based on the IEEE 802.15.4 standard (e.g., a ZigBee protocol connection), a Z-Wave connection, a wireless personal area network (WPAN) connection, an Infrared Data Association (IrDA) connection, or any combination thereof.

[0194] Signals and / or data detected and / or processed by the wearable medical device 110, wrist- worn monitor 118, and / or chest motion sensor device 120 can be transmitted, via the wireless transmitter 140, to remote servers for further processing and for preparing reports summarizing collected data. For example, data can be wirelessly transmitted from the wearable medical device110 to an intermediate or gateway device, such as a mobile phone running a data collection application. The mobile phone can be configured to store received data in memory and to transmit the received data to the remote server on a continuous or ongoing basis.

[0195] Once data is received by the remote server, the server can execute software to analyze the received data using various automatic algorithms for detecting respiratory and other events that occurred during sleep, as well as periods of REM, deep sleep, light sleep and wakefulness. For example, software on the remote server may analyze oxygen saturation data and arterial tone signal data to determining hypoxic desaturation information for the patient using the processes and methods for determining hypoxic burden described herein. In some examples, the remote server may also calculate or derive a pulse rate signal from the received data, which can also be used for the hypoxic burden analysis. In some examples, the received data, such as night data from the sleep study, can also be viewed by a technician and, if required, automatically detected events can be considered and revised manually. The received analyzed data can then be used to generate reports, such as comprehensive reports of a patient sleep study including statistics and graphic presentations of recorded data and test results. Once generated, the comprehensive report(s) including the overnight sleep study data can be stored in Web Server storage and delivered to interested parties (e.g., a prescribing physician, a caregiver, or the patient) via the Internet.

[0196] The medical system 100 and / or patient sleep probe 112 disclosed herein are configured to obtain patient physiological data, including the arterial tone signal data and oxygen saturation data described above. Furthermore, as previously described, obtained patient physiological data can be analyzed to measure hypoxic severity or deficiency for the patient and to determine, for example, a hypoxic burden value for the patient based on hypoxic deficiency values for detected episodes or events. Processes and methods for analyzing the patient data from the patient sleep probe 112 and / or from other medical devices 110 of the medical system 100 for measuring hypoxic severity or deficiency are described below in connection with the graphs and flow charts in FIGS. 3A-8E. The processes or methods can be performed by one or more controllers, processors, or computing devices of the medical system 100. In some examples, one or more of the processing steps shown in FIGS. 3A-8E can be performed by the controller 138 of the medical system 100 or wrist-worn monitor 118. In other examples, some or all of the processing steps can be performed by a portable computing device in communication with the controller 138. In other examples, some or all of the processing steps disclosed herein can be performed by a remote computing device, such as acomputing device used by a technician or clinician to generate a patient report. Some or all of the processing steps disclosed herein can also be performed by a remote computer server at a data processing facility and provided to a user, such as the patient or a clinician, over a computer network or the Internet.

[0197] FIG. 3A is a flow chart showing an exemplary process for using hypoxic desaturation information to determine hypoxic deficiency from individual desaturation events in the oxygen saturation data, and for calculating a hypoxic burden value for a patient for a duration of a sleep period under review. In this case, the hypoxic desaturation information includes information about an individual desaturation event as identified from the oxygen saturation data and correlated to corresponding arterial tone data. For example, the hypoxic desaturation information includes timing information regarding a beginning and an end of a desaturation event in the oxygen saturation data based on information regarding an arterial tone event in the arterial tone data corresponding to the desaturation event. The hypoxic burden value calculated from the hypoxic desaturation information can quantify cumulative effects of hypoxic events of a patient over a period of time, such as over a period of hours or over an entire night’s sleep. In some examples, hypoxic deficiency can be identified based on oxygen saturation data of the patient during sleep, such as oxygen saturation data for the patient obtained during an overnight sleep test. As previously described, hypoxic deficiency can also be identified based on oxygen saturation data along with arterial tone data which, as described herein, can be used to identify events that are representative of sympathetic activity of the patient and / or to determine which desaturation events should be considered in calculating the hypoxic deficiency and hypoxic burden for the patient. Further, in some examples, the events representative of sympathetic activity can be identified from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart rate data. Depending on implementation and available sensor types, the pulse or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data. Events representative of sympathetic activity can also be identified from the oxygen saturation data along with patient movement or motion data during sleep and / or patient snoring data during sleep.

[0198] In some examples, the arterial tone data and the oxygen saturation data can be obtained from sensors, such as the PPG or oxygen saturation sensor 130 and the arterial tone sensor 136 of the patient sleep probe 112. In some examples, processing steps for determining hypoxicdeficiency and hypoxic burden can be performed by processing circuitry of the patient sleep probe 112 or another of the medical devices 110 of the medical system 100. For example, obtained arterial tone data and oxygen saturation data can be processed and analyzed by the controller 138 of the wrist-worn monitor 118 and / or by other controllers, processes, smart phones, computers, or similar electronic devices of the medical system 100 and / or electric devices in communication with the devices of the medical system 100. In some examples, some or all of the processing steps shown in the flow chart of FIG. 3A can be performed by a technician console or computer after a sleep test is completed. The analyzed data can be used to generate a patient sleep report for sleep test data, which can be provided to the patient and / or to a patient’s caregiver, such as a physician, clinician, family member, or another responsible individual. Results in the sleep report can be used to assess whether a patient suffers from sleep disordered breathing or sleep apnea and, if warranted, to provide appropriate treatment for the patient.

[0199] As shown in FIG. 3A, a process for measuring hypoxic severity or deficiency in a patient during sleep can include an initial step 310 of providing a medical system 100 comprising medical devices 110 including the patient sleep probe 112 for the patient and, if necessary, assisting the patient to attach the patient sleep probe 112 and other medical devices 110 to appropriate portions of the patient’s body. For example, the patient sleep probe 112 can be configured to be worn on the patient at a location where an arterial tone signal (e.g., a peripheral arterial tone signal) is detectable. In some examples, the patient sleep probe 112 can be mounted or adhered to body areas including a toe, an ear (e.g., an ear lobe), forehead, an arm, a torso, abdomen, or a leg of the patient. In some examples, the patient sleep probe 112 is configured to be mounted or connected to a peripheral patient body portion or location, such as a peripheral digit (e.g., an index finger, middle finger, ring finger, pinky finger, or toes of the patient), in order to measure or detect a peripheral arterial tone signal. The medical system 100 and the patient sleep probe 112 can be provided to or obtained by the patient shortly before he or she plans to go to sleep and can be used for collecting patient sleep data while the patient is sleeping.

[0200] At step 312, the process further comprises obtaining and processing arterial tone data (e.g., peripheral arterial tone data) and oxygen saturation data for the patient. For example, the arterial tone data can be detected by an arterial tone sensor 136 of the patient sleep probe 112 configured to generate arterial tone data associated with the patient for monitoring arterial tone signals of the patient. The oxygen saturation data can be obtained from an oxygen saturationsensor of the patient sleep probe 112, such as the saturation sensor 130 shown in FIG. ID, that is configured to generate oxygen saturation data associated with the patient. Examples of arterial tone sensors and oxygen saturation sensors disposed in a patient sleep probe 112 and including emitter(s) and a photodetector(s) for measuring arterial tone (e.g., peripheral arterial tone) and oxygen saturation signals are shown, for example, in FIGS. 11 and 12. FIG. 3B is a graph showing arterial tone signal data (shown by waveform 302) and oxygen saturation data (shown by waveform 304) for a patient collected by the arterial tone sensor 136 and the oxygen saturation sensor 130, for example, during a patient sleep test. The graph in FIG. 3B also includes a waveform 306 for arterial tone amplitude and a waveform 308 for pulse rate.

[0201] At step 314, the process can further comprise detecting arterial tone events (e.g., changes) in the obtained arterial tone data. Examples of arterial tone changes are identified and enclosed by circles 352 in FIG. 3B. In some examples, an arterial tone change in the arterial tone data can comprise a portion of the data where arterial tone signal amplitude deviates from a previous value or from a predetermined baseline value by a predetermined amount and / or for a predetermined duration. For example, the arterial tone change can comprise an increase or decrease in arterial tone single amplitude compared to previously measured values and / or compared to a predetermined baseline value for arterial tone.

[0202] As previously described, the arterial tone signals can be representative of pulsatile volume changes in arteries of a digit (e.g., in a distal tip or fingertip of the patient). The pulsatile volume changes can reflect a relative state of the arterial vasomotor activity, which may relate indirectly to a level of sympathetic activation. Arterial vasoconstriction, which can mirror sympathetic activation, can be shown as attenuation of arterial tone signal amplitude. In patients, an arterial tone signal rises and falls with changes in the patient’s sympathetic nervous system. Such arterial tone changes can correspond to changes in oxygen saturation signal, actigraphy, and patient snoring signals. Attenuation of the arterial tone signal may reflect digital vasoconstriction and increased sympathetic activity and can serve as a marker for arousal from sleep. The arterial tone signal may also detect the peripheral vasoconstriction associated with REM sleep.

[0203] In some examples, the arterial tone events (e.g., changes) can occur before, after, or simultaneous with a corresponding change in oxygen saturation for the patient, which is described herein in some examples as a correlated desaturation event. In examples, a desaturation event may not be accompanied by or correspond with an arterial tone change, which can mean that thedesaturation event does not represent sympathetic activity of the patient and may not be considered in determining hypoxic severity or deficiency for the patient.

[0204] In some examples, the identified arterial tone events (e.g., changes) can comprise attenuation of the arterial tone signal amplitude. Attenuation of the arterial tone signal amplitude can comprise a decrease in arterial tone signal amplitude relative to a baseline or to a predetermined patient-specific amount. The baseline can be a predetermined tone based on previously measured data for the patient, such as a maximum arterial tone value, a minimum arterial tone value, or an average (e.g., mean, median, or mode) arterial tone valve for a predetermined period of time prior to or following the potential event or arterial tone change. For example, attenuation of the arterial tone signal amplitude can comprise a decrease in an arterial tone signal amplitude of about 20%, 15%, 10%, 5%, or 1% relative to the predetermined or patient-specific baseline for arterial tone. The predetermined period of time preceding an identified or potential arterial tone change or event can be a period of time, such as 1000 seconds, 500 seconds, 100 seconds, 30 seconds, 10 seconds, or 1 second. In some examples, the predetermined period preceding the identified event can be measured in terms of cardiac cycles. For example, the predetermined period can be about 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle preceding the identified change or event.

[0205] In some examples, attenuation of the arterial tone signal amplitude can comprise a decrease in an amplitude range for the peripheral arterial tone signal relative to the baseline for arterial tone range. For example, as shown in FIG. 3B, several potential arterial tone changes are identified by the shapes 352. For each potential arterial tone change, the arterial tone signal amplitude (shown by line LI in FIG. 3B) decreases compared to the arterial tone signal amplitude, shown by line L2, for a period of time prior to the identified potential arterial tone event (e.g., change). As previously described, in some instances, the baseline arterial tone can be based on a maximum valve for the predetermined period of time, a minimum valve for the predetermined period of time, or an average (e.g., mean or median) value for the predetermined period of time. As previously described, the arterial tone events can correspond with changes in the oxygen saturation signal for the patient. For example, lines L3 in FIG. 3B shows correlations between arterial tone events (e.g., areas of the arterial tone waveform identified by the shapes 352) and decreases in patient oxygen saturation (shown by the shapes 354 in FIG. 3B) occurring close in time to the identified arterial tone events.

[0206] In some examples, as shown at step 316, the process can alternatively include detecting desaturation events in saturation data received from the saturation sensor 130. For example, desaturation events can be identified based on detecting changes in oxygen saturation (e.g., oxygen saturation decreases by a predetermined amount (e.g., 1%, 2%, 5%, 10%, or 15%) from a baseline value) and correlating the timing of these possible desaturation events to arterial tone data. In particular, a correlated desaturation event can be identified where an arterial tone event, such as an arterial tone constriction (e.g., signal attenuation), occurs shortly before, after, or simultaneously with the identified possible desaturation event. For example, the process can include identifying saturation events having an arterial tone event occurring less than 10 seconds prior, less than 10 seconds after, less than 20 seconds prior, less than 20 seconds after, less than 30 seconds prior, less than 30 seconds after, less than 45 seconds prior, or less than 45 seconds after an identified desaturation event. In some examples, the window for identifying corresponding arterial tone events can be symmetrical about the timing of the beginning of the possible desaturation event as noted above - e.g., a same amount of time prior and a same amount of time after the beginning of possible desaturation event. In examples, the window can be asymmetrical about the timing of the beginning of the possible desaturation event as noted above - e.g., 10 seconds prior and 30 seconds after. In examples, the window can be user specified, e.g., via a physician input, technician input, or other authorized person input.

[0207] As described previously, heart rate and / or pulse rate data can also be used for identified saturation events that are correlated with, for example, sympathetic activation. Depending on implementation and available sensor types, the pulse or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data.

[0208] At step 318, following detection of the correlated arterial tone events in the arterial tone data and / or correlated desaturation events in the oxygen saturation data, the process can further comprise determining hypoxic desaturation information from the oxygen saturation data based on the detected or identified arterial tone events and / or desaturation events. For example, the determination of hypoxic desaturation information can include analyzing all available oxygen desaturation data to identify portions of the oxygen desaturation data that show desaturation correlated with corresponding arterial tone events (e.g., change). Such desaturation events that are correlated with an arterial tone event can be considered when calculating hypoxic severity or deficiency for a patient. As described above, desaturation events that occur without acorresponding arterial tone events may not be considered when calculating the hypoxic severity or deficiency for the patient. The determination of the hypoxic desaturation information can also include identifying a desaturation start time for desaturation and a corresponding desaturation termination time for the desaturation (e.g., a time when patient saturation level returns to a normal, baseline, or acceptable level). As described herein, the desaturation start and / or termination times can occur before, after, or simultaneously with the identified arterial tone event. Once portions of the oxygen saturation data showing desaturation and which are correlated with an identified arterial tone event are known, the hypoxic deficiency for the patient can be calculated.

[0209] In some instances, systems herein are configured to determine whether there is a corresponding arterial tone event for a particular desaturation event by taking into account timing between such events. For example, the time when an arterial tone event and pulse rate or heart rate change occur may not be the same and, as such, the system can account for such differences in timing. In some examples, a user is provided with a user interface to manually review events that appear to be correlated to determine whether a particular desaturation event should be considered when determining hypoxic deficiency for the patient. In other examples, a user, such as a technician, may input preferences or rules (e.g., via a technician user interface) about which types of events should be considered and which types of events should not be considered for determining hypoxic deficiency. For example, a user may input a preference via the technician user interface that only desaturation events with a corresponding arterial tone event and increase in pulse rate or heart rate are considered. In other cases, the user may enter a preference or rule via the technician user interface that a desaturation event is considered as long as there is a corresponding arterial tone event or change in pulse rate or heart rate within a predetermined period of time before or after the desaturation.

[0210] Examples of different types of events which could be considered to be correlated desaturation events are shown in FIG. 3C. Specifically, FIG. 3C is another graph showing waveforms for arterial tone signal amplitude (waveform 302), oxygen saturation (waveform 304), and pulse rate (waveform 308). The waveforms 302, 304, 308 in FIG. 3C show some instances of oxygen desaturation, which correspond with an arterial tone event, and other instances of desaturation, which do not appear to have a corresponding arterial tone event. Furthermore, in some examples, desaturation and arterial tone signal attenuation correspond with an increase in pulse rate.

[0211] For example, potential event A in FIG. 3C shows desaturation (enclosed by shape 356) in combination attenuation of the arterial tone signal (enclosed by shape 358) and an increase in pulse rate (shown by shape 360). The combination of arterial tone signal attenuation, and increased pulse rate is deemed to be representative of sympathetic activity of the patient. Therefore, the potential event A generally is considered to be relevant for determining the hypoxic deficiency for the patient.

[0212] Another potential event in FIG. 3C includes desaturation (enclosed by shape 362) and attenuation of the arterial tone signal (enclosed by shape 364). However, unlike in potential event A, potential event B does not also show an increase in pulse rate. In some examples, this scenario (decrease in oxygen saturation and attenuation of arterial tone signal without a corresponding increase in pulse rate or heart rate) can be identified as a correlated desaturation event and considered for determining hypoxic deficiency of the patient. In other instances, only events having desaturation, arterial tone signal attenuation, and increase pulse rate (or heart rate) (as shown by potential event A) are considered when determining hypoxic deficiency. The determination of whether to include a particular event in the determination of hypoxic deficiency can be made by a user, such as a technician preparing a patient report. In other examples, as previously described, a computer system can be configured to automatically select certain desaturation events for determining hypoxic deficiency and to exclude other desaturation events from calculations for hypoxic burden.

[0213] Another potential event C in FIG. 3C includes desaturation as shown by the generally downward trend in oxygen saturation (enclosed by shape 366 in FIG. 3C). However, there is no corresponding attenuation in the arterial tone signal (shown by shape 368). Furthermore, in potential event C, there is no increase in pulse rate. In some examples, potential event C would not be treated as a correlated desaturation event for determining hypoxic deficiency for the patient because there is no attenuation of the arterial tone signal or increase in pulse rate. As previously described, arterial tone signal attenuation and increase in pulse rate can be representative of patient sympathetic activity.

[0214] Another potential event D in FIG. 3C includes substantial desaturation as shown by the portion of the oxygen saturation waveform enclosed by shape 370. However, it is less clear whether there is a corresponding arterial tone event for potential event D. In particular, the arterial tone signal increases (enclosed by shape 372), which may not be representative of sympatheticactivity. As shown in FIG. 3C, the pulse rate (enclosed by shape 374) also increases, which can be an indication of sympathetic activity for the patient. In some examples, a scenario similar to potential event D (desaturation with an increase in both arterial tone signal amplitude and pulse rate) may be excluded from determining the hypoxic deficiency for the patient because the arterial tone event (enclosed by shape 372 in FIG. 3C) does not comprise attenuation of the arterial tone signal. In other examples, a situation similar to potential example D can be considered relevant for determining hypoxic deficiency for the patient because there is desaturation, pulse rate increase, and a change (e.g., an increase) in arterial tone signal amplitude. As discussed above, the determination of whether to include an event for determining hypoxic deficiency can be made manually by a system operator, such as a technician preparing a patient report, or automatically by a controller or processing device based, for example, on predetermined user preferences or selection criteria entered by the user.

[0215] Another potential event E shown in FIG. 3C includes attenuation of the arterial tone signal (portion of waveform enclosed by shape 376 in FIG. 3C) and increase in pulse rate (portion of waveform enclosed by shape 378), which are both representative of sympathetic activity for the patient. However, the oxygen saturation data (enclosed by shape 380) does not show desaturation and, in fact, shows that oxygen saturation of the patient increases following the arterial tone event. Therefore, because no desaturation occurred, the potential event E generally would not be considered for determining the hypoxic deficiency of the patient.

[0216] In another potential event F shown in FIG. 3C, there is desaturation in the oxygen saturation signal (portion of waveform enclosed by shape 382 in FIG. 3C) and an increase in pulse rate (portion of waveform enclosed by shape 384), which can be representative of sympathetic activity. However, there is no attenuation of the arterial tone signal (portion of arterial tone waveform enclosed by shape 386). In some examples, the potential event F can be considered to be an event because the desaturation and pulse rate (or heart rate) increase can indicate sympathetic activity and / or that an event has occurred. However, potential event F may not be considered to be an event because there is no attenuation of the arterial tone signal. Therefore, in some examples, a situation similar to potential event F would not be considered in determining hypoxic deficiency for the patient.

[0217] Once desaturation events in the oxygen saturation data that are correlated with arterial tone events (e.g., changes) are identified, in some examples, determination of the hypoxicdesaturation information can comprise identifying the desaturation start time for the correlated desaturation events. The desaturation start time can be a time or portion of the oxygen saturation data detected by the oxygen saturation sensor that deviates from a baseline saturation level of the patient, and which occurs simultaneous with or after an identified arterial tone event. In some examples, the baseline saturation level can be a maximum saturation level in the oxygen saturation data detected within a predetermined period of time preceding or after a particular desaturation event. The predetermined period can be, for example, 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, or 0.1 second before or after the desaturation event. The predetermined period can also be measured by a number of cardiac cycles (e.g., 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle) before or after the desaturation event. In other examples, the baseline saturation level (e.g., a minimum decrease that will be counted as a desaturation) can be a predetermined decrease (e.g., at least 10%, 5%, 4%, 3% or 2%) of a maximum or average saturation level for the patient. In other examples, the baseline saturation level can be a minimum saturation level for a period of time preceding an identified desaturation event. The baseline saturation level can also be an average (e.g., median or mode) of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one arterial tone change. In other examples, the baseline saturation level can be a predetermined value, such as a saturation level of 98%, 95%, 92.5%, 90%, 85% or 80%. The baseline saturation level for determining desaturation can also be set based on the patient saturation for a particular sleep position and / or sleep state of the patient, or based on the patient average saturation in wakefulness.

[0218] The determination of the hypoxic desaturation information can also include identifying a termination time for a desaturation event (e.g., the desaturation termination time). In some examples, the desaturation termination time can be a predetermined period of time (e.g., 10 seconds, 5 seconds, or 1 second), or predetermined number of cardiac cycles (e.g., 10 cardiac cycles, 5 cardiac cycles, or 1 cardiac cycle) after the identified desaturation start time. The termination time can also be a predetermined period of time or number of cardiac cycles after the minimum desaturation value for a desaturation event in the oxygen saturation waveform. In other examples, the desaturation termination time for the desaturation event can be when the oxygen saturation returns to the baseline saturation level or to within a predetermined percentage (e.g., within about 20%, 15%, 10%, 5%, or 1%) from the baseline saturation level. As discussed above, the baseline saturation level can be a predetermined saturation value, a maximum saturation of thepatient, a minimum saturation of the patient, or an average (e.g., median or mode) saturation of the patient over a predetermined period or during a particular sleep state or with a particular body position.

[0219] With continued reference to FIG. 3A, once the hypoxic desaturation information (e.g., a desaturation start time and desaturation termination time for each desaturation event being considered to determine hypoxic severity or hypoxic burden for the patient) is known, at step 320, the process can further comprise determining the hypoxic deficiency for the patient based on the hypoxic desaturation information. In some examples, the hypoxic deficiency for a particular event can be calculated as an area-under-the-curve for the oxygen saturation waveform between the desaturation start time and the desaturation termination time for the particular desaturation event. More specifically, the area-under-the-curve for a particular desaturation event can be an area defined by the saturation waveform and a baseline saturation level for the event or patient. The hypoxic deficiency quantifies an amount of desaturation (e.g., saturation lost over time) during the desaturation event compared to a patient’s baseline saturation level.

[0220] FIGS. 4A-4C are graphs with oxygen saturation waveforms 402 for a patient showing different ways that area-under-the-curve for a saturation waveform can be calculated. The line L4 in FIGS. 4A-4C represents a 90% baseline saturation level.

[0221] FIG. 4A shows that area-under-the-curve can be calculated using the 90% baseline saturation level (line L4). Specifically, the area-under-the-curve in FIG. 4A is the area between the desaturation portion of waveform 402 and the baseline saturation level shown by the line L4 between the activation time 408 and termination time 410 for the desaturation event.

[0222] FIG. 4B shows that area-under-the-curve can also be calculated using a patient-specific baseline level. Specifically, rather than using the 90% baseline level (as is done in FIG. 4A), in FIG. 4B, the baseline level L5 used for calculating the area under the curve is a patient-specific saturation level, which is higher than the 90% saturation level (line L4). In some examples, the patient-specific saturation level can be an initial saturation level for the patient, such as a saturation level for the patient at the beginning of the night, shortly before the patient goes to sleep. This baseline value for the patient can be input by a device user, such as a clinician or the patient, or measured by the patient sleep probe 112, for example, when the patient sleep probe 112 is first positioned on the patient.

[0223] FIG. 4C shows another example in which the area-under-the-curve is calculated based on a predetermined time period. In particular, in FIG. 4C, the area-under-the-curve is defined by a line L6 for each desaturation event extending between a first point and a second point. The first point is positioned where the saturation waveform deviates from a baseline saturation level, such as a patient’s maximum saturation level before desaturation occurs. The second point is positioned a fixed amount of time after the lowest point of the desaturation event (e.g., a nadir point for the desaturation event).

[0224] In other examples, while not shown in FIGS. 4A-4C, the baseline saturation level for calculating the area-under-the-curve can be defined as an average saturation level for a predetermined period of time prior to the desaturation event. In other examples, the baseline saturation level for calculating the area-under-the-curve can be defined as an average saturation level for a predetermined period of time after the desaturation event.

[0225] The calculated area-under-the-curve can be used to determine the hypoxic deficiency for the patient for a particular desaturation event. As previously described, hypoxic deficiency values for multiple desaturation events can be combined (e.g., added together or averaged) to determine an overall hypoxic burden for the patient. In some examples, hypoxic deficiency can be provided as a numerical value for an amount of saturation lost due to the desaturation event. In other examples, hypoxic deficiency can be provided as a dimensionless value or score representative of hypoxic severity of the desaturation event. For example, each desaturation event could be provided with an alphanumeric score, such as a score of 1-10 (e.g., 1 being the least severe and 10 being the most severe). In some examples, as described in further detail herein, once area-under- the-curve for each identified desaturation event is known, the overall hypoxic burden for the patient for a period of time can also be calculated based on the hypoxic deficiency for each desaturation event. For example, the hypoxic burden for an entire night’s sleep can be calculated by adding the area-under-the-curve for each identified desaturation event to provide a numerical value for total effects of desaturation for the entire night. In other examples, the hypoxic burden can be a normalized value based on the area-under-the-curve for each identified desaturation event and, for example, a total sleep time for the patient or another nominal value.

[0226] The processes described above are based on the expectation that correlations between an identified arterial tone event and desaturation event can be easily determined. In particular, the processes described above generally expect that the desaturation event occurs shortly beforeattenuation of the arterial tone signal. For example, desaturation generally starts before the sympathetic event and continues after the sympathetic event. This can occur because there is a delay between regaining of breathing and re-saturation of a peripheral digit (e.g., a patient’s finger), which occurs because it takes time for the oxygenated blood to travel from the lung through the heart and to the peripheral digit. In some examples, the re-saturation time can be measured as well. A longer re-saturation time can be indicative of low heart output, poor flow of blood, or increase in body mass that the heart is not supporting well. However, longer re-saturation can also be the result of a temporary flow issue at a location proximate to the proximal digit, such as a temporary flow issue to a patient’ s hand. The temporary flow can also occur, for example, due to patient body position (e.g., if the patient is laying on his or her arm in a way that blocks blood flow). However, in some examples, timing of the arterial tone event and the desaturation event can be difficult to analyze or recognize as described in the following examples. Therefore, in some cases, the processes discussed herein can be modified to consider a wider variety of desaturation events than may be identified by the previously described exemplary processes.

[0227] FIGS. 5A-5C are graphs of arterial tone signal data (waveform 502), oxygen saturation data (waveform 504), and pulse rate data (waveform 506) showing examples of timing issues that can occur between desaturation events, arterial tone events (e.g., changes), and pulse rate changes.

[0228] FIG. 5A shows that an arterial tone event, which may be representative of sympathetic activity, may be aligned with a rapid re-saturation in the oxygen saturation waveform 504. Specifically, as shown in FIG. 5A, the arterial tone signal attenuation 510 occurs substantially simultaneously with a rapid re-saturation 512. There is also a corresponding increase in pulse rate 514, which occurs at about the same time as the arterial tone signal attenuation 510.

[0229] FIG. 5B shows another example in which an arterial tone event (e.g., change) 510 and pulse rate increase 514 occur before the desaturation and re-saturation 512.

[0230] FIG. 5C shows another example in which sympathetic activation (and arousal) are delayed and even appear to occur with a normal saturation level. More specifically, as shown in FIG. 5C, the desaturation event 512 occurs first. After re-saturation, there is attenuation of the arterial tone signal, as shown by 510 (in FIG. 5C), and an increase in pulse rate, as shown by 514. This case may occur with a certain type of Cheyne Stoke respiration (CSR) patient, which can result in a slower re-saturation process, which is a common characteristic of CSR.

[0231] The processes described herein can be modified so that situations similar to those shown in FIGS. 5A-5C can also be classified as correlated desaturation events (e.g., desaturation events that are correlated with arterial tone signal attenuation) and can be considered in determining hypoxic severity or deficiency for the patient. In other examples, as previously described, arterial tone attenuation events that occur outside of desaturation and / or after rapid re-saturation (shown in FIGS. 5 A and 5C) may not be considered in determining hypoxic deficiency or hypoxic burden for the patient. In some examples, a computing device or processor can be configured to automatically determine which desaturation events are considered for determining hypoxic severity or deficiency and which desaturation events are not considered. In other examples, a user, such as a technician preparing a patient sleep report, can review each potential event and decide on a case-by-case basis, whether situations similar to those shown in FIGS. 5A-5C should be considered in calculations for hypoxic severity or deficiency for the patient.

[0232] FIG. 6A is a flow chart showing another process for measuring hypoxic severity in a patient during sleep based on arterial tone data (e.g., peripheral arterial tone data) and oxygen saturation data. FIG. 6B is a graph showing an arterial tone waveform 602 determined from the arterial tone data and a saturation waveform 604 showing the oxygen saturation data for the patient. The graph in FIG. 6B also includes an arterial tone amplitude waveform 606 and pulse rate waveform 608.

[0233] As in previous examples, the process in FIG. 6A can include an initial step 610 of providing a medical system 100 comprising medical devices 110 including the patient sleep probe 112 for the patient and, if necessary, assisting the patient to attach the patient sleep probe 112 and other medical devices 110 to appropriate portions of the patient’s body.

[0234] The process next includes a step 612 of obtaining and processing arterial tone data (e.g., peripheral arterial tone data) and oxygen saturation data for the patient. As previously described, such signals can be obtained from an arterial tone sensor 136 and oxygen saturation sensor 130 of a patient sleep probe 112.

[0235] The process next includes a step 614 of detecting arterial tone events (e.g., changes) in the arterial tone data. For example, as previously described, an arterial tone event can be attenuation of the arterial tone signal amplitude by an amount of, for example, about 20%, 15%, 10%, 5%, or 1% of a baseline value for arterial tone signal amplitude. Arterial tone attenuation events in the arterial tone waveform are shown by shape 650 in FIG. 6B.

[0236] Once the arterial tone events (e.g., changes) in the arterial tone data are identified, the process further comprises, at step 616, identifying desaturation events that are correlated in time with the arterial tone events (e.g., changes). As previously described, a correlated desaturation event can be a desaturation event that occurs before (e.g., within a predetermined period of time before) an identified arterial tone change. In other examples, the arterial tone change can occur substantially simultaneous with a rapid re-saturation of the patient (as shown in FIG. 5A). As previously described, desaturation events that are correlated with an arterial tone event are considered in determining hypoxic severity or hypoxic deficiency of the patient. Desaturation events that do not appear to be correlated with an arterial tone event or another indication of sympathetic activity may not be considered, in some implementations, in determining the hypoxic severity or hypoxic deficiency for the patient.

[0237] At step 618, the process further comprises identifying a first fiducial point in the oxygen saturation data, which can be representative of a desaturation start time or another feature of the desaturation waveform, based on a baseline saturation level for the patient and the at least one arterial tone change. For example, as shown in FIG. 6B, a first fiducial point 654 for an identified desaturation event can be a point at which the patient saturation waveform 604 deviates from a predetermined or patient-specific baseline saturation value by, for example, a predetermined percentage of 10%, 5%, 4%, 3% or 2% of the baseline value. As previously described, the baseline saturation value can be a maximum saturation value, a minimum saturation value, or average saturation value for the patient for a predetermined period of time before or after the desaturation event. The baseline saturation value can also be a predetermined saturation value, for example, selected by a user. While only one first fiducial point 652 is shown in FIG. 6B, it is understood that the process can comprise identifying a first fiducial point 652 for each identified desaturation event in the oxygen saturation data.

[0238] At step 620, the process further comprises identifying a second fiducial point 654, which can be representative of a desaturation termination time or another feature of the desaturation waveform, in oxygen saturation data for the identified desaturation events. In some examples, the second fiducial point 654 for a desaturation event can be the point at which the saturation waveform returns to the predetermined or patient-specific baseline saturation level, such as a baseline saturation level measured before a patient goes to sleep or a baseline saturation level based on a maximum, minimum, or average saturation level for the patient for a predetermined period oftime prior to or after the desaturation event. In other examples, the second fiducial point 654 can be positioned a predetermined period of time after the first fiducial point and / or a predetermined period of time after a minimum saturation level (e.g., the nadir point) for the desaturation event, regardless of whether the patient has re-saturated to the baseline saturation level. For example, the second fiducial point 654 can be positioned or identified one second, 5 seconds, 10 seconds, 30 seconds, or another selected duration after the first fiducial point 652 or after the nadir point in the saturation waveform 604. In other examples, the second fiducial point 654 can be identified or positioned on the oxygen saturation waveform 604 at a position that is 1 cardiac cycle, 5 cardiac cycles, 10 cardiac cycles, or more cardiac cycles after the first fiducial point 652 or after the nadir point. While only one second fiducial point 654 is shown in FIG. 6B, in some examples, second fiducial points 654 can be identified for each desaturation event in the oxygen saturation data.

[0239] Once the first fiducial point 652 and the second fiducial point 654 for desaturation events in the oxygen saturation data are identified, at step 622, the process further comprises determining the hypoxic deficiency information for the patient for a particular desaturation event. The hypoxic deficiency information can be calculated as an area-under-the curve of the oxygen saturation waveform 604 between the identified first fiducial point 652 and the second fiducial point 654 for a particular identified desaturation event. As previously described, area-under-the-curve for determining the hypoxic deficiency can be an area between the oxygen saturation waveform 604 and the predetermined or patient-specific baseline saturation value. Furthermore, in some examples, hypoxic deficiency for each desaturation event in the oxygen saturation data can be added together to provide an overall hypoxic burden and / or normalized to provide a normalized hypoxic burden value providing information about hypoxic severity for the patient during, for example, an entire sleep test.

[0240] FIG. 7 A is a flow chart for a process for determining an overall hypoxic burden for the patient, which takes into account multiple hypoxic deficiency values (e.g., hypoxic deficiency values calculated for multiple desaturation events 750) occurring during, for example, a patient sleep test. FIG. 7B includes graphs of an arterial tone (e.g., peripheral arterial tone) waveform 702 and an oxygen saturation waveform 704 of the patient. FIG. 7B also includes an arterial tone amplitude waveform 706 and a pulse rate waveform 708. Multiple desaturation events shown in the graphs are shown by shapes 750 in FIG. 7B.

[0241] As shown in FIG. 7A, the process comprises a step 710 of providing the medical system 100 comprising the patient sleep probe 112 and other medical devices 110 to the patient and, if needed, assisting the patient in positioning wearable portions of the system 100 on his or her body.

[0242] At step 712, the process further comprises obtaining and processing arterial tone data (e.g., peripheral arterial tone data) and oxygen saturation data for the patient. For example, arterial tone data can be acquired from the arterial tone sensor 136 of the patient sleep probe 112 and oxygen saturation data can be obtained from the oxygen saturation sensor 130 of the patient sleep probe 112, which are shown in FIG. IB. As previously described, the obtained data may have been recorded over a period of hours or days (e.g., a duration of a sleep test) and can include multiple instances of desaturation and re-saturation of the patient.

[0243] At step 714, the process further comprises detecting multiple arterial tone events (e.g., changes) in the obtained arterial tone data using, for example, any of the processes for identifying attenuation of an arterial tone signal, as previously described. The multiple arterial tone events (e.g., changes) are shown by shapes 752 in the arterial tone waveform of FIG. 7B.

[0244] At step 716, the process further comprises determining hypoxic desaturation information from the oxygen saturation data based on the arteria tone changes 752 detected in step 714. More specifically, in some examples, the hypoxic desaturation information can be determined from the oxygen saturation data using information from at least one arterial tone event (e.g., change) and / or pulse or heart rate data. Depending on implementation and available sensor types, the pulse rate or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data. The hypoxic desaturation information can also be determined from the oxygen saturation data and using patient movement or motion data during sleep and / or patient snoring data during sleep.

[0245] In some examples, as previously described, determining the hypoxic desaturation information can include identifying the desaturation start time 754 and the desaturation termination time 756 for the multiple detected desaturation events 750 using the various identification techniques described above, which can be based on a predetermined or patient-specific baseline saturation level.

[0246] At step 718, the process further comprises determining the hypoxic deficiency for the multiple detected desaturation events 750 based on the hypoxic desaturation information determined for each desaturation event. For example, as previously described, the hypoxicdeficiency can be a value based on the area-under-the-curve between the determined desaturation start time and the desaturation termination time for the multiple desaturation events. Areas-under- the-curve for the multiple desaturation events are shown by shapes 758 in FIG. 7B. As previously described, the area-under-the-curve can refer to an area defined by the oxygen saturation waveform 704 and the predetermined, event specific, or patient-specific baseline saturation value and extending between the desaturation start time 752 and the desaturation termination time 754 for each identified desaturation event 750.

[0247] Once hypoxic deficiency values for the multiple desaturation events 750 in the oxygen saturation data is known, at step 720, the process further comprises determining the overall hypoxic burden for the patient based on the multiple hypoxic deficiency values for the patient determined for the multiple desaturation events 750. In some examples, the overall hypoxic burden can be determined by adding together the determined hypoxic deficiency values for the multiple desaturation events, thereby providing an indication of total effects of desaturation or hypoxia for the patient for the period of time covered by the oxygen saturation data (e.g., for a predetermined period of hours, days, or for an entire duration of a sleep test).

[0248] At step 722, the process can further comprise determining a normalized overall hypoxic burden for the patient. In some examples, the normalized overall hypoxic burden can be based on an actual sleep duration for the patient. For example, the normalized overall hypoxic burden can be a ratio of overall hypoxic burden for the patient and actual sleep duration. The actual sleep duration can be determined, for example, based on signals detected by patient sensors, such as motion sensors, acoustic sensors, or vibration sensors positioned on or associated with the patient. In other examples, the actual seep duration can be determined by analyzing the arterial tone data or other physiological signals, such as signals detected by an electroencephalogram (EEG) sensor on the patient. In other examples, the actual sleep duration can be a value input by, for example, a user or the patient based on the patient’s self-reported sleep time.

[0249] In other examples, the normalized hypoxic burden for the patient can be based on a nominal, estimated, or average sleep duration for the patient. For example, an average sleep duration can be determined based on average nightly sleep duration for a subclass of individuals having common characteristics as the patient. For a forty-year old male patient, the average sleep duration can be average nightly sleep duration for males between 35 years old and 50 years old. For a female teenage patient, the average sleep duration can be an average sleep duration for allteenagers or for all female teenagers. In examples, the average or nominal sleep duration can be input by a user or by the patient using a user interface element in electric communication with a computing device of the medical system 100 or system controller 138.

[0250] In some examples, the hypoxic burden can also be reported for specific times during a sleep study, such as in terms of a hypoxic burden value for a particular patient sleep state, patient body position during sleep, and / or for times when treatment (e.g., using a CPAP device or mandibular advancement device) is being provided to the patient. For example, the process can include identifying desaturation events that occur during different sleep states (e.g., light sleep, deep (non-REM) sleep, and REM sleep) of the patient based, for example, on peripheral arterial tone measurements or EEG measurements for the patient. The process can then include determining, for example, an overall hypoxic burden for desaturation events during REM sleep by adding together or averaging hypoxic deficiency values for the desaturation events occurring during REM sleep. The hypoxic burden for REM sleep can also be a normalized value based on the overall hypoxic burden during REM divided by an amount of time that the patient was in REM during, for example, an overnight sleep study. In other examples, hypoxic burden can be reported for parts of the sleep study where the patient was in a particular body position. For example, the process can include determining a hypoxic burden for times when the patient was sleeping on his or her back based on hypoxic deficiency values for desaturation events occurring with the patient on his or her back. As previously described, patient body position can be determined, for example, based on measurements by movement or motion sensors positioned on the patient. In a similar manner, hypoxic burden can also be reported for times when the patient uses a particular treatment device, such as a CPAP machine, based on hypoxic deficiency values for desaturation devices occurring as the patient uses the particular treatment device. In some examples, usage information for treatment devices can be input manually by a user. In other examples, electronic treatment devices, such as a CPAP machine, can provide information about device usage to a system processor, which can use the usage information to determine, for example, the hypoxic burden for times when CPAP treatment is being provided to the patient.

[0251] FIGS. 8 A, 8B, and 8D show additional examples of processes and methods for measuring hypoxic severity or deficiency of a patient. The processes and methods shown in FIGS. 8 A and 8B use oxygen saturation data and arterial tone data along with other patient data for determining patient hypoxic deficiency. For example, the process or method can use oxygen saturation dataand arterial tone data, along with pulse rate or heart rate data. As previously described, depending on implementation and available sensor types, the pulse or heart rate data can, for example, be based on optical sensor data and / or electrocardiogram (ECG) electrode data. The process and method shown in FIG. 8D use oxygen saturation data, such as data provided by a PPG or saturation sensor, in combination with pulse rate data (e.g., provided by the PPG or saturation sensor) or heart rate data (e.g., provided by an ECG sensor) for determining patient hypoxic deficiency. FIG. 8E is a graph showing desaturation events (enclosed by rectangles 854) in an oxygen saturation waveform 804 and pulse rate events (enclosed by rectangles 856) in a pulse rate waveform 808.

[0252] The processes and methods can also use oxygen saturation data and arterial tone data along with patient movement or motion data during sleep for determining hypoxic deficiency. Depending on implementation and available sensor types, the patient movement or motion data during sleep can, for example, be based on motion sensors, including accelerometers, such as tri- axial accelerometers, gyroscopes, and / or other types of motion sensing devices. Such motion sensors can be disposed within a wrist worn portion of the patient sleep device, a digit probe portion of the patient sleep device, or any other predetermined location on the patient’s body.

[0253] In some examples, patient snoring data during sleep can also be used in combination with the other data types for determining hypoxic deficiency. Depending on implementation and available sensor types, the patient snoring data during sleep can, for example, be based on microphones or vibrational sensors, including audio sensors, vibrational sensors such as tri-axial accelerometers, and / or other types of audio capture devices. Such audio sensors can be disposed below a neck region of the patient, on an upper torso portion of the patient, a throat region of the patient, a face region of the patient, or any other predetermined location on the patient’s body.

[0254] FIG. 8C is a graph showing an arterial tone waveform 800, oxygen saturation waveform 802, motion (actigraphy) waveform 806, and an audio or acoustic waveform 808 (snore detection in dB) for the patient. As shown in FIG. 8C, in some instances, detected patient snoring, patient movement, and increase pulse rate can occur simultaneously with or nearly simultaneously with arterial tone signal attenuation. In some examples, as previously described, the attenuation of the arterial tone signal can occur shortly after desaturation and can terminate simultaneous with or shortly before re-saturation.

[0255] FIG. 8A is a flow chart showing an exemplary process for determining hypoxic deficiency for the patient for one or a plurality of desaturation events. The process shown in FIG.8A is based on arterial tone data, oxygen saturation data, and pulse rate data. As shown in FIG. 8A, the process comprises a step 810 of providing the medical system 100 comprising the patient sleep probe 112 and other medical devices 110 to the patient and, if needed, assisting the patient in positioning wearable portions of the system 100 on his or her body. In addition to the previously described patient sleep probe 112, which comprises the pulse oximeter or saturation sensor 130 and the arterial tone sensor 136, the system 100 can also be configured to measure pulse rate. For example, pulse rate can be determined from a peripheral arterial tone signal detected by the arterial tone sensor 136 of the patient sleep probe 112. In other examples, the system can include other devices for measuring pulse rate or heart rate. For example, the system 100 can include a chest sensor, such as the chest sensor 120 shown in FIGS. 1C-1E, configured to measure physiological signals representative of patient heart rate, such as an electrocardiogram (ECG) sensor or electrode. In other examples, the pulse rate can be measured by a heart rate sensor positioned on the patient’s chest or another body location. For example, the wrist-worn device 118 can include a pulse sensor.

[0256] At step 812, the process further comprises obtaining and processing arterial tone data (e.g., peripheral arterial tone data) and oxygen saturation data for the patient. For example, the arterial tone data can be detected by the arterial tone sensor 136 of the patient sleep probe 112 configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient. The oxygen saturation data can be obtained from an oxygen saturation sensor of the patient sleep probe 112, such as the saturation sensor 130 shown in FIG. ID, that is configured to generate oxygen saturation data associated with the patient. As previously described, the obtained data can be obtained over a period of hours or days (e.g., a duration of a sleep test) and can include multiple instances of desaturation and re-saturation of the patient.

[0257] At step 814, the process further comprises obtaining or determining pulse rate data for the patient for periods of time contemporaneous with periods of time of the arterial tone data and the saturation data. For example, as previously described, pulse rate data can be determined from the arterial tone signal or the oxygen saturation signal or measured by a heart rate sensor or heart rate monitor device. In some examples, patient heart rate can be determined from, for example, a patient ECG signal or another physiological parameter, which can be evaluated to determine heart rate.

[0258] At step 816, the process further comprises detecting one or more arterial tone events (e.g., changes) in the obtained arterial tone data using, for example, any of the processes for identifying attenuation of an arterial tone signal, as previously described.

[0259] At step 818, the process further comprises determining hypoxic desaturation information based on the arterial tone data, the oxygen saturation data, and the pulse rate information. As previously described, arterial tone attenuation and pulse rate increase can be representative of sympathetic activation or sympathetic activity for the patient. As described in connection with FIGS. 5A-5C, in some cases, a process or user may require that all three conditions (e.g., arterial tone signal attenuation, desaturation, and pulse rate increase) are present in order to classify a desaturation event as a correlated desaturation event, which is used for calculating hypoxic deficiency for the patient. In other examples, the process or user may require only that desaturation and one other condition (e.g., either arterial tone signal attenuation or pulse rate increase) is needed to classify an event as a correlated desaturation event. As previously described, determining the hypoxic desaturation information can also include determining a desaturation start time and a desaturation termination time for each of the correlated desaturation events.

[0260] At step 820, once the hypoxic desaturation information is determined, as in previous examples, the process further comprises determining the hypoxic deficiency for the patient for particular desaturation events based on the hypoxic desaturation information. In some examples, hypoxic deficiency can be calculated as an area-under-the-curve for the oxygen saturation waveform between the desaturation start time and the desaturation termination time for a particular correlated desaturation event. More specifically, the area-under-the-curve for a particular correlated desaturation event can be an area defined by the saturation waveform and a baseline saturation level for the patient. Thus, a determined hypoxic deficiency value quantifies the amount of desaturation experienced by the patient during the desaturation event compared to a patient’s baseline saturation level. Further, as described above, an overall hypoxic burden can be calculated based on multiple hypoxic deficiency values to provide, for example, information about hypoxic severity experienced by the patient over a number of hours or for a duration of a sleep study.

[0261] FIG. 8B is a flow chart showing another example of a method for determining hypoxic severity or deficiency for the patient based on arterial tone data and oxygen saturation data, along with motion or movement data. As previously described, depending on implementation and available sensor types, the patient movement or motion data can be based on motion sensors,including accelerometers, such as tri-axial accelerometers, gyroscopes, and / or other types of motion sensing devices. Such motion sensors can be disposed within a wrist worn portion of the patient sleep device, a digit probe portion of the patient sleep device, or any other predetermined location on the patient’s body. In some examples, motion sensor data (also referred to as actigraphy data) can be detected by motion sensor(s) positioned on a patient’s limbs, such as on an arm or leg. For example, actigraphy data can be obtained from a motion sensor of the wrist- worn device 118, shown in FIG. 1C. In other examples, signals detected by, for example, accelerometers of other wearable and / or portable devices worn by the patient at other body locations, such as an ankle bracelet, armband, belt, or similar wearable device can be used for detecting patient movement data. In other examples, motion sensor(s) and / or motion sensing devices can be used for detecting movement of fingers, hands, wrists, arms, legs, ankles, toes, abdomen, torso, neck, jaw, head, or any other body location of the patient.

[0262] As shown in FIG. 8B, the process comprises an initial step 822 of providing the medical system 100 comprising the patient sleep probe 112 and other medical devices 110 to the patient and, if needed, assisting the patient in positioning wearable portions of the system 100 on his or her body. In particular, in addition to the previously described patient sleep probe 112, which comprises the pulse oximeter or saturation sensor 130 and the arterial tone sensor 136, the system 100 can also include a device for detecting patient movement, such as a motion sensor of the wrist- worn device 118.

[0263] At step 824, the process further comprises obtaining and processing arterial tone data (e.g., peripheral arterial tone data) and oxygen saturation data for the patient. For example, the arterial tone data can be detected by the arterial tone sensor of the patient sleep probe 112, such as the arterial tone sensor 136 shown in FIG. ID, configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient during sleep. The oxygen saturation data can be obtained from an oxygen saturation sensor of the patient sleep probe 112, such as saturation sensor 130 shown in FIG. ID, that is configured to generate oxygen saturation data associated with the patient. As previously described, the obtained data can be obtained over a period of hours or days (e.g., a duration of a sleep test) and can include multiple instances of desaturation and re-saturation of the patient.

[0264] At step 826, the process further comprises obtaining or determining movement data for the patient for periods of time contemporaneous with periods of time covered by the arterial tonedata and the saturation data. For example, movement data can include information about movement of a patient’s limbs, such as jerking movements that can indicate arousal. Further, patient movement information can include movement information about movement of limbs, such as arms, hands, or wrists, by wrist-worn devices 118. As previously described, the movement data can also be provided by movement sensors, such as accelerometer-based devices worn by or attached to many other body locations of the patient.

[0265] At step 828, the process further comprises detecting one or more arterial tone events (e.g., changes) in the obtained arterial tone data using, for example, any of the processes for identifying attenuation of an arterial tone signal, as previously described. As in previous examples, pulse rate or heart rate can also be monitored, along with the patient movement or motion data, to detect changes in pulse rate or heart rate representative of sympathetic activation or arousal of the patient.

[0266] At step 830, the process further comprises determining hypoxic desaturation information based on the arterial tone data, the oxygen saturation data, and the patient movement information. As previously described, arterial tone signal attenuation and patient movement can be representative of sympathetic activation or sympathetic activity for the patient. In some cases, a process or user may require that all three conditions (e.g., arterial tone attenuation, desaturation, and patient movement) are met in order to classify a desaturation event as a correlated desaturation event. In other examples, the process or user may require only that desaturation and one other condition (e.g., either arterial tone attenuation or patient movement) is needed to classify an event as a correlated desaturation event. As previously described, determining the hypoxic desaturation information can also include determining a desaturation start time and a desaturation termination time for each of the correlated desaturation event.

[0267] At step 832, once the hypoxic desaturation information is determined, as in previous examples, the process further comprises determining the hypoxic deficiency for particular desaturation events based on the hypoxic desaturation information. In some examples, hypoxic deficiency can be calculated as an area-under-the-curve for the oxygen saturation waveform between the desaturation start time and the desaturation termination time for a particular desaturation event. More specifically, the area-under-the-curve for a particular desaturation event can be an area defined by the saturation waveform and a baseline saturation level for the patient. As previously described, the hypoxic deficiency value quantifies an amount of desaturation (e.g., saturation lost by the patient) during the desaturation event compared to a patient’s baselinesaturation level. Further, as described above, an overall hypoxic burden can be calculated based on multiple hypoxic deficiency values to provide, for example, information about hypoxic severity experienced by the patient over a number of hours or for a duration of a sleep study.

[0268] FIG. 8D is a flow chart showing a process or method using the oxygen saturation data, such as data provided by a PPG or saturation sensor 130, in combination with pulse rate data (e.g., provided by the PPG or saturation sensor 130) or heart rate data (e.g., provided by an ECG sensor) for determining patient hypoxic deficiency. Unlike in previous examples, the process or method of FIG. 8D does not use arterial tone data for determining desaturation events that are correlated with sympathetic activation of the patient and / or for determining the hypoxic desaturation information. As discussed previously, FIG. 8E is a graph showing correlations between an oxygen saturation waveform 804 and a pulse rate waveform 808. As shown in FIG. 8E, desaturation events (enclosed by rectangles 854) can be correlated in time with pulse rate events (enclosed by rectangles 856). In particular, the pulse rate events can be an increase in pulse rate, which can be representative of patient sympathetic activation or activity.

[0269] As shown in FIG. 8D, the process comprises a step 840 of providing the wearable medical device(s) to the patient. The devices can include, for example, a PPG or saturation sensor 130 for providing saturation data for the patient. As previously described, saturation data can be used for determining a saturation waveform for the patient. Signals detected by a PPG or saturation sensor 130 can also be used for determining pulse rate for the patient. In other examples, the pulse rate can be measured by a sensor positioned on the patient’s chest or another body location. For example, the wrist-worn device 118 (shown in FIGS. 1C-1E) can include a pulse sensor. In some examples, the wearable medical device(s) provided to the patient can also include an ECG electrode and / or ECG monitoring device. ECG signals detected by the ECG sensor and / or monitoring device can be used for determining patient heart rate.

[0270] At step 842, the process further comprises obtaining and processing oxygen saturation data for the patient. The oxygen saturation data can be obtained, for example, from the oxygen saturation sensor 130 configured to generate oxygen saturation data associated with the patient, such as an oxygen saturation sensor of a sleep probe 112. Oxygen saturation data can also be provided by another PPG or oxygen saturation sensing device 130, such as the sensing device shown in FIGS. 1A and IB. As previously described, the obtained data can be obtained over aperiod of hours or days (e.g., a duration of a sleep test) and can include multiple instances of desaturation and re-saturation of the patient.

[0271] At step 844, the process further comprises obtaining or determining pulse rate or heart rate data for the patient for periods of time contemporaneous with periods of time of the saturation data. The pulse rate data can be obtained from a PPG or saturation sensor. In examples, the heart rate data can be obtained from an ECG electrode or ECG sensor.

[0272] At step 846, the process further comprises detecting saturation events (e.g., decreases in oxygen saturation by a predetermined amount (e.g., 15%, 10%, 2%, or 1%) from a baseline value) in the obtained saturation data using, for example, any of the processes for identifying desaturation events, as previously described.

[0273] At step 848, the process further comprises identifying a correlated event in the patient’s pulse rate or heart rate representative of sympathetic activation occurring close in time to the detected desaturation event(s). For example, an increase in pulse rate or heart rate representative of sympathetic activation can occur within about 10 seconds prior to or after an identified desaturation event. In other examples, the increase in pulse rate or heart rate can occur about 20 seconds prior to the desaturation event, about 20 seconds after the desaturation event, about 30 seconds prior to the desaturation event, about 30 seconds after the desaturation event, about 45 seconds prior to the desaturation event, or 45 seconds after the desaturation event. As in previous examples, identified desaturation events that are correlated in time with other events (e.g., changes in pulse rate or heart rate) can be considered in determining the hypoxic desaturation information and / or hypoxic deficiency values. Desaturation events that are not correlated in time with a change, particularly an increase, in pulse rate or heart rate may not be considered in calculating the hypoxic desaturation information or hypoxic deficiency value for the patient.

[0274] At step 850, the process further comprises determining hypoxic desaturation information based on the oxygen saturation data and the heart rate or pulse rate. As previously described, pulse rate increase can be representative of sympathetic activation or sympathetic activity for the patient. As previously described, determining the hypoxic desaturation information can also include determining a desaturation start time and a desaturation termination time for each of the correlated desaturation events.

[0275] At step 852, once the hypoxic desaturation information is determined, as in previous examples, the process further comprises determining the hypoxic deficiency for the patient forparticular desaturation events based on the hypoxic desaturation information. In some examples, hypoxic deficiency can be calculated as an area-under-the-curve for the oxygen saturation waveform between the desaturation start time and the desaturation termination time for a particular correlated desaturation event. More specifically, the area-under-the-curve for a particular correlated desaturation event can be an area defined by the saturation waveform and a baseline saturation level for the patient. Thus, a determined hypoxic deficiency value quantifies the amount of desaturation experienced by the patient during the desaturation event compared to a patient’s baseline saturation level. Further, as described above, an overall hypoxic burden can be calculated based on multiple hypoxic deficiency values to provide, for example, information about hypoxic severity experienced by the patient over a number of hours or for a duration of a sleep study.

[0276] The processes and methods described above and illustrated in FIGS. 3A-8E provide hypoxic burden based on the arterial tone data and oxygen saturation data for the patient detected by the patient sleep probe 112. A variety of different types of devices and sensors can be used for providing such arterial tone and saturation data, including digit probes and clips, as well as other wearable sensors and sensing devices configured to be mounted to different areas of a patient’s body. Having generally described processes and methods for monitoring and / or analyzing data from patient sleep devices 112 for measuring hypoxic severity of the patient, features of the medical system 100, medical devices 110, and patient sleep probe 112 used for collecting such data will now be described in detail.

[0277] As previously described, the patient sleep probe 112 for obtaining the arterial tone data and oxygen saturation data can be a digit probe 912, such as the exemplary digit probe 912 shown in FIGS. 9A and 9B. As previously described, the arterial tone senor 136 and the oxygen saturation sensor 130 of the patient sleep probe 112 can be positioned in the digit probe 912.

[0278] As shown in FIGS. 9 A and 9B, the digit probe 912 can comprise a tubular, cylindrical, or similar elongated housing 914 including an open proximal end 916 and a closed distal end 922. The open proximal end 916 of the digit housing 914 can be adapted for facilitating insertion of a digit of the patient into the digit housing 914. The digit housing 914 can be formed from a rigid plastic (e.g., acrylonitrile butadiene styrene (ABS), polyester, polycarbonate, polypropylene, polyethylene, or polyethylene terephthalate). The digit housing 914 can comprise an external digit housing surface 918 (shown in FIG. 9B) and an internal digit housing surface 920 (shown in FIG. 9B).

[0279] As previously described, the digit probe 912 can be configured to be positioned on and / or used with digits of a patient, such as on fingers or toes. Furthermore, the digit probe 912 can be adjustable, so that it can be used with many or all possible digit dimensions. When used with a hand and fingers, the digit probe 912 can be configured to allow for fixation to any or all of the index finger (pointer finger or forefinger), middle finger, ring finger, little finger (pinky), or thumb. Accordingly, the dimensions of the digit probe 912 may be different corresponding to the average person’s dimensions for these patient digits. When used with a foot and toes, the digit probe 912 can be configured to allow for fixation to any or all of a hallux (big toe or great toe), second toe (long toe), third toe (middle toe), fourth toe (ring toe), and / or fifth toe (little, pinky, or baby toe). Furthermore, when correctly positioned on and / or fixed to the digit, the digit probe 912 can receive, surround, and / or enclose both a volar (also referred to a front or palmar) portion of the digit and a dorsal (also referred to as a rear) portion of the digit.

[0280] For a digit probe 912 configured to be worn on a patient’s middle finger, the digit housing 914 can have an axial length of about 4 cm to about 8 cm. The open proximal end 916 of the digit housing 914 can have an outer diameter of about 3 cm to about 4 cm and an inner diameter of about 2 cm to about 3 cm. In some implementations, the dimensions of the digit housing 914 can be adjusted to accommodate varying digit sizes of the patient. For example, the inner diameter of the housing 914 can vary within a range of about 2 cm to about 3 cm when the patient inserts his or her middle finger into the housing 914. As noted, the dimensions depend on the patient’s digit. In some implementations, the systems, methods, and devices as described herein can be configured to allow for fixation to any or all of the index finger (pointer finger or forefinger), middle finger, ring finger, little finger (pinky), or thumb. Accordingly, the dimensions may be different corresponding to the average person’s dimensions for the foregoing patient digits.

[0281] In some examples, the digit probe 912 can be configured to receive or cover the distal part of the digit of the patient and to apply pressure, such as a uniform or substantially uniform pressure, to portions of the digit while sensors detect or obtain signals representative of, for example, light transmittance through tissue of the digit received within the digit probe 912. As previously described, the applied uniform or substantially pressure may improve signal quality for arterial tone measurements meaning that changes in blood flow characteristics can be more easily and accurately identified. In particular, a static uniform or substantially uniform pressure field provided by the digit probe 912 may inhibit or prevent pooling of venous blood in the distal endof the digit while allowing pulsatile blood delivered by the arteries to be returned via the veins. In some examples, the pressure applied by the uniform or substantially uniform pressure field may be sufficient to prevent free venous flow due to, for example, hydrostatic pressure and shock waves, while allowing the veins to carry blood delivered by the arteries out of the finger. In some examples, the pressure required to prevent venous pooling may differ from patient to patient. In some examples, noise reduction (e.g., improved signal to noise ratio) in the arterial tone signal (e.g., peripheral arterial tone) or measurement may also be achieved by applying sufficient pressure to partially unload, but not occlude, the wall tension of the arteries in the finger, when the finger is near heart level. This may allow the arterial wall to move freely to accommodate the pulsatile blood delivery of the heart. The applied pressure may be slightly above the maximum pressure in the veins when the hand is fully lowered (e.g., 5% higher and / or the like).

[0282] In some examples, the pressure applied to the digit by the digit probe 912 is provided as a uniform or substantially uniform pressure field within a predetermined range extending from a proximal portion (e.g., a middle or proximal phalanges portion) of the digit to a distal tip of the digit. In particular, the digit probe 912 can be configured to apply the uniform or substantially uniform pressure (e.g., a sub-diastolic and / or peripheral arterial pressure) to a portion of the digit, while sensing physiological signals representative of, for example, pulsatile volume changes of the patient’s arteries.

[0283] In order to provide the uniform or substantially uniform pressure field, the digit probe 912 can comprise a pressure device, which can be disposed within an interior of the digit housing 914, for providing or applying the uniform or substantially uniform sub-diastolic pressure field to the digit of the patient. The pressure device can be configured to facilitate unloading of arterial wall tension. Further, the pressure device can be configured to mitigate distal venous pooling or distention to avoid induction of venoarterial-mediated vasoconstriction.

[0284] In an example implementation, as shown in FIG. 9B, the digit probe 912 includes both an oxygen saturation sensor and an arterial tone sensor within the same physical probe or housing. For example, in one implementation, there are two separate light emitting devices, 952, 954 and a common light detecting device 956. The first light emitting device 952 in turn can include at least one light emitting diode, photoemitter, or any combination thereof. Similarly, the second light emitting device 952 in turn can include at least one other light emitting diode, photoemitter, or any combination thereof. In this example, the common light detecting device 956 can include at leastone of a photodiode, a photodetector, a photosensor, a photoresistor, a semiconductor based photodetector, any combination thereof, and / or the like. The oxygen saturation sensor can be based on the first light emitting device 952 being configured to one or more wavelengths that reflect oxygenation of the blood (e.g., provide signals indicative of both oxygenated and nonoxygenated hemoglobin). In examples, the first light emitting device 952 can include wavelength of about 650 nm (e.g., substantially visible red), 660 nm, about 780 nm (e.g., substantially infrared), 800 nm, 910 nm, and 940 nm.

[0285] The arterial tone sensor, on the other hand can be based on the second light emitting device 954, which can be configured to emit one or more wavelengths that are not affected by the oxygenation of blood. The arterial tone sensor, as such, produces arterial tone signals (and corresponding data) configured to reflect an amount of blood pulsating through the patient’s artery (e.g., a finger artery). In examples, the wavelength can be within a range of about 200 nm to about 600 nm. In some examples, the second light emitting device 954 is configured to be located on the patient’s digit so that the signal is based on smaller blood vessels (e.g., arterioles and capillaries) without signal contribution from larger arteries. For example, smaller vessels have larger ability to dilate or constrict than the larger blood vessels, and as such the signal based on these smaller blood vessels can be more sensitive to sympathetic activation than signals based on larger blood vessels.

[0286] The common light detecting device 956 is electrically connected to a controller or processor configured to separate the transmitted light from the two light emitting devices 952, 954 and provide oxygen saturation signal (and corresponding data) in a first channel, and arterial tone signal (and corresponding data) in a second, different channel.

[0287] As previously described, in some examples, an inner portion of the optical digit probe 912 can provide the uniform or substantially uniform pressure field. For example, a uniform or substantially uniform pressure field may be achieved by inserting an elastic member 958 into the open proximal end 916 of optical digit probe 912 and attaching the elastic member 958 to the open end of the optical digit probe 912, such that an enclosed seal is formed between an inner portion of the optical digit probe 912 and the elastic member 958, to define a pocket or chamber 960. A fluid (such as an inert gas) may be inserted (e.g., injected and / or the like) into the chamber 960 and cause the elastic member 958 to elastically deform. The pneumo-optical sensor comprising the light emitters 952, 954 and detector 956 may be utilized in conjunction with theelastic member 958 to apply the uniform subdiastolic pressure to the portion of the patient’s body (e.g., to a distal two-thirds of the digit, such as a fingertip of the wearer’s finger, etc.), whereby the uniform or substantially uniform subdiastolic pressure may one or more of: clamp the finger probe to the wearer’s finger, facilitate unloading of arterial wall tension, facilitate increase in a dynamic range of a peripheral arterial signal of the patient relative to oxygen saturation or PPG signals without the uniform subdiastolic pressure, and / or mitigate distal venous pooling or distention to avoid induction of venoarterial-mediated vasoconstriction.

[0288] In some examples, the uniform or substantially uniform pressure field applied by the digit probe 912 to particular portions of the digit is intended to be a static and uniform or substantially uniform (e.g., within 10%, 5%, or 1% of uniform) pressure across surfaces of the digit, including the volar surface, dorsal surface, and distal tip. The target range for the uniform or substantially uniform pressure can be selected in order to provide a relatively large operating zone in which pressure remains substantially constant with changes in digit volume. Changes in digit volume can be due to changes in instantaneous blood volume related to arterial blood volume of the digit. The relationship between pressure and digit volume is shown in the graph of FIG. 2, which shows an operating zone of about 60 mmHg to about 64 mmHg where the pressure remains substantially constant with the changes in volume. However, an actual pressure value for a particular digit is a function of the thickness and mechanical characteristics of the distensible material. For example, the pressure range or operating zone for the patient sleep probe 112 can be about 40 mmHg to about 70 mmHg.

[0289] The patient sleep probe 112 comprising the arterial tone sensor 136 and the oxygen saturation sensor 130 can also comprise a digit clip 1012, as shown in FIGS. 10A-10C, instead of a tubular digit probe 912. As shown in FIGS. 10A-10C, the clip 1012 comprises two or more members 1014, 1016 (referred to herein as “clip members”), which can be elongated trays, shells, plates, or other supports, configured to move relative to one another (e.g., in a parallel configuration, in a pivotally coupled configuration, or in some other configuration), to facilitate an increase / decrease in distance between the clip members 1014, 1016 during relative movement thereof. For example, the clip members 1014, 1016 can be pivotally coupled at a hinge point, can be connected through a pivot rod, biasing member, and / or spring. The clip members 1014, 1016 can also be connected by a ratchet mechanism, which secures the clip members 1014, 1016 together and is size-adjustable so that the clip 1012 can be used with digits of different sizes. Inexamples in which the clip 1012 comprises two members 1014, 1016 pivotally coupled to one another via a hinge 1018 (shown in FIG. 10A), the hinge 1018 may be operatively disposed at a proximal end 1020 or a distal end 1022 of the clip 1012, or at any position between the proximal end 1020 and the distal end 1022 of the clip members 1014, 1016.

[0290] In some examples, the proximal ends 1020 of the clip members 1014, 1016 can form or define an opening 1024 (shown in FIG. 10 A) or gap sized to receive the digit being monitored by the clip 1012. Furthermore, the clip members 1014, 1016 can comprise inwardly facing or inner surfaces 1026a, 1026b (shown in FIGS. 10B and 10C) configured to receive and support portions of the patient’s digit. For example, the first clip member 1014 can comprise an inner surface 1026a (shown in FIG. 10B) configured to receive a dorsal portion of the patient’s digit. The second clip member 1016 can comprise inner surface 1026b configured to receive portions of the volar surface of the digit.

[0291] In some examples, the clip members 1014, 1016 can be molded structures formed, for example, from a rigid plastic (e.g., acrylonitrile butadiene styrene (ABS), polyester, polycarbonate, polypropylene, polyethylene, or polyethylene terephthalate). The clip 1012 can also include sealing structures, such as an internal O-ring or cushion, positioned to provide a tight seal around the wearer’s digit. As previously described, the wearer’s digit can be, for example, a finger or toe. For example, the digit clip 1012 can be inserted onto a little finger, a ring finger, middle finger, or a pointer or index finger of the patient. In other examples, the optical digit clip 1012 can be configured to be worn on a big toe (hallux), second toe, third toe, fourth toe, fifth toe, or on any other convenient extremity. In some examples, the clip members 1014, 1016 can be sized to receive a distal phalanges and a portion of a middle phalanges of the digit. In other examples, the clips members 1014, 1016 can be extended in length and configured to receive the distal phalanges, middle phalanges, and a portion of the proximal phalanges of the digit.

[0292] Dimensions of the clip members 1014, 1016 of the digit clip 1012 can depend upon the type of digit being monitored by the wearable medical device. For an optical digit clip 1012 configured to be worn on a wearer’s middle finger, the clip members 1014, 1016 can have an axial length LI (shown in FIG. 10 A) of about 4 cm to about 8 cm. The open proximal end 1024 of the clip 1012 (e.g., gap between proximal ends 1020 of the first clip member 1014 and the second clip member 1016) can have an outer diameter GDI (shown in FIG. 10A) of about 3 cm to about 4 cm and an inner diameter ID1 (shown in FIG. 10 A) of about 2 cm to about 3 cm. In someimplementations, the dimensions of the clip members 1014, 1016 can be adjusted to accommodate varying digit sizes of the patient. For example, an inner diameter of a digit space 328 (FIG. 10B) defined by inner surfaces 1026a, 1026b of the clip members 1014, 1016 can vary within a range of about 2 cm to about 3 cm when the patient inserts his or her middle through the open proximal end 1024.

[0293] In some examples, two clip members 1014, 1016 of the clip 1012 are pivotally connected at the hinge 1018, meaning that the clip 1012 can be moved between a closed position (shown in FIG. 10A) and an open position by, for example, rotating the first clip member 1014 and / or the second clip member 1016 about the hinge 1018, as shown by arrow Al in FIG. 10A. The hinge 1018 can be structured to provide sufficient clearance between the clip members 1014, 1016 so that the clip members 1014, 1016 can be easily opened and closed without blocking each other. For example, clip members 1014, 1016 can include cut-out portions or other structural features to provide sufficient clearance between clip members 1014, 1016. In other examples, the hinge 1018 can include a slot (e.g., a vertical slot in ring or tab portion 1025), which receives protrusion 1030 and allows for upward movement thereof, whereby the clip members 1014, 1016 can move vertically relative to one another and pivot relative to one another.

[0294] The clip 1012 can also include various pressure applying materials, such as cushions, pads, membranes, or supports comprising, for example, air, foam, gel, or hydrogel attached to inner surfaces 1026a, 1026b of the clip members 1014, 1016 and / or disposed within a digit space 1028 enclosed by the clip members 1014, 1016. Additional pressure applying material (e.g., air, gel, hydrogel, etc.) can be disposed proximate to the distal ends 1022 of the clip members 1014, 1016 for contacting and applying pressure to distal tip of the digit. The additional pressure applying material near the distal ends 1022 can be configured to optimize or smooth out force / pressure applied to the distal tip of the digit at or adjacent hinge 1018 by the clip members 1014, 1016 as the clip 1012 closes. Otherwise, pressure may be applied to the distal tip of the digit and / or to other surface of the digit less uniformly.

[0295] As shown in FIGS. 10B and 10C, the clip 1012 comprises a uniform pressure applicator 1048 disposed in the digit space 1028. The uniform pressure applicator 1048 is configured to uniformly distribute pressure generated within the digit space 1028 to portions of the digit. In particular, the uniform pressure applicator 1048 can be configured to apply radially inwardly directed pressure (shown by arrows A3 in FIG. 10C) to the volar surface and the dorsal surface ofthe digit. The uniform pressure applicator 1048 can also apply radially inwardly directed pressure to side surfaces of the digit between the dorsal surface and the volar surface. The uniform pressure applicator 1048 can also be configured to apply a substantially uniform axially directed pressure (shown by arrows A4 in FIG. 10B) to the distal tip of the digit. For example, a magnitude of the radial pressure against the dorsal and volar surfaces can be equal to or substantially equal (e.g., within about 10%, 5%, or 1%) to the axial pressure against the distal tip of the digit. As previously described, the uniform or substantially uniform distribution of pressure to surfaces of the digit received within the digit space 1028 can facilitate unloading of arterial wall tension. The unloading of the arterial wall tension can facilitate an increase in a dynamic range of an arterial tone (e.g., peripheral arterial tone) signal measured by optical sensors of the clip 1012 compared to signals detected by sensors without applying uniform subdiastolic pressure to the digit. Uniform pressure distribution can also mitigate distal venous pooling or distention to avoid induction of venoarterial- mediated vasoconstriction. As such, the uniform pressure applicator 1048 contributes to the improved signal quality for peripheral arterial tonometry signals provided by sensors of the optical digit clip 1012.

[0296] The uniform pressure applicator 1048 can be configured to apply and / or distribute at least two types of pressure or external forces to surfaces of the digit. First, the uniform pressure applicator 1048 can be configured to apply pressure produced by the clip 1012, which bias the clip members 1014, 1016 toward the closed position. In order to apply such external force / pressure to the digit, the uniform pressure applicator 1048 can be configured to contact sides and / or peripheral portions of the digit received within the digit space 1028.

[0297] In addition to uniformly distributing external force / pressure generated by relative movement of the first clip member 1014 toward the second clip member 1016 and / or pressure due to the biasing force of the biasing member or spring, the uniform pressure applicator 1048 is also configured to uniformly distribute and apply forces resulting from elastic deformation or wall tension produced by the uniform pressure applicator 1048 itself. In some examples, the uniform pressure applicator 1048 can comprise membrane(s) or sheet(s) disposed within the digit space 1028. The membrane(s) or sheet(s) can initially be loose or flaccid and can be contacted and displaced by the digit as the digit is inserted into or received within the digit space 1028. Displaced portions of a sheet(s) or membrane(s) are configured to exert the additional force against surfaces of the digit due to wall tension or elastic deformation of the sheet(s) or membrane(s). Theseadditional elastic deformation or wall tension forces are governed by Laplace’s law relating differences in pressure between pressurized fluid in fluid-containing chambers (e.g., containing air, an inert gas, or inert liquid) enclosed by the sheet(s) or membrane(s) and the unpressurized digit space 1028. In this regard, a distending pressure within a distensible space is substantially proportional at equilibrium to a wall tension measure in a wall of the space divided by a principal radii of curvature of the space. In this regard, a static pressure applied by the fluid within the fluidcontaining chamber remains substantially constant irrespective of changes in volume of the digit space 1028, e.g., changes in volume caused by arterial blood flow within the patient’s digit received within the digit space 1028. In examples, if the patient’s digit were to be partially removed from within the digit space 1028, the remaining portion of the patient’s digit will still be subject to substantially same external pressure. As with forces related to movement of the clip members 1014, 1016, the elastic deformation or wall tension force or pressure is applied uniformly or substantially uniformly to surfaces of the digit received within the digit space 1028. Specifically, the uniform pressure applicator 1048 is configured to uniformly distribute the wall tension or elastic deformation forces in both a radial direction (shown by arrows A3 in FIG. 10C) to the volar and dorsal surfaces of the digit and in axial (e.g., longitudinal) direction of digit (shown by arrows A4 in FIG. 10C) at, for example, the distal tip of the digit.

[0298] Features of the uniform pressure applicator 1048 for providing the elastic deformation or wall tension force will now be described in detail. The uniform pressure applicator 1048 can comprise a first or inner membrane 1050, a second or outer membrane 1052, and a first chamber 1054 and a second chamber 1056 between the membranes 1050, 1052. The chambers 1054, 1056 can contain a fluid (e.g., a liquid, pressurized gas, or air at atmospheric pressure). Pressurization of the fluid in the chambers 1054, 1056 resulting from elastic deformation of the second or outer membrane 1052 causes the first or inner membrane 1050 to exert force against the digit. This force can be an elastic deformation force or a wall tension force. In some examples, the first chamber 1054 and the second chamber 1056 can be fluidly coupled with one another via openings, gaps, or slots 1058 defined by an inner shell portion 1060 of the first clip member 1014 or the second clip member 1016. In some examples, the first clip member 1014 or the second clip member 1016 can also include holes, gaps, or openings 1062 for expelling a fluid (e.g., air) from the clip 1012 as the second chamber 1056 expands, which occurs as the digit is received within the digit space 1028.

[0299] In operation, upon insertion of the digit into the digit space 1028, the outer membrane 1052 elastically deforms to accommodate increased pressure caused by insertion of the digit. Due to wall tension or elastic deformation forces, the outer membrane 1052 pressurizes the chambers 1054, 1056 with a pressure or force that is transmitted through the fluid in the chambers 1054, 1056 and exerted against the inner membrane 1050 and digit. Due to curvature of the outer membrane 1052, the pressure at equilibrium is a function of the wall tension of the outer membrane 1052 divided by the two principal radii of curvature of a shape enclosed by the outer membrane 1052. By allowing for pressurization of the chambers 1054, 1056, the uniform pressure applicator 1048 effectively maintains a constant or relatively constant pressure within the digit space 1028 when the digit is inserted into the digit space 1028, regardless of a size of the digit. Additionally, because the chambers 1054, 1056 are filled with fluid, the pressure is generally applied uniformly to the digit, via the inner membrane 1050.

[0300] In some examples, when the two chambers 1054, 1056 are present, inserting the digit into the digit space 1028 expands / stretches the flaccid inner membrane 1050, which causes corresponding elastic expansion / stretching of the outer membrane 1052 as the fluid (e.g., air) in the first chamber 1054 is pushed through the slots 1058 into the second chamber 1056, thereby pressurizing fluid in the fluidly coupled first and second chambers 1054, 1056. The pressurized fluid exerts substantially uniform pressure on the digit via the flaccid inner membrane 1050, which is pressed onto and conforms to the exterior surfaces of the digit. Thus, the wall tension or elastic deformation force exerted on the digit provides an added or addition force or pressure, which is exerted on the digit in combination with forces / pressures resulting from moving the first clip member 1014 toward the second clip member 1016 and / or the biasing forces of the biasing member or spring.

[0301] In some examples, an additional hole or slot 1058 can also be defined in the inner membrane 1050. The additional hole or slot 1058 can be positioned proximate to the portion of the digit space 1028, which receives the distal tip of the digit. In this configuration, the digit inserted into the digit space 1028 may function as a pressurizing component as well as a seal for the first chamber 1054. Specifically, when the digit is inserted, even though the inner membrane 1050 contains the opening or slot 1058, air can be trapped and pressurized within a sealed space by surfaces of the clip 1012, membrane(s) 1050, 1052, and the digit. This pressurization prevents the fluid or air in the chambers 1054, 1056 from passing into the digit space 1028 anddepressurizing the chambers 1054, 1056, meaning that the inner membrane 1050 remains collapsed against the digit. In this configurations, there can also be a small gap or buffer of air within the digit space 1028 proximate to the distal tip of the digit. The air gap or buffer can be fluidly coupled with air in the chambers 1054, 1056. Upon insertion of the digit into the digit space 1028, the chambers 1054, 1056 are pressurized, as previously described. Furthermore, uniform or substantially uniform pressure can be applied to the distal tip of the digit because the small gap or air buffer is pressurized along with fluid (e.g., air) in the chambers 1054, 1056. In other examples, an inner surface of the first or inner membrane 1050 can be flush and pressed against the distal tip as well as other surfaces of the digit, as described above, and can provide uniform pressure to the distal tip of the digit.

[0302] In some examples, as shown in FIGS. 10B and 10C, a peripheral edge of the inner membrane 1050 and a peripheral edge of the outer membrane 1052 are both connected to or about the proximal ends 1020 and / or proximal opening 1024 of the first and second clip members 1014, 1016. In this configuration, the clip 1012 comprises a single inner membrane 1050 and a single outer membrane 1052, each of which span or extend between the first clip member 1014 and the second clip member 1016. In other examples, the clip 1012 can include separate membranes for the first clip member 1014 and the second clip member 1016.

[0303] Having described the structure of the digit probe 912 and digit clip 1012 of the patient sleep probe 112, features of the optical sensors, such as an arterial tone sensor and oxygen saturation sensor will now be described in detail. In some examples, as described above, the optical sensors (e.g., the saturation sensor 130 and the atrial tone sensor 136) are enclosed within a single device or housing, such as within the sleep probe 112. Schematic drawings showing features of a patient sleep probe 1210 including a clip housing 1212 and optical sensors 1266, 1288 for detecting arterial tone data and oxygen saturation data are shown in FIGS. 11 and 12. However, it is understood that the oxygen saturation sensor and the peripheral arterial tone sensor can also be separate devices (such as the saturation sensing device 130 and arterial tone sensing device 136 shown in FIGS. 1A and IB). Such separate sensing devices work according to the optical sensor principles described herein and generally comprise similar or identical electrical components, such as photodetectors and LEDs, as the optical sensors of the patient sleep probe 1210.

[0304] In examples, the optical sensors 1266, 1288 of the patient sleep probe 1210 can be arranged in either a transmissive configuration or a reflective configuration. In the transmissiveconfiguration, a photodetector is located on the opposite side of the housing 1212 from the LED, with skin tissues in between the LED and photodetector. In the transmissive configuration, attenuated light intensity is measured for light after the light passes through skin tissues. In the reflective configuration, the photodetector is located next to the LED and the photodetector measures attenuated light intensity for light that is reflected from the skin tissues. In some examples, the patient sleep probe 1210 includes an LED that emits light and a photodetector to measure the amount of transmitted and / or reflected light. In some examples, the patient sleep probe 1210 can also include an emitter driver to drive the LED, a filter to remove noise (e.g., motion and / or interference) artifacts and enhance the quality of the obtained signal, an analog-to- digital converter, and a microprocessor.

[0305] As previously described, the patient sleep probe 1210 can be configured to measure arterial tone data and oxygen saturation data, which are measured using light sources of various wavelengths. When the wavelength of light increases, the depth of penetration through a patient’s tissue also increases. For example, the patient sleep probe 1210 can use LED wavelengths in a range of 200 nm to 1000 nm. Light at such wavelengths can reach the epidermis with capillaries, dermis with arterioles, and arteries of subcutaneous tissues, respectively. Major blood vessels and arteries with strong pulsation are generally located in the skin dermis or subcutaneous tissue. Moreover, certain wavelengths and / or wavelength ranges (e.g., wavelengths in range of 600 nm to 950 nm, particularly red 660 nm and infrared 910 nm and 940 nm) are affected by the oxygenation of blood and as such are better suited for oxygen saturation measurements. For peripheral arterial tone measurements, LED lights are configured to be at wavelengths or ranges of wavelengths that are not affected by the oxygenation of the blood. For example, the wavelengths for arterial tone measurements can be in a range of about 200 nm to about 600 nm. In this range, changes in the arterial tone signal may be a reflection of an amount of blood pulsating through the patient’s finger, regardless of oxygenation. In a similar manner, a saturation sensing device 130 (such as the sensing device 130 in FIGS. 1A and IB) comprises a photodetector and at least one LED operating at a wavelength and / or wavelength range (e.g., wavelengths in range of 600 nm to 950 nm, particularly red 660 nm and infrared 910 nm and 940 nm) affected by the oxygenation of blood. An arterial tone sensing device (such as the arterial tone sensing device 136 in FIGS. 1A and IB) can comprise a photodetector and an LED operating at wavelengths or ranges of wavelengths thatare not affected by the oxygenation of the blood. For example, the arterial tone sensing device 136 can comprise an LED operating in a range of about 200 nm to about 600 nm.

[0306] As shown in FIGS. 11 and 12, the patient sleep probe 1210 comprising the clip housing 1212 further comprises the optical-based physiological sensors, such as an oxygen saturation sensor 1288 and an arterial tone sensor 1266, which can be positioned in the housing 1212 along with associated electronic circuitry. For example, the sensors 1266, 1288 can be positioned on a first clip member 1214 or a second clip member 1216 of the housing 1212. The clip members 1214, 1216 can also comprise structures for providing mechanical support for the electronic components of the housing 1212 and the sensors 1266, 1288, such as a circuit board and / or computer processor, which can be in electronic communication with the sensors 1266, 1288. In particular, the electronic components and associated circuitry can comprise electronics circuits for receiving and / or processing signals representative of physiological parameters of the patient and for transmitting the received and processed physiological information to other devices through, for examples, a wireless transmitter or a connection cables between the devices.

[0307] The oxygen saturation sensor 1288 can be configured to measure the level of oxygen saturation in the patient’s blood by shining a beam of light through the tissue and detecting the amount of light that is absorbed. In some examples, the oxygen saturation sensor 1288 comprises EED(s) that emits light in the red wavelength (about 660 nm) and in an IR (Infra-Red) wavelength (about 910 nm to about 940 nm). The oxygen saturation sensor 1288 can be configured to measure absorbance of the digit at both red and infrared light at peak wavelengths of approximately 660 nm and 910 nm, respectively. Comparing the light absorbance for the different wavelengths can be representative of oxygen saturation of the blood according to known pulse oximetry principles. In some examples, the PPG FED can have a maximum optical output power of about 65 mW.

[0308] The arterial tone sensor 1266, such as a peripheral arterial tone sensor, can be configured to be positioned at or proximate to the digit. The arterial tone sensor 1266 comprises a peripheral arterial tone light-emitting diode (FED) and is configured to measure the pulsating movement of blood within one or more arteries. As previously described, the peripheral arterial tone sensor 1266 measures signals representative of pulsatile volume changes in arteries of the digit (e.g., in a distal tip of the digit), which reflect a relative state of the arterial vasomotor activity, and which relate indirectly to a level of sympathetic activation. Peripheral arterial vasoconstriction, whichcan be indicative of sympathetic activation, can also be shown as attenuation of arterial tone signal amplitude for signals detected by the arterial tone sensor 1266.

[0309] In some examples, the patient sleep probe 1210 comprises or is in electronic communication with a controller, computer processor, or computing device, such as the controller 138 (shown in FIG. IB) of the wrist-worn monitor device 118. In some examples, the controller 138 can be configured to control acquisition of the physiological signals from the oxygen saturation sensor 1288 or arterial tone sensor 1266 and / or to control the transmission of data (e.g., data collected during a sleep study) based on physiological signals detected by the sensors 1266, 1288. As previously described, signals detected by the sensors 1266, 1288 can be used for determining oxygen saturation and arterial tone for the patient which, as described herein are used to determine hypoxic severity or hypoxic deficiency of the patient. Physiological signals detected by the oxygen saturation sensor 1288 and / or arterial tone sensor 1266 can also be used for determining other patient physiological parameters, such as blood pressure, pulse rate, heart rate, and other physiological parameter values for the patient.

[0310] With continued reference to FIGS. 11 and 12, the arterial tone sensor 1266 comprises the arterial tone LED 1268 for emitting light in suitable wavelength(s) for detecting peripheral arterial tone signals. The arterial tone sensor 1266 further comprises a detector (e.g., a photodetector 1270) for detecting reflectance or transmittance of the light from or through portion(s) of the digit. For example, the photodetector 1270 can be an optical detector configured to detect intensity of visible, ultraviolet, and / or infrared light. The oxygen saturation sensor 1288 can comprise one or more PPG LEDs 1290 positioned to project light towards either the same photodetector 1270 used for detecting the peripheral arterial tone signals or to a different photodetector. As previously described, PPG LEDs 1290 can be configured to emit light in the red and infrared wavelengths. Oxygen saturation for the patient can be based on a ratio of the red and infrared light absorbance.

[0311] In some examples, as shown in FIG. 11, the arterial tone LED 1268 and / or the PPG LED 1290 are mounted to one of the first clip member 1214 or the second clip member 1216 and the photodetector 1270 is mounted to the other of the first clip member 1214 or the second clip member 1216. This configuration is a transmissive configuration where skin tissue is positioned between the LED 1268, 1290 and the photodetector 1270, such that emitted light passes through the skin tissue and to the photodetector 1270. For example, as shown in FIG. 11, the LED 1268, 1290 aremounted to the dorsal or first member 1214 and the photodetector 1270 is mounted to the second or volar clip member 1216.

[0312] In other examples, as shown in FIG. 12, the peripheral arterial tone sensor 1266 can comprise an arterial tone LED 1268 and photodetector 1270 mounted to the same clip member 1214, 1216, in a reflectance-type clip configuration. For example, as shown in FIG. 12, the arterial tone sensor 1266 comprises a peripheral arterial tone FED 1268 mounted to the second or volar clip member 1216 and a photodetector 1270, which is also mounted to the second or volar clip member 1216. Positioning both the peripheral arterial tone FED 1268 and the photodetector 1270 on the volar or second clip member 1216 and proximate to a volar surface of the digit can be preferable to positioning portions of the peripheral arterial tone sensor 1266 proximate to the dorsal surface of the digit. In particular, volar portions of the digit are generally soft and fleshy, with areas of subcutaneous fat. As such, portions of arteries are generally more visible in the volar portion of the digit, meaning that better light reflectance signals can be obtain from the volar portion of the digit than from the dorsal portion, thereby providing a better arterial tone (e.g., peripheral arterial tone) signal. In some examples, as shown in FIG. 12, the PPG FED 1290 is mounted to the first clip member 1214 in a transmissive configuration to emit light through skin tissue towards the photodetector 1270. In other examples, the PPG FED 1290 can be positioned on the second clip member 1216 along with the peripheral arterial tone FED 1268 and photodetector 1270 in a reflectance configuration.

[0313] FIGS. 13 and 14 show attachment devices 1312 for securing patient sleep probes, such as an optical digit probe or digit clip 1310, to the patient. The attachment devices 1312 can include various arrangements of straps, tethers, bands, sleeves, collars, and similar connectors for securing the patient sleep device to a particular digit of the patient. The attachment device 1312 can be configured to hold the patient sleep probe or digit clip 1310 in place on the digit of the patient during continuous, long-term use, thus preventing the patient sleep device from becoming dislodged, disconnected, or from falling off of the digit of the patient at an inappropriate or unexpected time. The attachment device 1312 can improve the quality of the physiological data obtained during a clinical study by, for example, ensuring that the patient sleep device remains properly positioned on the patient’s digit for the duration of the sleep study. In particular, the attachment device 1312 can prevent loss or interruption of signal fidelity and / or medical data, which occurs when the patient sleep device falls off of the digit of the patient.

[0314] FIG. 13 shows an example of a patient sleep probe comprising the optical digit clip 1310 and the attachment device 1312, which can be removably attached, permanently connected, or integral with the optical digit clip 1310. As in previous examples, the optical digit clip 1310 comprises a digit housing, which can be formed from a rigid plastic (e.g., acrylonitrile butadiene styrene (ABS), polyester, polycarbonate, polypropylene, polyethylene, or polyethylene terephthalate). The digit housing can be formed from a first clip member 1314 and a second clip member 1316, which include an external digit housing surface 1318 and an internal digit housing surface. The clip members 1314, 1316 further includes a distal end 1322, an open proximal end 1324, and a cylindrical, annular, or tubular sidewall 1326 extending between the open proximal end 1324 and the distal end 1322. The open proximal end 1324 of the digit housing 1316 is adapted for facilitating insertion of a digit of the patient into the digit housing 1316. The digit can be, for example, a finger or toe of the patient. For example, the optical digit clip 1310 can be configured for insertion onto a middle finger of the patient.

[0315] The optical digit clip 1310 further comprises the attachment device 1312, which, in some examples, can be partially or entirely formed from a thermoplastic elastomer, such as silicone, polypropylene, low molecular weight polyethylene, synthetic rubber (e.g., polychloroprene) or natural rubber (e.g., isoprene). In other examples, portions of the attachment device 1312 can be formed from more rigid plastic materials, such as acrylonitrile butadiene styrene (ABS), polyester, polycarbonate, polypropylene, high molecular weight polyethylene, or polyethylene terephthalate. In some examples, the attachment device 1312 comprises a housing fastening portion 1315 connected to the external digit housing surface 1318 of one of the clip members 1314, 1316 and a skin securement portion 1332 extending from the housing fastening portion 1315 configured to releasably couple the attachment device 1312 to a skin surface of the wearer or patient. In some examples, the attachment or housing fastening portion 1315 and the digit housing 1316 are separate parts that are adhered together by an adhesive or fastener. For example, an adhesive, such as an acrylic adhesive or a low surface energy (LSE) adhesive, can be used to adhere the attachment or housing fastening portion 1315 to the digit housing 1316. Adhesives used for this application can include features such as high initial bond for immediate usability, good chemical and humidity resistance, -40°F to 300°F short-term temperature resistance, anti-lifting performance on curved surfaces, and no major surface preparation or primer application needed. As a specific example, the adhesive can include an acrylic adhesive such as 300LSE manufactured by 3M of Saint Paul,Minnesota, USA. For example, the attachment or housing fastening portion 1315 can include an inwardly facing surfaces and an outwardly facing surface. The inwardly facing surface can be adhered to the external digit housing surface 1318 of the digit housing 1316. In particular, the inwardly facing surface can be permanently and immovably fixed to the external digit housing surface 1318 of the digit housing 1316.

[0316] In some examples, the housing fastening portion 1315 can be provided on a distal end of the attachment device 1312 and the skin securement portion 1332 can be on a proximal end of the attachment device 1312. In such cases, the attachment device 1312 can further comprise a middle portion 1340 between the housing fastening portion 1315 and the skin securement portion 1332. The middle portion 1340 and / or housing fastening portion 1315 can extend proximally over or beyond the open proximal end 1324 of the digit housing 1316, as shown in FIGS. 13.

[0317] In some examples, the attachment device 1312 can be an elongated or longitudinal member, such as a longitudinal attachment device, having a narrow distal end 1334, a narrow proximal end 1336, and longitudinal sides 1338 extending therebetween. The attachment device 1312 can be positioned or oriented relative to the digit housing 1316, such that a longitudinal axis LI of the elongated housing fastening portion 1315 is substantially parallel to a longitudinal axis L2 of the digit housing 1316. The longitudinal axis LI of the attachment device 1312 can correspond to an insertion direction of the digit of the patient into the digit housing 1316.

[0318] The attachment device 1312 further comprises the skin securement portion 1332 including an inwardly facing surface configured to contact the skin surface of the patient and an outwardly facing surface. In some examples, the inwardly facing surface includes an adhesive, such a hydrogel and / or removable adhesive, for attaching the skin securement portion to the skin surface of the patient. The skin securement portion 1332 can be an elongated member having an axis L3. The axis L3 can be transverse or substantially transverse (e.g., about 90 degrees) relative to the axis LI, L2 of the clip members 1314, 1316 and housing fastening portion 1315. In an example, the skin securement portion 1332 can be configured to at least partially wrap about the digit of the patient, e.g. around a proximal phalange of the finger. In an example, the skin securement portion 1332 can be configured to attach to a proximal phalange portion of the front of the hand (when viewed towards the palm).

[0319] FIG. 14 shows another example of an attachment device 1502 connected to a patient sleep probe 1410 comprising a digit clip 1412. The attachment device 1502 is configured to besecured to or worn about a wrist of the patient. The attachment device 1502 of FIG. 14 comprises a fastening portion 1514 connected to an external surface of one of the clip members 1414, 1416 and a skin securement portion 1532 configured to be releasably coupled to a skin surface of the patient. Unlike in the previous example, in which the skin securement portion of the attachment device connected to portion(s) of the digit (e.g., to third or proximal portions of the same digit that is inserted into the digit housing), the skin securement portion 1532 of FIG. 14 is configured to be worn on a wrist, forearm, and / or arm of the patient for releasably coupling the attachment device 1502 to the patient. For example, the skin securement portion 1532 can comprise a strap, ribbon, tether, sleeve, band, cuff, collar, bracelet, or similar wearable connector or anchor configured to be worn on the wrist, forearm, or arm of the patient for securing the digit clip 1412 in place and for preventing the digit clip 1412 from detaching from the digit of the patient at unexpected or inappropriate times. The attachment device 1502 can also include a middle portion 1540, such as a tether or strap, extending between the housing fastening portion 1514 and the skin securement portion 1532 of an appropriate length to extend from the patient’s finger to the wrist, forearm, or arm of the patient. The middle portion 1540, such as the tether or strap, can be configured to rest against an outwardly facing side of the patient’s hand when the digit clip 1412 is worn by the patient.

[0320] As shown in FIG. 14, the skin securement portion 1532 of the attachment device 1502 is an annular or partially annular bracelet 1564 configured to be worn about the wrist of the patient. The bracelet 1564 can be formed from a stretchable and / or elastomeric material so that the bracelet 1564 can expand, allowing the bracelet 1564 to be used for patients with substantial variability in wrist size. In addition, in some examples, the bracelet 1564 can include a clasp, lock, buckle, or another resizing mechanism for resizing the bracelet 1564 to provide additional size adjustability for the bracelet 1564.

[0321] Having described the wearable medical device 110 and patient sleep probe 112, as well as the various exemplary attachment devices used to secure the patient sleep probe 112 to the digit of the patient, physiological monitoring systems 1900 for controlling the wearable medical device 110 and / or for collecting, storing, analyzing, and providing feedback about physiological information detected by the patient sleep probe 112 and / or the wearable medical device 110 will now be described in detail. Exemplary physiological monitoring systems 1900 for collecting and analyzing data collected by the patient sleep probe 112 and associated wearable medical devices110 are shown in FIGS. 15A-15C. Specifically, FIGS. 15A-15C are schematic drawings and block diagrams of the system 1900 showing communication pathways for transmitting detected information and other data from the patient sleep probe 112 and wearable medical device 110 to remote computer devices or computer servers. Further, FIG. 15B shows a patient lying on a bed wearing the wearable medical device 110 and patient sleep probe 112, as may occur during an overnight sleep study. FIG. 15C shows an awake patient sitting in a chair while wearing the wearable medical device 110 and the patient sleep probe 112, as may occur when the patient sleep probe 112 is used for periodic or continuous monitoring of patient physiological parameters.

[0322] As shown in FIGS. 15A-15C, the system 1900 comprises a remote monitoring device 1902 (shown in FIG. 15A) in communication with the wearable medical device 110. For example, the remote monitoring device 1902 can be in communication with the controller 138 of the wrist- worn monitor 118 and / or with other electronic or monitoring circuitry of the wearable medical device 110 for receiving information detected by sensors 130, 136 of the patient sleep probe 112. The system 1900 can also include a wireless communication network 1906, and / or a wired connection 1908 for transmitting information, such as data detected by sensors of the wearable medical device 110, from the wearable medical device 110 to the remote monitoring device 1902.

[0323] Devices of the wireless communications network 1906 can include one or more of the following types of communication circuitry: cellular communications circuitry, Bluetooth® communications circuitry, Advanced Message Queuing Protocol (AMQP) circuitry, Constrained Application Protocol (CoAP) circuitry, WiFi circuitry, ZigBee circuitry, Z-Wave circuitry, wireless personal area network (WPAN) circuitry, Infrared Data Association (IrDA) circuitry, or any combination thereof. For example, wireless communications circuitry of the remote monitoring device 1902 may be configured to establish at least one of the following types of wireless connections with the wearable medical device 110 and / or patient sleep probe 112: a cellular connection, a Bluetooth® connection, an Advanced Message Queuing Protocol (AMQP) connection, a Constrained Application Protocol (CoAP) connection, a WiFi connection, a ZigBee connection, a Z-Wave connection, a wireless personal area network (WPAN) connection, an Infrared Data Association (IrDA) connection, or any combination thereof.

[0324] In some examples, the remote monitoring device 1902 can include one or more devices capable of receiving information from and / or communicating information to the wearable medicaldevice 110 and / or to other computer servers (e.g., via the wireless communication network 1906, via wired connection 1908, etc.). In some examples, the remote monitoring device 1902 can include a server or a group of servers. Additionally or alternatively, the remote monitoring device 1902 can include at least one other computing device separate from or including the server and / or group of servers, such as a portable and / or handheld device (e.g., a computer, a laptop, a personal digital assistant (PDA), a smartphone, a tablet, and / or the like), a desktop computer, and / or other like devices, as described herein. In some examples, the remote monitoring device 1902 may include at least one network interface (e.g., a server network interface and / or the like), at least one data storage device (e.g., a server database and / or the like), at least one processor (e.g., a server processor and / or the like), any combination thereof, and / or the like. For example, the remote monitoring device 1902 may include at least one processor operatively connected to a non- transitory computer-readable medium. In some examples, the remote monitoring device 1902 can be in communication with at least one data storage device (e.g., a server database and / or the like), which may be local or remote to the remote monitoring device 1902. In some examples, the remote monitoring device 1902 may be capable of receiving information from, storing information in, communicating information to, or searching information stored in the data storage device (e.g., a server database and / or the like).

[0325] In some examples, the system 1900 can be configured for conducting a home and / or remote sleep study using the patient sleep probe 112 and wearable medical device 110 of the present disclosure. In particular, as shown in FIGS. 15B and 15C, the wrist-worn monitor 118 can be strapped to a wrist of a patient and the patient sleep probe 112 can secured to the patient’s digit or finger. For example, as previously described, the attachment devices disclosed herein can be used to secure the patient sleep probe 112 to the digit of the patient ensuring that the patient sleep probe 112 does not become dislodged during the home and / or remote sleep study. The wrist-worn monitor 118 can be configured to receive PPG signals, as well as an arterial tone signal and / or oxygen saturation data from the patient sleep probe 112. The wrist-worn monitor 118 can also receive actigraphy (movement) data from the chest motion sensor device 120 and transmit the relevant data using an application running on a mobile device, such as the gateway device 1910, via the communication network 1906 to a remote computer system 1930 (e.g., one or more web servers) for further processing.

[0326] The system 1900 depicted in FIGS. 15A-15C is useful for conducting a home and / or remote sleep study, such as an overnight sleep study. For example, as shown in FIG. 15B, the patient may wear the wearable medical device 110 and the patient sleep probe 112 while sleeping in a bed. Data such as physiological data obtained from the sleep study can be stored on the remote computer system 1930 and obtained, preferably after conclusion of the sleep study, for evaluation. The data may include respiratory and other events that occurred during sleep as well as periods of REM, deep (non-REM) sleep, light sleep, and wakefulness. The pulse rate signal may be derived from the peripheral arterial signal and used in the automatic analysis. For example, the system 1900 can be configured to generate various parameters, including but not limited to: a respiratory disturbance index, an apnea-hypopnea index, a central apnea-hypopnea index, a percentage of total sleep time with Cheyne-Stokes Respiration pattern and sleep staging identification. A report may be generated, and the relevant data of the sleep study may be viewed on a screen and the automatically detected events can be revised manually by a physician as needed.

[0327] As previously described, the patient sleep probe 112 and wearable medical devices 110 disclosed herein can be used for obtaining physiological measurements for a patient remote from a medical facility, such as at home. For example, as previously described, the patient sleep probe 112 and medical devices 110 disclosed herein can be used for Home and / or Remote Sleep Tests, such as HST devices as described herein. In order to guide patients in performing such at home tests, the patient can be provided with verbal or written instructions for performing the at home study. For example, the instructions can guide the patient in how to correctly remove the patient sleep probe 112 from packaging and prepare the patient sleep probe 112 for use. The instructions may also include guidance for how to attach the patient sleep probe 112 to the patient’s digit and / or for using the attachment device to secure the patient sleep probe 112 in place on the digit. The instructions can also include guidance on how long the patient sleep probe 112 should be worn and / or on how to transmit collected data from the wearable medical device 110 to the remote server after the study has been completed.

[0328] In some examples, instructions can be provided on an electronic device, such as a patient’s smart phone or personal computer. Examples of instruction screens or a user interface for guiding the patient in performing an HST-based at-home study using the patient sleep probe 112 and wearable medical device 110 are shown in FIGS. 16A-16F. Specifically, FIG. 16A is a Welcome Screen explaining to the patient the type of study that will be performed. FIG. 16B isan instruction screen showing the patient how to attach the wrist-worn monitor to his or her wrist. FIG. 16C is an instruction screen showing the patient how to attach the chest motion sensor device to his or her chest. FIG. 16D is an instruction screen showing the patient how to attach the patient sleep probe 112 to his or her finger. Specifically, as shown in FIG. 16D, the patient is instructed to attach the patient sleep probe 112 to any finger of his or her non-dominant hand. FIG. 16E is a Start Recording screen providing a virtual button for the patient to press when he or she is ready to begin recording sleep study data. Finally, FIG. 16F is a Good Morning or Study Completed Screen informing the patient that the sleep study has been completed and that recorded data is being transmitted from the wearable medical device 110 to the remote computer server.

[0329] Although various non-limiting examples of the invention have been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred aspects, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed examples, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any example can be combined with one or more features of any other aspect or example.

Claims

WHAT IS CLAIMED IS:

1. A sleep test system for measuring hypoxic severity in a patient during sleep, comprising: a patient sleep device configured to be coupled to the patient during sleep, the patient sleep device comprising an arterial tone sensor configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient, and an oxygen saturation sensor configured to generate oxygen saturation data associated with the patient; and at least one controller configured to communicate with the patient sleep device, the at least one controller configured to detect at least one arterial tone event in the arterial tone data, determine hypoxic desaturation information from the oxygen saturation data based on the at least one arterial tone event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

2. The sleep test system of claim 1 , wherein the patient sleep device comprises a digit housing comprising an external device housing surface, an internal device housing surface, and a proximal end adapted for facilitating insertion of a digit of the patient into the digit housing, and wherein the arterial tone sensor and the oxygen saturation sensor are disposed in the housing and configured to be positioned proximate to the digit of the patient.

3. The sleep test system of claim 2, wherein the digit of the patient comprises at least one of an index finger, middle finger, ring finger, pinky finger, or toes of the patient.

4. The sleep test system of claim 2, wherein the digit housing comprises a pressure device configured to apply a uniform or substantially uniform sub-diastolic pressure field to the digit of the patient.

5. The sleep test system of claim 2, wherein the digit housing is configured to apply the uniform or substantially uniform sub-diastolic pressure field to at least a volar surface, a dorsal surface, and a distal tip of the digit of the patient.

6. The sleep test system of claim 4, wherein the pressure device comprises at least one membrane configured to apply pressure to the digit due to elastic deformation of the at least one membrane by the digit.

7. The sleep test system of claim 4, wherein the pressure device is configured to apply the uniform or substantially uniform pressure of from about 40 mmHg to about 80 mmHg to surfaces of the digit.

8. The sleep test system of claim 1, wherein the patient sleep device further comprises: a first clip member comprising a first surface configured to receive a first portion of a digit of the patient; and a second clip member coupled to the first clip member and comprising a second surface configured to receive a second portion of the digit, wherein the first clip member and the second clip member define a digit space with the arterial tone sensor and the oxygen saturation sensor disposed within the digit space.

9. The sleep test system of claim 8, wherein the first clip member and the second clip member are configured to receive the digit of the patient in the digit space, and wherein one of the first clip member or the second clip member is movable toward the other of the first clip member or the second clip member to generate pressure within the digit space.

10. The sleep test system of claim 9, wherein the patient sleep device further comprises a uniform pressure applicator configured to uniformly or substantially uniformly distribute the pressure generated within the digit space to a dorsal portion of the digit and a volar portion of the digit.

11. The sleep test system of claim 1, wherein the patient sleep device is configured to be worn on the patient at a location where arterial tone is detectable.

12. The sleep test system of claim 1, wherein the patient sleep device is configured to be mounted to at least one of a toe, an ear, forehead, an arm, a torso, abdomen, or a leg of the patient.

13. The sleep test system of claim 1, wherein the patient sleep device is configured to be coupled to the patient during at least one of a home and / or remote sleep apnea test, a home and / or remote sleep disordered breathing test, and / or for sleep stage identification.

14. The sleep test system of claim 1, further comprising a wrist-worn monitor in wired or wireless communication with the patient sleep device comprising processing circuitry for receiving and processing signals provided by the arterial tone sensor or the oxygen saturation sensor.

15. The sleep test system of claim 1, wherein the arterial tone sensor is configured to detect signals representative of an arterial tone waveform of the patient and the oxygen saturation sensor is configured to detect signals representative of a saturation waveform that is correlated in time with the arterial tone waveform.

16. The sleep test system of claim 1 , wherein the arterial tone sensor comprises at least one emitter configured to emit light towards the patient and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the patient.

17. The sleep test system of claim 16, wherein the at least one emitter of the arterial tone sensor is configured to emit light within a wavelength of about 200 nm to about 600 nm.

18. The sleep test system of claim 16, wherein the arterial tone sensor is a transmissive sensor, in which light from the at least one emitter passes through the patient and is detected by the at least one detector.

19. The sleep test system of claim 16, wherein the arterial tone sensor is a reflective-type sensor, in which light from the at least one emitter reflects from the patient and is detected by the at least one photodetector.

20. The sleep test system of claim 1, wherein the oxygen saturation sensor comprises at least one emitter configured to emit light towards a digit and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the digit.

21. The sleep test system of claim 20, wherein the oxygen saturation sensor comprises a first emitter configured to emit light at a first wavelength configured to be absorbed by oxygenated hemoglobin of the patient and a second wavelength configured to be absorbed by deoxygenated hemoglobin of the patient.

22. The sleep test system of claim 1 , further comprising an attachment device comprising a fastening portion connected to an external surface of the patient sleep device and a securement portion configured to be worn on a wrist, forearm, and / or arm of the patient for releasably coupling the attachment device to the patient.

23. The sleep test system of claim 1, wherein to determine the hypoxic desaturation information, the at least one controller is configured to identify portions of the oxygen saturation data that correspond in time with the detected at least one arterial tone event.

24. The sleep test system of claim 1 , wherein the determination of the hypoxic desaturation information is based on a baseline saturation level for the patient and the at least one arterial tone event.

25. The sleep test system of claim 24, wherein the baseline saturation level is a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

26. The sleep test system of claim 25, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

27. The sleep test system of claim 24, wherein the baseline saturation level is at least one of 20%, 15%, 10%, 5%, or 1% of a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

28. The sleep test system of claim 24, wherein the baseline saturation level is an average of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one arterial tone event.

29. The sleep test system of claim 1, wherein to determine the hypoxic desaturation information, the at least one controller is configured to: identify a first fiducial point in the oxygen saturation data based on a baseline saturation level for the patient and the at least one arterial tone event, identify a second fiducial point in the oxygen saturation data, and determine the hypoxic desaturation information based on an area under curve between the first fiducial point and the second fiducial point.

30. The sleep test system of claim 29, wherein the at least one controller is configured to identify the second fiducial point in the oxygen saturation data as being subsequent to the at least one arterial tone event and substantially equal in value to the baseline saturation level.

31. The sleep test system of claim 29, wherein the at least one controller is configured to identify the second fiducial point in the oxygen saturation data as being subsequent to a desaturation start time and having a value within a predetermined percentage of the baseline saturation level.

32. The sleep test system of claim 29, wherein the at least one controller is configured to determine the second fiducial point in the oxygen saturation data as being subsequent to the at least one arterial tone event and a maximum value of the oxygen saturation data within a predetermined post-event duration.

33. The sleep test system of claim 1, wherein the arterial tone event comprises an arterial tone change that is representative of sympathetic activity of the patient.

34. The sleep test system of claim 1, wherein the at least one controller is configured to detect the at least one arterial tone event based on a change in amplitude of an arterial tone signal of the arterial tone data.

35. The sleep test system of claim 34, wherein the arterial tone event detected by the at least one controller comprises attenuation of the arterial tone signal.

36. The sleep test system of claim 34, wherein the attenuation of the arterial tone signal comprises a decrease in an amplitude range in the arterial tone signal relative to a predetermined baseline value for arterial tone signal range.

37. The sleep test system of claim 1, wherein the at least one controller is configured to determine a pulse rate for the patient based on at least one of the arterial tone data or the oxygen saturation data.

38. The sleep test system of claim 1, further comprising a heart rate sensor configured to determine a heart rate for the patient, andwherein the at least one controller is configured to determine the hypoxic desaturation information based on the at least one arterial tone event and on identified changes in the determined heart rate of the patient.

39. The sleep test system of claim 1, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient.

40. The sleep test system of claim 1, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient and an actual sleep duration for the patient.

41. The sleep test system of claim 1, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values and a nominal sleep duration for the patient.

42. The sleep test system of claim 41, further comprising a user interface element, and wherein the nominal sleep duration for the patient is input via the user interface element.

43. The sleep test system of claim 1, further comprising at least one movement or motion sensor to generate movement information for the patient, and wherein the at least one controller is configured to determine the hypoxic burden desaturation information based on the at least one arterial tone event and the movement information.

44. The sleep test system of claim 1, further comprising at least one snoring sensor for generating snoring information for the patient, and wherein the at least one controller is configured to determine the hypoxic burden desaturation information based on the at least one arterial tone event and the snoring information.

45. A computer-implemented method for measuring hypoxic severity in a patient during sleep, the method comprising: detecting, with at least one computer processor, at least one arterial tone event in arterial tone data generated by at least one arterial tone sensor configured for monitoring arterial tone events in the patient; determining, with the at least one computer processor, hypoxic desaturation information from oxygen saturation data based on the detected at least one arterial tone event; and determining, with the at least one computer processor, at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

46. The computer-implemented method of claim 45, wherein the arterial tone data is representative of an arterial tone waveform of the patient and the oxygen saturation data is representative of a saturation waveform that is correlated in time with the arterial tone waveform.

47. The computer-implemented method of claim 45, wherein determining the hypoxic desaturation information comprises, with the at least one computer processor, identifying portions of the oxygen saturation data that correspond in time with the detected at least one arterial tone event.

48. The computer-implemented method of claim 45, wherein the determination of the hypoxic desaturation information is based on a baseline saturation level for the patient and the at least one arterial tone event.

49. The computer-implemented method of claim 48, wherein the baseline saturation level is a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

50. The computer-implemented method of claim 49, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

51. The computer-implemented method of claim 48, wherein the baseline saturation level is at least one of 20%, 15%, 10%, 5%, or 1% of a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one arterial tone event.

52. The computer-implemented method of claim 48, wherein the baseline saturation level is an average of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one arterial tone event.

53. The computer-implemented method of claim 45, wherein determining the hypoxic desaturation information comprises: identifying a first fiducial point in the oxygen saturation data based on a baseline saturation level for the patient and the at least one arterial tone event, identifying a second fiducial point in the oxygen saturation data, and determining the hypoxic desaturation information based on an area under curve between the first fiducial point and the second fiducial point.

54. The computer-implemented method of claim 53, wherein the second fiducial point in the oxygen saturation data is identified as being subsequent to the at least one arterial tone event and substantially equal in value to the baseline saturation level.

55. The computer-implemented method of claim 54, wherein the second fiducial point in the oxygen saturation data is identified as being subsequent to a desaturation start time and having a value within a predetermined percentage of the baseline saturation level.

56. The computer-implemented method of claim 54, wherein the second fiducial point in the oxygen saturation data is identified as being subsequent to the at least one arterial tone event and a maximum value of the oxygen saturation data within a predetermined post-event duration.

57. The computer-implemented method of claim 45, wherein the at least one arterial tone event comprises an arterial tone change that is representative of sympathetic activity of the patient.

58. The computer-implemented method of claim 45, wherein the detecting the at least one arterial tone event is based on a change in amplitude of an arterial tone signal of the arterial tone data.

59. The computer-implemented method of claim 58, wherein the detected at least one arterial tone event comprises attenuation of the arterial tone signal.

60. The computer-implemented method of claim 59, wherein the attenuation of the arterial tone signal comprises a decrease in an amplitude range in the arterial tone signal relative to a predetermined baseline value for arterial tone signal range.

61. The computer-implemented method of claim 45, further comprising determining a pulse rate for the patient based on at least one of the arterial tone data or the oxygen saturation data, and wherein the hypoxic desaturation information is based on the pulse rate.

62. The computer-implemented method of claim 45, further comprising, with the at least one processor, determining an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient.

63. The computer-implemented method of claim 45, further comprising determining an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient and an actual sleep duration for the patient.

64. The computer-implemented method of claim 45, further comprising determining an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values and a nominal sleep duration for the patient.

65. The computer-implemented method of claim 45, further comprising receiving movement information for the patient, wherein the determination the hypoxic burden desaturation information for the patient is based on the at least one arterial tone event and the movement information.

66. The computer-implemented method of claim 45, further comprising determining snoring information for the patient, wherein the determination of the hypoxic burden desaturation information is based on the at least one arterial tone event and the snoring information.

67. A patient sleep device for measuring hypoxic severity in a patient during sleep, comprising: a device housing comprising a proximal end adapted for facilitating insertion of a digit of the patient into the device housing; an arterial tone sensor disposed in an interior of the device housing configured to generate arterial tone data associated with the patient for monitoring arterial tone changes in the patient; an oxygen saturation sensor disposed in the interior of the device housing configured to generate oxygen saturation data associated with the patient; and a controller disposed in the interior of the device housing or mounted to an exterior surface of the device housing and in communication with the arterial tone sensor and the oxygen saturation sensor, wherein the controller is configured to: identify at least one arterial tone event in the arterial tone data, determine hypoxic desaturation information from the oxygen saturation data based on the at least one arterial tone event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

68. The patient sleep device of claim 67, wherein the digit of the patient comprises at least one of an index finger, middle finger, ring finger, pinky finger, or toes of the patient.

69. The patient sleep device of claim 67, wherein the device housing comprises a pressure device configured to apply a uniform or substantially uniform sub-diastolic pressure field to the digit of the patient.

70. The patient sleep device of claim 67, wherein the device housing is configured to apply the uniform or substantially uniform sub-diastolic pressure field to at least a volar surface, a dorsal surface, and a distal tip of the digit of the patient.

71. The patient sleep device of claim 70, wherein the pressure device comprises at least one membrane configured to apply pressure to the digit due to elastic deformation of the at least one membrane by the digit.

72. The patient sleep device of claim 70, wherein the pressure device is configured to apply the uniform or substantially uniform pressure of from about 40 mmHg to about 80 mmHg to surfaces of the digit.

73. The patient sleep device of claim 67, wherein the device housing comprises: a first clip member comprising a first surface configured to receive a first portion of a digit of the patient; and a second clip member coupled to the first clip member and comprising a second surface configured to receive a second portion of the digit, wherein the first clip member and the second clip member define a digit space with the arterial tone sensor and the oxygen saturation sensor disposed within the digit space.

74. The patient sleep device of claim 73, wherein the first clip member and the second clip member are configured to receive the digit of the patient in the digit space, and wherein one of the first clip member or the second clip member is movable toward the other of the first clip member or the second clip member to generate pressure within the digit space.

75. The patient sleep device of claim 74, further comprises a uniform pressure applicator configured to uniformly or substantially uniformly distribute the pressure generated within the digit space to a dorsal portion of the digit and a volar portion of the digit.

76. The patient sleep device of claim 67, wherein the patient sleep device is configured to be worn on the patient at a location where arterial tone is detectable.

77. The patient sleep device of claim 67, wherein the patient sleep device is configured to be mounted to at least one of a toe, an ear, forehead, an arm, a torso, abdomen, or a leg of the patient.

78. The patient sleep device of claim 67, wherein the patient sleep device is configured to be coupled to the patient during at least one of a home and / or remote sleep apnea test, a home and / or remote sleep disordered breathing test, and / or for sleep stage identification.

79. The patient sleep device of claim 67, wherein the arterial tone sensor is configured to detect signals representative of an arterial tone waveform of the patient and the oxygen saturation sensor is configured to detect signals representative of a saturation waveform that is correlated in time with the arterial tone waveform.

80. The patient sleep device of claim 67, wherein the arterial tone sensor comprises at least one emitter configured to emit light towards the patient and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the patient.

81. The patient sleep device of claim 80, wherein the at least one emitter of the arterial tone sensor is configured to emit light within a wavelength of about 200 nm to about 600 nm.

82. The patient sleep device of claim 80, wherein the arterial tone sensor is a transmissive sensor, in which light from the at least one emitter passes through the patient and is detected by the at least one detector.

83. The patient sleep device of claim 80, wherein the arterial tone sensor is a reflective-type sensor, in which light from the at least one emitter reflects from the patient and is detected by the at least one photodetector.

84. The patient sleep device of claim 67, wherein the oxygen saturation sensor comprises at least one emitter configured to emit light towards the digit and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the digit.

85. The patient sleep device of claim 84, wherein the oxygen saturation sensor comprises a first emitter configured to emit light at a first wavelength configured to be absorbed by oxygenated hemoglobin of the patient and a second wavelength configured to be absorbed by deoxygenated hemoglobin of the patient.

86. The patient sleep device of claim 67, further comprising an attachment device comprising a fastening portion connected to an external surface of the patient sleep device and a securement portion configured to be worn on a wrist, forearm, and / or arm of the patient for releasably coupling the attachment device to the patient.

87. A sleep test system for measuring hypoxic severity in a patient during sleep, comprising: at least one sensor configured to be coupled to the patient during sleep and to detect signals representative of oxygen saturation of the patient and a pulse rate or heart rate of the patient; and at least one controller configured to communicate with the at least one sensor, the at least one controller configured toreceive and process the signals from the at least one sensor to determine oxygen saturation data and pulse rate or heart rate data for the patient; detect at least one desaturation event in the oxygen saturation data; detect at least one pulse or heart rate event in the pulse rate or heart rate data; determine hypoxic desaturation information from the oxygen saturation data for the at least one desaturation event when there is a corresponding at least one pulse rate or heart rate event, and determine at least one hypoxic deficiency value for the patient based on the hypoxic desaturation information.

88. The sleep test system of claim 87, wherein the at least one sensor comprises an oxygen saturation sensor.

89. The sleep test system of claim 88, wherein the oxygen saturation sensor comprises at least one emitter configured to emit light towards a digit and at least one detector configured to detect light from the at least one emitter transmitted through or reflected from the digit.

90. The sleep test system of claim 88, wherein the oxygen saturation sensor comprises a first emitter configured to emit light at a first wavelength configured to be absorbed by oxygenated hemoglobin of the patient and a second wavelength configured to be absorbed by deoxygenated hemoglobin of the patient.

91. The sleep test system of claim 88, wherein the at least one controller is configured to determine the pulse rate data based on the signals detected by the oxygen saturation sensor.

92. The sleep test system of claim 87, wherein the at least one sensor comprises an oxygen saturation sensor and a heart rate sensor, and wherein the at least one controller isconfigured to determine the oxygen saturation data based on signals detected by the oxygen saturation sensor and determine the heart rate data based on signals detected by the heart rate sensor.

93. The sleep test system of claim 92, wherein the heart rate sensor comprises at least one of an electrocardiogram (ECG) electrode, ECG sensor, or ECG monitoring device.

94. The sleep test system of claim 87, wherein to determine the hypoxic desaturation information, the at least one controller is configured to identify portions of the oxygen saturation data that correspond in time with the at least one pulse rate or heart rate event.

95. The sleep test system of claim 87, wherein the determination of the hypoxic desaturation information is based on a baseline saturation level for the patient and the at least one pulse rate or heart rate event.

96. The sleep test system of claim 95, wherein the baseline saturation level is a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one pulse rate or heart rate event.

97. The sleep test system of claim 96, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

98. The sleep test system of claim 95, wherein the baseline saturation level is at least one of 20%, 15%, 10%, 5%, or 1% of a maximum saturation value in the oxygen saturation data detected within a predetermined period of time preceding or following the at least one pulse rate or heart rate event.

99. The sleep test system of claim 95, wherein the baseline saturation level is an average of saturation values of the oxygen saturation data for a predetermined period of time preceding the at least one pulse rate or heart rate event.

100. The sleep test system of claim 87, wherein the at least one pulse rate or heart rate event comprises a change in pulse rate or heart rate compared to a baseline pulse or heart rate value of the patient.

101. The sleep test system of claim 100, wherein the baseline pulse or heart rate value is a maximum or average value in the pulse rate or heart rate data detected within a predetermined period of time preceding the at least one pulse rate or heart rate event.

102. The sleep test system of claim 101, wherein the predetermined period of time comprises 1000 seconds, 500 seconds, 100 seconds, 10 seconds, 1 second, 0.1 second, 1000 cardiac cycles, 500 cardiac cycles, 100 cardiac cycles, 10 cardiac cycles, or 1 cardiac cycle.

103. The sleep test system of claim 100, wherein the at least one pulse rate or heart rate event comprises an increase in pulse rate or heart rate compared to a baseline pulse or heart rate value.

104. The sleep test system of claim 87, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient.

105. The sleep test system of claim 87, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values determined for the patient and an actual sleep duration for the patient.

106. The sleep test system of claim 87, wherein the at least one controller is configured to determine an overall hypoxic burden for the patient based on a plurality of the at least one hypoxic deficiency values and a nominal sleep duration for the patient.

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