Apparatus for detecting and treating apnea

Abstract

An apparatus detects a sign of apnea or hypopnea and treats it. The apparatus includes a respiration detection unit configured to detect a signal related to a respiratory movement of a subject. The apparatus includes a sleep detection unit configured to detect a signal related to a sleeping status of the subject. The apparatus includes a control unit. The control unit is configured to receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject. The control unit or the apparatus determines, based on the amplitude of the respiratory movement and the sleep-wake state, determines whether the subject is in a state of hypopnea or apnea.

Description

APPARATUS FOR DETECTING AND TREATING APNEAField

[0001] The present disclosure relates to apparatuses and methods for detecting and treating apnea or hypopnea.Background

[0002] Sleep apnea syndrome (SAS) is a sleep disorder in which breathing is repeatedly interrupted during sleep (NPL 1), and the respiratory amplitude decreases during sleep. Sleep apnea causes not only sleeplessness but also the increased incidence of various diseases and symptoms, e.g. high blood pressure, heart attack, cardiac arrhythmia, stroke and depression.

[0003] Continuous positive airway pressure (CPAP) is the most common treatment for obstructive sleep apnea (NPL 2). However, patients with SAS feel frustrated because of several problems of CPAP (NPL 3). Therefore, most works have been focused on treatments of SAS (PL1, PL 2, PL 3, NPL 4). However, these treatments require behavior changes or invasive procedures.

[0004] Another method is to detect snoring sounds using a microphone and apply stimulation to the subject when a snore occurs (PL 3). However, this method is not suitable to detect sleep apnea, because sleep apnea usually does not occur when the subject snores. During snoring, the airway is narrowed, but the patient is still breathing. Therefore the patient is not in the state of apnea or hypopnea. In addition, breathing sounds during an apnea state are usually similar to normal breathing sounds. Thus these are difficult to distinguish from each other.

[0005] Actigraphy and electrocardiography are useful to perform sleep stage classification or sleep-wake classification (NPL 5, NPL 6). However, these methods must be carried out by bringing a device in contact with the patients during the measurements.

[0006] Citation List

[0007] Patent Literature PL 1: T.R. Shantha, “Device for snoring and obstructive sleep apnea treatment,” US9072613B2. PL 2: F. Li, Z. Li, “Method and device for intelligently stopping snoring,” WO2015027744A1. PL 3: H. Taki, et. al., “Sleep apnea treatment apparatus and method,” WO2020 / 109863A2.

[0008] Non-Patent Literature NPL 1: https: / / www.sleepfoundation.org / sleep-apnea NPL 2: https: / / www.sleepfoundation.org / excessive-sleepiness-osa / treatments / cpap-treatment NPL 3: https: / / www.mayoclinic.org / diseases-conditions / sleep-apnea / in-depth / cpap / art-20044164 NPL 4: http: / / www.sleepreviewmag.com / 2014 / 09 / alternative-therapies-obstructive-sleep-apnea / NPL 5: Timothy Morgenthaler, et al., Practice parameters for the use of actigraphy in the assessment of sleep and sleep disorders: an update for 2007, Sleep. 2007 Apr; 30(4). NPL 6: Mustafa Radha, et al., Sleep stage classification from heart-rate variability using long short-term memory neural networks, Sci Rep. 2019 Oct 2; 9(1).Summary

[0009] The inventors found that patients can stop respirations even while awake, and that millimeter radar detection systems alone can detect such events as respiration abnormality during sleep. An object of the present disclosure is to provide apparatuses and methods to detect the respiratory movement as well as the sleep state with little frustration for the patients, and thereby to detect apnea / hypopnea in real time and to determine a right timing of applying stimulations to the subject, only when the subject is sleeping.

[0010] One general aspect includes an apparatus for treating patients having SAS. Another aspect includes an apparatus for detecting an apneic or hypopneic state. Further another aspect includes an apparatus for treating SAS. In some embodiments, the apparatus includes: a respiration detection unit configured to detect a signal related to a respiratory movement of a subject; a sleep detection unit configured to detect a signal related to a sleeping status of the subject; and a control unit. In some embodiments, the control unit is configured to receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement, and receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject. In some embodiments, the control unit or the apparatus, based on the amplitude of the respiratory movement and the sleep-wake state, determines whether there is a sign of hypopnea or apnea or whether the subject is in a state of hypopnea or apnea.

[0011] In some embodiments, the apparatus includes: a radar unit configured to transmit an electromagnetic waves to a subject; and to detect the electromagnetic wave reflected by the subject; and from the detected electromagnetic wave, to generate a radar signal including a phase signal. In some embodiments, a controller is configured to instruct the radar unit to transmit the electromagnetic waves to the subject and to receive an output signal from the radar unit including the phase signal and based on the output signal including the phase signal, to determine a sleep-wake state of the subject and determine whether the subject is in a state of apnea or hypopnea.

[0012] The terms “system”, “unit”, “part”, “member”, and “means” used herein generally refer to a single hardware and / or software component or a group of multiple single hardware and / or software components, and are interchangeably used.

[0013] The term “sleep-wake classification” used herein generally refers to an act or a step of classifying the status of the subject to either “sleeping” or “awake, to determine the sleep-wake state of the subject.

[0014] The term “sleep stage classification” used herein generally refers to an act or a step of classifying the status of the subject to either one of “wake”, “REM”, “N1”, “N2”and “N3” according to the definition by the American Academy of Sleep Medicine (AASM) or either one of “wake”, “REM”, “S1”, “S2”, “S3”, and “S4” according to the definition by Rechtschaffen & Kales (R&K). Another classification may be used.

[0015] Respiratory Detection Unit In some embodiments, the apparatus may include a unit configured to detect signals related to respiratory movements of the subjects. In some embodiments, the unit for respiratory detection, or the respiratory detection unit, may be a radar unit. The details of the radar unit will be explained below.

[0016] The respiratory detection unit may be disposed inside the body of the apparatus, integrated in the apparatus, or attached or fixed to the apparatus. In some embodiments, the respiratory detection unit may be disposed as a unit separate from the apparatus and be configured to be connected to the apparatus. The connection may be wired or wireless. The respiratory detection unit may be connected to the control unit for communication. The communication may be at least data transmission from the respiratory detection unit to the apparatus.

[0017] In some embodiments, the respiratory detection unit may detect signals related to movements of the chest or thorax of the subject. In some embodiments, the respiratory detection unit may detect signals related to movements of the belly or abdomen of the subject. Any one or more of other body parts which move in relation to the respiration may be measured.

[0018] As a sign or a symptom of apnea or hypopnea, the amplitude of the respiratory movement of a body part decreases from, or becomes smaller than, the amplitude of healthy respiratory movements. In some embodiments, if the amplitude is smaller than that of a healthy state, it may be determined to be a sign of apnea or hypopnea. In some embodiments, the amplitude of the healthy state may be measured for the same subject. In some embodiments, the amplitude of the healthy state may be measured for another person, or may be a statistically obtained value.

[0019] In some embodiments, if the amplitude is smaller than a predetermined value, it may be determined to be a sign of apnea or hypopnea. The predetermined value may be 80%, 70%, 60%, 50%, 40%, 30% or the like of the amplitude of a healthy state or non-apnea state. For example, if the amplitude becomes smaller than 70 % of the non-apnea state or if the amplitude decreases by more than 30% of the non-apnea state, it may be determined to be a sign of apnea or hypopnea.

[0020] Radar Unit In some embodiments, the respiratory detection unit may be a radar system or unit. In some embodiments, the sleep detection unit may be a radar system or unit. In some embodiments, the respiration detection unit is a first radar unit, and the sleep detection unit is a second radar unit. In some embodiments, both the respiration detection unit and the sleep detection unit are provided as one single radar unit. Such a single radar unit can serve, or is configured, both to detect the respiration state of the subject and to detect the sleeping state of the subject. Thereby, for example, the entire apparatus may be designed small and compact.

[0021] The radar unit is configured to transmit electromagnetic waves such as microwaves, laser light, millimeter waves, and infrared waves. The typical ranges of the frequencies are from 300 MHz to 30 GHz for microwave, 30 GHz to 300 GHz for millimeter wave, and 57 GHz to 71 GHz (according to IEEE 802.11ad / WiGig). The radar unit may be a microwave radar unit. The radar unit may be a millimeter-wave radar unit. The radar unit may be an ultra-wideband millimeter-wave radar unit.

[0022] A millimeter-wave radar unit may be used to obtain vital information such as information related to respirations and heartbeats. In general, the chest moves about some millimeters with normal respirations, and about some tens of micron meters with heartbeats. Movements of those amplitudes can be detected as time-change in the phase of the radar signal.

[0023] The radar unit may include, or may be connected to, one or more transmitting antennas and one or more receiving antennas. The transmitting antenna is configured to transmit one or more microwaves or millimeter waves. The transmitting antenna is configured to adjust its transmitting direction towards a subject, or to transmit the microwaves or millimeter waves to the subject. The receiving antenna is configured to receive microwaves or millimeter waves reflected from the subject.

[0024] The radar unit may have multiple transmitting antennas and multiple receiving antennas. According to MIMO (Multiple-input-multiple-output) method, n channels of transmitting antennas and m channels of receiving antennas constitutes n × m channels of virtual array antennas, which allows the received waves of the virtual array antennas to be sampled at a high rate and multiple I-Q (in-phase)-Q(quadrature) data to be generated, for each transmission unit (for example, a chirp set). Multiple chirp sets are continuously transmitted in series. Thus the obtained IQ data forms a radar cube of the direction of the sampling direction which corresponds to the distance, the virtual array antennas which correspond to the direction, and the number of chirp sets which corresponds to the time. By Fast Fourier transformation (FFT) of the distance and the direction the IQ data of the target can be specified.

[0025] By following the change of the specified IQ data in the time direction or each time frame, the phase change can be observed if the target body part is moving. Movements of a body part related to respirations and heartbeats have periodicities, which appears as a circle on a complex plane called an I-Q plot. The trajectory of the I-Q plot can be demodulated by using, for example the arctangent demodulation (ATD), and a phase unwrapping, and the movements of the subject’s skin can be obtained. By applying a filtering process, the components of respirations and those of heartbeats can be separated. Thus, instantaneous respiration frequency and heart rate can be calculated. Furthermore, by a frequency analysis, each average value can be obtained.

[0026] In the above explanation, the MIMO method is used as an example only. Other methods may be employed.

[0027] The microwaves or millimeter waves may be modulated to be transmitted. An example of such a modulation is a pulse modulation. The modulation may be done by using a pulse compression technique. Examples of such a pulse compression technique include, but are not limited to, m-sequence, Hadamard sequence and the like. Multiple pulses may be transmitted and received to detect the target. Phase shifts can be detected from the received signals of multiple pulses, which enables obtaining other information such as the Doppler frequency and velocity.

[0028] In some embodiments, phase signals may be calculated from the radar signals. The phase signals may be used to determine the sleep-wake state of the subject. The phase signals may be used to calculate the amplitude of respiratory movements (also referred to as the respiratory amplitude) of the subject.

[0029] It may be determined that abnormality of respiration is occurring: if the respiratory amplitude is lower than a threshold or has decreased by an amount greater than a threshold or by a rate or ratio greater than a threshold, if the respiratory amplitude is lower than that when the subject is snoring by an amount greater than a threshold or by a rate or ratio greater than a threshold, or if the respiratory amplitude is lower than that observed a certain period of time ago by an amount greater than a threshold or by a rate or ratio greater than a threshold. A flag that a respiratory abnormality is occurring (also referred to as “respiratory abnormality flag”) may be turned on if it has been determined that abnormality of respiration is occurring, and be turned off if the respiratory amplitude is back to the normal value or if it does not fulfill the condition.

[0030] The radar unit may be a Doppler radar unit. Alternatively, the control unit is configured to calculate Doppler effects based on the radar signals from the radar unit. The frequency of the radar signal shifts in accordance with the velocity of the target.

[0031] The frequency shift is expressed by using the time differential of the phase. The Doppler velocity, which corresponds to the velocity of the target in the line-of-straight direction, is expressed by the Doppler frequency, can be determined. By using a multi-static radar, the velocity vector of the target itself can be determined.

[0032] If the Doppler velocity changes in time, the time-frequency analysis is performed to separate frequency components. As an exemplary algorithm of the time-frequency analysis is short-time Fourier transform (STFT). STFT is a function of time and frequency and thus gives a spectrogram which shows the time-frequency distribution of the radar signals. Using such a spectrogram the changes in the Doppler velocity can be analyzed, and micro-Doppler, or for example movements of each body part can be detected.

[0033] The Doppler velocity reflects a body movement of the subject such as movements of arms, legs, and a body rolling. Human body is a complex structure including multiple parts such as the torso, the limbs, and the head that are connected. These parts exhibit complex movements.

[0034] For example, an ultra-wide radar can be used to analyze the dimensions of space, time and distance. For example, movements of body parts can be recognized by using a time-frequency analysis. For example, movements of body parts can be recognized by applying a convolutional neural network (CNN) to an I-Q plot of the received radar signals. Such a model using CNN can differentiate multiple gestures or movements of different body parts.

[0035] Thus, the Doppler shifts due to movements of those parts are useful to analyze vital information. Such methods enable analyzing the movements of each body part at a high accuracy. If such a body movement is detected, it may be determined that the subject is not sleeping. Thus, the Doppler velocity is useful for the sleep stage classification or the sleep-wake classification.

[0036] In some embodiments, the phase signals may be used to obtain the heartbeat intervals. Electrocardiogram has been used to acquire the variation of heartbeat intervals or the heart rate variability. But according to some embodiments of the present disclosure, the phase signals of the Doppler signals from the subject can also be used for the sleep stage classification or the sleep-wake classification.

[0037] In some embodiments, the radar unit may continuously, or intermittently continue to, transmit electromagnetic waves and receive reflected electromagnetic waves. In some embodiments, the radar unit may continuously, or intermittently continue to, generate and output radar signals. The radar unit may not always have to output signals continuously. The radar unit may also conduct a buffering, an event-driven output, a queuing, or the like. The control unit may receive or sample the signals outputted from the radar signals, to store and / or process the same. Such output signals from the radar unit may be time-series data.

[0038] In this specification or the appended claims, the radar unit is described to process some calculations. The radar unit may include a processing unit to conduct some processing or calculations. But the same processing may be conducted by the controller. In other words, the processes or calculations described to be processed by a unit should not be construed in a limiting manner. Such processes or calculations may be conducted by another unit than the specifically described unit. For example, the processor of the controller unit may execute the program codes for the other units. For example, multiple processors arranged in multiple units may cooperate to execute the program codes for the multiple units.

[0039] Sleep Detection Unit In some embodiments, the apparatus may include a unit configured to detect signals related to the sleeping status of the subjects. In some embodiments, the unit for sleep detection, or the sleep detection unit, may be a radar unit. In some embodiments, the sleep detection unit may be a sound detection unit. The details of the sound detection unit will be explained below.

[0040] The sleep detection unit may be disposed inside the body of the apparatus, integrated in the apparatus, or attached or fixed to the apparatus. In some embodiments, the sleep detection unit may be disposed as a unit separate from the apparatus and be configured to be connected to the apparatus. The connection may be wired or wireless. The sleep detection unit may be connected to the control unit for communication. The communication may be at least data transmission from the sleep detection unit to the apparatus.

[0041] In some embodiments, the sleep detection unit may detect signals related to sleeping statuses of the subject. In some embodiments, the sleep detection unit may detect signals related to movements of parts of the body. In general, large movements occur while awake. Thus, movements peculiar to sleep may be detected by judging the amplitude, the speed, the pattern and the like of movements. Examples of the parts that show typical movements of sleep include, but are not limited to, arms, legs, or the entire body. Examples of the movements include, but are not limited to, raising an arm, raising a knee, and rolling the body. For example, if the subject is turning over in bed, it may be determined that the subject is awake.

[0042] In some embodiments, the determination of a sleep-awake status of the subject may be made based on the frequency at which the speed of the body exceeds a predetermined threshold. The frequency refers to the number of such occurrences within a specified period of time. For instance, the speed of the body may be measured at intervals of 0.2 seconds over a duration of approximately 5 minutes. If the frequency at which the speed of the body exceeds a certain value, the subject may be determined to be awake. Conversely, if the frequency is below the certain value, the subject may be determined to be asleep.

[0043] Such body movements may be detected by a radar unit. In general, such movements are fast enough, and therefore may be detected by using a Doppler velocity. Doppler velocity methods can detect movements which are faster than respiratory movements.

[0044] In some embodiments, the sleep detection unit may detect snores, breathing or respiratory sounds such as the sounds caused by air passing through the respiratory sounds or airflow sounds in the respiratory tract.

[0045] In some embodiments, the sleep detection unit may include another device such as a wearable device, an actigraphic device, a pulse wave device, and the like. The control unit may have an actigraphy function or an actigraphy program which process information related to body movements received from devices and units connected to the control unit.

[0046] Radar Unit as Sleep Detection Unit In some embodiments, the radar unit may be used as the sleep detection unit. In general, body movements during sleep are greater than when awake. For example, the Doppler velocity measured by the radar unit is smaller during sleep than while awake. For example, low-frequency heart rate variability is dominant while awake. Fluctuation of respiratory rate and sudden increase in heart rate occur during REM sleep. Thus, millimeter-waves may be applied to a body part of the subject, and reflected waves may be detected. From the reflected waves, body movements of the subjects may be identified.

[0047] For example, the Doppler velocity may be calculated at regular time intervals. For example, data may be collected over 30-second periods in seven sets (typically 300 points × 7 sets), and the number of points exceeding a threshold may be determined for each set. A weight is then applied to these results, and their total is compared to a predefined threshold. If the total exceeds the threshold, the subject is determined to be awake.

[0048] A flag that the subject is sleeping (sleeping flag) may be turned on if the body movements are smaller than a threshold, and be turned off if the body movements become great again. Such a flag or a condition may be used to determine the timing of an application of stimulation.

[0049] The criterion of a flag may be set in accordance with the sleep stage. The sleep stage may be determined in accordance with the body movements by using millimeter waves. In some embodiments, the sleeping flag may be turned on if the sleeping stage is 3 or 4 and be turned off if the sleeping stage is 1 or 2. SAS is not likely to occur during sleeping stages 3 and 4 or during REM (rapid eye movement) sleeping stages. Also dreams during these sleeping stages can affect the respirations. Thus, avoiding sleeping stages 1 and 2 and taking only sleeping stages 3 and 4 can increase the accuracy of the sleeping flag.

[0050] Sound Detection Unit as Sleep Detection Unit In some embodiments, the sleep detection unit may include, or may be a sound detection unit such as a microphone. The sleep detection unit may be positioned away from the subject, or not in contact with the subject, as a non-contact means. It is sufficient for the sleep detection unit to detect snore sounds. The sleep detection unit may be attached to the skin or the cloth of the subject, to detect sounds of air passing through the respiratory tract.

[0051] In general, one snores only during sleeping. Thus, snoring is a sign that the subject is sleeping. The subject can be considered to be still sleeping right after the snore stops. For example, the subject is considered to be sleeping for a certain period of time, for example, 120 seconds, after a snore stops. A flag that the subject is sleeping may be turned on for 120 seconds after a snore stops, and be turned off each time a new snore is detected.

[0052] In some embodiments, a snore may be detected in the sound signals by using characteristics of a sound pressure, frequency components, respiration periods, or a combination of two or three thereof. For example, it may be determined that the subject is snoring if the received sound signals include a sound at certain frequencies, or the received sound signals include a sound pressure higher than a threshold for a certain period of respirations. In some embodiments, a snore may be detected by using a model that has been trained by machine learning of snoring sounds.

[0053] A snore may be detected by performing a frequency analysis. In general, detected sounds include multiple frequency components. The frequency components can vary in time. Such a variation of the frequency components in time may be characterized by performing a short-time FFT having a relatively short time window. The time window may be, for example, shorter than a second. A certain characteristic of the frequency components can repeat with a periodicity. Such a variation of the frequency components in time may be used to identify a snore. The periodicity may be, for example, some seconds, for example, 5 seconds. Then the subject is likely to be snoring.

[0054] Radar signals may be used in addition thereto to identify a snore. If the radar signals and the sound signals include a characteristic of the same periodicity or other characteristics in common, it may be determined that the subject is snoring. For example, the respiration periods may be determined by using the radar unit.

[0055] In some embodiments, both radar signals and sound signals may be used to obtain information or an index related to respiration, such as breathing interruption, hypopnea, and precursor condition of apnea and hypopnea. One of them or multiple of them may be obtained.

[0056] The states of a normal breath and apnea are difficult to distinguish by only using the respiration sounds. In general, the respiratory sounds are relatively large during a snore, but relatively small during a normal breath but also during states of hypopnea, apnea. According to a standard medical definition, a subject is diagnosed as having "apnea" when the subject has an interruption of breathing for 10 seconds or longer. But in reality, airflow does not completely stop and air can still pass when the lungs move. Thus, it has been difficult to distinguish between a normal breathing and apnea or hypopnea by conventional methods.

[0057] Radar can detect movements of the subject’s chest. In general, the chest movements are relatively small during states of hypopnea and apnea but relatively large during a normal breath but also during a snore. Thus only the usage of both radar signals and sound signals enables distinguishing between a normal breathing and apnea or hypopnea.

[0058] Stimulation Unit In some embodiments, the apparatus may include a unit configured to apply stimulations to the subjects. The degree of the stimulation to be applied is adjusted as not to waken the subject or as to cause a micro-arousal for the subject. In some embodiments, the apparatus may not include a stimulation unit or be configured without a stimulation unit.

[0059] In some embodiments, the unit for stimulation application, or the stimulation unit, may cause auditory stimulations, tactile stimulation, vibration stimulations, visual or light stimulations, electric stimulations, heat stimulations and the like. The stimulation unit may be or include a speaker which causes sounds as auditory stimulations.

[0060] The examples of sounds include, but are not limited, to a low frequency sound, ultrasound, audible sound. In some examples, the frequency may be set outside of an audible range. In some examples, the frequency may be set at a low part of the audible range. In some examples, the frequency may be set between 30 Hz and 60 Hz. A non-audible sound may not be heard by others, or non-subject persons, who are present near the subject. A low frequency sound in the audible range may least impact the non-subject persons near the subject.

[0061] In some embodiments, the stimulation sound may be a chirp signal or a sweep signal. The chirp signal may be an up-chirp signal, a down-chirp signal, or a combination of the two. An example of the stimulation sound may be a chirp signal starting at 30 Hz and increasing to 60 Hz.

[0062] The stimulation unit may be or include a fan which generates winds as tactile stimulations. The stimulation unit may be or include a light source which generates lights. The lights to be emitted may be a flashlight, light pulses, or the like. The stimulation unit may be or include an electric stimulator that generate an electric current so as to flow through a part of the subject’s body in contact therewith. The electric current may be a galvanic current, electric pluses, or the like. The stimulation may be a thermal stimulation. A heating element may be attached to a skin or the cloth of the subject and be heated. A heated element may be brought into contact with the subject.

[0063] The stimulation unit may be or include a vibrator, a mechanical oscillator or a mechanical actuator that can generate vibrations. The vibration stimulation unit may be attached to a part of the body of the subject, such as arm, leg, foot, head and the like. The vibration stimulation unit may be wirelessly or wiredly connected to the apparatus, a main body of the apparatus or the control unit.

[0064] In some embodiments, if the sleeping flag is ON and the respiratory abnormality flag is ON, the control unit may send a command to the stimulation unit to apply a stimulation to the subject. The control unit may send a command to apply a stimulation to the subject only after a certain period of time from the point of time when both conditions are fulfilled. This can avoid too frequent applications of stimulation, which can happen if the flag of respiration abnormality is highly sensitive. On the other hand, it should not wait for too long a time, because it could oversee a respiratory arrest. The holding time may preferably be set between one second and 3 seconds.

[0065] A flag that the stimulation has been applied (stimulation flag) may be turned on if one stimulation has been applied, and turned off if a certain period of time, for example 10 seconds or 20 seconds, has passed since the last application of stimulation.

[0066] In some embodiments, if the sleeping flag is ON, the control unit does not send a command to the stimulation unit to apply a stimulation, or the control unit sends a command to the stimulation unit to hold the next stimulation application. In some embodiments, if the sleeping flag is ON, the respiratory abnormality flag is ON, and the stimulation flag is OFF, the control unit may send a command to the stimulation unit to apply a next stimulation to the subject.

[0067] The power of the stimulation unit may not have to remain on all the time, to restrict unnecessary power consumption. But the power of the stimulation unit may not be shut off and turned on each time the stimulation must be applied, even though the timing of the next stimulation has not been determined yet. Therefore, the power of the stimulation unit may be turned on from a waiting state, or the stimulation unit may be set ready for the next stimulation application, once a snore is detected. This can reduce the power consumption, increase the lifetime of the unit, and still allow the operation of the unit to be effective.

[0068] If the stimulations have been repeated for times more than a threshold within a certain period of time, it may be determined that the stimulation application is not effective for the subject or that the stimulation is not applied to the subject. In such a case, a flag that an apparatus is normally working (also referred to as “apparatus abnormality flag”) may be turned on. In some embodiments, while the apparatus abnormality flag is ON, the control unit may send a command to the stimulation unit to apply a next stimulation to the subject.

[0069] Control Unit In some embodiments, the control unit is configured to communicate with, to receive information and signals from, to send information, signals, instructions and orders to, and / or to control, the other units such as the respiration detection unit, the sleep detection unit, and the stimulation application unit.

[0070] The control unit may include a circuitry. The control unit may include a processor or a processing unit. The control unit may include one or more processors or processing units. The processing unit may be a central processing unit (CPU). The processing unit may include an arithmetic logic unit, a microprocessor, a general-purpose controller, a single core or multicore processor, or multiple processors for parallel computations. The processors are operable to execute instructions, software, programs, or program codes stored in a memory or a storage.

[0071] The control unit may include or be connected to a storage. The storage may be a non-transitory storage medium that stores programs and data for providing the functionality described herein. The storage may be, but is not limited to, a dynamic random access memory (DRAM) device, a static random access memory (SRAM), a flash memory, or some other memory devices. In some embodiments, the storage may be a non-volatile memory or a similar permanent storage device or media. Examples of such a storage include, but are not limited to, a hard disk device, a floppy disk device, a CD-ROM device, a DVD-ROM device, a DVD-RAM device, a DVD-RW device, a magnetic-tape data storage device, and some other mass storage device for storing information on a more permanent basis.

[0072] The control unit may include or be connected to a memory. The memory may store instructions and data that may be executed by the processing unit. The instructions and data may include codes for performing the techniques described herein. The processing unit may move the programs and data stored in the storage to the memory, and execute and use them. The memory may be a cash memory. The memory may be, but is not limited to, a dynamic random access memory (DRAM) device, a static random access memory (SRAM), a flash memory, or some other memory devices.

[0073] In some embodiments, the control unit may have a timer or a timer function. The timer may be a hardware timer. The timer may be a software timer.

[0074] In some embodiments, the control unit is configured to receive from the respiration detection unit the detected signal related to the respiratory movement of the subject. It may also determine an amplitude of the respiratory movement of the subject. In some embodiments, the control unit is configured to receive from the sleep detection unit the signal related to the sleeping status of the subject. It may also determine a sleep-wake state of the subject.

[0075] Some embodiments and examples of the present disclosure will now be discussed in detail by referring to the following figures. The embodiments and examples, with reference to the accompanying drawings, are given as examples only, and they should not be interpreted as being limiting. FIG. 1 shows a flowchart of a sleep apnea treatment method according to an embodiment. FIG. 2 shows a flowchart of a sleep apnea treatment method according to an embodiment. FIG. 3 shows a schematic diagram of a sleep apnea treatment apparatus according to an embodiment. FIG. 4 shows a block diagram of a sleep apnea treatment apparatus according to an embodiment. FIG. 5 shows a schematic diagram of a sleep apnea treatment apparatus according to an embodiment. FIG. 6 shows a block diagram of a sleep apnea treatment apparatus according to an embodiment. FIG. 7 shows a block diagram of a sleep apnea treatment apparatus according to an embodiment.

[0076] Embodiment of Process 1 FIG. 1 shows a flowchart S100 of steps of determining the sign of apnea of the subject and treating the subject.

[0077] Signals related to respiratory movements of the subject are detected (S111). Based on the signals related to respiratory movements, the amplitude of the respiratory movement is calculated (S112). If the amplitude is smaller than a threshold (S113), then no action is taken until the result of the sleep state is given. If the amplitude is not smaller or greater than a threshold, the respiratory movement is classified as normal and the process returns to the signal detection (S113, S111).

[0078] Signals related to the sleeping state of the subject are detected (S121). Based on the signals related to the sleeping state, the sleep-wake state of the subject is determined (S122). If the subject is sleeping (S123), then no action is taken until the result of the respiratory movement is given. If the subject is not sleeping or awake, the process returns to the signal detection (S123, S121).

[0079] If the amplitude is smaller than a threshold (S113) and the subject is sleeping (123), or if both of the two conditions are fulfilled, it is determined that the subject is in an apnea state (S140). Then, the stimulation is applied to the subject (S150). After the stimulation is applied, and if either one or both of the two conditions are not fulfilled (S140), the process returns to the signal detection (S111, S121).

[0080] Embodiment of Process 2 FIG. 2 shows a flowchart S200 of steps of determining the sign of apnea of the subject and treating the subject.

[0081] Signals related to respiratory movements of the subject are detected (S211). Based on the signals related to respiratory movements, the amplitude of the respiratory movement is calculated (S212). If the amplitude is smaller than a threshold (S213), then no action is taken until the results of the sleep state and the clock are both given. If the amplitude is not smaller, or is greater, than a threshold, the respiratory movement is classified as normal and the process returns to the signal detection (S213, S211).

[0082] Signals related to the sleeping state of the subject are detected (S221). Based on the signals related to the sleeping state, the sleep-wake state of the subject is determined (S222). If the subject is sleeping (S223), then no action is taken until the result of the respiratory movement and the clock are both given. If the subject is not sleeping or awake, the process returns to the signal detection (S223, S221).

[0083] At the very beginning of the process, if the amplitude is smaller than a threshold (S213) and the subject is sleeping (223), in other words, these two conditions are fulfilled, the stimulation is applied to the subject (S250). Once the first stimulation has been applied, the clock starts to count the time (S231). If the time has passed a threshold, e.g. 10 seconds, 20 seconds then no action is taken until the result of the respiratory movement and the clock are both given.

[0084] 10 seconds is an exemplary period of time in which a couple of respirations generally occur. A change in the amplitude may be detected by measuring the respiratory movements for one respiration period. By taking two or more respiration periods, it may be more accurately determined whether there is a change in the respiratory amplitude. But another length of time may be taken to determine whether there is a change in the respiratory amplitude.

[0085] If the amplitude is smaller than a threshold (S213), the subject is sleeping (S223), and the certain time has passed since the last application of the stimulation (S233), or if all of the three conditions are fulfilled again (S240), it is determined that the subject is in an apnea state (S240). Then, the next stimulation is applied to the subject (S250). If any one or any two of the three conditions are not fulfilled, the process returns to the signal detection (S211, S221), while the clock keeps counting the time (S231).

[0086] In some embodiments, if it is determined that that subject is still in an apnea state after stimulations were applied to the subject for more than a certain times, the intensity of a stimulation may be increased, and / or the duration of a stimulation may be increased. In some embodiments, if it is determined that the subject is in a wake state for a certain period of time, for example one minute, the intensity of the next stimulation may be decreased and / or the duration of the next stimulation may be decreased.

[0087] Embodiment of Apparatus 1 FIG. 3 shows a schematic diagram of an apparatus 100 according to an embodiment, to explain the functions of the apparatus and the interaction thereof with a subject 170.

[0088] The apparatus 100 includes a control unit 110, a respiration detection unit 120, a sleep detection unit 130, and a stimulation application unit 140. In this embodiment, the respiration detection unit 120 is an ultra-wideband millimeter-wave radar unit, the sleep detection unit 130 is a sound detection unit including a microphone, and the stimulation unit 140 is a low frequency sound unit.

[0089] The radar unit 120 has multiple transmitting antennas 121 and multiple receiving antennas 123. The control unit 110 instructs the radar unit 120 to transmit millimeter waves 122 from the transmitting antennas 121 towards the subject 170. The millimeter waves 124 reflected by the body surface (typically the chest) of the subject 170 are detected by the receiving antennas 123. The radar unit 120 converts the detected signals to communication signals and sends the same to the control unit 110.

[0090] The microphone of the sound detection unit130 picks up sounds 134 emitted by the subject 170. The sounds from the subject 170 typically include snoring sounds and breathing sounds. The sound detection 130 converts the detected signals to communication signals and send the same to the control unit 110.

[0091] The control unit 110 receives the information sent from the radar unit 120 and the information sent from the sound detection unit 130. Based on the received information, the control unit 110 determines whether there is a sign of apnea or hypopnea and / or whether it is the right timing to apply a stimulation to the subject 170.

[0092] If it has determined that there is a sign of apnea or hypopnea and / or that it is the right timing to apply a stimulation to the subject 170, the control unit 110 sends instructions to the stimulation unit 140, to apply a stimulation to the subject 170.

[0093] Embodiment of Apparatus 1-1 FIG. 4 shows a block diagram of a sleep apnea treatment apparatus 300 according to an embodiment. This embodiment may be employed to the above explained Apparatus Embodiment 1. The apparatus 300 includes a control unit 310, a radar unit 320, a sound detection unit 330 which is typically a microphone, and a stimulation application unit 340. The apparatus 300 further includes a communication unit 350 or an I / O port to communicate with external devices or a network, and a display 360. The control unit 310 includes a process unit 311, a memory 312 and a storage 313. These units and components can communicate with each other via a bus 370.

[0094] The memory 313 is a non-transitory computer readable memory that stores a program code to be executed by the process unit 311 to perform the steps explained in the present embodiment.

[0095] The process unit 311 includes a radar transmission order part 311a, a phase signal calculation part 311b, a respiratory amplitude calculation part 311c, a respiratory state determination part 311d, a sound pressure calculation part 311e, a snoring detection part 311f, a sleep stage determination part 311g, an apnea state determination part 311h, and a stimulate application order part 311i.

[0096] The radar unit 320 is an ultra-wideband millimeter-wave radar unit. The radar unit 320 includes multiple transmitting antennas 321 and multiple transmitting antennas 323.

[0097] The radar transmission order part 311a sends a signal or an order to the radar unit 320 to transmit ultra-wideband millimeter-waves.

[0098] Upon receiving the order from the radar transmission order part 311a, each of the multiple transmitting antennas 321 transmit its respective ultra-wideband millimeter-waves to a subject (not shown). The ultra-wideband millimeter-waves are modulated by using a pulse compression technique such as m-sequence.

[0099] The transmitted ultra-wideband millimeter-waves are reflected at the body surface of the subject. Each of the multiple receiving antennas 321 receives its respective ultra-wideband millimeter-waves. The radar unit 320 sends the information of the received radar signals to the memory 312, to store the information therein as radar signals.

[0100] The phase signal calculation part 311b refers to the radar signals stored in the memory 312 and calculates the phase signal of each of the radar signals, or each of the radar signals from the respective receiving antennas.

[0101] The respiratory amplitude calculation part 311c refers to the phase signals calculated by the phase signal calculation part 311b, and calculates the respiratory amplitude, or the amplitude of respiration movements of the body part of interest.

[0102] The respiratory state determination part 311d refers to the respiratory amplitude calculated by the respiratory amplitude calculation part 311d and determines whether the respiratory movements have become smaller by a certain amount than the reference amplitude.

[0103] The sound detection unit 330 detects sounds including sounds emitted from the subject, which may include snoring sounds. The sound detection unit 330 sends the information of the received sound signals to the memory 312, to store the information therein as sound signals.

[0104] The sound pressure calculation part 311e refers to the sound signals stored in the memory 312, and calculates the sound pressure which indicates an impact

[0105] The snoring detection part 311f refers to the sound pressure calculated by the sound pressure calculation part 311e, and determines whether the subject is snoring.

[0106] The sleep stage determination part 311g determines that the subject is sleeping, or in a sleeping state, if it has been determined that the subject is snoring. The sleep stage determination part 311g determines that the subject is awake, or in a wake state, if it has been determined that the subject is not snoring.

[0107] The apnea state determination part 311h refers to the output of the respiration state determination part 311d and the sleep stage determination part 311g. If the obtained respiratory amplitude is smaller than a threshold and the subject is sleeping, in other words, if both of the two conditions have been fulfilled, the apnea state determination part 311h determines that it is a sign of apnea or hypopnea for the subject.

[0108] The stimulate application order part 311i refers to the output of the apnea state determination part 311h. If it has been determined that there is a sign of apnea or hypopnea for the subject, the stimulate application order part 311i sends a signal or an order to the stimulation unit 340 to apply a stimulation to the subject.

[0109] In the above description, the sleep state is determined based on the snoring sound of the subject. But the present disclosure should not be limited to this embodiment. In some embodiments, the sleep state may be determined based on both the snoring sound and the phase signal from the radar unit.

[0110] Embodiment of Apparatus 2 FIG. 5 shows a schematic diagram of an apparatus 200 according to an embodiment, to explain the functions of the apparatus and the interaction thereof with a subject 270.

[0111] The apparatus 200 includes a control unit 210, a radar unit 220 which functions as a respiration detection unit and a sleep detection unit, and a stimulation application unit 240. In this embodiment, the respiration detection unit 220 is an ultra-wideband millimeter-wave radar unit, and the stimulation unit 240 is a low frequency sound unit.

[0112] The radar unit 220 has multiple transmitting antennas 221 and multiple receiving antennas 223. The control unit 210 instructs the radar unit 220 to transmit millimeter waves 222 from the transmitting antennas 221 towards the subject 270. The millimeter waves 224 reflected by the body surface (typically the chest) of the subject 270 are detected by the receiving antennas 223. The radar unit 220 converts the detected signals to communication signals and send the same to the control unit 210.

[0113] The control unit 210 receives the information sent from the radar unit 220. Based on the received information, the control unit 210 determines whether there is a sign of apnea or hypopnea and / or whether it is the right timing to apply a stimulation to the subject 270.

[0114] If it has determined that there is a sign of apnea or hypopnea and / or that it is the right timing to apply a stimulation to the subject 270, the control unit 210 sends instructions to the stimulation unit 240, to apply a stimulation to the subject 270.

[0115] Embodiment of Apparatus 2-1 FIG. 6 shows a block diagram of a sleep apnea treatment apparatus 400 according to an embodiment. This embodiment may be employed to the above explained Apparatus Embodiment 2. The apparatus 400 includes a control unit 410, a radar unit 420, and a stimulation application unit 440. The apparatus 400 further includes a communication unit 450 or an I / O port to communicate with external devices or a network, and a display 460. The control unit 410 includes a process unit 411, a memory 412 and a storage 413. These units and components can communicate with each other via a bus 470.

[0116] The storage 413 is a non-transitory computer readable memory that stores a program code to be executed by the process unit 411 to perform the steps explained in the present embodiment.

[0117] The process unit 411 includes a radar transmission order part 411a, a phase signal calculation part 411b, a respiratory amplitude calculation part 411c, a respiratory state determination part 411d, a sleep stage determination part 411g, an apnea state determination part 411h, and a stimulate application order part 411i.

[0118] The radar unit 420 is an ultra-wideband millimeter-wave radar unit. The radar unit 420 includes multiple transmitting antennas 421 and multiple transmitting antennas 423.

[0119] The radar transmission order part 411a sends a signal or an order to the radar unit 420 to transmit ultra-wideband millimeter-waves.

[0120] Upon receiving the order from the radar transmission order part 411, each of the multiple transmitting antennas 421 transmit its respective ultra-wideband millimeter-waves to a subject (not shown). The ultra-wideband millimeter-waves are modulated by using a pulse compression technique such as m-sequence.

[0121] The transmitted ultra-wideband millimeter-waves are reflected at the body surface of the subject. Each of the multiple receiving antennas 421 receives its respective ultra-wideband millimeter-waves. The radar unit 420 sends the information of the received radar signals to the memory 412, to store the information therein as radar signals.

[0122] The phase signal calculation part 411b refers to the radar signals stored in the memory 412 and calculates the phase signal of each of the radar signals, or each of the radar signals from the respective receiving antennas.

[0123] The respiratory amplitude calculation part 411c refers to the phase signals calculated by the phase signal calculation part 411b, and calculates the respiratory amplitude, or the amplitude of respiration movements of the body part of interest.

[0124] The respiratory state determination part 411d refers to the respiratory amplitude calculated by the respiratory amplitude calculation part 411c and determine whether the respiratory movements have become smaller by a certain amount than the reference amplitude.

[0125] The sleep stage determination part 411g refers to the phase signals calculated by the phase signal calculation part 411b, determines whether the subject is sleeping or awake. For example, the radar signals include large movements of a body part compared to a reference, it determines that the subject is not sleeping, awake, or in a wake state. For example, the radar signals do not include large movements of a body part compared to a reference, it determines that the subject is sleeping, or in a sleep state.

[0126] The apnea state determination part 411h refers to the outputs of the respiration state determination part 411d and the sleep stage determination part 411g. If the obtained respiratory amplitude is smaller than a threshold and the subject is sleeping, in other words, if both of the two conditions have been fulfilled, the apnea state determination part 411h determines that it is a sign of apnea or hypopnea for the subject.

[0127] The stimulate application order part 411i refers to the output of the apnea state determination part 411h. If it has been determined that there is a sign of apnea or hypopnea for the subject, the stimulate application order part 411i sends a signal or an order to the stimulation unit 440 to apply a stimulation to the subject.

[0128] Embodiment of Apparatus 2-2 FIG. 7 shows a block diagram of a sleep apnea treatment apparatus 500 according to an embodiment. This embodiment may be employed to the above explained Apparatus Embodiment 2. The apparatus 500 includes a control unit 510, a radar unit 520, and a stimulation application unit 540. The apparatus 500 further includes a communication unit 550 or an I / O port to communicate with external devices or a network, and a display 560. The control unit 510 includes a process unit 511, a memory 512 and a storage 513. These units and components can communicate with each other via a bus 570.

[0129] The memory 513 is a non-transitory computer readable memory that stores a program code to be executed by the process unit 511 to perform the steps explained in the present embodiment.

[0130] The process unit 511 includes a radar transmission order part 511a, a phase signal calculation part 511b, a respiratory amplitude calculation part 511c, a respiratory state determination part 511d, a Doppler velocity calculation part 511e, a heartbeat intervals calculation part 511f, a sleep stage determination part 511g, an apnea state determination part 511h, and a stimulate application order part 511i.

[0131] The radar unit 520 is an ultra-wideband millimeter-wave radar unit. The radar unit 520 includes multiple transmitting antennas 521 and multiple transmitting antennas 523.

[0132] The radar transmission order part 511a sends a signal or an order to the radar unit 520 to transmit ultra-wideband millimeter-waves.

[0133] Upon receiving the order from the radar transmission order part 511, each of the multiple transmitting antennas 521 transmit its respective ultra-wideband millimeter-waves to a subject (not shown). The ultra-wideband millimeter-waves are modulated by using a pulse compression technique such as m-sequence.

[0134] The transmitted ultra-wideband millimeter-waves are reflected at the body surface of the subject. Each of the multiple receiving antennas 521 receives its respective ultra-wideband millimeter-waves. The radar unit 520 sends the information of the received radar signals to the memory 512, to store the information therein as radar signals.

[0135] The phase signal calculation part 511b refers to the radar signals stored in the memory 512 and calculates the phase signal of each of the radar signals, or each of the radar signals from the respective receiving antennas.

[0136] The respiratory amplitude calculation part 511c refers to the phase signals calculated by the phase signal calculation part 511b, and calculates the respiratory amplitude, or the amplitude of respiration movements of the body part of interest.

[0137] The respiratory state determination part 511d refers to the respiratory amplitude calculated by the respiratory amplitude calculation part 511c and determines whether the respiratory movements have become smaller by a certain amount than the reference amplitude.

[0138] The Doppler velocity calculation part 511e refers to the phase signals calculated by the phase signal calculation part 511b, and calculates the Doppler velocity of a part of the subject.

[0139] The heartbeat interval calculation part 511f refers to the phase signals calculated by the phase signal calculation part 511b, and calculates the heartbeat interval of the subject.

[0140] The sleep stage determination part 511g refers to the outputs of the Doppler velocity calculation part 511e and the heartbeat interval calculation part 511f. If the Doppler velocity is below a threshold and the heartbeat interval is below a threshold, in other words, if both of the two conditions have been fulfilled, the apnea state determination part 511h determines that it is a sign of apnea or hypopnea for the subject.

[0141] The stimulate application order part 511i refers to the output of the apnea state determination part 511h. If it has been determined that there is a sign of apnea or hypopnea for the subject, the stimulate application order part 511i sends a signal or an order to the stimulation unit 540 to apply a stimulation to the subject.

[0142] Embodiment 3 In some embodiments, an apparatus may include or be connected to a radar unit. The radar unit may transmit electromagnetic waves to a subject and receive electromagnetic waves reflected by the surface of the subject. The radar unit may generate radar signals to be processed (also referred to as “radar signal”, and the like). Typically, the radar unit may generate multiple radar signals, which is a collection of discretely sampled data obtained continuously over time. This plurality of data points are used as the basis for applying Fourier transform to estimate the Doppler velocity. Here, the terms “multiple” and “plurality” denote a sufficient number of sampling points necessary to accurately analyze the velocity components of the subjects. The apparatus may include a controller unit which receives the radar signal or output signal from the radar unit.

[0143] The signal from the radar unit may include a phase signal. The output signal from the radar unit, which may include the phase signal, may be used to calculate the Doppler velocity of a certain body part of the subject, the heartbeat intervals of the subject, and the like. In some embodiments, the Doppler velocity and the heartbeat intervals may be used to obtain the sleep-wake state of the subject, and / or determine whether the subject is or is being in a state of apnea or hypopnea, or in an apneic or hypopneic state. In some embodiments, the Doppler velocity may be used to obtain the sleep-wake state of the subject, without using heartbeat intervals.

[0144] In some embodiments, the radar unit may continuously, or intermittently continue to, generate output signals, or output the same as time-series data. Thus, the controller unit may receive and / or process the time-series data of the radar signals.

[0145] In some embodiments, an amplitude of the respiratory movement of the subject, for example the chest, may be monitored. A decreasing trend in the amplitude of the respiratory movement may indicate that the subject is likely to be in, or transitioning into a state of apnea or hypopnea. This decreasing trend may serve as an indicator or precursor to a state of apnea or hypopnea.

[0146] If the amplitude of the respiratory movement falls below a predetermined threshold, the subject may be determined to be in a state of apnea or hypopnea. For example, the threshold amplitude may be set relative to a reference amplitude. For example, the threshold amplitude may be configured to be significantly smaller than the reference amplitude, such as 70% of the reference amplitude. To determine the current respiratory amplitude, the control unit may calculate the average of the envelope amplitude of a first group of data points that are temporally proximate to the current time. The reference amplitude, on the other hand, may be calculated as the average of the envelope amplitude of a second group of data points that temporally precede the first group.

[0147] For example, to determine the current respiratory amplitude, the control unit may calculate the average of the envelope amplitude of a first group including data points temporally proximate to the current time. On the other hand, the reference amplitude may be calculated as the average of the envelope amplitude of a second group including data points temporally preceding the first group.

[0148] The ratio of the current respiratory amplitude to the reference amplitude may be calculated to search or detect the boundary or transition between the normal respiration and apnea / hypopnea. To refine the detection, the boundary between the first group and the second group may be shifted iteratively. The boundary with the minimum amplitude ratio may indicate the boundary or the transition point between the normal respiration and apnea / hypopnea.

[0149] In certain cases, the amplitude of respiratory movement decreases very slowly, making it unclear when a state of apnea or hypopnea begins. In such scenarios, a statistical analysis of time-series amplitude values of respiratory movement may be employed to determine whether the subject has entered a state of apnea or hypopnea. For instance, time-series amplitude values of respiratory movement over a predefined period, such as 30 seconds, may be divided into two groups: a first group representing a more recent time interval and a second group representing an earlier time interval, e.g., 15 seconds each. If the amplitudes of the first group are significantly smaller than those of the second group, it may be determined that the subject is in a state of apnea or hypopnea.

[0150] In some embodiments, the subject may be determined to be in a state of apnea or hypopnea or to be exhibiting a precursor to a state of apnea or hypopnea, if the amplitude of the respiratory movement falls below a predetermined threshold and if the subject is determined to be in a sleeping state.

[0151] In some cases, a radar unit alone may have difficulty in determining a termination of the state of apnea or hypopnea. The determination of such termination may take into account whether the subject exhibits snoring. The presence of snoring is a clear indication that the subject is not in a state of apnea or hypopnea. In some embodiments, the termination of a state of apnea or hypopnea in the subject may be determined based on the detection of snoring exhibited by the subject. In some embodiments, the termination of a state of apnea or hypopnea in the subject may be determined even if the amplitude of the respiratory movement of the subject does not increase. In some embodiments, the determination that the subject is in a state of apnea or hypopnea may be invalidated or canceled, if the subject exhibits snoring.

[0152] According to some embodiments, signs and occurrences of apnea or hypopnea can be detected in real-time. This real-time detection enables timely intervention including treatment and stimulation, which are critical for the effective management and treatment of sleep apnea and hypopnea.

[0153] The present disclosure also provides following embodiments: A001. An apparatus, or an apparatus to according to any of the embodiments, the apparatus comprising: a respiration detection unit configured to detect a signal related to a respiratory movement of a subject; a sleep detection unit configured to detect a signal related to a sleeping status of the subject; and a control unit configured to: receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; and based on the amplitude of the respiratory movement and the sleep-wake state, determine whether there is a sign of hypopnea or apnea. A011a. The apparatus of A001 or any of the embodiments, wherein the respiration detection unit is a respiration detection radar unit configured to detect a radar signal related to a respiratory movement of a subject, and wherein the sleep detection unit is a sleep detection sound unit configured to detect a sound signal related to a sleeping status of the subject. A011b. An apparatus, or an apparatus to according to any of the embodiments, the apparatus comprising: a respiration detection radar unit configured to detect a radar signal related to a respiratory movement of a subject; a sleep detection sound unit configured to detect a sound signal related to a sleeping status of the subject; a control unit configured to: receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; and based on the amplitude of the respiratory movement and the sleep-wake state, determine whether there is a sign of hypopnea or apnea. A012. The apparatus of A011a or A011b, or any of the embodiments, wherein the signal related to the respiratory includes a signal of a sound emitted from a respiratory action of the subject. A013. The apparatus of A012, or any of the embodiments, wherein said determining the sleep-wake state of the subject comprises determining whether the sound emitted from the subject includes a snore, and determining that the subject is in a sleeping state / the subject is sleeping / the sleep-wake state is a sleeping state, if the subject is snoring. A021. An apparatus, or any of the embodiments, comprising: a radar unit configured to detect a radar signal related to a respiratory movement of a subject and to detect a radar signal related to a sleeping status of the subject; and a control unit configured to: receive from the radar unit the detected radar signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement, and the detected radar signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; and based on the amplitude of the respiratory movement and the sleep-wake state, determine whether there is a sign of hypopnea or apnea. A022. The apparatus of A021 or any of the embodiments, wherein said determining the sleep-wake state of the subject comprises determining whether the detected radar signal related to the sleeping status of the subject includes a signal related to a body movement of the subject. A023. The apparatus of A022 or any of the embodiments, wherein said determining the sleep-wake state of the subject comprises determining whether the body movement of the subject is greater than a threshold / has a certain characteristic. A024. The apparatus of A023 or any of the embodiments, wherein said determining whether the body movement of the subject includes whether the subject moves an arm of the subject or a body of the subject is rolling. A031. The apparatus of any one of A011 to A021 or any of the embodiments, wherein said determining whether there is the sign of hypopnea or apnea comprises determining: whether the amplitude of the respiratory movement is smaller than a threshold; and whether the subject is in a sleeping state. A035. The apparatus of any one of A011 to A021 or any of the embodiments, wherein said determining whether there is the sign of hypopnea or apnea comprises determining: whether the amplitude of the respiratory movement is smaller than a threshold; whether the subject is in a sleeping state; and whether a certain period of time has passed since a last application of a stimulation to the subject. A036. The apparatus of A035 or any of the embodiments, wherein the certain period of time since the last application of the stimulation is set to be shorter than 10 seconds or 20 seconds. A041. The apparatus of any one of A011 to A031 or any of the embodiments, further comprising a stimulation unit configured to apply a stimulation to the subject, and wherein the control unit further configured to, if it is determined that there is a sign of hypopnea or apnea, cause the stimulation unit to apply the stimulation to the subject. A042. The apparatus of A041 or any of the embodiments, wherein the stimulation unit is configured to emit a low-frequency sound. A043. The apparatus of A041 or any of the embodiments, wherein the low-frequency sound is a sound having a frequency lower than 60 Hz. A044. The apparatus of A041 or any of the embodiments, wherein the stimulation unit is configured to emit a chirp wave of starting at a frequency of 30 Hz and increasing up to 60 Hz.

[0154] A101. An apparatus, or an apparatus according to any of the embodiments, the apparatus being configured to be connected to: a respiration detection unit configured to detect a signal related to a respiratory movement of a subject; and a sleep detection unit configured to detect a signal related to a sleeping status of the subject, the apparatus comprising a control unit configured to: receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; and based on the amplitude of the respiratory movement and the sleep-wake state, determine whether there is a sign of hypopnea or apnea. A111. An apparatus, or an apparatus of the embodiments, the apparatus being configured to be connected to: a respiration detection unit configured to detect a signal related to a respiratory movement of a subject; a sleep detection unit configured to detect a signal related to a sleeping status of the subject; and a stimulation unit configured to apply a stimulation to the subject, the apparatus comprising a control unit configured to: receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; based on the amplitude of the respiratory movement and the sleep-wake state, determine whether there is a sign of hypopnea or apnea; and if it is determined that there is a sign of hypopnea or apnea, cause the stimulation unit to apply the stimulation to the subject.

[0155] A201. An apparatus comprising: a radar unit configured to: transmit electromagnetic waves to a subject; detect electromagnetic waves reflected by the subject; from the detected electromagnetic waves, generate a plurality of radar signals including a plurality of phase signals; and calculate a plurality of Doppler velocities from the plurality of radar signals, and a controller configured to: instruct the radar unit to transmit the electromagnetic waves to the subject; receive the radar signals from the radar unit including the plurality of phase signals and the a plurality of Doppler velocities; and based on the output signal including the phase signal, determine a sleep-wake state of the subject and determine whether the subject is in a state of apnea or hypopnea. A211. The apparatus according to A201 or any of the embodiments, wherein the radar unit is an ultra-wideband millimeter-wave radar unit. A221. The apparatus according to A201 or any of the embodiments, wherein the control unit is configured to: calculate Doppler velocities and a heartbeat interval from the phase signal, and determine the sleep-wake state of the subject based on the Doppler velocities and the heartbeat interval. A225. The apparatus according to A221 or any of the embodiments, wherein the control unit is configured to: calculate an amplitude of a respiratory movement of the subject, and determine that the subject is in a state of apnea or hypopnea, if the amplitude of the respiratory movement falls below a threshold and if the subject is in a sleeping state. A231. The apparatus according to A225 or any of the embodiments, further comprising a sound detection unit, wherein the control unit is configured to cancel the determination that the subject is in a state of apnea or hypopnea, if a sound signal from the sound detection unit includes a snoring sound of the subject. A241. The apparatus according to A225 or A231, or any of the embodiments, wherein the controller unit is configured to: sample the amplitude of the respiratory movement as time-series data over a certain period of time, group the time-series data representing multiple amplitude values of the respiratory movement sampled over the certain period of time into two groups: (i) a first group including data points temporally proximate to the current time, and (ii) a second group including data points temporally preceding the first group, and determine that the subject is in a state of apnea or hypopnea if the amplitude values of the first group are significantly smaller than those of the second group and if the subject is in a sleeping state. A251. The apparatus according to A225 or any of the embodiments, further comprising a stimulation unit, wherein the controller unit is configured to instruct the stimulation unit to apply a stimulation to the subject if it is determined that the subject is in a state of apnea or hypopnea. A252. The apparatus according to A251 or any of the embodiments, wherein the controller unit is configured to instruct the stimulation unit to apply the stimulation to the subject within a predetermined time after determining that the subject is in a state of apnea or hypopnea. A253. The apparatus according to A252 or any of the embodiments, wherein the predetermined time to apply the stimulation is below 10 seconds from the determination that the subject is in the state of apnea or hypopnea. A254. The apparatus according to A253 or any of the embodiments, wherein the stimulation unit is a speaker configured to apply a sound to the subject.

[0156] B001. A method of detecting or treating apnea, or a method according to any of the embodiments, comprising: by a respiration detection unit, detecting a signal related to a respiratory movement of a subject; by a sleep detection unit, detecting a signal related to a sleeping status of the subject; and by a control unit, receiving from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receiving from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; and based on the amplitude of the respiratory movement and the sleep-wake state, determining whether there is a sign of hypopnea or apnea. B011. A method of detecting or treating apnea, or any method according to any of the embodiments, comprising: by a respiration detection unit, detecting a signal related to a respiratory movement of a subject; by a sleep detection unit, detecting a signal related to a sleeping status of the subject; by a control unit, receiving from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; by a control unit, receiving from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; by a control unit, based on the amplitude of the respiratory movement and the sleep-wake state, determining whether there is a sign of hypopnea or apnea; and by a control unit, if it is determined that there is a sign of hypopnea or apnea, causing a stimulation unit to apply the stimulation to the subject. B201. A method of detecting or treating apnea, or any method according to any of the embodiments, comprising: using a radar unit to: transmit electromagnetic waves to a subject; detect electromagnetic waves reflected by the subject; from the detected electromagnetic waves, generate a plurality of radar signals including a plurality of phase signals; and calculate a plurality of Doppler velocities from the plurality of radar signals, and using a controller to: instruct the radar unit to transmit the electromagnetic waves to the subject; receive the radar signals from the radar unit including the plurality of phase signals and the a plurality of Doppler velocities; and based on the output signal including the phase signal, determine a sleep-wake state of the subject and determine whether the subject is in a state of apnea or hypopnea. B221. The method according to B201 or any of the embodiments, further comprising: using the control unit to: calculate Doppler velocities and a heartbeat interval from the phase signal, and determine the sleep-wake state of the subject based on the Doppler velocities and the heartbeat interval. B225. The method according to B221 or any of the embodiments, further comprising: using the control unit to: calculate an amplitude of a respiratory movement of the subject, and determine that the subject is in a state of apnea or hypopnea, if the amplitude of the respiratory movement falls below a threshold and if the subject is in a sleeping state. B231. The apparatus according to B225 or any of the embodiments, further comprising: using a sound detection unit, and using the control unit is to cancel the determination that the subject is in a state of apnea or hypopnea, if a sound signal from the sound detection unit includes a snoring sound of the subject. B251. The method according to B225 or any of the embodiments, further comprising: using the controller unit to instruct a stimulation unit to apply a stimulation to the subject if it is determined that the subject is in a state of apnea or hypopnea. C001. A software program configured to cause a computer to execute the method of B001 or B011, a method according to any of the embodiments. D001. A non-transitory storage medium storing the software program of C001 or any of the embodiments.

[0157] Terms and phrases used in this application, and variations thereof, especially in the appended claims, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing, the term ‘including’ should be read to mean ‘including, without limitation,’ ‘including but not limited to,’ or the like; the term ‘comprising’ as used herein is synonymous with ‘including,’ ‘containing,’ or ‘characterized by,’ and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps; the term ‘having’ should be interpreted as ‘having at least;’ the term ‘includes’ should be interpreted as ‘includes but is not limited to;’ the term ‘example’ is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof.

[0158] A group of items linked with the conjunction ‘and’ should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as ‘and / or’ unless expressly stated otherwise. Similarly, a group of items linked with the conjunction ‘or’ should not be read as requiring mutual exclusivity among that group, but rather should be read as ‘and / or’ unless expressly stated otherwise.

[0159] With respect to the use of substantially any plural and / or singular terms herein in the English language, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity. The indefinite article “a” or “an” does not exclude a plurality.

[0160] Any of the embodiments or any of the aspects disclosed herein is independently combinable, partly or wholly with other embodiments described herein in any way, e.g., one, two, or three or more embodiments may be combinable in whole or in part. Further, any of the features of any of the embodiments or any of the aspects disclosed herein is applicable to any of the other embodiments and aspects, or may be made optional to other embodiments or aspects.

[0161] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions may now occur to those skilled in the art without departing from the invention. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is therefore contemplated that the invention shall also cover any such alternatives, modifications, variations or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. An apparatus comprising: a respiration detection unit configured to detect a signal related to a respiratory movement of a subject; a sleep detection unit configured to detect a signal related to a sleeping status of the subject; and a control unit configured to: receive from the respiration detection unit the detected signal related to the respiratory movement of the subject and determine an amplitude of the respiratory movement; receive from the sleep detection unit the signal related to the sleeping status of the subject and determine a sleep-wake state of the subject; and based on the amplitude of the respiratory movement and the sleep-wake state, determine whether the subject is in a state of hypopnea or apnea.

2. An apparatus comprising: a radar unit configured to: transmit electromagnetic waves to a subject; detect electromagnetic waves reflected by the subject; from the detected electromagnetic waves, generate a plurality of radar signals including a plurality of phase signals; and calculate a plurality of Doppler velocities from the plurality of radar signals, and a controller configured to: instruct the radar unit to transmit the electromagnetic waves to the subject; receive the radar signals from the radar unit including the plurality of phase signals and the plurality of Doppler velocities; and based on the output signal including the phase signal, determine a sleep-wake state of the subject and determine whether the subject is in a state of apnea or hypopnea.

3. The apparatus according to Claim 2, wherein the radar unit is an ultra-wideband millimeter-wave radar unit.

4. The apparatus according to Claim 2, wherein the control unit is configured to: calculate Doppler velocities and a heartbeat interval from the phase signal, and determine the sleep-wake state of the subject based on the Doppler velocity and the heartbeat interval.

5. The apparatus according to Claim 4, wherein the control unit is configured to: calculate an amplitude of a respiratory movement of the subject, and determine that the subject is in a state of apnea or hypopnea, if the amplitude of the respiratory movement falls below a threshold and if the subject is in a sleeping state.

6. The apparatus according to Claim 5, further comprising a sound detection unit, wherein the control unit is configured to cancel the determination that the subject is in a state of apnea or hypopnea, if a sound signal from the sound detection unit includes a snoring sound of the subject.

7. The apparatus according to Claim 5 or 6, wherein the controller unit is configured to: sample the amplitude of the respiratory movement as time-series data over a certain period of time, group the time-series data representing multiple amplitude values of the respiratory movement sampled over the certain period of time into two groups: (i) a first group including data points temporally proximate to the current time, and (ii) a second group including data points temporally preceding the first group, and determine that the subject is in a state of apnea or hypopnea if the amplitude values of the first group are significantly smaller than those of the second group and if the subject is in a sleeping state.

8. The apparatus according to Claim 5, further comprising a stimulation unit, wherein the controller unit is configured to instruct the stimulation unit to apply a stimulation to the subject if it is determined that the subject is in a state of apnea or hypopnea.

9. The apparatus according to Claim 8, wherein the controller unit is configured to instruct the stimulation unit to apply the stimulation to the subject within a predetermined time after determining that the subject is in a state of apnea or hypopnea.

10. The apparatus according to Claim 9, wherein the predetermined time to apply the stimulation is below 10 seconds from the determination that the subject is in the state of apnea or hypopnea.

11. The apparatus according to Claim 10, wherein the stimulation unit is a speaker configured to apply a sound to the subject.

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