SYSTEMS AND METHODS FOR OPERATING AN IMPLANTABLE MEDICAL DEVICE BASED ON SENSE POSITION INFORMATION - Patent application

Abstract

A system and / or method for controlling operation of an implantable medical device in response to sensed position information.

Description

Detailed Description of the Invention

[0001] Many patients benefit from therapy provided by implantable medical devices. For example, some people suffer from various forms of sleep disordered breathing (SDB). For some patients, external respiratory therapy equipment and / or simple surgical intervention may not be able to treat their sleep disordered breathing behavior. These and other implantable medical device therapy applications may reference sensed patient information to improve the operation of such systems. [Brief description of the drawings]

[0002] [Figure 1] 1 is a block diagram that generally illustrates a patient care system according to the principles of the present disclosure. [Diagram 2] FIG. 2 is a block diagram that generally represents an implantable medical device useful in the care system of FIG. 1, in a partially assembled state. [Diagram 3] 3 is a block diagram that generally represents the implantable medical device of FIG. 2 in an assembled state and an implantable sensor according to the principles of the present disclosure assembled to the implantable medical device. [Figure 4] FIG. 1 is a block diagram of portions of another patient care system including an implantable sensor carried within a housing of an implantable pulse generator assembly in accordance with the principles of the present disclosure. [Diagram 5] FIG. 2 is a block diagram that generally represents an exemplary sensor lead useful in the patient care system of FIG. 1, including a stimulating electrode and an implantable sensor. [Figure 6] FIG. 1 is a block diagram that generally represents an exemplary system including an implantable pulse generator assembly and a separate implantable sensor, in accordance with the principles of the present disclosure. [Figure 7A] 1A-1C are schematic representations of axis orientation diagrams of a three-axis accelerometer useful as one non-limiting example of an implantable sensor of the present disclosure; [Figure 7B] FIG. 1 is a block diagram illustrating a cross-sectional view of an exemplary IPG assembly carrying an implantable sensor implanted within the body in relation to an axial orientation view. [Figure 8] 13A-13C are schematic representations of posture information obtained for a patient in a recumbent position, according to some embodiments of the present disclosure; [Figure 9A] FIG. 2 is a block diagram that generally represents an exemplary control portion. [Figure 9B] 9B is a diagram illustrating a schematic representation of at least some examples of different modalities of the control portion of FIG. 9A. [Figure 9C] FIG. 2 is a block diagram that generally represents an exemplary user interface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0003] In the following detailed description, reference is made to the accompanying drawings, which form a part of this specification and which show, by way of illustration, specific examples in which the present disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description should not be interpreted in a limiting sense. It is to be understood that the features of the various examples described herein may be combined with each other, either in part or in whole, unless otherwise specified.

[0004] At least some examples of the present disclosure are directed to systems and devices for the diagnosis, treatment, and / or other care of medical conditions. At least some examples may include implantable devices and / or methods involving the use of implantable devices.

[0005] At least some examples of the present disclosure are directed to systems and methods for controlling at least one function or operation of an implantable medical device system, including an implantable medical device implanted in a patient, based on sensed posture information of the patient. In some embodiments, one or more sensors implanted in the patient are utilized to sense or detect the posture information of the patient. In some embodiments, the operation of the implantable medical device system controlled in response to the sensed posture information relates to an operating mode of the implantable medical device in delivering therapy to the patient. In some embodiments, the systems and methods of the present disclosure incorporate one or more algorithms that result in an action being taken in response to a determination that the patient is in a specified posture or a determination that the probability that the patient is in the specified posture is above a threshold. In other embodiments, the systems and methods of the present disclosure incorporate one or more algorithms that result in an action being taken in response to a determination that the patient is not in a specified posture or a determination that the probability that the patient is not in a specified posture is above a threshold. In some embodiments, the operation of the implantable medical device system controlled in response to the sensed posture information relates to determining or designating a current posture of the patient. In some embodiments, the operation of the implantable medical device system controlled in response to the sensed posture information relates to determining or designating that the patient's current posture is not a designated or particular posture. In some embodiments, the operation of the implantable medical device system controlled in response to the sensed posture information relates to calibrating information signaled by one or more sensors. In some embodiments, the operation of the implantable medical device system controlled in response to the sensed posture information relates to generating information or data for review by the patient and / or caregiver.

[0006] In some examples, the systems and methods of the present disclosure are configured and used for sleep disordered breathing (SDB) therapy, such as obstructive sleep apnea (OSA) therapy, which may include monitoring, diagnosis, and / or stimulation therapy. However, in other examples, the systems are used for other types of therapy, including, but not limited to, other types of neurostimulation or cardiac therapy. In some embodiments, such other implementations include, but are not limited to, therapies for central sleep apnea, complex sleep apnea, cardiac disorders, pain management, stroke, deep brain stimulation, and respiratory disorders.

[0007] An example of a patient treatment system 20 according to the principles of the present disclosure is depicted diagrammatically in FIG. 1. The patient treatment system 20 includes an implantable medical device (IMD) 30, one or more implantable sensors 32, a posture module or handler 34, and an optional external device 36. Details regarding the various components are provided below. Generally speaking, the IMD 30 is configured for implantation in a patient and configured to provide and / or assist in the delivery of a therapy to the patient. The implantable sensor 32 can take a variety of forms and is generally configured for implantation in a patient and to sense parameters indicative of at least the posture of the patient. The implantable sensor 32 may be carried by the IMD 30, may be connected to the IMD 30, or may be a stand-alone component not physically connected to the IMD 30. The posture module 34 is programmed (or connected to a separate programmed module) to receive information from the implantable sensor 32 and recognize or identify or determine a current posture of the patient based, at least in part, on the information from the implantable sensor 32. In some embodiments, the posture module 34 is programmed (or connected to a separate programmed module) to affect (or not affect) one or more control routines, etc., associated with the operation of the system 20. As described below, the posture module 34 may be incorporated by the IMD 30 (e.g., installed in a software application operated by the IMD 30) or may exist partially or entirely with other components of the system 20. If provided, the external device 36 may wirelessly communicate with the IMD 30 and is operable to facilitate the performance of one or more operations as described below (e.g., the external device 36 may be used to initially program the IMD 30, which then processes information (e.g., posture information) and delivers therapy independently of the external device 36). In other embodiments, the external device 36 may be omitted (e.g., the IMD 30, the implantable sensor 32, and the posture module 34 perform one or more of the operations described below without the need for an external device).

[0008] FIG. 2 is a block diagram that generally represents one example of an IMD 50 useful in the systems and methods of the present disclosure, for example as the IMD 30 of the system 20 of FIG. 1. The IMD 50 may include an implantable pulse generator (IPG) assembly 52 and a stimulation lead 54. The IPG assembly 52 may include a housing 60 that includes circuitry 62 and a power source 64 (e.g., a battery), and an interface block or header connector 66 carried or formed by the housing 60. The housing 60 is configured to render the IPG assembly 52 suitable for implantation in a human body and may incorporate biocompatible materials and hermetic seal(s). The circuitry 62 may include circuit components and wiring apparent to one skilled in the art appropriate for generating a desired stimulation signal (e.g., converting energy provided by the power source 64 into a desired stimulation signal), for example in the form of a stimulation engine. In some embodiments, the circuitry 62 may include telemetry components for communicating with external devices, as known in the art. For example, circuitry 62 may include a transmitter that converts power to a signal associated with a transmitted data packet, a receiver that converts the signal to power, a combined transmitter / receiver (or transceiver), an antenna, etc.

[0009] In some embodiments, the stimulation lead 54 includes a lead body 80 having a distally located stimulation electrode 82. At an opposite end of the lead body 80, the stimulation lead 54 includes a proximally located plug-in connector 84 that is configured to be removably connectable to an interface block 66 (e.g., the interface block 66 can optionally include or provide a stimulation port sized and shaped to receive the plug-in connector 84, as known in the art).

[0010] Generally speaking, the stimulation electrode 82 may optionally be a cuff electrode and may include some non-conductive structure biased (or otherwise configurable) to releasably secure the stimulation electrode 82 around the target nerve. Other configurations are acceptable. Additionally, the stimulation electrode 82 may include an array of electrode bodies for delivering a stimulation signal to the target nerve. In some non-limiting embodiments, the stimulation electrode 82 may include at least some of the features and attributes substantially similar to those described in U.S. Pat. No. 8,340,785, issued Dec. 25, 2012, and / or U.S. Patent Application Publication No. 2011 / 0147046, issued Jun. 23, 2011, the entire teachings of each of which are incorporated herein by reference in their entirety.

[0011] In some examples, the lead body 80 is a generally flexible, elongated member having sufficient elasticity to allow the lead body 80 to be advanced subcutaneously and manipulated to place the stimulation electrode 82 at a desired location adjacent to a nerve, such as an airway-related nerve (e.g., hypoglossal nerve, vagus nerve, etc.). In some examples, such as in cases of obstructive sleep apnea, the nerve may include, but is not limited to, a nerve and associated muscle that causes movement of the tongue and associated muscles to restore airway patency. In some examples, the nerve may include, but is not limited to, the hypoglossal nerve, and the muscle may include, but is not limited to, the hypoglossal muscle. In some examples, the lead body 80 may have a sufficient length to extend from the IPG assembly 52 implanted in one body location (e.g., orbit) to a target stimulation location (e.g., head, neck). Once generated via the circuit 62, the stimulation signal is selectively transmitted to the interface block 68 for delivery to such nerve via the stimulation lead 54.

[0012] Returning to FIG. 1 , the implantable sensor 32 can take a variety of forms suitable for implantation in a human patient, and generally includes a sensor component in the form of or similar to a motion-based transducer. In some embodiments, the motion-based transducer sensor component of the implantable sensor 32 can be or include an accelerometer (e.g., single or multi-axis accelerometer), a gyroscope, a pressure sensor, etc., as known in the art. The implantable sensor 32 can provide information along a single axis, or along multiple axes (e.g., a 3-axis accelerometer, a 3-axis gyroscope (3 rotational axes), a 6-axis accelerometer (3 linear and 3 rotational axes), a 9-axis accelerometer (3 linear, 3 rotational and 3 magnetic axes), etc.). Regardless of the exact form, the sensor component of the implantable sensor 32 can sense information indicative of, among other things, the patient's posture. For reference, information generated by the implantable sensor 32 is signaled to and acted upon by the posture module 34, as described below, although information from the implantable sensor 32 may be utilized by other modules or engines (e.g., a therapy manager module that manages therapy delivered to the patient by the IMD 30, as described below).

[0013] The implantable sensor 32 may be connected to the IMD 30 in a variety of ways. For example, with additional reference to the IMD 50 of FIG. 2, the implantable sensor 32 may include a lead body carrying a motion-based transducer sensor element at a distal end and a plug-in connector at a proximal end. The plug-in connector may be connected to an interface block 66 (e.g., the interface block 66 may include or provide a sensing port sized and shaped to receive the plug-in connector of the implantable sensor 32), and the lead body extends from the IPG assembly 52 to position the sensor element at a desired anatomical location. Thus, body motion related information sensed via the motion-based transducer element is transmitted to the circuit 62 via the interface block 66.

[0014] Alternatively, as reflected by the block diagram of FIG. 3, the implantable sensor 32 may be physically coupled to the interface block 66 and thereby carried by the IPG assembly 52 (e.g., the implantable sensor 32 may be considered a component of the IMD 50). Among other features, this optional configuration may eliminate tunneling and / or other surgical steps typically associated with placing sensing leads within a patient and may facilitate long-term stability and easy fixation of the implantable sensor 32 because it occurs in conjunction with fixation of the IPG assembly 52. ​​In some embodiments, the physical coupling of the implantable sensor 32 to the IPG assembly 52 is performed prior to implantation of those components.

[0015] In some embodiments, the housing of the implantable sensor 32 is sized and shaped to maintain the motion-based transducer sensor components in a fixed orientation relative to the IPG assembly 52, such that the motion-based transducer implantable sensor 32 fits over (e.g., adjacent) the housing 60 of the IPG assembly 52. ​​This configuration facilitates achieving and maintaining proper orientation of multiple orthogonal axes of the motion-based transducer sensor components relative to various axes of the patient's body, such as the anterior-posterior axis.

[0016] 4, the implantable sensor 32 (particularly the motion-based transducer sensor components as described above) may be incorporated within the structure of the interface block 66 or within the structure of the housing 60. By these and similar configurations, the sensor components of the implantable sensor 32 are electronically connected to circuitry 62 within the housing 60 or other enclosure of the IPG assembly 52.

[0017] In yet other embodiments, the implantable sensor 32 can be incorporated into the structure of the stimulation lead 54. For example, FIG. 5 is a block diagram that generally represents a stimulation lead 100 including a stimulation electrode 102 and a motion-based transducer sensor 104 (similar to the implantable sensor 32 described above) according to one example of the present disclosure. In some examples, the stimulation lead 100 includes at least some of the substantially same features and attributes as the lead 54 of FIG. 2, except for additionally including the motion-based transducer sensor 104. As shown in FIG. 5, the lead 100 includes a lead body 106 having a proximal end 108 configured to be removably connectable to a port of an IPG assembly (e.g., the interface block 68 of the IPG assembly 52 of FIG. 2) and an opposing distal end 110 on which the motion-based transducer sensor 104 and the electrode 102 are mounted. In some examples, the sensor 104 is not necessarily at the distal end 110 of the lead body 106, but is located closer to the distal end 106 than to the proximal end 104 of the lead 100. In some optional embodiments, the portion of the lead 100 in which the motion-based transducer sensor 104 is located includes a mechanism (e.g., a rotatable sleeve) that allows for selective rotation of the motion-based transducer sensor 104, which in turn allows for adopting a desired orientation of the different axes 112 of the motion-based transducer sensor 104 (e.g., when the motion-based transducer sensor 104 is a multi-axis accelerometer).

[0018] In yet other embodiments, the implantable sensor 32 may be wirelessly connected to the IMD 30. For example, FIG. 6 is a block diagram that generally represents a system including the IPG assembly 52 and a separate implantable sensor 150 described above, according to one example of the present disclosure. The implantable sensor 150 includes at least some of the substantially identical features and attributes of the implantable sensor including a motion-based transducer sensor component described above, except for the lack of physical coupling of the implantable sensor 150 to the IPG assembly 52; instead, the implantable sensor 150 is wirelessly electrically and communicatively coupled to the IPG assembly 52. ​​With this in mind, the interface block 66 need not provide a sensing port for the implantable sensor 150, or the sensing port may be used for a second sensor (not shown). In some embodiments, the circuitry 62 of the IPG assembly 52 and the circuitry of the implantable sensor 150 (not shown) communicate via wireless communication path 152 according to known wireless protocols such as Bluetooth, NFC, MICS, 802.11, etc., with each of the circuitry 62 and implantable sensor 150 including corresponding components for implementing the wireless communication path 152. In some examples, similar wireless paths are implemented to communicate with devices outside the patient's body to at least partially control the implantable sensor 150 and / or the IPG assembly 52, to communicate with other devices (e.g., other sensors) within the patient's body, or to communicate with other sensors outside the patient's body, as described in more detail below.

[0019] Regardless of how the implantable sensor 32 is associated with the IPG assembly 52, in some embodiments the implantable sensor 32 is configured to generate information indicative of sensed forces in three directions or axes. For example, in some embodiments the implantable sensor 32 is a three-axis accelerometer that may sense or measure static and / or dynamic forces of acceleration on three axes. Static forces include the constant force of gravity. By measuring the amount of static acceleration due to gravity, logic or programming (e.g., software) operating on information from the accelerometer sensor can figure out the angle at which the sensor is tilted relative to the Earth. By sensing the amount of dynamic acceleration, logic or programming operating on information from the accelerometer sensor can quickly identify which direction the sensor is moving. Single-axis and multi-axis models of accelerometers detect the magnitude and direction of acceleration (or acceleration as appropriate) as a vector quantity. In these and similar types of sensor constructions, the output from the implantable sensor may include vector quantities in one, two, or three axes. For example, FIG. 7A provides an axial orientation indication 200 of a three-axis accelerometer useful as an implantable sensor 32 in some non-limiting embodiments. The three axes and three outputs of a three-axis accelerometer are conventionally labeled X, Y, and Z, with the three axes X, Y, Z being mutually orthogonal. Using these and related constructs, an attempt may be made to implant the implantable sensor 32 within the patient's body such that the axes X, Y, Z are generally aligned with the plane or axis of the patient. For example, in FIG. 7B, the patient's body 202 can be seen as having a left side 204 and an opposite right side 206, along with an anterior portion 208 and an opposite posterior portion 210. A conventional coordinate system for the patient's body 202 includes an anterior-posterior (AP) axis and a lateral-medial (LM) axis as labeled in FIG. 7B, and a superior-inferior (SI) axis (vertical or head-to-toe) that is in the plane of the view of FIG. 7B.In the non-limiting embodiment of FIG. 7B where the implantable sensor 32 is a three-axis accelerometer disposed within the housing 60 of the IPG assembly 52, the implantable sensor 32 is positioned relative to the housing 60, which is positioned relative to the patient's body 202 such that the X, Y, and Z axes of the sensor are approximately aligned with the patient's body coordinate system. For example, the Z axis of the implantable sensor may be aligned with the AP axis, the X axis may be aligned with the LM axis, and the Y axis may be aligned with the SI axis. The patient's posture (including body position) may be specified with reference to the body coordinate system, such that the X, Y, and Z information from the sensor 32 may be used to determine the posture when the sensor axes X, Y, and Z are aligned with the body coordinate system axes. However, precise alignment may be difficult to achieve. Similar concerns may arise when the implantable sensor 32 is implanted at a location separate from the housing 60 of the IPG assembly 52. As described below, some methods of the present disclosure may include calibrating the information signaled from the implantable sensor 32 for possible misalignment between body coordinate system axes or other concerns related to determining or designating a patient's posture based on the information from the implantable sensor 32. The calibration of the present disclosure may also address other possible concerns, such as changing the orientation of the implantable sensor 32 (or the IPG assembly 52 having an embodiment in which the implantable sensor 32 is carried within a housing 60) relative to the patient's body after implantation. For example, for a particular patient and implantation location (e.g., a high BMI patient, a female patient, etc.), the pocket in which the device is implanted may change between a standing position and a lying position, and the calibration system and method of the present disclosure may account for these differences.

[0020] Returning to FIG. 1 , regardless of the type of implantable sensor 32, the posture module 34 is programmed to perform one or more actions, as described below, based on information from the implantable sensor 32 (e.g., the output of the implantable sensor 32 is an input to the posture module 34). Generally speaking, in some non-limiting examples, the posture module 34 is programmed to detect, determine, or designate the patient's current posture (including body position) based at least in part on information signaled by the implantable sensor 32. In other non-limiting examples, the posture module 34 is programmed to detect, determine, or designate that the patient is not in a particular posture (e.g., the patient is not supine) based at least in part on information signaled by the implantable sensor 32. As described below, some non-limiting embodiments of the present disclosure relate to methods for determining or designating a current posture, optionally including calibrating the information signaled from the implantable sensor 32. In some non-limiting embodiments, the posture module 34 is further programmed (or signals information suggestive of a specified current posture to another programmed module or engine) to perform one or more operations or routines related to control of the system 20 (e.g., controlling operation of the IMD 30, the implantable sensor 32, the external device 36, etc.). As described below, some non-limiting embodiments of the present disclosure relate to methods for operating based on a determined current posture. Other non-limiting examples of the present disclosure relate to methods for operating based on a determination that the patient is not in a particular or specified posture. The posture module 34 can further be programmed (or signals information suggestive of a specified current posture to another programmed module or engine) to provide information suggestive of a determined current posture (or other information that may be targeted by information from the implantable sensor 32) to the patient and / or caregiver. As described below, some non-limiting embodiments of the present disclosure relate to methods for generating and / or reporting information to the patient and / or caregiver.The posture module 34 (or logic similar to the posture module 34 as described below) may be incorporated into a separate module or engine programmed to perform a specific task (e.g., the logic of the posture module 34 as described below may be part of a therapy control engine and utilized to control the stimulation therapy delivered to the patient). The posture module 34 (or algorithms as described below) may reside partially or wholly with the IMD 30 (e.g., circuit 62 (FIG. 2)), partially or wholly with the external device 36, or with a separate device or component (e.g., the cloud, etc.).

[0021] Posture judgment As alluded to above, in some embodiments, the posture module 34 is programmed or designed (e.g., a suitable algorithm) to detect, determine or designate the patient's current posture based on information from the implantable sensor 32. At least in this context, the term "posture" may refer to at least identifying whether the patient is in a generally vertical or lying position, such as supine, prone, left lateral position (e.g., left lateral position), right lateral position (e.g., right lateral position), etc. In some instances, the term "posture" may be referred to as "posture."

[0022] In some examples, the attitude module 34 rejects non-attitude components from an accelerometer-type implantable sensor via low-pass filtering for each of the multiple axes of the accelerometer sensor. In some examples, attitude is determined at least in part via detecting a gravity vector from the filtered axes.

[0023] In some examples, one potential posture classification protocol implemented by posture module 34 involves determining whether the patient is active or stationary. In some examples, if the magnitude of a vector of acceleration measured via an accelerometer-type implantable sensor meets or exceeds a threshold (optionally for a period of time), the measurement may indicate the presence of a non-gravitational component indicative of non-sleep activity. In some examples, the threshold is about 1.15 G. Conversely, a measurement of acceleration of about 1 G (corresponding to the presence of only a gravitational component) may indicate stationary.

[0024] In some examples, one potential posture classification protocol implemented by posture module 34 includes determining whether at least an upper body portion (e.g., torso, head / neck) of the patient is in a generally vertical position (e.g., upright position) or lying down. In some examples, a generally vertical position may include standing or sitting. In some examples, this determination may involve observing the angle of the accelerometer-based implantable sensor between the Y axis and the gravity vector, which may be referred to as the y-direction cosine. In some examples, if such angle is less than 40 degrees, the measurement suggests that the patient is in a generally vertical position and therefore likely not asleep.

[0025] In some examples, if the measured angle (e.g., y-direction cosine) is greater than 40 degrees, the measured angle indicates that the patient is lying down. In this case, one exemplary posture classification protocol implemented by the posture module 34 includes classifying sub-postures, such as whether the patient is in a supine, prone, or lateral position. In some non-limiting examples, after identifying the likely lying positions, the posture classification protocol determines whether the patient is in a supine or prone position. In some examples, a supine state determination is made when the absolute value of the z-direction cosine (the angle of the accelerometer-type implantable sensor between the Z-axis (calibrated to represent the AP axis of the patient's body) and the gravity vector) is less than or equal to 45 degrees, and a prone state determination is made when the absolute value of the z-direction cosine is greater than or equal to 135 degrees. If neither of these criteria are met, the patient may be lying down on the left or right side (e.g., lateral position). Thus, in some non-limiting examples, the posture classification protocol performs further classification via pitch angle, where if the pitch angle is less than or equal to minus 45 degrees or greater than or equal to minus 135 degrees, the patient is designated as lying on the right side, and if the pitch angle is greater than or equal to 45 degrees or the pitch angle is less than or equal to 135 degrees, the patient is designated as lying on the left side. In some examples, a similar determination can be made using direction cosines.

[0026] The above description provides some non-limiting examples of some posture determination or designation protocols that may be implemented by posture module 34. Multiple other posture determination or designation techniques are also contemplated in this disclosure and may be a function of the type of implantable sensor 32 and / or other information provided by one or more additional sensors.

[0027] In some embodiments, the posture module 34 is programmed to distinguish between a supine sleep position and a near supine reclining position. For reference, the near supine reclining position may be a state in which the patient is on a reclining bed, on an adjustable type bed, lying on a sofa or the like and not trying to sleep (e.g., watching television), and sleeping in bed. The absolute vertical distance between the head and torso of a patient in a supine sleep position is less than the absolute vertical distance between the head and torso of a patient in a near supine reclining position. Alternatively or in addition, in some embodiments, the posture module 34 is programmed to take into account or characterize the position of the patient's neck and / or head and / or body (e.g., as part of determining the patient's rotational position during reclining). For example, the posture module 34 can be programmed to estimate the position of the patient's neck based on the position of the body. A determination that the patient's torso is slightly offset may mean that the head position is different. In some non-limiting embodiments, the systems and methods of the present disclosure can take into account or characterize the position of the patient's neck and / or head in conjunction with information from sensors with a microstimulator implanted in the patient's neck or sensors integrated into the stimulation leads. In other examples, two (or more) position-type sensors (e.g., accelerometers) can be provided, each implanted in a different region of the patient's body (e.g., torso, head, neck) and providing sufficient information to the posture module 34 to estimate the position of the patient's neck and / or head and / or body.

[0028] Additionally or alternatively, in some embodiments, the systems and methods of the present disclosure may include a posture module 34 programmed to determine or designate lying positions in addition to the four "primary" lying positions described above (i.e., supine, prone, left lateral, and right lateral). For example, and with further reference to FIG. 8, lying positions may be classified or characterized as including supine 220, prone 222, left lateral 224, right lateral 226, left supine 228, left prone 230, right supine 232, and right prone 234. 8 in a variety of ways, for example, when implantable sensor 32 is a 3-axis accelerometer, posture module 34 may be programmed to implement a 15 degree radial offset to the information received from implantable sensor 32 once a determination is made that the patient is lying down. Multiple other techniques may be used, and the number of lying positions that may be classified by posture module 34 is in no way limited to the information illustrated by FIG.

[0029] Additionally or alternatively, in some embodiments, the systems and methods of the present disclosure may include a posture module 34 programmed to determine or designate the patient's current posture or position utilizing a time analysis or probability-based approach. For example, the posture module 34 may be programmed to designate the current posture or position based on a time average of information from the implantable sensor 32 (e.g., a time averaging algorithm), thereby minimizing the effects of small artifacts in the information from the implantable sensor 32, e.g., due to arm movements, leg movements, jerking, etc., especially when the patient is asleep. By way of example, one approach to determine or designate that the patient is lying down and sleeping in a supine position may include reviewing the dot product of vector information from the implantable sensor 32 (e.g., the patient's head-to-toe vector information) and gravity or a vertical reference vector or head-to-toe (described in more detail below). If the patient is lying down and sleeping in a supine position, this dot product will be approximately zero. If the patient's limbs randomly jerk during sleep, the dot product of the corresponding vector information from the implantable sensor 32 with gravity or a vertical reference vector may no longer be approximately zero, even though the patient is still lying down and sleeping in a supine position. By utilizing time averaging or other probabilistic approaches, the posture module 34 will not assign a "new" posture or position to the patient in response to information generated by the implantable sensor 32 when the patient jerks his / her limb. However, in some embodiments, the temporal analysis or probabilistic approach can distinguish between the patient making small movements while sleeping and the patient getting out of bed upon awakening. In a related embodiment, the motion artifacts may be filtered by considering the overall magnitude of the vector information from the implantable sensor 32 over a short period of time. For example, when the patient is lying down and sleeping, the overall magnitude of the vector information from the implantable sensor 32 is approximately 1g, and when the patient jerks his / her limbs during sleep, this overall magnitude temporarily rises.Motion artifacts such as these can be filtered by ignoring temporary spikes of overall magnitude less than a predetermined duration (e.g., a few seconds). In other embodiments, a low-pass filter can be applied to the implantable sensor signal to achieve a similar result.

[0030] Additionally or alternatively, in some embodiments, the systems and methods of the present disclosure may include a posture module 34 programmed to determine or designate the patient's current posture or position utilizing other probability-based approaches. For example, the systems and methods may operate a program or algorithm to perform an action when the probability that the patient is in a particular posture exceeds a certain threshold. Depending on the function triggered by the detection, a low or high threshold may be appropriate. Similarly, the systems and methods of the present disclosure may optionally include taking an action when the probability that the patient is in a particular posture falls below a certain threshold. In yet other examples, the systems and methods of the present disclosure may include determining, based on information from the implantable sensor 32, that the patient is not in a particular posture (e.g., the system is programmed to take an action when information from the implantable sensor 32 is designated by the posture module 34 to suggest that the patient is not supine) or that the probability that the patient is not in a particular posture exceeds a threshold. As a non-limiting example, some of the probability-based approaches or techniques of the present disclosure may include correlating the likelihood that the patient is not in a particular posture with the likelihood that the patient is in a particular posture. For example, if the "specific position" is supine, then the relationship between the probability that the patient is not supine ("not_probability_supine") and the probability that the patient is supine ("probability_supine") may be correlated as follows: not_probability_supine=1-probability_supine In practice, there may be different error sources in determining "not_probability_supine" and "probability_supine". For example, if different sensors or algorithms are used for each determination, the above formula will not hold and therefore these two probabilities will be different. This extends to the probability of multiple attitude instructions, each with a different error source. For example, if one is interested in adding a bias to the algorithm to reduce sensitivity to one error source in "not_probability_supine", this may be different than the threshold utilized for "1-probability_supine".

[0031] Additionally or alternatively, the systems and methods of the present disclosure may include calibration to compensate, account for, or address the possibility that the location of the implantable sensor 32 within the patient's body (the location from which posture determination can be made) may be unknown and / or may have changed over time (e.g., movement due to changes in the implant pocket with changes in posture as described above, possible temporary reorientation). In some examples, the posture module 34 may be programmed (e.g., an algorithm) to perform such a calibration, such as when the patient is determined to be walking, because such behavior is consistent with a gravity vector (e.g., of an accelerometer optionally used as the implantable sensor 32) pointing downward. In some examples, the posture module 34 may be programmed to perform the calibration, for example, by measuring the gravity vector in at least two known patient orientations of the implantable sensor / accelerometer 32 orientation. In some embodiments, the output of the implantable sensor 32 is used to detect the patient's posture in terms of the patient's body coordinate system, and if the orientation of the implantable sensor 32 is such that the implantable sensor axes are not aligned with the body axes, a calibration can be applied to the information provided by the implantable sensor 32 to correct for or account for this misalignment.

[0032] In some embodiments, the calibration performed by the posture module 34 may include establishing or creating a vertical baseline gravity vector. For example, the vertical baseline gravity vector may be determined by the posture module 34 during times when the patient is deemed likely to be upright (e.g., based on various information such as information from the implantable sensor, information from other sensors, time of day, patient history, etc., the likelihood or probability that the patient is upright and / or engaged in an activity (e.g., walking) in which the patient is likely to be upright) and may be determined as a time average value during periods of higher activity. Once established, the vertical baseline gravity vector may be utilized by the posture module 34 to calibrate information subsequently received from the implantable sensor 32. The vertical baseline gravity vector may be determined / reset periodically (e.g., at predetermined intervals).

[0033] Additionally or alternatively, the calibration performed by the posture module 34 may include establishing or creating a horizontal baseline gravity plane (alternatively, a horizontal baseline vector or a “head-to-toe” vector (relative to the patient's anatomy)). For reference, a “vertical gravity vector” may be considered a vector truly aligned with the direction of gravity relative to the Earth. A “horizontal gravity plane” may be considered a plane truly perpendicular to the vertical gravity vector, and a horizontal gravity vector (such as a head-to-toe vector) may be considered a vector that exists only in the horizontal gravity plane. With this in mind, in some embodiments, the horizontal baseline gravity plane may be determined by the posture module 34 during a time when the patient is deemed likely to be lying down (e.g., based on various information such as information from the implantable sensor 32, information from other sensors, time of day, patient history, etc., a likelihood or probability that the patient is lying down and / or engaged in low activity (e.g., sleeping) that is likely to cause the patient to be lying down) and may be determined as a time average value during the period of lower activity. Once established, the horizontal baseline gravity plane can be utilized by the posture module 34 to calibrate information subsequently received from the implantable sensor 32. The horizontal baseline gravity plane can be determined / reset periodically (e.g., at predetermined intervals). In some embodiments, the horizontal baseline gravity plane can be determined by the cross product of various vectors obtained during periods of low activity to reduce or eliminate artifacts from rotation (e.g., the patient is lying down and changes position from back, stomach, side, etc.). The cross product of two vectors obtained from the implantable sensor 32 when the patient is considered lying down should be approximately equal to the vertical baseline gravity vector. Under circumstances where this is not true, it can be assumed that one or both of the vectors under consideration are not indicative of the patient in a lying down position and therefore are less useful (or used as the horizontal baseline gravity vector) in determining or specifying the horizontal baseline gravity plane.

[0034] Additionally or alternatively, the calibration performed by the posture module 34 may include establishing or creating a vertical baseline gravity vector and a horizontal baseline gravity plane (or a horizontal baseline gravity vector in the horizontal baseline gravity plane, otherwise) as described above (and useful for calibrating information from the implantable sensor 32 as part of a posture characterization or determination process) and verifying the usefulness of the calibration values ​​so obtained. For example, a dot product of a specified vertical baseline gravity vector and a specified vector of the horizontal baseline gravity plane is generated and compared to a threshold value. From this comparison, a usefulness of one or both of the specified vertical baseline gravity vector and the specified horizontal baseline gravity plane (or the specified horizontal baseline gravity vector) is generated. For example, if the dot product is close to zero, one or both of the specified vertical baseline gravity vector and the specified horizontal baseline gravity vector (or plane) may be verified and used to calibrate information from the implantable sensor 32.

[0035] Additionally or alternatively, the calibration performed by the posture module 34 may include receiving a predetermined vertical baseline gravity vector and one or more predetermined horizontal baseline gravity vectors (e.g., indicative of prone, supine, left lateral, right lateral positions) useful for calibrating information from the implantable sensor 32. The predetermined baseline gravity vectors may be input during the implant procedure (e.g., input by a clinician using the external device 36 in the operating room), as part of a programming appointment (e.g., after implantation, the patient mimics each target posture or position and the posture module 34 is prompted (e.g., via the external device 36) to indicate the corresponding vector information from the implantable sensor 32 as the predetermined baseline gravity vector), or as part of an at-home calibration procedure performed by the patient (e.g., the external device 36 is a smartphone operating a software application, etc.). In some embodiments, the posture module 34 is programmed to validate the usefulness of the predetermined baseline gravity vectors so generated. For example, the dot and / or cross product of each pair of predetermined baseline gravity vectors may be taken and an error check performed to ensure that all predetermined baseline gravity vectors are approximately vertical (i.e., within 5% of a truly vertical relationship). If any predetermined baseline gravity vector(s) are found to not be approximately vertical, the predetermined baseline gravity vector(s) may be further reviewed for their usefulness as a calibration factor or for possible other steps to be taken to obtain a viable predetermined baseline gravity vector(s). Conversely, if the error check confirms the viability of the predetermined baseline gravity vector, the predetermined baseline gravity vector may then be used to calibrate information from the implantable sensor 32. In yet other embodiments, the posture module 34 may be programmed such that the vectors are compared to a reference vector and, if there appears to be a difference, a notification may be provided to the patient and / or clinician to re-perform the predetermined baseline gravity vector entry procedure.

[0036] Additionally or alternatively, the calibration performed by the posture module 34 may include determining the orientation of the implantable sensor 32 within the patient's body based on polarity information of the respiratory and / or cardiac waveforms provided by or derived from the implantable sensor 32 and / or other suitable sensor components associated with the patient. In one embodiment, the motion signal is extracted or otherwise eliminated from the respiratory waveform because the motion signal has a significantly larger amplitude than the respiratory signal. In some examples, this extraction may be implemented via recognition of motion associated with the X-axis or Y-axis of the accelerometer sensor having a signal power significantly greater than the signal power of the Z-axis in the accelerometer sensor, for example, the accelerometer sensor is implanted such that its Z-axis is generally parallel to the anterior-posterior axis of the patient's body in some examples. If the patient's respiratory signal is maximal in a particular axis (not necessarily aligned with either X, Y, or Z), the motion artifacts can be eliminated by filtering the signal that is not aligned with the axis in which the respiratory signal is maximal. In one embodiment, the motion signal sensed via the accelerometer sensor may be differentiated from the respiratory signal sensed via the accelerometer according to high frequency content above a configurable threshold. Polarity information of the respiratory and / or cardiac waveforms may be reviewed, for example, to determine the likelihood that the patient is asleep (and thus lying down) and / or to determine the likelihood that the patient is engaged in greater activity (and thus upright). Upon determining that the patient is currently likely to be lying down and / or likely to be upright, the posture module 34 may be programmed to review the current information from the implantable sensor 32, and if the current information is not consistent with the determined likely body position (e.g., it is determined that the patient is likely to be lying down and the current information (e.g., vector information) from the implantable sensor 32 does not directly indicate that the patient is lying down), the posture module 34 may determine a calibration factor to be applied to the information from the implantable sensor 32 based on the difference between the current information and the expected information.

[0037] Additionally, alternatively, the calibration performed by the posture module 34 may include determining an expected change in information from the implantable sensor 32 upon awakening. Based on information (current and / or tracked / historical information) from the implantable sensor 32 and / or one or more additional sensors associated with the patient, it may be determined if the patient is likely asleep (and thus lying down) and if the patient is likely awakening from sleep and changing to an upright position (e.g., the patient gets out of bed in the morning after a night's sleep). Upon determining that the patient is likely currently changing position upon awakening from sleep, the posture module 34 may be programmed to review the current information from the implantable sensor 32, and if the current information is not aligned with the determined likely body position (e.g., it is determined that the patient is likely currently upright and the current information (e.g., vector information) from the implantable sensor 32 does not directly suggest that the patient is upright), the posture module 34 may determine a calibration factor to be applied to the information from the implantable sensor 32 based on the difference between the current information and the expected information.

[0038] Additionally or alternatively, the calibration performed by the posture module 34 may include reviewing current information from the implantable sensor 32 when the patient is likely to be asleep (and therefore likely to be lying down). For example, the posture module 34 may incorporate or receive information from an internal clock. With reference to information from the internal clock, the posture module 34 may be programmed to specify that the patient is likely to be lying down during certain times of the day (e.g., 9:00 PM-7:00 AM, etc.). The "likely to be lying down" time frame may be pre-programmed into the posture module 34 and / or may be learned over time (based on tracked / historical information). If it is determined that the patient is likely currently lying down, the posture module 34 can be programmed to review the current information from the implantable sensor 32, and if the current information is not consistent with the determined likely position (e.g., it is determined that the patient is likely currently lying down and the current information (e.g., vector information) from the implantable sensor 32 does not directly indicate that the patient is lying down), the posture module 34 can determine a calibration factor to be applied to the information from the implantable sensor 32 based on the difference between the current information and the expected information.

[0039] Additionally or alternatively, the calibration performed by the posture module 34 may include referencing information generated by a post-implant patient calibration program. The patient calibration program may be implemented as part of a software application operated by the external device 36 (e.g., the external device 36 may be a smartphone operating a software application, a custom external programmer operating a patient calibration routine, a remote control, etc., programmed to effectuate the patient calibration) to walk the patient through a calibration sequence in which the patient is prompted to assume various target postures or positions, and while the patient is in a particular posture or position, the posture module 34 is prompted to present current information from the implantable sensor 32 as corresponding to that particular posture or position. The results of this calibration sequence may be used to calibrate, adjust, or correct information later provided by the implantable sensor 32 and / or to "teach" the posture module 34 of different orientations of the implantable sensor 32 relative to the patient. In some embodiments, the software application is programmed to prompt the patient to assume a vertical position and to receive instructions indicating that the patient is in a vertical position to establish a predetermined vertical baseline gravity vector. Alternatively or in addition, the software application is programmed to prompt the patient to assume a horizontal supine position and to receive instructions indicating that the patient is in the horizontal supine position to establish a predetermined horizontal supine baseline gravity vector. Other baseline vectors can be determined from the established predetermined horizontal supine baseline gravity vector (e.g., a predetermined horizontal prone baseline gravity vector, a predetermined horizontal left lateral baseline gravity vector, a predetermined horizontal right lateral baseline gravity vector, etc.). In yet other embodiments, the software application can be programmed to prompt the patient to assume one or more of a vertical body position, a horizontal prone position, a horizontal left lateral position, and a horizontal right lateral position, and to receive corresponding instructions from the patient to establish a predetermined vertical baseline gravity vector, a predetermined horizontal prone baseline gravity vector, a predetermined horizontal left lateral baseline gravity vector, and a predetermined horizontal right lateral baseline gravity vector.

[0040] Additionally or alternatively, the calibration performed by the posture module 34 may include a clinician programming at least one patient position into the posture module 34 while the patient is in the operating room (e.g., during the implant procedure). For example, the clinician may program the posture module 34 in which the patient is currently lying down. Upon information that the patient is currently lying down (or some other position or body position), the posture module 34 may be programmed to review the current information from the implantable sensor 32, and if the current information is not consistent with the lying down position (e.g., the current information (e.g., vector information) from the implantable sensor 32 does not directly indicate that the patient is lying down), the posture module 34 may determine a calibration factor to be applied to the information from the implantable sensor 32 based on the difference between the current information and the expected information.

[0041] Controlling Behavior As described above, in some non-limiting embodiments, attitude module 34 is programmed to control one or more operational characteristics of system 20 based on the determined or specified attitude (or is in communication with another module or engine programmed to control operational characteristics based on the attitude determined or specified by attitude module 34).

[0042] For example, the posture module 34 may be programmed (or communicate with another programmed module or engine) to select or implement a particular operating mode of the IMD 30 based on the determined current posture. An "operating mode" of the IMD 30 may include one or more of stimulation parameters, sensing parameters, timing parameters, and diagnostic parameters. For example, the posture module 34 (or another module or engine provided in the system 20 that receives posture information from the posture module 34) may be programmed with various predefined stimulation therapy settings or modes suitable for different sleep positions of the patient (e.g., the stimulation therapy settings or modes for one sleep position (e.g., supine, prone, left lateral, right lateral, etc.) may be different from those for another sleep position). If the posture module 34 determines that the patient is in a particular posture, the IMD 30 is operated to implement the corresponding stimulation therapy setting or mode. In these and related embodiments, the posture module 34 (or another module or engine provided with the system 20 that receives posture information from the posture module 34) can be programmed to automatically switch operation of the IMD 30 between stimulation therapy settings in response to a determined change in the patient's posture. In still other optional embodiments, the posture module 34 is programmed to determine a dot product value from the vector information provided by the implantable sensor 32 as a threshold parameter for initiating (or interrupting) delivery of therapy from the IMD 30. In still other optional embodiments, if the posture module 34 determines that the patient is not in a particular posture or position, the IMD 30 operates to implement a specified mode or stimulation therapy setting. In these and related embodiments, the posture module 34 (or another module or engine provided with the system 20 that receives posture information from the posture module 34) can be programmed to automatically switch operation of the IMD 30 between stimulation therapy settings in response to a determination that the patient is not in a particular posture.In yet other optional embodiments, the systems and methods of the present disclosure include monitoring the patient for various postures in a particular sequence and then triggering a specified function when the sequence of postures is found to have occurred. In any of the examples of control of motion described in this disclosure, a particular control feature may be implemented when the patient is determined or estimated to be in a particular posture or when the patient is determined or estimated to be not in a particular posture.

[0043] Additionally or alternatively, in some embodiments, the posture module 34 may be programmed (or in communication with another module or engine of the system 20 programmed) to effect changes to a particular therapy delivered to the patient by the IMD 30 based on the determined posture and optionally other factors, which is similar to auto-titration. In these and related embodiments, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) may, for example, automatically increase or decrease one or more parameters of a particular stimulation therapy mode upon identifying, for example, that the patient is in a different stage of sleep. In some examples, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) incorporates algorithm(s) or programming that provide posture-based automatic amplitude adjustments, providing a relatively consistent correlation between the treatment amplitude and the determined posture.

[0044] For reference, stages of sleep are typically divided into non-rapid eye movement (non-REM) and rapid eye movement (REM). There are three stages of non-REM sleep: N1, N2, and N3. N1 occurs immediately after falling asleep and is typically characterized as "light sleep." During sleep, a person typically passes through three stages of non-REM sleep before entering REM sleep or stage. Obstructive sleep apnea may be less prevalent in N1 than in REM.

[0045] Additionally or alternatively, in some embodiments, the posture module 34 may be programmed (or in communication with another module or engine of the system 20 programmed) to effect a change in a particular therapy delivered to the patient by the IMD 30 under circumstances where the patient is likely to be in a light sleep state (e.g., N1) as derived from information of the implantable sensor 32. For example, the posture module 34 may be programmed to identify when the patient is likely to be sleeping or attempting to sleep, and to track changes in the patient's posture or position while the patient is deemed to be sleeping or attempting to sleep. In circumstances where the system 20 is programmed to deliver a therapy to the patient when the patient is sleeping, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) may be further programmed to modify a currently delivered therapy if it is determined that the patient is likely to be changing position while sleeping. For example, if it is determined that the patient has changed positions for a predetermined period of time (e.g., 5 minutes, 15 minutes, 30 minutes, etc.) or has changed positions more than once, the patient is likely in a lighter sleep state, and if the stimulation therapy continues to be delivered at a predetermined level, the stimulation may make it more difficult for the patient to enter a deeper sleep state. In these and other examples, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) can be programmed to prompt the IMD 30 to pause the stimulation therapy being delivered to the patient and / or to ramp down the intensity of the stimulation therapy being delivered to the patient. A "pause" can be considered, in some embodiments, as a rapid ramp down until the stimulation therapy is no longer delivered. The pause or ramp down can affect the predetermined period or some other parameter (e.g., respiratory cycle, determination of unchanged sleep position), and the IMD 30 is prompted to resume or ramp up the stimulation therapy being delivered to the patient.

[0046] Additionally or alternatively, in some embodiments, the posture module 34 may be programmed (or communicate with another module or engine of the system 20 programmed) to effect a change in a particular therapy delivered to the patient by the IMD 30 under circumstances where the patient is likely to temporarily exit a sleep state, as derived from information of the implantable sensor 32. For example, the posture module 34 may be programmed to identify when the patient is likely to be sleeping or attempting to sleep, and to track changes in the patient's posture or position while the patient is deemed to be sleeping or attempting to sleep. In circumstances where the system 20 is programmed to deliver a therapy to the patient when the patient is asleep, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) may be further programmed to modify a currently delivered therapy if it is determined that the patient is likely to temporarily exit a sleep state. For example, during times when the patient is normally asleep, the patient may awaken to go to the bathroom or get a drink of water, and if stimulation therapy continues to be delivered at a predetermined level during the temporary departure from sleep, the stimulation may be undesirable to the patient. Thus, in some embodiments in which the patient is determined to have a substantial change in posture during a period in which the patient is expected to be asleep, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) can be programmed to prompt the IMD 30 to pause the stimulation therapy being delivered to the patient and / or to ramp down the intensity of the stimulation therapy being delivered to the patient. In a related embodiment, the pause or ramp down may occur for a predetermined period of time and the IMD 30 may be prompted to resume or ramp up the stimulation therapy delivered to the patient, or alternatively, or in addition, the delivery of the stimulation therapy may be resumed or ramped up after expiration of a predetermined period upon determining that the patient has returned to a bed position, automatically after expiration of a predetermined period of time, and following a determination that the patient has not moved (e.g., an "auto-extend" pause).

[0047] In any of the above embodiments in which the posture module 34 operates to provide an automatic pause or ramp-down in a delivered therapy for a predetermined period of time, the posture module 34 may be further programmed (or in communication with another module or engine of the system 20 programmed) to incorporate or implement a pause or ramp-down extension at the end of the predetermined period under circumstances in which the patient is determined to be not in a sleep position, moving, etc. In any other embodiment, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) is programmed to provide an automatic pause function coupled to an automatic start time function. For example, the system 20 may be programmed to begin delivery of a therapy at a predetermined time (e.g., 10:30 p.m.), but after the predetermined time when the stimulation therapy is delivered, this automatic start time is automatically paused until it is estimated or determined (e.g., information from the implantable sensor 32 via the posture module 34) that the patient is asleep or likely to be asleep.

[0048] Additionally or alternatively, in some embodiments, the posture module 34 may be programmed (or communicate with another module or engine of the programmed system 20) to execute an alert-type action or routine under circumstances where the patient is in a position that is likely to result in poor sleep quality (and therefore likely to experience sleep disordered breathing) as derived from information of the implantable sensor 32. For example, the posture module 34 may be programmed to identify when the patient is likely to be sleeping or attempting to sleep, and when the patient is determined to be in a particular posture or position (e.g., supine) based on information from the implantable sensor 32, and the posture module 34 (or another module or engine provided in the system 20 and in communication with the posture module 34) is programmed to deliver an uncomfortable output to the patient intended to cause or prompt the patient to change orientation. For example, the IMD 30 may be prompted to increase the level of a currently delivered stimulation therapy or may be prompted to deliver rapid multi-pulse stimulation. Alternatively or in addition, the IPG assembly 52 may be prompted to vibrate. Alternatively, or in addition, an audio alert may be generated at one or both of the IPG assembly 52 and the external device 36.

[0049] Additionally or alternatively, in some embodiments, the posture module 34 may be programmed (or communicate with another module or engine of the programmed system 20) to one or more of begin, resume, or ramp up (e.g., increase intensity) the delivered stimulation therapy upon determining that the patient has entered or is likely to have entered a sleep state. For example, the posture module 34 may estimate or determine multiple current postures of the patient over time. If the multiple postures suggest that the patient has entered a sleep state based on stored algorithms or other predetermined parameters, the posture module 34 prompts the IPG assembly 52 to begin delivering the stimulation therapy. In related embodiments in which the posture module 34 is programmed to affect an "auto-pause" in the delivered stimulation therapy (e.g., in response to determining that the patient is awake or in a light sleep state), the posture module 34 is programmed to prompt resumption of the stimulation therapy upon determining that the patient has entered or is likely to have entered a sleep state based at least in part on posture information. In other related embodiments in which system 20 is programmed to ramp down a currently delivered stimulation therapy under one or more circumstances (e.g., in response to a determination that the patient is awake or in a light sleep state), posture module 34 is programmed to prompt a ramp up of the stimulation therapy upon determining, at least in part, that the patient has entered a deep or deeper sleep state based on the posture information.

[0050] Additionally or alternatively, in some embodiments, the posture module 34 may be programmed (or in communication with another module or engine of the system 20 programmed) to effect changes in a treatment protocol or mode, or other treatment parameters, based at least in part on learned or detected trends (e.g., sleep trends) of the patient over time, as derived from information of the implantable sensor 32. For example, the posture module 34 (or another module or engine of the system 20 in communication with the posture module 34) may be programmed to track or record posture (or other information) during times when the patient is deemed likely to be asleep, and the tracked information may include, for example, time of day, day of week, etc. From this information, the posture module 34 may determine the patient's sleep trends over time (e.g., one or more days, one or more weeks, or one or more months), e.g., the period during which the patient typically sleeps. The learned sleep trends determined by the posture module 34 may be further divided by day of the week or consecutive days of the week (e.g., weekend sleep trends and weekday sleep trends). The posture module 34 (or another module or engine of the system 20) can be further programmed to review the current time, current day of the week, or other sleep trend parameters along with the patient's current specified posture with the learned sleep trend information to prompt operation of the IMD 30 (e.g., to initiate or terminate delivery of a therapy, such as a stimulation therapy). For example, the current time and the determined current posture can be recorded as a data pair and compared to previously recorded sleep trend information to determine whether the current time and current posture suggest that the patient is likely to be entering or exiting a sleep state. Based on this comparison, the IMD 30 can be prompted to initiate delivery of a therapy (if the patient is likely to be entering a sleep state) or terminate delivery of a therapy (if the patient is likely to be exiting a sleep state).Alternatively or additionally, the current day of the week, the current time, and the current posture can be recorded as a data set and compared to previously recorded sleep trend information to determine whether the current time, the current day of the week, and the current posture suggest that the patient is likely to be entering or exiting a sleep state. Based on this comparison, the IMD 30 can be prompted to begin delivery of therapy (if the patient is likely to be entering a sleep state) or end delivery of therapy (if the patient is likely to be exiting a sleep state).

[0051] Additionally or alternatively, in some embodiments, posture module 34 may be programmed (or in communication with another module or engine of programmed system 20) to determine contextual information of the patient during periods when the patient is awake, as derived, at least in part, from information of implantable sensor 32. For example, contextual information such as activity level, pelvic floor pressure, etc., may be determined or estimated based on posture-related information alone or in combination with additional non-posture information.

[0052] Diagnostic Data As mentioned above, in some non-limiting embodiments, the posture module 34 is programmed to provide information to the patient and / or caregiver, for example via the external device 36, related to the determined current posture or other information suggested by the information from the implantable sensor 32. By way of reference, the IMD 30 may be configured to interface (e.g., via telemetry) with various external devices. For example, the external device 36 may include, but is not limited to, a patient remote, a physician remote, a clinician portal, a mobile device, a mobile phone, a smartphone, a desktop computer, a laptop computer, a tablet personal computer, and the like. The external device 36 may include a smartphone or other type of handheld (or wearable) device that is held and operated by the patient in whom the IMD 30 is implanted. In another example, the external device 36 may include a personal computer operated by a medical professional for the patient, and the like. The external device 36 may include a computing device designed to remain in the patient's home or a caregiver's office.

[0053] In view of the above, the posture module 34 may be programmed (or communicate with another module or engine of the programmed system 20) to identify information from the implantable sensor 32 indicative of the occurrence of Zwitterr's syndrome. "Zwitterr's syndrome" refers to the patient's intentional or unintentional rotation or other manipulation of the IPG assembly 52 within the skin pocket, which may lead to a malfunction of the IMD 30. For example, the logic (e.g., algorithm) of the posture module 34 may recognize a substantial change in the information from the implantable sensor 32, e.g., at a specified time. As a non-limiting example, the time may be designated as when the patient is likely to be in a supine position or posture (e.g., 1:00 a.m.), where if the information from the implantable sensor 32 is found to have a particular vector direction on the day prior to the specified time (or over several consecutive days prior to the specified time) and a substantially different vector direction (e.g., a substantially opposite vector direction) on the current day at the specified time, the implantable sensor 32 may be deemed to have likely flipped. If the implantable sensor 32 is carried within the housing of the IPG assembly 52, this same information may be considered to be indicative of a possible inversion of the IPG assembly 52. ​​Under these and similar circumstances, the posture module 34 may be programmed to notify or alert the clinician (via the external device 36) of the possible occurrence of Twiddler's Syndrome.

[0054] Alternatively or in addition, the posture module 34 may be programmed (or communicate with another module or engine of the programmed system 20) to identify information from the implantable sensor 32 indicative of the occurrence of device movement. For reference, in some embodiments, the sensor component of the implantable sensor 32 is implanted in the patient separately from the IPG assembly 52, while in other embodiments, the implantable sensor 32 is carried in a housing of the IPG assembly 52, which is then implanted in the patient. In any case, a typical implantation technique may include using a suture or similar attachment device to secure the subject device (e.g., the sensor component or the IPG assembly 52) to the patient's anatomy. Over time, the attachment between the device and the subject anatomy may degrade or deteriorate, and the device may then move away from the correct implantation location and / or orientation. With this in mind, the logic (e.g., algorithm) of the posture module 34 may recognize a change in information from the implantable sensor 32, for example, at a specified time, as indicative of possible device movement. As a non-limiting example, a time may be specified as when the patient is likely to be in a bed position or posture (e.g., 1:00 a.m.), and if information from the implantable sensor 32 is found to have a particular vector orientation that is changing over time, the implantable sensor 32 may be deemed to have likely moved from a first implanted location. If the implantable sensor 32 is carried within a housing of the IPG assembly 52, this same information may be deemed to indicate that the IPG assembly 52 may have moved. Under these and similar circumstances, the posture module 34 may be programmed to notify or alert the clinician (via the external device 36) of the likely occurrence of device movement.

[0055] Alternatively or in addition, the posture module 34 may be programmed (or communicate with another module or engine of the programmed system 20) to record posture-related information during certain activities of the patient and report it to the clinician and / or the patient via the external device 36. For example, the posture module 34 may record or determine one or more of the percentage of time the patient spends in each position during a sleep event, the effectiveness of the therapy delivered by the IMD 30 in each position during a sleep event, the self-titration therapy settings (e.g., amplitude, electrode configuration, pulse characteristics, etc.) in each position during a sleep event, etc. In related embodiments, the posture module 34 may operate (or communicate with) a sleep stage determination engine that may determine sleep stages. In some embodiments, such determinations are made according to the relative stability of respiration rate throughout the treatment period (e.g., during expected sleep time). In some non-limiting examples, the sleep determination engine determines and tracks awake time, bedtime, posture, sleep / wake cycles, and / or the number and depth of REM periods. In some examples, the posture module 34 can operate (or communicate) with a sleep quality engine to determine sleep quality, for example, according to a combination of sleep time parameters, sleep stage parameters, and severity index parameters (e.g., apnea-hypopnea index measurements). In some non-limiting embodiments, sleep stages can be determined via at least one of activity information, posture information, respiratory information, respiratory rate variability (RRV) information, heart rate variability (HRV) information, and heart rate information. Other information that can be tracked by the posture module 34 (or other modules or engines of the system 20) and delivered to the clinician and / or patient via the external device 36 can include one or more of apnea-hypopnea index, respiratory rate, sleep disordered breathing, peripheral capillary oxygen saturation (SpO2), heart rate, snoring, and the like. In yet other embodiments, the posture module 34 can be programmed to generate a posture notification at the external device 36 when stimulation (or other therapy) is being provided by the IMD 30.

[0056] Alternative Operating Modes In some non-limiting examples of the present disclosure, posture module 34 is programmed to detect posture changes and not necessarily detect or designate the patient's current posture (under some or all circumstances). For example, posture module 34 can be programmed or configured (e.g., operating logic or algorithms) such that when the patient is deemed or known to be asleep, posture module 34 does not detect or designate the patient's current posture (as do other modules or engines of system 20), but instead detects posture changes such as overall posture changes (e.g., moving from left lateral to supine, moving from supine to prone, etc.).

[0057] In other embodiments, the posture module 34 does not detect or determine posture (nor does any other module or engine of the system 20), but tracks the gravity vector of the implantable sensor 32 over time. In these and related embodiments, the posture module 34 is programmed or configured to allow a user (e.g., patient, caregiver, etc.) to define certain gravity vector orientations for the implantable sensor 32 (or for the IPG assembly 52, in which the implantable sensor 32 is carried within a housing of the IPG assembly 52) that may be associated with different operational modes. Any number of these defined vectors / modes may be established with varying ranges of influence. As a non-limiting example, the posture module 34 (or other module or engine of the system 20) may be programmed or configured to enable therapy delivery during a defined period of time when no or minimal movement by the patient is detected and the monitored gravity vector (or other monitored patient information related to posture) is within a predetermined range.

[0058] Additionally or alternatively, a change in the monitored gravity vector of a certain or predetermined magnitude can be used to reset the therapy ramp (e.g., therapy is being delivered at a predetermined level or intensity and a detected change in the monitored gravity vector is sufficient to prompt a ramp down of the delivered therapy level, with the ramp down or delivery of a lower level of therapy continuing until the monitored gravity vector returns to a predetermined range (e.g., suggesting a "change" in the patient's condition is complete) and the delivered therapy is ramped up to the predetermined level or intensity). In other embodiments, when monitoring the gravity vector over time, the system can be programmed to make changes in therapy based on at least one of the current vector, a change in the vector (e.g., vector, cosine calculation), or repeating changes in the vector (e.g., suggesting walking, breathing, etc.).

[0059] As alluded to in the above description, one or both of the IMD 30 and the external device 36 include a controller, control unit, or control portion that facilitates the execution of a specified action. FIG. 9A is a block diagram that generally represents a control portion 300 according to one example of the present disclosure. In some examples, the control portion 300 includes a controller 302 and a memory 304. In some examples, the control portion 300 provides an example implementation of a control portion that forms, implements, and / or manages a portion of any one of the devices, systems, assemblies, circuits, managers, engines, functions, parameters, sensors, electrodes, modules, and / or methods as depicted throughout the present disclosure in connection with FIGS. 1-8.

[0060] Generally, the controller 302 of the control portion 300 includes an electronics assembly 306 (e.g., at least one processor, microprocessor, integrated circuits, logic, etc.) and associated memory or storage devices. The controller 302 is electrically coupled to and communicates with the memory 304 to generate control signals to direct the operation of at least some devices, systems, assemblies, circuits, managers, modules, engines, functions, parameters, sensors, electrodes, and / or methods as represented throughout this disclosure (e.g., the posture module 34 (FIG. 1) may be a software program stored in a storage device, loaded into the memory 304, and executed by the electronics assembly 306). Additionally, in some examples, these generated control signals include, but are not limited to, using a therapy manager 308 stored in the memory 304 to at least manage a therapy delivered to the patient, e.g., a therapy for sleep disordered breathing, and / or manage and operate the detection of a specified body motion in a manner described in at least some examples of the present disclosure. It will be further appreciated that the control portion 300 (or another control portion) may also be used to operate the general functions of the various treatment devices / systems described throughout this disclosure.

[0061] In response to or based on commands received via a user interface (e.g., user interface 310 of FIG. 9C) and / or via machine-readable instructions, controller 302 generates control signals for implementing management and operation of therapy implementation, therapy monitoring, therapy administration, and / or sensing and control of specified body motions in accordance with at least some of the foregoing examples of this disclosure. In some examples, controller 302 is embodied in a general-purpose computing device, while in some examples, controller 302 is incorporated into or associated with at least some of the associated devices, systems, assemblies, circuits, sensors, electrodes, device components and / or managers, engines, parameters, functions, etc. described throughout this disclosure.

[0062] For purposes of this disclosure, when referring to the controller 302, in embodiments in which the electronics assembly 306 comprises or includes at least one processor, the term "processor" shall mean a currently or future developed processor (or processing resource) or microprocessor that executes a sequence of machine-readable instructions contained in a memory. In some examples, execution of a sequence of machine-readable instructions, such as instructions provided via the memory 304 of the control portion 300, causes the processor to perform actions, such as operating the controller 302 to implement sleep disordered breathing (SDS) therapy and related management and / or management and operation of detection of specified body movements, as generally described (or consistent with) in at least some examples of this disclosure. The machine-readable instructions, as represented by the memory 304, may be loaded into a random access memory (RAM) for execution by the processor from their storage location in a read-only memory (ROM), a mass storage device, or some other persistent storage (e.g., a non-transitory or non-volatile tangible medium). In some examples, memory 304 includes a computer-readable tangible medium that provides non-volatile storage of machine-readable instructions executable by a process of controller 302. In other examples, hard-wired circuitry can be used in place of or in combination with machine-readable instructions to implement the described functions. For example, electronics assembly 306 may be embodied as part of at least one application specific integrated circuit (ASIC), at least one integrated circuit, a microprocessor, and an ASIC, etc. In at least some examples, controller 302 is not limited to any particular combination of hardware circuitry and machine-readable instructions, nor is it limited to any particular source of machine-readable instructions executed by controller 302.

[0063] FIG. 9B is a diagram 320 that illustrates, in accordance with one example of the present disclosure, at least some of the ways in which the control portion 300 may be implemented. In some examples, the control portion 300 is implemented entirely within or by the IPG assembly 322, as described above in connection with FIG. 2, which has at least some of the substantially same features and attributes as the IPG assembly 52. ​​In some examples, the control portion 300 is implemented entirely within or by a remote control 330 (e.g., a programmer) outside the patient's body, such as the patient control 332 and / or the physician control 334. In some embodiments, the remote control 330 is similar to the external device 36 (FIG. 1) described above. In some examples, the control portion 300 is implemented partially within the IPG assembly 322 and partially within the remote control 330 (at least one of the patient control 332 and the physician control 334). In some examples, the control portion 300 may be implemented via a server accessible via the cloud and / or other network paths. In some examples, the control portion 300 may be distributed or allocated among multiple devices or resources, such as servers, IMDs, and / or user interfaces.

[0064] In some examples, in relation to the control portion 300, the user interface (310 in FIG. 9C) is implemented in a remote control 330. FIG. 9C is a block diagram that generally represents the user interface 310, according to one example of the present disclosure. In some examples, the user interface 310 forms part of and / or is accessible via a device external to the patient, by which the treatment system can be at least partially controlled and / or monitored. The external device hosting the user interface 310 may be a patient remote portion (e.g., 332 in FIG. 9B, e.g., a smartphone running a custom software application), a physician remote portion (e.g., 334 in FIG. 9B), and / or a clinician portal portion. In some examples, the user interface 310 includes a user interface or other display that provides simultaneous display, activation, and / or manipulation of at least some of the various systems, assemblies, circuits, engines, sensors, components, modules, functions, parameters, as described in relation to FIGS. 1-8. In some examples, at least some portions or aspects of the user interface 310 are provided via a graphical user interface (GUI), and may include a display and input.

[0065] Returning to FIG. 1 , information from the implantable sensor 32, including the motion-based transducer sensor component, can optionally be utilized to sense or detect other parameters associated with the patient, which may or may not include involuntary actions. Additionally, in some embodiments, the IMD 30 can be controlled to operate in response to involuntary actions by the patient, as sensed by the implantable sensor 32. Non-limiting examples of some possible control features implemented by the systems and methods of the present disclosure can include at least some of the substantially same features and attributes described in U.S. Patent Application No. 16 / 092,384, filed October 9, 2018, and entitled “ACCELEROMETER-BASED SENSING FOR SLEEP DISORDERED BREATHING (SDB) CARE,” the teachings of which are incorporated herein by reference in their entirety. In related embodiments, the systems of the present disclosure can include one or more additional implantable sensors (in addition to the implantable sensor 32). The information signaled by the one or more additional implantable sensors may optionally be used (along with information from implantable sensor 32) as part of recognizing or identifying the occurrence of a patient's posture, as described above. Alternatively, or in addition, the information signaled by the one or more additional implantable sensors may be used to monitor the patient, formulate a treatment regimen, etc., as described, for example, in U.S. Patent Application Serial No. 16 / 092,384.

[0066] Although specific examples have been illustrated and described herein, various alternative and / or equivalent implementations may be substituted for the specific examples illustrated and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.

Claims

1. A care system comprising: a first implantable sensor for detecting posture information of a patient; an implantable medical device (IMD) for delivering stimulation therapy to the patient; a posture module programmed to calibrate information signaled by the first implantable sensor to account for possible changes in a position of the first implantable sensor relative to the patient over time; Including, A care system, the care system being programmed to affect operation of the implantable medical device (IMD) based on the detected posture information.

2. 10. The system of claim 1, wherein the system is configured to provide care for a patient having sleep disordered breathing (SDB), the care comprising delivering an SDB stimulation therapy to the patient.

3. The system of claim 1 , wherein the posture module is programmed to determine that the patient is not in a specified posture based on the detected posture information.

4. The care system comprises: determining a current posture of the patient based on the detected posture information; storing a plurality of determined current postures over time; and modifying a currently delivered stimulation therapy if the plurality of determined current postures indicate the patient is in a light sleep state.

5. The care system comprises: determining a current posture of the patient based on the detected posture information; storing a plurality of determined current postures over time; and if the plurality of determined current postures indicates the patient has entered a sleep state, beginning or resuming delivery of a stimulation therapy.

6. 6. The system of claim 5, wherein the system is programmed to ramp up an intensity of a currently delivered stimulation therapy over a period of time upon determining that the patient has entered a sleep state.

7. 10. The system of claim 1, wherein the system is programmed to determine an overall change in posture from the detected posture information when the patient is deemed to be asleep.

8. 10. The system of claim 1, wherein the posture module is programmed to determine a vertical baseline gravity vector for calibrating information signaled by the first implantable sensor.

9. 9. The system of claim 8, wherein the posture module is programmed to determine the vertical baseline gravity vector as a time-averaged position during a plurality of periods during which the patient is designated as upright.

10. 10. The system of claim 1, wherein the posture module is programmed to determine a horizontal baseline gravity plane for calibrating information signaled by the first implantable sensor.

11. 11. The system of claim 10, wherein the first implantable sensor is configured to provide vector information in at least one of three orthogonal axes, and the posture module is further programmed to calibrate the vector information with respect to the horizontal baseline gravity plane.

12. 12. The system of claim 11, wherein the posture module is programmed to determine the horizontal baseline gravity plane based on information signaled by the first implantable sensor during at least one period during which the patient is designated as at least inactive or asleep.

13. 13. The system of claim 12, wherein the posture module is programmed to determine the horizontal baseline gravity plane as a time-averaged position during a plurality of periods during which the patient is designated as inactive.

14. 13. The care system of claim 12, wherein the horizontal baseline gravity plane implies a horizontal baseline gravity vector extending within the horizontal baseline gravity plane, and wherein the posture module is further programmed to verify the determined horizontal baseline gravity plane by reviewing a cross product of a horizontal vector included in the information signaled by the first implantable sensor during the at least one period during which the patient is designated as inactive.

15. 15. The system of claim 14, wherein the posture module is programmed to validate the determined horizontal baseline gravity plane when the reviewed cross product is approximately equal to a determined vertical baseline gravity vector.

16. 16. The care system of claim 15, wherein the posture module is programmed to determine a vertical baseline gravity vector and to validate the determined horizontal baseline gravity plane and the determined vertical baseline gravity vector by reviewing a dot product of the determined vertical baseline gravity vector and one or more horizontal baseline gravity vectors of the determined horizontal baseline gravity plane.

17. 2. The care system of claim 1, wherein the posture module is programmed to receive a predetermined vertical baseline gravity vector, a predetermined horizontal supine baseline gravity vector, a predetermined horizontal prone baseline gravity vector, a predetermined horizontal left lateral baseline gravity vector, and a predetermined horizontal right lateral baseline gravity vector to calibrate information signaled by the first implantable sensor.

18. The attitude module: a dot product of the predetermined vertical baseline gravity vector and at least one of the predetermined horizontal supine baseline gravity vector, the predetermined horizontal prone baseline gravity vector, the predetermined horizontal left lateral baseline gravity vector, and the predetermined horizontal right lateral baseline gravity vector; 18. The care system of claim 17, further programmed to verify the predetermined vertical baseline gravity vector, the predetermined horizontal supine baseline gravity vector, the predetermined horizontal prone baseline gravity vector, the predetermined horizontal left lateral baseline gravity vector, and the predetermined horizontal right lateral baseline gravity vector by reviewing at least one of the cross products of each pair of the predetermined horizontal supine baseline gravity vector, the predetermined horizontal prone baseline gravity vector, the predetermined horizontal left lateral baseline gravity vector, and the predetermined horizontal right lateral baseline gravity vector.

19. 2. The care system of claim 1, wherein the posture module is programmed to review at least one of the patient's sensed respiration information, the patient's sensed cardiac waveform polarity information, and the patient's sensed cardiac waveform phase change information to estimate an orientation of the first implantable sensor with respect to the Earth and calibrate the information signaled by the first implantable sensor.

20. The attitude module: executing a calibration routine to calibrate the information signaled by the first implantable sensor upon determining that the patient has aroused from a sleep state and changed posture; prompting the patient to assume different positions and receiving indications that the patient has assumed a particular position to calibrate information signaled by the first implantable sensor; The care system of claim 1 , programmed to perform at least one of the following:

21. 2. The care system of claim 1, wherein the posture module is programmed to receive at least one predetermined posture indication from a clinician after implantation of the first implantable sensor and to calibrate information signaled by the first implantable sensor.

22. 2. The care system of claim 1, wherein the posture module is programmed to calibrate information signaled by the first implantable sensor based on a predicted posture of the patient and to reference an internal clock in deriving the predicted posture of the patient.

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