Systems and methods for monitoring sleep based on surface biopotentials

Abstract

Systems and methods for biometric analysis are described. In some embodiments, a system may include a wearable device configured to be worn on a portion of an arm of a user while the user sleeps. The wearable device may include a plurality of electrodes disposed on an interior of the wearable device and configured to obtain biopotential signals from the user's arm. The system also may include a processor configured to analyze biopotential data derived from the biopotential signals to determine one or more characteristics relating to sleep of the user, and generate an output based on the one or more characteristics relating to the sleep of the user.

Description

PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1Systems and Methods for Monitoring Sleep Based on Surface BiopotentialsRELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 18 / 905,612, filed October 3, 2024. The following related applications are incorporated by reference in their entireties: U.S. Patent Application No. 17 / 933,287, filed September 19, 2022 and issued as U.S. Patent No. 11,762,473, U.S. Patent Application No. 18 / 161,052, filed January 28, 2023, and U.S. Patent Application No. 16 / 890,507, filed June 2, 2020 and issued as U.S. Patent No. 11,157,086.TECHNICAL FIELD

[0002] Various aspects of the present disclosure relate generally to systems and methods for collecting and using biopotential signals.BACKGROUND

[0003] Generally, gesture control may rely on gesture data. Arrangement and placement of electrodes of biopotential sensing wearable devices to gather biopotential signals may be a challenge. Moreover, in some cases depending on form factor, biopotential chips of biopotential sensing wearable devices have limited surface area and / or volume to gather not only the biopotential signals but also other relevant data (e.g., acceleration data and / or angular rate data). Thus an arrangement of signal processing components may also be a challenge.

[0004] The present disclosure is directed to overcoming one or more of these above -referenced challenges.SUMMARY OF THE DISCLOSURE

[0005] According to an aspect of the present disclosure, a system for monitoring sleep is provided. The system includes a wearable device configured to be worn on a portion of an arm of a user while the user sleeps. The wearable device includes a plurality of electrodes disposed on an interior of the wearable device and configured to obtain biopotential signals from the user's arm. The wearable device also includes a processor configured to analyze biopotential data derived from the biopotential signals to determine one or more characteristics relating to sleep of the user, and generate an output based on the one or more characteristics relating to the sleep of the user.

[0006] According to other aspects of the present disclosure, the system may include one or more of the following features. The wearable device may further include an accelerometer configured to output acceleration data indicating an acceleration of the portion of the user's arm, and a gyroscope configured to output angular rate data indicating an angular rate of the portion of the user's arm. The processor may be further configured to analyze the acceleration data and the angular rate data in combination with the biopotential data to determine the one or more characteristics relating to the sleep of the user. The wearable device may further include a sensor configured to detect heart rate or heart rate variability of the user, wherein the processor may be further configured to receive heart rate data or heart rate variability data from the sensor, and analyze the heart rate data or heart rate variability data inPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 combination with the biopotential data to determine the one or more characteristics relating to sleep of the user. The wearable device may further include a memory configured to store the biopotential data over multiple sleep sessions, and the processor may be further configured to analyze trends in the stored biopotential data across the multiple sleep sessions. The processor may be further configured to generate a sleep quality report based on the analyzed trends.

[0007] The one or more characteristics relating to the sleep of the user may include at least one of: sleep stages, sleep duration, sleep quality, sleep onset latency, number of microarousals during sleep, duration of microarousals during sleep, sleep efficiency, rapid eye movement (REM) sleep percentage, non-REM sleep percentage, body movements during sleep, or heart rate variability during sleep. The processor may be configured to determine the one or more characteristics relating to the sleep of the user by detecting a presence or absence of muscle atonia. The one or more characteristics relating to the sleep of the user may be an amount, onset, end, duration, or percentage of REM sleep. The processor may be configured to determine the one or more characteristics relating to the sleep of the user by detecting a change in one or more of signal quality, noise, or frequency variance of the biopotential signals. The one or more characteristics relating to sleep of the user may comprise whether the user is in REM sleep or non-REM sleep, and the processor may be configured to determine whether the user is in REM sleep or non-REM sleep by detecting a change in noise, signal amplitude, or frequency content of the biopotential signals.

[0008] The processor may be further configured to trigger an action based on the one or more characteristics relating to the sleep of the user. The action may comprise at least one of: adjusting environmental conditions in a sleeping area of the user, providing haptic feedback through the wearable device, sending a notification to a caregiver, or recommending changes in behavior or a sleep routine of the user. The processor may be further configured to predict cognitive performance of the user based on the one or more characteristics relating to the sleep of the user.

[0009] According to another aspect of the present disclosure, a method for monitoring sleep is provided. The method includes obtaining, by a plurality of electrodes disposed on an interior of a wearable device worn on a portion of an arm of a user while the user sleeps, biopotential signals from the user's arm. The method also includes analyzing, by a processor, biopotential data derived from the biopotential signals to determine one or more characteristics relating to sleep of the user, and generating, by the processor, an output based on the one or more characteristics relating to the sleep of the user.

[0010] According to other aspects of the present disclosure, the method may include one or more of the following features. The method may further include wearing the wearable device on a left arm of the user while the user sleeps. The one or more characteristics relating to the sleep of the user may include at least one of: sleep stages, sleep duration, sleep quality, sleep onset latency, number of microarousals during sleep, duration of microarousals during sleep, sleep efficiency, REM sleep percentage, non-REM sleep percentage, body movements during sleep, or heart rate variability during sleep. Determining the one or more characteristics relating to the sleep of the user may comprisePCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 detecting a presence or absence of muscle atonia. The one or more characteristics relating to the sleep of the user may be an amount, onset, end, duration, or percentage of REM sleep.[Oi l] According to another aspect of the present disclosure, a system for monitoring sleep is provided. The system includes a wearable device configured to be worn on a portion of an arm of a user while the user sleeps. The wearable device includes a plurality of electrodes disposed on an interior of the wearable device and configured to obtain biopotential signals from the user's arm. The wearable device also includes a processor configured to analyze biopotential data derived from the biopotential signals to determine whether the user is asleep or awake, and generate an output based on the determination of whether the user is asleep or awake.

[0012] According to other aspects of the present disclosure, the processor may be further configured to use the determination of whether the user is asleep or awake to detect or measure a number or duration of microarousals during sleep.

[0013] Additional objects and advantages of the disclosed technology will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of the disclosed technology.

[0014] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed technology, as claimed.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary aspects and together with the description, serve to explain the principles of the disclosed technology.

[0016] FIG. 1 depicts an example environment for gesture control using a wearable device.

[0017] FIGS. 2A-2C depict block diagrams of aspects of a wearable device.

[0018] FIGS. 3A-3C depict schematic diagrams of aspects of a biopotential sensor of a wearable device.

[0019] FIGS. 4A-4D depict graphics of different arrangements of hub electrodes of a wearable device.

[0020] FIGS. 5A-5E depict graphics of different aspects of a biopotential sensor of a wearable device with hub electrodes and wristband electrodes.

[0021] FIGS. 6A-6D depict graphics of different aspects of wristband electrodes of a biopotential sensor.

[0022] FIGS. 7A-7B depict graphics of different aspects of hub electrodes disposed in a curved arrangement.

[0023] FIGS. 8A-8B depict graphics of different aspects of electrodes of a biopotential sensor.

[0024] FIGS. 9A and 9B depict flowcharts of routines of a wearable device.

[0025] FIG. 10 shows exemplary hardware of a wrist wearable to be worn by a user.

[0026] FIG. 11 shows an exemplary generation of nerve data to be used by the system.PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1

[0027] FIG. 12 shows an exemplary machine learning model trained to generate and output one or more characteristics relating to sleep associated with input sensor data.

[0028] FIG. 13 shows an exemplary machine learning model that is trained to generate an assessment of sleep based on input sensor data.

[0029] FIG. 14. depicts a flowchart of an exemplary method of monitoring sleep.

[0030] FIG. 15 depicts an example system that may execute techniques presented herein.DETAILED DESCRIPTION

[0031] In general, the present disclosure is directed to methods and systems for gesture control using biopotential sensing wearable devices. As discussed in detail herein, a wearable device of the present disclosure may be configured to be worn on a portion of an arm of a user. The wearable device may include a plurality of electrodes disposed on an interior of the wearable device and configured to obtain biopotential signals from the user’s arm. The wearable device may also include a biopotential chip. The biopotential chip may be configured to output, directly or indirectly, biopotential data, acceleration data, and / or angular rate data, or derivatives thereof (“gesture data”), to a machine learning classifier. The biopotential chip may include an accelerometer, a gyroscope and biopotential signal processing components on the same substrate. The machine learning classifier may be configured to generate, based on the gesture data, a gesture output indicating a gesture performed by the user.

[0032] In some cases, the biopotential device may include switches or a multiplexer to dynamically rearrange signal pathways between the plurality of electrodes and analog inputs on the biopotential chip (and / or other biopotential chips). In this manner, the wearable device may be reconfigured based on remote instructions (e.g., from a server) or over time (as a user provides feedback during training). Thus, the wearable device may improve over time without requiring hardware replacement of components.

[0033] In some cases, the plurality of electrodes may include one or more wristband electrodes and / or a plurality of hub electrodes in a hub. In this manner, the wristband electrodes may enable the wearable device to sense biopotentials away from the hub and increase a range of gesture detection.

[0034] In some cases, the hub electrodes may be arranged in a curved manner. In this manner, the hub electrodes provide increased signal quality across the hub electrodes, especially in contrast to flatly arranged hub electrodes near the edges of a hub.

[0035] Thus, methods and systems of the present disclosure may be improvements to computer technology and / or gesture detection technology using biopotential data.Environment

[0036] FIG. 1 depicts an example environment 100 for gesture control using a wearable device 110. The environment 100 may include a user 105, the wearable device 110, a user device 115, local device(s) 120, network(s) 125, and a server 130. The wearable device 110 may obtain gesture data, so that a gesture output can be generated (e.g., by the wearable device 110, the user device 115, the server 130). The gesture output may indicate a gesture performed by the user 105. The wearable device 110,PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 the user device 115, and / or the server 130 may then perform one or more command actions based on the gesture output, such as control remote devices (e.g., robots, UAMs, or systems), control local devices, such as the user device 115 or the local devices 120, and the like.

[0037] The user 105 may wear the wearable device 110 on a portion of an arm of the user 105, such as the wrist and / or the forearm of the user 105. The wearable device 110 may be gesture control device, a smartwatch, or other wrist or forearm wearable (e.g., a smart sleeve).

[0038] In some cases, the user device 115 may be a personal computing device, such as a cell phone, a tablet, a laptop, or a desktop computer. In some cases, the user device 115 may be an extended reality (XR) device, such as a virtual reality device, an argument reality device, a mixed reality device, and the like.

[0039] The local device(s) 120 may be other information technology devices in environments, such as the home, the office, in public, and the like. The local device(s) 120 may include speakers (e.g., smart speakers), TVs, garage doors, doors, cars, internet of things (loT) devices that control various electrical and mechanical devices. Thus, local device(s) 120 may generally be any software controllable device or system that can receive action commands from the wearable device 110 or the user device 115 based on gesture outputs.

[0040] The network(s) 125 may include one or more local networks, private networks, enterprise networks, public networks (such as the internet), cellular networks, satellite networks, to connect the various devices in the environment 100. In some cases, the wearable device 110 may connect to server 130 (or local device 120) via the user device 115 and / or network(s) 125, while in some cases the wearable device 110 may connect to the server 130 (or a local device 120) directly or via the network(s) 125. For instance, in some cases, the wearable device 110 may connect to the local device 120 over a short range communication standard (such as Bluetooth or WIFI) and connect to the server 130 via a longer range communication standard (such as 4G, 5G, or 6G cellular communications, or satellite communications) .

[0041] The server 130 may perform certain actions, such as host ML classifiers, provide software updates to components of the environment 100, and provide personalization data for the wearable device 110. In the case of hosting ML classifiers, the server 130 may receive requests from the wearable device 110 (e.g., via user device 115 or not) to generate a gesture output (e.g., using a certain ML classifier) based on gesture data; process the request to generate the gesture output; and transmit the gesture output and / or an action command based on the gesture output to the wearable device 110. In some cases, the user device 115 may host ML classifiers and perform the same process for the wearable device 110. In some cases, the wearable device 110 may host the ML classifiers and perform the process onboard the wearable device 110.

[0042] In the case of providing software updates to components of the environment 100, the server 130 may transmit software updates and / or ML classifiers updates to the wearable device 110 (e.g., to change certain features thereon), transmit software features and / or ML classifiers updates to the userPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 device 115 (e.g., to change certain features thereon), and / or transmit software updates to the local device(s) 120 (to change certain features thereon). In some cases, the software updates may change what gesture output corresponds to what action command. In some cases, for the wearable device 110, the software updates may change how biopotential signals are processed onboard the wearable device 110, such configurations of connection states (as discussed herein), how encryption is handled, how communications are handled, and the like.

[0043] FIGS. 2A-2C depict block diagrams 200A, 200B, and 200C of aspects of a wearable device 110. The aspects of the wearable device 110 in block diagrams 200A, 200B, and 200C may apply to the wearable device 110, as discussed in FIG. 1 above.

[0044] In FIG. 2A, diagram 200A may depict a biopotential sensor 205, a central processing unit 210 (“CPU 210”), a memory 215, a display / user interface 220 (“UI 220”), a haptic feedback module 225 (e.g., a vibration motor), and a machine learning classifier 230 (“ML classifier 230”) in a wearable device 110.

[0045] The biopotential sensor 205 may detect gesture data (e.g., biopotential signals, acceleration data, and / or orientation data of a portion of a user’s arm). In some cases, the biopotential chip 250 may have the ML classifier 230 onboard and the biopotential chip 250 may provide the gesture data to the ML classifier 230, so that the ML classifier 230 may generate a gesture output indicating a gesture performed by the user 105. In some cases, the biopotential chip 250 may relay the gesture data to the ML classifier 230 (e.g., in the CPU 210 or outside the wearable device 110, such as in the user device 115, a local device 120, and / or the server 130). Further details of the biopotential sensor 205 are discussed herein.

[0046] The memory 215 may store instructions (e.g., software code) for an operating system (e.g., a wearable device O / S) and at least one application, such as a biopotential sensor application. The memory 215 may also store data for the wearable device 110, such as user data, configurations of settings, and the like, but also biopotential sensor data. The biopotential sensor data may include various bits of data, such as raw biopotential data for gesture data, processed gesture data, gesture outputs, user feedback for the same, and the like.

[0047] The CPU 210 may execute the instructions to execute the O / S and the at least the biopotential sensor application. The O / S may control certain functions, such as interactions with the user 105 via the UI 220 and / or the haptic feedback 225. The UI 220 may include a touch display, display, a microphone, a speaker, and / or software or hardware buttons, switches, dials, and the like. The haptic feedback 225 may be an actuator to cause movement of the wearable device 110 (e.g., a vibration and the like) to indicate certain states or data. The CPU 210 may also include a communication module to send and receive communications to, e.g., the server 130, the user device 115, and / or the local device(s) 120.

[0048] The biopotential sensor application, via the CPU 210, may also interact with the user via the UI 220 and / or the haptic feedback 225. In some cases, the biopotential sensor application, via the CPUPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1210, may send and receive communications to, e.g., the server 130, the user device 115, and / or the local device(s) 120. In some cases, the biopotential sensor application, via the CPU 210, may instruct the biopotential sensor 205 to change connection states, such as from gesture detection mode to ECG detection mode, and the like, as discussed herein. In some cases, the biopotential sensor application, via the CPU 210, may interface between the biopotential sensor 205 and the O / S.

[0049] The ME classifier 230 may, based on the gesture data, generate the gesture output indicating the gesture performed by the user 105. As discussed above, the ML classifier 230 may be hosted on the wearable device 110, the user device 115, or the server 130. Generally, the ML classifier 230 may be a trained ML model to classify a gesture based on one or more of biopotential signals, acceleration data, and / or orientation data of a portion of a user’s arm). Lor instance, the ML classifier 230 may be trained on a training dataset (e.g., gesture data and / or labels) in a supervised, an unsupervised, or semisupervised manner. In some cases, the ML classifier 230 may output a result set of gestures with confidence values, and select a gesture with a highest confidence value as an identified gesture. In some cases, the ML classifier 230 may only identify a gesture if a confidence value is above a threshold, further details for ML classification of gestures may be found in U.S. Patent Nos. 10,070,799, 10,802,598, 11,199,908, and 11,157,086, and U.S. Patent Application Nos. 16 / 196,462, 16 / 774,825, and 16 / 737,252, each of which is incorporated by reference herein in its entirety. For instance, the gestures may include: index finger lift, index finger lift-and-hold, index finger swipe, thumbs up, wrist roll (e.g., palm open, fist closed, index finger or thumb extended), wrist shake, and others.

[0050] In FIG. 2B, diagram 200B shows a first embodiment of the biopotential sensor 205. In this case, the biopotential sensor 205 may include a biopotential chip 250 and a neural front end 255 (“NFE 255”). The NFE 255 may include an analog front end 250D of the biopotential chip 250 and electrodes 235 and signal pathway components 240 off of the biopotential chip 250. The biopotential chip 250 may include a processor 250A, an inertial measurement unit 250B (“IMU 250B”), an encryption module 250C, the analog front end 250D, analog-to-digital converters 250E (“ADCs 250E”), and a communications module 25 OF (“comms module 25 OF”). The biopotential chip 250 may be manufactured as an integral unit and have all of the processor 250A, the IMU 250B, the encryption module 250C, the analog front end 250D, the ADCs 250E, and the communications module 25 OF located on a common unitary substrate.

[0051] The electrodes 235 may each be metal configured to contact a portion of skin to detect a biopotential signal. For instance, the electrodes 235 may include a plurality of electrodes 235 disposed on an interior of the wearable device 110 and configured to obtain biopotential signals from the user’s arm. In some cases, the electrodes 235 may be a solid metal electrode with a face of various shapes, e.g., a polygon, a square, a circle, an arc segment, a circle sector (with or without extending to a center of the circle), and the like. The face may be configured to contact the portion of the skin. The face may be flat or curved (e.g., a dome of a certain radius). The solid metal electrode may be made of stainless steel, and the like. The solid metal electrode may extend from the face for a given length. In some cases,PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 the solid metal electrode may include a threaded portion to engage a first retention member that has a corresponding opposite threaded portion. In some cases, the solid metal electrode may include a pressure fit portion that engages a second retention member that pressure fit holds the solid metal electrode via the pressure fit portion. In some cases, the first or second retention member may retain the solid metal electrode to a housing (e.g., of a wristband electrode) or a housing of a hub. In some cases, the solid metal electrode may be an “active electrode” that buffers biopotential signals. In this case, the solid metal electrode may also include a printed circuit board (PCB) and signal pathway components 240 for active buffering of the biopotential signal (hereinafter “buffer components”). For instance, the buffer components may include one or combinations of an amplifier, a capacitor, a power source, a filter, and the like.

[0052] In some cases (e.g., on a wristband), the electrodes 235 may be metal filament grouped in certain arrangements. For instance, the metal filament may be sewn into (e.g., in the case of a textile) or placed onto (e.g., in the case of a rubber or other material) an interior face of a wristband into various shapes, e.g., a polygon, a square, a circle, an arc segment, a circle sector (with or without extending to a center of the circle), and the like. In some cases, the metal filament electrode may be an “active electrode” that buffers biopotential signals. In this case, the metal filament electrode may be connected to a PCB and buffer components for active buffering of the biopotential signal. The metal filament electrode may be proximately located to the PCB and buffer components, such as on a housing protecting the PCB and buffer components, or on an opposite side of a wristband from the housing with the PCB and buffer components. In some cases, the housing for the PCB and buffer components may be attached to the wristband, embedded in the wristband, surround the wristband, or separate and reconnected the wristband, and the like. In some cases, the housing may be a rigid material (e.g., rubber or plastic). In some cases, the housing may be a laminate or shielded textile.

[0053] In some cases, the wearable device 110 is a smartwatch and the plurality of electrodes 235 are disposed in a circular arrangement on an inner surface of a hub of the smartwatch. In this case, the plurality of electrodes 235 may be configured to contact a top of the user’s arm when the smartwatch is worn. In some cases, the biopotential chip 250 may be disposed in the hub of the smartwatch. In some cases, at least one of the plurality of electrodes 235 is a wristband electrode. The wristband electrode may be disposed on an interior surface of a wristband of the smartwatch. The wristband electrode may be configured to contact a portion of the user’s arm different than the top of the user’s arm when the smartwatch is worn. The wristband electrode may be electrically coupled to the biopotential chip 250 disposed in the hub of the smartwatch.

[0054] The signal pathway components 240 may include electrical conductors (e.g., metal wires that are insulated or not), traces, and the like . In some cases, the signal pathway components 240 may include switches to change signal pathways of biopotential signals.

[0055] The analog front end 250D (see, generally, FIGS. 3A-3C) may include a plurality of analog inputs 305 (see FIG. 3 A) configured to be coupled to and receive the biopotential signals from thePCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 plurality of electrodes 235. In some cases, one or more of the plurality of analog inputs 305 may be coupled to respective differential amplifiers 315 (see FIG. 3A). The differential amplifiers 315 may be configured to amplify differences in signals between pairs of electrodes.

[0056] The ADCs 250E may include a plurality of ADCs. The ADCs 250E may be configured to convert the biopotential signals to biopotential data. For instance, the ADCs 250E may be connected to outputs of corresponding differential amplifiers 315 and may convert the differential signals to biopotential data.

[0057] The IMU 25 OB may be disposed onboard the biopotential chip 250. The IMU 25 OB may include at least an accelerometer and a gyroscope. The accelerometer may output acceleration data of a portion of a user’s arm and the gyroscope may output orientation data (e.g., an angular position or angular rate) of a portion of a user’s arm.

[0058] The processor 250A may be configured to process the biopotential data outputted by the ADCs 250E, the acceleration data outputted by the accelerometer of the IMU 250B, and / or the orientation data outputted by the gyroscope of the IMU 250B (collectively, “initial gesture data”). For instance, the processor 250A may time sync the initial gesture data, format the initial gesture data for transmission, and send the initial gesture data (as processed into gesture data) to the comms module 250F.

[0059] In some cases, the processor 250A may encrypt the initial gesture data using the encryption module 250C. For instance, to encrypt the initial gesture data, using the encryption module 250C, the encryption module 250C may store (and, optionally generate) a private biopotential key and a public biopotential key, and store one or more external public keys corresponding to the ML classifier, the CPU 210, the device 115, or the server 130. The processor 250A (or the encryption module 250C) may retrieve the private biopotential key and an external public key corresponding to a destination (e.g., the ML classifier, the CPU 210, the device 115, orthe server 130), and encrypt the initial gesture data using the private biopotential key and an external public key. The processor 250A may transmit, e.g., separately or in a same packet or a first packet), the public biopotential key to one or more of the ML classifier, the CPU 210, the device 115, orthe server 130 (referred to as “endpoint”). The endpoint may store the public biopotential key. The endpoint may have a corresponding private key to the external public key. The endpoint may transmit the public key to the processor 250A, so that the processor 250A may store it in encryption module 250C. The endpoint may use the public biopotential key and its private key to decrypt any encrypted gesture data received from the biopotential chip.

[0060] In some cases, the processor 250A may normalize the initial gesture data. For instance, to normalize the initial gesture data, the processor 250A may map the initial gesture data into a defined range of values based on data type. In some cases, the biopotential data outputted by the ADCs 250E may be scaled (e.g., proportionally in accordance with the values of the biopotential data with respect to a maximum biopotential signal value) between a first value (e.g., 0) and a second value (e.g., 1 or 100, and the like), In some cases, the acceleration data outputted by the accelerometer of the IMU 250B may be scaled (e.g., proportionally in accordance with the values of the acceleration data with respectPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 to a maximum acceleration value) between a first value (e.g., -1) and a second value (e.g., 1). In some cases, the orientation data outputted by the gyroscope of the IMU 25 OB may be scaled if the orientation data includes rates of change (e.g., rotational velocity or rotational acceleration) of orientation between a first value (e.g., 0) and a second value (e.g., 1 or 100, and the like). By normalizing the initial gesture data using the processor 250A of the biopotential chip, the initial gesture data may be better formatted for analysis by a classifier.

[0061] The comms module 25 OF may then transmit the gesture data to the ML classifier 230, whether the ML classifier is onboard the wearable device 110, the user device 115, or the server 130. For instance, the comms module 25 OF may transmit the gesture data to the CPU 210, so that the CPU 210 may process it (e.g., via the biopotential application) or transmit the gesture data to the user device 115 or the server 130.

[0062] In some cases, the processor 250A may control connection states between electrodes 235 and biopotential chips, an ECG chip 270, or specific differential amplifiers within biopotential chips, as discussed herein. In these cases, the processor 250A may cause switches or a multiplexer to change signal pathways from form a currently active connection state (for a first mode) to a new active connection state (for a second mode). For instance, the connection states may correspond to various modes, such as a biopotential sensing mode, a training mode, an ECG detection mode, right arm mode, left arm mode, an impendence measurement mode, and the like.

[0063] In some cases, the switches or multiplexer may be configured to apply a plurality of connection states between the plurality of electrodes 235 and the differential amplifiers (of a same or a different biopotential chip) or analog inputs of an ECG chip. For instance, in some cases, the switches or multiplexer may apply a first connection state in which a first pair of electrodes of the plurality of electrodes 235 is connected to a first differential amplifier. The first differential amplifier may be configured to amplify a difference in signals obtained by the first pair of electrodes in the first connection state. The switches or the multiplexer may then apply a second connection state in which a second pair of electrodes of the plurality of electrodes 235 is connected to the first differential amplifier, and the first differential amplifier may be configured to amplify a difference in signals obtained by the second pair of electrodes in the second connection state. In some cases, at least one of the electrodes of the second pair of electrodes is not included in the first pair of electrodes.

[0064] In FIG. 2C, diagram 200C shows a second embodiment of the biopotential sensor 205. In this case, the biopotential sensor 205 may include the biopotential chip 250 with at least one other biopotential chip, such as second biopotential chip 265, and an ECG chip 270. In some cases, the biopotential sensor 205 may be connected to different sets of electrodes 235, such as hub electrodes 235A and wristband electrodes 235B. In some cases, the hub electrodes 235A may have signal pathway components 240A that are the same or different than signal pathway components 240B for the wristband electrodes 235B. For instance, the signal pathway components 240B for the wristband electrodes 235B may be located proximate the wristband electrodes 235B (e.g., outside a housing of the biopotentialPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 sensor 205 and on a wristband). As the wristband electrodes 235B may be outside the housing of the biopotential sensor 205, the signal pathway for biopotential signals from the wristband electrodes 235B may pass through a wrist signal port 260.

[0065] In some cases, the biopotential signals from the hub electrodes 235A and the wristband electrodes 235B may be routed to a same or different biopotential chip, or switched between biopotential chips. For instance, due to form factor and / or chip sizing constraints, different (e.g., pairings of) biopotential signals may be processed on different biopotential chips. In some cases, the biopotential chips may process the biopotential signals differently. Generally, the processor 250A may instruct switches or a multiplexer to route certain biopotential signals to certain biopotential chips (or certain differential amplifiers of a biopotential chip) by changing a connection state between electrodes 235 and biopotential chips (or differential amplifiers of a biopotential chip).

[0066] In some cases, the hub electrodes 235A and the wristband electrodes 235B may be connected to the biopotential chip 250 in a first connection state (e.g., by switches or a multiplexer), and the hub electrodes 235A and the wristband electrodes 235B may be connected to the second biopotential chip 265 in a second connection state (e.g., by switches or a multiplexer). For instance, the switches or multiplexer may be controlled by the processor 250A to change the connection state between the first connection state (for a first mode, such as biopotential sensing mode) and the second connection state (for a second mode, such as a training mode).

[0067] In some cases, the hub electrodes 235A may be connected to the biopotential chip 250, while the wristband electrodes 235B may be connected to the second biopotential chip 265 (or vice versa). In some cases, a first subset the hub electrodes 235 A may be connected to the biopotential chip 250, a first subset the wristband electrodes 235B may be connected to the biopotential chip 250, a second subset the hub electrodes 235A may be connected to the second biopotential chip 265, and a second subset the wristband electrodes 235B may be connected to the second biopotential chip 265.

[0068] In some cases, all (or subsets of) the hub electrodes 235A and the wristband electrodes 235B may be selectively connected (e.g., by switches or a multiplexer, in a third connection state) to the ECG chip 270. The ECG chip 270 may also be connected to an ECG electrode 275, which may be different from the hub electrodes 235A and wristband electrodes 235B and located on the biopotential sensor such that the ECG electrode 275 would not ordinarily contact the wrist of the person. For instance, the switches or multiplexer may be controlled by the processor 250A to change the connection state between the first connection state or the second connection state to the third connection state. For example, a processor of the biopotential sensor 205 may detect that a user has contacted the ECG electrode (e.g., with one or more fingers of the hand opposite the arm on which the biopotential sensor 205 is worn), and in response to determining that the user has contacted the ECG electrode, the system may switch the signal pathway components for the hub electrodes and / or wristband electrodes such that at least some of the signals from these electrodes are directed to the ECG chip 270.PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1

[0069] The ECG chip 270 may process the biopotential signals from all (or subsets of) the hub electrodes 235A and the wristband electrodes 235B and the biopotential signal from the ECG electrode 275, and generate ECG data. The ECG data may be a digital signal based on the biopotential signals. The ECG chip 270 may transmit the ECG data to an ECG processor 280. The ECG processor 280 may receive the ECG data and produce an electrocardiogram based on the ECG data. For instance, the ECG chip 270 (to generate the ECG data, or the ECG processor 280 based on the digital signal) may fdter power line interference (e.g., 60 Hz in the US), and measure frequency of cardiac pulses (e.g., heart rates). For instance, cardiac pulses of a cardiac signal may have three (3) primary structures, that are areas of a waveform for the cardiac signal. In some cases, the ECG chip 270 may detect the primary structures and compare magnitudes and relative magnitudes of the detected primary structures. In some cases, the ECG chip 270 may cause an alert to be transmitted or output (e.g., to the user or a Doctor) about certain detected cardiac anomalies indicated by comparisons of the magnitudes and relative magnitudes of the detected primary structures. The ECG processor 280 may be a part of the wearable device 110 (e.g., be hosted on the CPU 210 or separate from the CPU 210) or on a different device, such as the user device 115 or the server 130.

[0070] In some cases, the second biopotential chip 265 may include some or all of the same features as the biopotential chip 250. In some cases, the second biopotential chip 265 may include the IMU 250B and the IMU 250B may be omitted from the biopotential chip 250.

[0071] In some cases, the processor 250A of the biopotential chip 250 or the biopotential application, executed by the CPU 210, (or a different device, such as the user device 115 or the server 130) may determine that an impedance determination check is to be performed. For instance, the CPU 210 or the processor 250A of biopotential chip 250 may determine that the impedance determination check is to be performed in response to an impedance check timer elapsing (e.g., for inter or intra-session wearing), in response to a recalibration process being conducted, or in response certain signal characteristics changing over time. For instance, the biopotential chip 250 may detect presence of significant (e.g., higher than a threshold value) amount of interference (e.g., electrical line frequency, e.g., 60Hz in the US) in the biopotential signals. The presence high interference may be indicative of poor electrode-skin contact, that is high impedance. The detection of the interference may be performed in parallel to gesture classification continuously, or periodically (e.g., depending upon implementation considerations, such as space, volume, electrical power draw, and / or component cost). In some cases, detecting interference (instead of, e.g., only periodically switching to impendence measurement) may avoid interrupting gesture classification, whereas switching to impendence measurement periodically may interrupt the gesture classification. In this case, user convenience may be maintained for gesture classification. In response to this determination, an impedance command may be transmitted (e.g., from the CPU 210, the user device 115, or the server 130) to the processor 250A (or the processor 250A may have determined to perform the impedance check). The processor 250A may then cause a connection state change by changing a state of switches or the multiplexer so as to connect certain electrodes to certainPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 points, such as to an impedance processing circuit of the first or second the second biopotential chips (if configured to perform impedance measurements).

[0072] For instance, in an impedance measurement mode, the processor 250A may connect a stimulus source to at least one first electrode (e.g., a first electrode) of the plurality of electrodes 235, and connect the at least one first electrode and at least one second electrode of the plurality of electrodes 235 to an impedance processing circuit of the first or second biopotential chips, so that electrical signals from the at least one first electrode and at least one second electrode may be carried to the impedance processing circuit. The stimulus source may then apply a stimulus to the at least one first electrode, and the biopotential chip may receive corresponding electrical signals. The second biopotential chip 265 may analyze the electrical signals from the at least one first electrode and the least one second electrode to determine an impedance measurement signal. The impedance measurement signal may include a response to the stimulus applied to the at least one first electrode. The biopotential chip may, based on the impedance measurement signal, determine an impedance between the at least one first electrode and the at least one second electrode.

[0073] The chip may output the determined impedance between the at least one first electrode and the at least one second electrode to the processor 250A, and the processor 250A (or CPU 210, or another device, such as user device 115 or server 130) may determine whether the signal quality is impaired. For instance, the signal quality may be impaired if the determined impedance between the at least one first electrode and the at least one second electrode satisfied an impairment condition (e.g., is greater than a first threshold or less than a second threshold) . In some cases, based on the determined impedance between the at least one first electrode and the at least one second electrode and / or the impairment condition being satisfied, the wearable device 110 (or the user device 115) may present to the user 105 an indication that signal quality is impaired. For instance, the indication may be a haptic feedback, an audio noise, a display graphic, and the like. In some embodiments, the impedance measurement, or derivative thereof, may be provided to the ML classifier 230 and used as an input for gesture determination. For example, the ML classifier may be trained to apply higher confidence or to make gesture classifications more quickly, based on less data, or based on smaller signal deviations when it is determined that impedance measurements indicate high contact quality. In some case, the impendence measurements may be an input to the ML classifier. For example, an impendence measurements may be periodically or simultaneously obtained with gesture data (e.g., EMG and wrist motion data), and the multiple data sources may analyzed by the ML classifier to determine gesture classifications and / or to modify confidence rating or others parameters relating to classifications or confidences.

[0074] The biopotential chip 250 may have a first low-power state and an active state. In some cases, the first low-power state may turn off (e.g., not enable, not provide power to) at least the ADCs 250E and the differential amplifiers 315 and turn on (e.g., enable, provide power to) the accelerometer and the gyroscope. In some cases, the active state may turn on (e.g., enable, provide power to) the ADCsPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US125 OE, the differential amplifiers 315, the accelerometer, and the gyroscope. The biopotential chip 250 may be configured to transition from the first low-power state to the active state in response to an activate command. In some cases, the biopotential chip 250 may determine the activate command be based on detecting certain acceleration and / or orientation data while in the first lower-power state. In some cases, the activate command may be generated externally from the biopotential chip 250 (e.g., from the user device 115 or the server 130), and the biopotential chip 250 may receive activate command, via the CPU 210. In response to determining (or receiving) the activate command in the first low-power state, the biopotential chip 250 may turn on (e.g., enable, provide power to) the ADCs 250E and the differential amplifiers 315.

[0075] In some cases, the biopotential chip 250 may have a second low-power state. The second low- power state may turn off (e.g., not enable, not provide power to) at least the accelerometer and the gyroscope and turn on (e.g., enable, provide power to) the ADCs 250E and / or the differential amplifiers 315. In this case, the biopotential chip 250 may determine the activate command be based on detecting a certain gesture or combination of gestures. In response to determining (or receiving) the activate command in the second low-power state, the biopotential chip 250 may turn on (e.g., enable, provide power to) the accelerometer and the gyroscope.

[0076] FIGS. 3A-3C depict schematic diagrams 300A, 300B, and 300C of aspects of a biopotential sensor 205 of a wearable device 110. The aspects of the biopotential sensor 205 of the wearable device 110 in block diagrams 300A, 300B, and 300C may apply to the wearable device 110, as discussed in FIGS. 1 and 2A-2C above. Diagrams 300A, 300B, and 300C may be modified to have different arrangements and include less or more components as shown.

[0077] In FIG. 3A, diagram 300A may depict a first arrangement aspects of the electrodes 235 (which may be hub electrodes or wristband electrodes), the signal pathway components 240, and the analog front end 250D. For instance, in diagram 300A, each electrode 235 may be connected to an analog inputs 305 of the analog front end 250D. In some cases, the signal pathway components 240 may include signal conductors (e.g., wires and / or traces) and other elements, such as a capacitor 320. In some cases, the signal pathway components 240 may include only the signal conductors. In some cases, none, some, or all of the electrodes 235 may have a second analog input 305 that (based on control of a switch 340 on the analog front end 250D) shorts the signal pathway to a ground 335. In some cases, the switch 340 may connect on a first side or a second side of the capacitor 320.

[0078] On the analog front end 250D, the analog front end 250D may include at least the plurality of differential amplifiers 315. Each of the differential amplifiers 315 may be coupled (or couplable) to a first electrode and a second electrode at a first input and a second input, respectively.

[0079] In some cases, the analog front end 250D may also include a multiplexer 310. The multiplexer may include a plurality of signal muxes 310A and a plurality of connection points 310B. For instance, each analog input 305 may correspond a signal mux 310A. The signal mux 310A may connect its respective analog input 305 to one (or more) of a set of connection points 310B. For instance, the set ofPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 connection points 310B may include some or all of the plurality of connection points 310B. Thus, each electrode 235 connected to an analog input 305 may be connected to first input or a second input of some or all of the differential amplifiers 315, thereby enabling the biopotential sensor 205 to change a sensed biopotential data.

[0080] In some cases, the multiplexer 310 may also change a signal pathway for an analog input 305 to a certain analog input 305 on a different biopotential chip (e.g., the biopotential chip 265) or an analog input 305 on the ECG chip 270. In this case, the multiplexer 310 may include additional connection points 310B so that the signal muxes 310A may connect the electrodes 235 to, via the analog input 305 of the analog front end 250D, to an analog input 305 on a different biopotential chip (e.g., the biopotential chip 265) or an analog input 305 on the ECG chip 270.

[0081] The analog front end 250D may also include various arrangements of analog filter(s) that include resistors 325, a bias 330, capacitors 320, and / or the ground 335. The elements of the analog filter(s) may be omitted or included, and, if included, may be arranged in various different arrangements to perform a filtering function. For instance, first analog filters may be in between the analog input 305 and the differential amplifiers 315. For instance, in diagram 300A, the first analog filters may be in between the analog input 305 and the signal muxes 310A of the multiplexer 310.

[0082] In FIG. 3B, diagram 300B may depict a second arrangement aspects of the electrodes 235, the signal pathway components 240, and the analog front end 250D. The second arrangement may be the same as the first arrangement, but also include a plurality of amplifiers 350 and a plurality of second analog filters 345. In some cases, the amplifiers 350 may be in between the analog inputs 305 and second analog filters 345. In some cases, the amplifiers 350 may be in between the analog inputs 305 and the multiplexer 310 with the second analog filters 345 arranged in between the multiplexer 310 and the differential amplifiers 315. The amplifiers 350 may amplify a signal received by an analog input 305. The second analog filters 345 may include a differential amplifier 315 coupled in series to a pair of resistors 325 and a capacitor 320.

[0083] In FIG. 3C, diagram 300C may depict a third arrangement aspects of the electrodes 235, the signal pathway components 240, and the analog front end 250D. The third arrangement may be the same as the first arrangement, but also include a plurality of amplifiers 350 (like in the second arrangement), with third second analog filters with resistors 325 and capacitors 320 in between the amplifiers 350 and the differential amplifiers 315 (e.g., before the multiplexer 310).

[0084] In general, including capacitors 320 and / or resistors 325 in the first, second, or third analog filters may regulate the biopotential signal for signal quality. In some cases, a capacitor 320 may make the system less vulnerable to DC shifts (of the biopotential signal) than if directly coupled. In some cases, an electrode may become charged due to polarization, and the effect of the polarization may be lessened by the capacitor 320. In some cases, the resistor 325 may lessen the effect of voltage read changing due to skin impedance changing. That is to say, the skin may have a constantly shifting impedance, but if skin is in series with a large value resistor, the shifting values of skin resistance mayPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 contribute a relatively small amount (e.g., compared to the resistor 325) to the noise of the front end system. For instance, an effective resistance may be equal to the resistance of the skin and the resistance of the front end system, but if the resistance of the front end system is greater (e.g., lOx, lOOx, and the like) than the resistance of the skin, the effective resistance is substantially the resistance of the resistance of the front end (and accounted for in design).

[0085] FIGS. 4A-4D depict graphics 400A, 400B, 400C, and 400D of different arrangements of hub electrodes 235A of a wearable device 110. The different arrangements of the hub electrodes 235A of the wearable device 110 in graphics 400A, 400B, 400C, and 400D may apply to the wearable device 110, as discussed in FIGS. 1, 2A-2C, and 3A-3C above. Graphics 400A, 400B, 400C, and 400D may be modified to have different arrangements and include less or more components as shown.

[0086] In FIG. 4A, graphic 400A may depict the ECG electrode 275 and a first arrangement (e.g., a pair) of hub electrodes 402 and 404. In some cases, a first hub electrode 402 or a second hub electrode 404 may be a reference electrode that inputs a biopotential signal to the ECG chip 270. For instance, the first hub electrode or the second hub electrode may be connected to a biopotential chip, such as the biopotential chip 250 or the second biopotential chip 265 in, e.g., the first or second connection state, and then connected to the ECG chip 270 in the third connection state. In some cases, the ECG electrode 275 is positioned on the wearable device 10 such that the ECG electrode 275 is not in contact with the user’s arm when the wearable device 110 is being worn on the arm of the user 105. For instance, as depicted in FIG. 4A, the ECG electrode 275 is positioned on a side of the wearable device 110 and not in contact with the user’s arm when the wearable device 110 is being worn. In some cases, the ECG electrode 15 may be positioned on other locations (not depicted), such as a top of the wearable device 110 or on a wristband (on an exterior facing surface of the wristband).

[0087] In some cases, the processor 250A may detect that the user 105 has contacted the ECG electrode 275; and in response to detecting that the user has contacted the ECG electrode, transition from a current connection state (e.g., the first connection state or the second connection state) to the third connection state. In this manner, hub electrodes 402 or 404 may provide dual functionality including at least biopotential sensing for gesture control and ECG sensing as a reference electrode, thereby increasing functionality while minimizing a number of sensor components that interact with users.

[0088] In FIG. 4B, graphic 400B may depict a second arrangement of the hub electrodes 235A. For instance, the hub electrodes 235A may be a plurality of circle sector electrodes that extend from an interior diameter to an exterior diameter. In some cases, the circle sector electrodes may be centered on a same center point (e.g., to surround the center point in a circular arrangement (e.g., a ring)). The circle sector electrodes may be uniform in arc length (see, e.g., FIG. 4C) or not uniform in arc length (see FIGS. 4B or 4D). In FIG. 4B, the circle sector electrodes may include a first circle sector type 414 and a second circle sector type 416. The first circle sector type 414 may have a larger arc length then the second circle sector type 416. In some cases, the hub electrodes 235A may have a same or different number of the first circle sector type 414 as a number of the second circle sector type 416. For instance,PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 as depicted in FIG. 4B, there may be eight electrodes of the first circle sector type 414 and four electrodes of the second circle sectortype 416. In some cases, the arrangement of electrodes of the first circle sector type 414 and the second circle sector type 416 may be symmetrical along at least one axis 415.

[0089] In some cases, different sets of hub electrodes 235A may be used as reference inputs to the ECG chip 270 when in the third connection state. For instance, in graphic 400B-1, a first group 406A of hub electrodes 235A may be connected to the ECG chip 270 as reference electrodes, while a second group 408A may not be connected to the ECG chip 270, when in the third connection state. In this case, the first group 406A may form first continuous sequence of adjacent hub electrodes 235A, while the second group 408A may form a second continuous sequence of adjacent hub electrodes 235A. In other cases, such as in graphics 400B-2, 400B-3, or 400B-4, the first group 406B / 406C / 406D may not be adjacent third group 412B / 412C / 412D of reference electrodes, thereby being separated by the second group 408B / 408C / 408D and a fourth group 410B / 410C / 410D. The sequence length (e.g., a number of adjacent electrodes) for each group may be the same or different. For instance, in graphic 400B-2, the first group 406B (one electrode of first circle sector type 414) may be separated from the second group 412B (one electrode of first circle sector type 414) by the fourth group 41 OB (a double electrode of second circle sector type 416); in graphic 400B-3, the first group 406C (one electrode of first circle sector type 414) may be separated from the second group 412C (one electrode of first circle sector type 414) by the fourth group 410C (two electrodes of second circle sector type 416 and one electrode of first circle sector type 414); and in graphic 400B-4, the first group 406D (one electrode of first circle sector type 414) may be separated from the second group 412D (one electrode of first circle sector type 414) by the fourth group 410D (two electrodes of second circle sector type 416 and two electrodes of first circle sector type 414). Of note, as the fourth group is increased in number of electrodes (and if the first group and third group stay the same), the second group is decreased in number of electrodes. Thus, in this manner, different regions of skin may be used as a reference for the ECG chip 270. In some cases, the processor 250A may change the selection of reference electrodes for the ECG chip 270. In some cases, the processor 250A may have the selection of reference electrodes stored as a configuration that is preset.

[0090] In FIG. 4C, graphic 400C may depict a third arrangement of circle sector electrodes 422 of a uniform arc length and depict how the circle sector electrodes 422 may be inserted into holes in a bottom 420 of a hub (or case) of the wearable device 110 and connected to a PCB 418. In some cases, the hub electrodes 235A of the first circle sector type 414 and the second circle sector type 416 may be inserted and connected in a similar manner. In some cases, the PCB 418 may be a disk to affix (e.g., via a first retention member) the circle sector electrodes 422 once inserted through the holes in the bottom 420. In some cases, the circle sector electrodes 422 may be affixed by the holes in the bottom via a second retention member (e.g., via pressure fit of the walls of the holes). The PCB 418 may include bufferPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 components. The PCB 418 may carry biopotential signals to the analog inputs 305, via signal pathway components 240 (e.g., signal conductors and traces).

[0091] In FIG. 4D, graphic 400D may depict other arrangements of non-uniform arc length circle sector electrodes. In graphic 400D-1, a fourth arrangement 424 of hub electrodes 235 A may include a third circle sector type 424 A and a fourth circle sector type 424B. The third circle sector type 424 A may have a longer arc length than the fourth circle sector type 424B. For instance, the third circle sector type 424 A may have an arc length twice as long as the fourth circle sector type 424B, such that a single electrode of the third circle sector type 424A may have a same surface area as two electrodes of fourth circle sector type 424B. In some cases, the third circle sector type 424A may have an arc length corresponding to (or near to) 90° and the fourth circle sector type 424B may have an arc length corresponding to (or near to) 45°. The fourth arrangement 424 may, in sequence in a ring, proceed as follows: one electrode of the third circle sector type 424 A, two electrodes of the fourth circle sector type 424B, one electrode of the third circle sector type 424A, and two electrodes of the fourth circle sector type 424B. In the graphic 400D-2, a fifth arrangement 426 may have a same arrangement as in the fourth arrangement, but one electrode of the third circle sector type 424A may be replaced by two electrodes of the fourth circle sector type 424B. In graphic 400D-3, a sixth arrangement 428 may have a same arrangement as the fifth arrangement, but the remaining electrode of the third circle sector type 424A and the adjacent electrodes of the fourth circle sector type 424B may be replaced by a fifth circle sector type 428A. The fifth circle sector type 428A may have an arc length corresponding to (or near to) 180°. In some cases, the hub electrodes 235A of the third, fourth, and fifth sector type may be inserted and connected in a similar manner as discussed in FIG. 4C.

[0092] In this manner, the hub electrodes 235A may be arranged in different arrangements that have trade-offs. For instance, uniform arc length circle sectors may ensure each electrode is in contact with a similar amount of skin to sense biopotential signals, while non-uniform arc length circle sectors may provide a greater range of functionality (e.g., for sensing ECG data, or sensing different combinations of bio-electrical activity). Moreover, in the cases where switches or a multiplexer enable dynamic signal paths (e.g., to different differential amplifiers 315 or the ECG chip 270), different combinations (based on configuration data for each connections state) of the circle sector electrodes may be used for biopotential sensing or as reference electrodes.

[0093] In some cases, the hub electrodes 235A may include electrodes of different form factors (e.g., the first circle sector type 414, the second circle sector type 416, and the like, as discussed herein). The electrodes of different form factors may include sets of at least two electrodes of a same form factor or sets of at least two electrodes that have different form factors and same surface areas. In this manner, electrodes that have a same form factor or a same surface area may be input connection points 310B of a same differential amplifier 315. For instance, a pair of electrodes of the first circle sector type 414, or a pair of electrodes of the second circle sector type 416, may have a same surface area (and form factor). The pair of electrodes may input biopotential signals to connection points 310B of a same differentialPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 amplifier 315. In some cases, the differential amplifier 315 may subtract the biopotential signals correctly if the signals are from electrodes of equal surface area. Thus, in some cases, all electrodes in an array may have equal surface area or not, but each pair of electrodes which forms a channel may have equal surface areas.

[0094] In some cases, the surface area of the hub electrodes 235A may be larger or smaller for different form factors. Larger surface area form factors may have a greater resistance to noise (as compared to smaller surface area form factors). In this case, larger surface area form factors may provide for a more resilient system over all. Smaller surface area form factors may provide space for additional electrodes and channels (as compared to larger surface are form factors). In this case, having more electrodes and channels may provide additional biopotential signals to provide greater classification breadth (e.g., enable classifying a larger number of a plurality of gestures as compared to larger surface area form factors). In some cases, providing more channels may be useful for more complicated inferences in machine learning model. For example, a machine learning model may classify a smaller number of gestures using fewer channels, while the machine learning model may classify a larger number of gestures using a greater number of channels.

[0095] In some cases, size of the hub electrodes 235A may also enable placement of electrodes where better (or different) placements may enable better signal quality (or signals for different gestures). For instance, certain locations on a wrist or forearm may provide better signals (for certain gestures) and electrodes may take certain shapes or surface areas to accommodate the locations where the better signal is located.

[0096] In some cases, symmetry of (at least a some) of the hub electrodes 235A along an axis (such as the at least one axis 415) may match (or align with) areas of symmetry in the wrist or forearm. For instance, a symmetrical layout may enable left and right wrist use, as the muscles in wrists are functionally symmetrical.

[0097] Thus, various arrangements and selections of form factor may be designed. Each such arrangement and selection may have different benefits and tradeoffs.

[0098] FIGS. 5A-5E depict graphics 500A, 500B, 500C, 500D, and 500E of different aspects of a biopotential sensor 205 of a wearable device 110 with hub electrodes 235A and wristband electrodes 235B. The different aspects of the biopotential sensor 205 of the wearable device 110 in graphics 500A, 500B, 500C, 500D, and 500E may apply to the wearable device 110, as discussed in FIGS. 1, 2A-2C, 3A-3C, and 4A-4D above. Graphics 500A, 500B, 500C, 500D, and 500E may be modified to have different arrangements and include less or more components as shown.

[0099] In FIG. 5 A, graphic 500A may depict a wearable device 110 with hub electrodes 508 (corresponding to hub electrodes 235A) and wristband electrodes 512 (corresponding to wristband electrodes 235B). The wearable device 110 may include a hub 504 with a biopotential chip 502 (corresponding to biopotential chip 250) disposed inside the hub 504. The hub 504 may have a sealed housing. The sealed housing may be water and / or air impermeable.PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1

[0100] In some cases, the hub 504 may be rigid (e.g., made out of plastic or metal, and the like). In some cases, the hub 504 may be flexible (e.g., made out of silicon or a rubber, and the like). In some cases, the hub 504 may be 504 may include multiple rigid segments to enable a "semi flexible" behavior. For instance, the hub 504 may have rigid segments with joints that bend to allow for a degree of flexibility (see, e.g., wristband 510 in graphic 600B-2 as an example of this type of structure). The hub 504 may have the hub electrodes 508 (e.g., a plurality of hub electrodes 508) disposed on an interior surface of the hub 504, so as to contact a user’s arm (e.g., wrist or forearm). For instance, the hub 504 may be positioned over the top of a user’s wrist, so that the hub electrodes 508 may sense biopotentials from the top of the wrist.

[0101] The biopotential chip 502 may include the plurality of analog inputs 305 and the plurality of ADCs 250E configured to receive signals from the plurality of analog inputs 305, as discussed herein. The biopotential chip 502 may also receive signals from the accelerometer and the gyroscope, as discussed herein. The hub electrodes 508 may be electrically connected, via conductors disposed within the hub 504, to one or more analog inputs 305 of the plurality of analog inputs 305 of the biopotential chip 502.

[0102] The sealed housing of the hub 504 may include an electrical port 539 (see FIG. 5D or 5E). The electrical port 539 may be electrically connected to at least one analog input (e.g., on a one-to-one basis for a number of wristband electrodes 512) of the plurality of analog inputs 305 of the biopotential chip 502. In some cases, the electrical port 539 may also include a connection to a voltage source of the biopotential chip 502, so as to provide power to the wristband electrodes 512.

[0103] The wearable device 110 may include a wristband 510. The wristband 510 may be made out suitable materials, such as textiles, metal, silicon, rubber, plastic, and the like. The wristband 510 may have the wristband electrodes 512 (e.g., one or more, or a plurality of wristband electrodes 512) disposed on an interior surface of the wristband 510, so as to contact a user’s arm (e.g., wrist or forearm). For instance, the wristband 510 may be configured so that the wristband electrodes 512 are generally placed in a same location on a user each time the wearable device 110 is worn by the user. In some cases, the wristband 510 is a closed loop (e.g., does not open). In these cases, the wristband 510 may be adjustable or stretchy to fit over a hand of a user. In some cases, the wristband 510 is configured to be opened and closed by a clasp, or other suitable locking mechanism. In some cases, a wristband electrode 512 may be a part of the clasp or other suitable locking mechanism. The wristband 510 may have one or more wristband conductors to carry biopotential signals from the wristband electrodes 512 to the biopotential chip 502, as discussed herein. For instance, the one or more wristband conductors may electrically connect the wristband electrodes 512 to the electrical port 539 of sealed housing of the hub 504. The wristband 510 and the hub 504 together may be configured to encircle the wrist (or forearm) of the user 105. In some cases, the one or more wristband conductors may be a conductive fabric. In some cases, the one or more wristband conductors may be signal conductors (e.g., wires) thatPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 are shielded (or not). For instance, the signal conductors may be embedded into the wristband 510 or attached to an exterior (or interior) surface of the wristband 510.

[0104] The wearable device 110 may also have a hub-wristband junction 506. The hub-wristband junction 506 may secure the wristband 510 to the hub 504. For instance, the hub-wristband junction 506 may secure the wristband 510 to the hub 504 on two sides of the hub 504. The hub-wristband junction 506 may be in a same location as the electrical port 539 of the sealed housing of the hub 504, so that the one or more wristband conductors may pass electrically signals into the hub 504 via the electrical port 539.

[0105] In this manner, the wearable device 110 may obtain biopotential data based on signals received by both hub electrodes 508 and wristband electrodes 512 and processed by the ADCs 250E of the biopotential chip 502. In some cases, the biopotential chip 502 may obtain wrist location data based on outputs from the accelerometer and the gyroscope, and the biopotential chip 502 may be configured to transmit the biopotential data and the wrist location data to a ML classifier 230, discussed herein. The ML classifier 230 be configured to analyze the biopotential data and the wrist location data to generate a gesture output indicating a gesture performed by the user 105.

[0106] In some cases, the hub electrodes 508 are disposed in a curved arrangement. The curved arrangement may have a curvature in a plane that extends perpendicular to a length of the forearm when the wearable device 110 is worn on the wrist. For instance, the curvature may correspond to a curved surface with a radius equal to a shallowest curvature of a distribution of user wrists (or forearms). The distribution may be a distribution of an expected population of users (e.g., military users would have a larger wrist or forearm, while civilian population may have smaller wrists or forearms). The shallowest curvature may be within a selected standard deviation of a mean curvature to avoid capturing outliers in a distribution. In other cases, a radius of curvature may be less than 0.5 cm, less than 1 cm, less than 2 cm, less than 3 cm, less than 4 cm, or less than 5 cm. In this manner, hub electrodes 508 may have a consistent fit that may apply across a population of users.

[0107] In some cases, the wristband electrodes 512 may be active electrodes. In this case, the wristband electrodes 512 may be coupled to buffer components (such as one or more wristband amplifiers). The buffer components (e.g., the one or more wristband amplifiers) may be disposed between the wristband electrodes 512 and the one or more wristband conductors. The buffer components may be configured to amplify signals received by the wristband electrodes 512 to buffer the signals from noise and / or interference as the signals travel through the one or more wristband conductors.

[0108] In some cases, the wristband 510 may be adjustable to a plurality of length states. In this case, each of the plurality of length states may have a respective circumference when the wristband 510 is worn. Moreover, the wristband 510 and the wristband electrodes 512 may be configured so that the wristband electrodes 512 may be situated at a constant position relative to the hub 504 in each of the plurality of length states. In this manner, the wristband electrodes 512 may be disposed at a predetermined position on the user’s wrist (or forearm) across a range of wrist sizes of users.PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1

[0109] In some cases, the wristband 510 may connect to the hub 504 on two sides of the hub 504, at the hub-wristband junction 506. In some cases, the wristband 510 may be adjustable relative to the hub 504 on both of the two connections between the wristband 510 and the hub 504. In some cases, the wristband 510 may be adjustable on only one of the two connections between the wristband 510 and the hub 504. In some cases, the wristband 510 may not be adjustable on the two connections between the wristband 510 and the hub 504. Thus, in cases where the wristband 510 is adjustable, the adjustment may enable precise (and consistent) placement of electrodes relative to the location of electrode signals, even across various wrist shapes and sizes. In some cases, the adjustment on both sides may be made while still allowing electrical connection between wristband electrodes in the wristband 510 and the hub 504, or across various electrodes in the wristband 510.

[0110] In some cases where both sides are adjustable, a first side of the wristband 510 may lock more securely than a second side of the wristband 510. For, the first side may be adjusted to secure the wristband electrodes to the position for a user’s wrist once, and the user may use the second side to put the device on and take the device off. In some cases, the first side may where the electrical port 539 is located.

[0111] In FIG. 5B, graphic 500B shows aspects of trace lengths of conductors connecting the hub electrodes 508 to the analog inputs 305. For instance, in graphic 500B-1, the hub electrodes 508A, 508B, 508C, 508D, and 508E may have respective trace lengths 516A, 516B, 516C, 516D, and 516E to locations 514A, 514B, and 514C of certain analog inputs 305. The trace lengths 516A, 516B, 516C, 516D, and 516E may be significantly different (e.g., a longest trace length being more than double or triple in length as compared to a smallest trace length). Thus, biopotential signals being carried on the trace lengths 516A, 516B, 516C, 516D, and 516E may be exposed to environmental electrical noise to differing degrees, in accordance with their trace length. Thus, the biopotential signals may have differing signal to noise ratios that may be a challenge to filter out (e.g., via differential amplifiers 315).

[0112] In contrast, in graphic 500B-2, the hub electrodes 508A, 508B, 508C, and 508D may have respective trace lengths 518A, 518B, 518C, and 518D to locations 520A and 520B of certain analog inputs 305. The trace lengths 518A, 518B, 518C, and 518D may be significantly similar (e.g., within 5%, 3%, or 1% of each other). Thus, biopotential signals being carried on the trace lengths 518A, 518B, 518C, and 518D may be exposed to environmental electrical noise to a similar degree, in accordance with their trace length. By using equal trace lengths, common noise (such as 60 Hz radiofrequency noise) may apply equally to the various traces, and this noise may be effectively cancelled using differential amplifiers or other signal averaging circuitry or logic. Thus, the biopotential signals may have similar signal to noise ratios that may be a relatively easier to filter out (e.g., via differential amplifiers 315). For instance, the locations 520A and 520B of certain analog inputs 305 may be relatively equidistant to each of the hub electrodes 508A, 508B, 508C, and 508D. In contrast, the locations 514A, 514B, and 514C of certain analog inputs 305 may be relatively closer to certain of thePCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 hub electrodes 508A, 508B, 508C, 508D, and 508E and relatively further from others of hub electrodes 508A, 508B, 508C, 508D, and 508E.

[0113] In FIG. 5C, graphic 500C depicts trace lengths of conductors 522 from hub electrodes 508 to analog inputs 305 in a different arrangement. The arrangement of conductors 522 may have at least two axis of symmetry, such a first axis of symmetry 522A and a second axis of symmetry 522B. Due to the first axis of symmetry 522A and the second axis of symmetry 522B, the trace lengths may significantly similar. In particular, the conductors 522 may be sixteen (16) identical circuits, each positioned proximate (e.g., within a threshold distance) to a respective electrode. As each conductor 522, has an identical circuit protecting the biopotential signal from each individual electrode, the sixteen biopotential signals are exposed to the same amount of noise (e.g., a variation less than 1%).

[0114] In some cases, each conductor 522A (of conductors 522) may have a spring contact 524, atrace 526, and a buffer circuit 528. The spring contact 524 may electrically connect directly to an electrode (e.g., below the spring contact 524, that is into the graphic 500C). The spring contract 524 may be a biased deformable conductive metal to ensure electrical connection to the electrode even in the presence of vibration or shock. The trace 526 may be an electrical conduit on a PCB board. The trace 526 may be a very short trace (e.g., less than 1 mm, less than 2 mm, less than 3 mm, less then 4 mm, and the like) electrically connecting the spring contact 524 and the buffer circuit 528. In some cases, the trace 526 may be configured to a top layer of a PCB and connected to the buffer circuit 528. Thus, in this manner, the electrodes may be as close as possible to the buffer circuit, and thus reduce exposure of the biopotential signals to noise. The buffer circuit 528 may include buffer components and electrically connect the electrode (via the spring contact 524 and the trace 526) to an analog input 305. The buffer circuit 528 may protect the biopotential signals from noise by various means, as discussed herein. In FIG. 5D, graphic 500D may depict the hub-wristband junction 506 of the hub 504 to secure the wristband 510 to the hub 504 and pass signals (and power) between the wristband 510 and hub 504 with a non-adjustable connection (to adjust a length of the wristband 510). For instance, each of a first end and second end of the wristband 510 may have first connectors 530 configured to connect to second connectors 536 of the hub-wristband junction 506. In some cases, the first connectors 530 and second connectors 536 may be a snap fit, a ball-joint connection, and the like. For instance, the second connectors 536 may flex while the first connectors 530 are inserted, and flex back to hold the first connectors 530 after the first connectors 530 are fully inserted.

[0115] Also depicted in graphic 500D, wristband conductors 532A, 532B, 532C, 532D, and 532E may be embedded in a material 534 (e.g., textile, rubber, silicon, and the like) of the wristband 510. After the first connectors 530 are connected to the second connectors 536, the wristband conductors 532A, 532B, 532C, 532D, and 532E may be electrically connected (e.g., by insertion and / or contact, and the like) to corresponding electrical junctions 538A, 538B, 538C, 538D, and 538E of the electrical port 539 ofthe sealed housing ofthe hub 504. For instance, one of electrical junctions 538A, 538B, 538C, 538D, and 538E may provide power to wristband electrodes 512, while four of electrical junctions 538A,PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1538B, 538C, 538D, and 538E may receive signals from the wristband electrodes (e.g., in the case of four wristband electrodes 512).

[0116] Accordingly, as shown the exemplary embodiment of FIG. 5D, a wristband may have biopotential electrodes, and wire traces carrying signals from those wristband electrodes may connect to a hub of a smartwatch using an electrical port on the hub. In some embodiments, the band may mechanically and releasably couple (e.g., via snap fit or latch) to the hub, and in the process of being mechanically coupled, and electrical connection between the wristband electrodes and processing circuitry (such as that described above with reference to FIGS. 2-3) may automatically be established, without need for separate mechanical and electrical connections. This may advantageously allow for simple and intuitive connections between wristband and hub, so that wristbands may easily be released and replaced, e.g., for user customization in sizing or style, or to replace damaged items.

[0117] In FIG. 5E, graphic 500E may depict the hub-wristband junction 506 of the hub 504 to secure the wristband 510 to the hub 504 and pass signals (and power) between the wristband 510 and hub 504 with an adjustable connection on both sides (to adjust a length of the wristband 510). At each hubwristband junction 506, the wearable device 110 may have one of a first retention member 544 or a second retention member 548. For instance, the first retention member 544 may be textile retainer (e.g., a bar) that may be configured to open and close to retain a first portion of the wristband 510A (e.g., made of textile 540). The second retention member 548 may be textile retainer (e.g., a bar) that may be configured to open and close to retain a second portion of the wristband 510B (e.g., made of textile 540). The second retention member 548 may also pass electrical signals to electrical junctions 538A, 538B, 538C, 538D, and 538E of the electrical port 539 (preferably, a combined electrical port / mechanical coupling) of the sealed housing of the hub 504. For instance, the second retention member 548 may pass the electrical signals via an electrical conductor (e.g., a wire or slip ring).

[0118] The first portion of the wristband 510A and the second portion of the wristband 510B may be connected by a third portion of the wristband 510C, via additional first retention members 544 and second retention members 548. The third portion of the wristband may include the wristband electrodes 512 and be made of textile 540. Thus, the power and signals may be transmitted between the wristband electrodes 512 and electrical port 539 via wristband conductors 546.

[0119] The first retention member 544 and the second retention member 548 may each be paired with an adjustment member 542. The adjustment member 542 may lock the textile 540 of each of the first portion of the wristband 510A and the second portion of the wristband 510B in place (e.g., by compression, tension, or torsion).

[0120] It is desirable that electrodes 512 be able to maintain a common radial location on the lower side of a user’s wrist regardless of the size of the user’s wrist. The ML classifier may be trained based on an expectation that the electrodes will be located in or near that predetermined radial location, which has known electrical relationships to the muscles and nerves of the arm and wrist. In conventional wristbands that are tightened on only one side, tightening the band moves the material of the bandPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 relative to the wrist, which, if electrodes were incorporated, would result in the electrodes being undesirably shifted relative to the wrist. Conversely, in the embodiment shown in FIG. 5E (and in other embodiments within the scope of this disclosure), the size of the wristband may be adjusted while the position of the wristband electrodes relative to the wrist is maintained.

[0121] FIGS. 6A-6D depict graphics 600A, 600B, 600C, and 600D of different aspects of wristband electrodes 512 (corresponding to wristband electrodes 235B) of a biopotential sensor 205. The different aspects of the wristband electrodes 512 of the biopotential sensor 205 in graphics 600A, 600B, 600C, and 600D may apply to the wearable device 110, as discussed in FIGS. 1, 2A-2C, 3A-3C, 4A-4D, and 5A-5E above. Graphics 600A, 600B, 600C, and 600D may be modified to have different arrangements and include less or more components as shown.

[0122] In FIG. 6A, graphic 600A may depict different arrangements of buffer components and housings of active wristband electrode 512. In graphic 600A-1, the housing is attached to an interior of the wristband with the buffer components sealed inside and an electrode attached to the housing on an interior of the wristband. In graphic 600A-2, the housing is attached to an exterior of the wristband with the buffer components sealed inside and an electrode attached to an interior of the wristband and connected to the buffer components via, e.g., a wristband conductor or the electrode extends through the wristband. In graphic 600A-3, the housing is attached to an exterior of the wristband with the buffer components sealed inside and an electrode attached to the housing on the interior of the wristband, as the housing may extend through a portion of the wristband. In graphic 600A-4, the housing is attached to and surrounds the wristband with the buffer components sealed inside and an electrode attached to an interior facing side of the housing on an interior of the wristband.

[0123] In FIG. 6B, graphic 600B may depict an active electrode housing for wristband electrodes 512 surrounding the wristband 510 (in graphic 600B-2) and a hub 504 (in graphic 600B-1).

[0124] In FIG. 6C, graphic 600C may depict textile wristband electrodes 512 (in graphic 600C-1) and conductors from the electrical port 539 connecting to analog inputs 305 (in graphic 600C-2).

[0125] In FIG. 6D, graphic 600D may depict features of textile wristband electrodes 512. For instance, the wristband 510 may include portions e-textile that includes wristband conductors 646 shielded using a shield 644 (e.g., a layer of textile or laminate covering the wristband conductors on a textile). The textile wristband electrodes 512 may be e-textile fabric thread (metal filament and the like) that is built into a shape to act as an electrode. The textile wristband electrodes 512 may be connected to the wristband conductors 646, which may run the electrical port 539 where extensions 642 of wristband conductors 646 may be connected to the electrical port 539. In this case, the textile wristband electrodes 512 may “passive electrodes” that do not have buffer components. Moreover, in this case, the wristband 510 may include a middle region of textile 640 between the textile wristband electrodes 512 to provide stretch to the wristband 510. Furthermore, the wristband conductors 646 may be shaped in certain arrangements (e.g., sine wave) to elongate with a stretching of the e-textile.PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1

[0126] FIGS. 7A-7B depict graphics 700A and 700B of different aspects of hub electrodes 235A disposed in a curved arrangement. The different aspects of the hub electrodes 235 A disposed in a curved arrangement in graphics 700A and 700B may apply to the wearable device 110, as discussed in FIGS. 1, 2A-2C, 3A-3C, 4A-4D, 5A-5E, and 6A-6D above. Graphics 700A and 700B may be modified to have different arrangements and include less or more components as shown.

[0127] In FIG. 7A, graphic 700A may depict different perspectives of a curved arrangement of hub electrodes 508. In graphic 700A-2, the hub electrodes 508 are depicted arranged in an array (e.g., four by four matrix). The curved arrangement of the array may have a curvature in a plane 702 that extends perpendicular to an axis the length of the forearm when the wearable device 110 is worn on the wrist. The curved arrangement of the array may not have a curve in the axis the length of the forearm. In graphic 700A-1, the curvature in the plane 702 that extends perpendicular to the axis the length of the forearm may be recognized by the facing direction of hub electrodes 508. For instance, a plane 704 arranged normal from a face of hub electrode 508 from a first group (e.g., on far left) would intersect a plane 706 arranged normal from a face of hub electrode 508 from a second group (e.g., on far right).

[0128] In FIG. 7B, graphic 700B may depict how signals may be collected from the curved arrangement of hub electrodes 508. Generally, the hub electrodes 508 may be attached to a PCB 710 (graphic 700B-1) or PCB 714 (graphic 700B-2), with or without buffer components, to secure the hub electrodes 508 to the hub 504. In graphic 700B-1, each hub electrode 508 may have a single PCB 710 to attach to, and each PCB 710 may be independent of any other PCB 710 (that is not connected to other PCB 710 and may be flexible independent of the other PCB 710). Sets of hub electrodes 508 may be attached respective PCB 714, and each PCB 714 may be independent of any other PCB 714 (that is not connected to other PCB 714 and may be flexible independent of the other PCB 714). The sets of hub electrodes 508 may include hub electrodes along a row (or column) of the array, so that the PCB 714 may be curved into position in accordance with the curvature in the plane 702.

[0129] In both cases, the PCB 710 and PCB 714 are mounted to a flexible PCB 712. The flexible PCB 712 may carry signals to the biopotential chip 250 and power from the biopotential chip 250 to the hub electrodes 508.

[0130] In this manner, the hub electrodes 508 may be curved to match a curved surface of a user’s wrist or forearm. Thus, the hub electrodes 508 may have more uniform contact between the electrode face and the user’s skin, and generate mor accurate biopotential data (and more accurate gesture detection).

[0131] In some cases, the hub 504 may also be flexible. The hub 504 and / or the PCBs may (combined) have a flex with spring constant to start in a flat arrangement and then the user 105 may strap the hub 504 down (and thereby curve the PCBs and electrodes 508) so that the hub electrodes 508 are in contact with skin of the user 105. In some cases, to strap down the hub, the straps may have attachment points at ends of the hub 504. In this case, this may be easier to attach straps to the hub 504. In some cases, the strap may strap down over top of the hub 504. In this case, it may be harder to attach the straps, butPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 the force maybe evenly distributed across the hub electrodes 508. In this case, the curvature in the plane 702 (at default without straps) may correspond to a curved surface with a radius equal to median curvature of a distribution of user wrists (or forearms). The distribution may be a distribution of an expected population of users (e.g., military users would have a larger wrist or forearm, while civilian population may have smaller wrists or forearms). The median curvature may be selected from within one standard deviation of a mean curvature, preferably on the larger end of the distribution, so to flex down to the skin of users while being strapped down.

[0132] FIGS. 8A-8B depict graphics 800A and 800B of different aspects of electrodes 235 of a biopotential sensor 205. The different aspects of the electrodes 235 of the biopotential sensor 205 in graphics 800A and 800B may apply to the wearable device 110, as discussed in FIGS. 1, 2A-2C, 3A- 3C, 4A-4D, 5A-5E, 6A-6D, and 7A-7B above. Graphics 800A and 800B may be modified to have different arrangements and include less or more components as shown.

[0133] In FIG. 8A, graphic 800A may depict an active electrode with a solid metal body 806 (as assembled in 800A-1, and in exploded form 800A-2) that affixes to a hub or case via a first retention member 802. The solid metal body 806 may include a face 806A and an extended portion 806B. The extended portion 806B may have a thread for engaging a corresponding thread of the first retention member 802. The first retention member 802 may affix the solid metal body 806 to the hub or case. In some cases, the PCB 804 (with buffer components) may be affixed by the first retention member 802 to the solid metal body 806 (and / or a portion of an interior of the hub or case).

[0134] In FIG. 8B, graphic 800B may depict an active electrode with a solid metal body 810 (as assembled in 800B-1, and in exploded form 800B-2) that affixes to a hub or case via a second retention member 808. The solid metal body 810 may include a face 810A and an extended portion 810B. The extended portion 810B may have a pressure fit portion (e.g., increasing in diameter away from the face) for engaging the second retention member 808. The second retention member 808 may be a hollow cylinder for receiving the extended portion 810B. The hollow cylinder may have tapering walls (e.g., decreasing in diameter toward the face). The second retention member 808 may affix the solid metal body 810 to the hub or case. In some cases, the PCB 804 (with buffer components) may be affixed to the second retention member 808 on an exterior of the hollow cylinder of the second retention member 808. In some cases, the active electrode may be attached to the housing of the hub 504 via a clip.Example Routine(s)

[0135] FIGS. 9A and 9B depict flowcharts of routines of a wearable device. FIG. 9A depicts a flowchart of an exemplary routine 900A for outputting gesture data to a ML classifier. In the routine 900A, the routine 900A may be performed by one or more systems, such as biopotential chip 250 that performs certain data obtains and outputs the biopotential data, the acceleration data, and the angular rate data, or derivatives thereof, as discussed herein. The routine 900A may start at block 902, where the biopotential chip 250 may receive biopotential signals from a plurality of electrodes. At block 904, the biopotential chip 250 may convert the biopotential signals to biopotential data. At block 906, thePCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 biopotential chip 250 may receive, from an accelerometer disposed onboard the biopotential chip, acceleration data indicating an acceleration of the portion of the user’s arm. At block 908, the biopotential chip 250 may receive, from a gyroscope disposed onboard the biopotential chip, angular rate data indicating an angular rate of the portion of the user’s arm. At block 910, the biopotential chip 250 may output the biopotential data, the acceleration data, and the angular rate data, or derivatives thereof, to a machine learning classifier.

[0136] FIG. 9B depicts a flowchart of an exemplary routine 900B for switching connection states from a first connection state to a second connection state. In the routine 900B, the routine 900B may be performed by one or more systems, such as the biopotential chip 250 that performs the switch between different connection states, as discussed herein.

[0137] The routine 900B may start at block 912, where the biopotential chip 250 may apply, by a multiplexer, a first connection state, associated with a first mode, between a plurality of electrodes and a plurality of differential amplifiers. At block 914, the biopotential chip 250 may process biopotential signals in accordance with the first mode. For instance, the first mode may correspond to first one of obtain biopotential data, obtain training data, obtain ECG data, obtain impedance data, and the like, as discussed herein. At block 916, the biopotential chip 250 may determine to switch from the first connection state to a second connection state associated with a second mode. For instance, the biopotential chip 250 may receive an external command to switch modes. At block 918, the biopotential chip 250 may apply, by the multiplexer, the second connection state between the plurality of electrodes and the plurality of differential amplifiers. At block 920, the biopotential chip 250 may process biopotential signals in accordance with the second mode. For instance, the second mode may correspond to second one of obtain biopotential data, obtain training data, obtain ECG data, obtain impedance data, and the like, as discussed herein.

[0138] FIG. 10 shows exemplary hardware of a wrist wearable 1002 to be worn by a user. Through the use of electrodes such as dual-use ENG / ECG electrodes, wearable 1002 may collect (e.g., passively collect) biopotential signals (in some embodiments in combination with other information such as IMU data that can be analyzed to determine a state of the user) from the user, which may be fed as input into one or more of the machine learning models described with respect to FIGS . 12 and 13. The biopotential signals may provide information related to one or more components that comprise a motor unit and / or nerve bundle. For example, such components may include, but are not limited to, a nerve, one or more neuromuscular junctions, and / or muscle fibers enervated by the nerve. In some embodiments, the biopotential signals may provide information on signal activity of the respective components. For example, an EMG signal may be the sum of signals associated with the aforementioned signal activity summed across multiple motor units. In some embodiments, the signal activity may emanate from nerve bundles within the user’s arm, which may include the ulnar nerve bundle 1004, the radial nerve bundle 1006, the median nerve bundle 1010, the extensor digitorum 1012, the extensor carip ulnaris 1008 and / or the extensor carpi radialis 1014. In some embodiments, additional machine learning algorithmsPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 related to the generation and processing of ENG, described with respect to FIG. 11, may be included in the system described with respect to FIGS. 12 and 13. In some embodiments, these algorithms (in addition with other signal processing techniques described herein) may remove one more movement artifacts and / or other noise by movement of the wearable 1000. For example, the system provided herein may anticipate the presence of one or more movement artifacts in a given frequency range (e.g., below 10 Hz) and, accordingly, employ a signal processing technique (e.g., a high-pass fdter) that eliminates data / signals within the frequency range. The algorithms described herein may correct for varied placement and / or movement of the wearable 1000 across the nerve bundles, for example, the ulnar 1004, radial 1006, and median nerve bundles 1010. For example, one or more techniques may be employed for placement agnostic feature identification, or in other words, the machine learning model described herein may leam / identify features that when computed are robust to variance in where a user places the wearable 1000 on the wrist. In some embodiments, a heatmap 1000 of the wrist physiology may be generated and may allow for reconstruction of raw biopotential signals which may be used in to identify placement agnostic features. The machine learning model may be an encoding model that leams / identifies placement agnostic features from a representation of the data, which may optionally be processed and / or described in commonly owned U.S. Application No. 18 / 161,054, filed January 28, 2023 and incorporated by reference herein in its entirety.

[0139] FIG. 11 shows an exemplary generation of nerve data to be used by the system. At 1100, EMG data (in some embodiments, in combination with additional information that can relate to the context of the scenario, for example, whether the user is awake or asleep) may be captured by one or more electrodes coupled to the wearable device. The EMG data may indicate neuromuscular signals (e.g., bulk neuromuscular signals). In some embodiments, the neuromuscular signals may not be suitable to be used as input to the models described with respect to FIGS. 12 and 13. In such a case, it may be preferable to extract granular neural information from the neuromuscular signals. At step 1102, the electrodes may be disposed on the wearable device in a formation that has been determined to improve signal quality and / or facilitate accurate classification of the collected EMG data. At step 1104, signal processing technique(s) may be applied to the EMG data to improve the stability of the signals associated with the EMG data. At step 1106, one or more transformations or other operations may be applied to the EMG data to extract the granular neural information from the neuromuscular signals associated with the EMG data.

[0140] FIG. 12 shows an exemplary system for monitoring sleep of a user and generating an assessment of sleep of the user. For example, the system may be configured to monitor and determine characteristics relating to sleep of the user and generate assessments of sleep quality, duration, and patterns. In other embodiments, the system may be configured to detect microarousals and sleep disorders such as insomnia, sleep apnea, or restless leg syndrome. The system may also provide insights into sleep cycles, including REM and non-REM stages, and offer recommendations for improving sleep hygiene. Additionally, the system may be configured to trigger an action based on the sleep monitoringPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 or assessment. For instance, the system may adjust environmental conditions such as room temperature or lighting in a sleeping area of a user, activate a white noise machine, provide haptic feedback through the wearable device, send notifications or alerts to the user or a caregiver in response to detected sleep disturbances or patterns, or recommend changes in behavior or sleep routine. Furthermore, the data collected by the system may be input into machine learning models. These models may be trained to recognize patterns, predict sleep-related issues, or personalize recommendations based on individual user data. The machine learning models may continuously improve their accuracy and effectiveness as they process more data over time, leading to more precise sleep assessments and tailored interventions.

[0141] At step 1202, sensor data, which may include biopotential data, may be obtained from a subject wearing a wearable device described in FIGS. 10 and 11. Steps 1204 may be repeated using a multitude of subjects, for example, until a threshold of minimal biopotential data needed to train the machine learning model 1200 is met. The sensor data may be used as input to train the machine learning model 1200. Sensor data may include EMG data, ENG data, IMU data, ECG data, photoplethysmography (PPG) data, and / or the like. For example, the wearable device may include one or more EMG electrodes that can sense and generate EMG data from the surface of a subject’s skin, which may be fed into the machine learning model. The data may be indicative of metrics or characteristics that may be used to assess sleep of the subject. As described herein, the metrics or characteristics may relate to sleep stages, sleep duration, sleep quality, sleep onset latency, number of microarousals during sleep, duration of microarousals during sleep, sleep efficiency, REM sleep percentage, non-REM sleep percentage, body movements during sleep, or heart rate variability during sleep, and / or the like. Monitoring the metrics or characteristics over a period of time may provide insight into the progression of sleep conditions or disorders. In some embodiments, the system may include a graphical user interface (GUI) framework that can render a display to the user of the information related to the recorded data log. In some embodiments, the metrics may be proxies for the presence or progression of sleep conditions or disorders.

[0142] As described with respect to FIG. 11, the wearable device may include additional hardware capable of generating ENG and / or EMG data using EMG electrodes and / or using dual-use ENG / ECG electrodes. In some embodiments, other data in addition to the biopotential data may be collected and used as input to the machine learning model 1200 described herein. Such data may include, but is not limited to, IMU data (e.g., data generated based on an accelerometer, a gyroscope, etc. coupled to the wearable device, which is described in detail above), photoplethysmography (PPG) data (e.g., which may be used to detect volumetric changes in blood in peripheral circulation), ECG data (e.g., which may be used to detect changes in heart rate and / or heart rate variability), Electrodermal Activity (EDA) data (e.g., also known as Galvanic Skin Response (GSR), this data measures electrical conductance of the skin based on detected moisture level and can provide insights into the psychological and / or physiological state of the user), skin temperature (TS) data (e.g., this data measures the temperature of the surface of the skin and can provide insights into the user’s thermoregulatory process in response toPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 external stressors / environmental conditions), ambient light sensor (ALS) data or other data generated from light-based technologies (e.g., the data generated from this device measures the intensity of ambient light and, when translated into a digital signal, can assist in auto-adj usting / controlling lighting conditions related to the wearable), and / or other data generated from biosensors such as optical biosensors, fluorescence-based sensors, absorbance / colorimetric sensors etc.

[0143] At step 1204, the state of the subject may be determined. The state may be determined upon the system receiving the sensor data as input. The state of the subject may relate to a physical and / or mental state of the subject. For example, the state of the subject may be awake or a particular stage of sleep. A desired state may be a state that the machine learning model 1200 has been configured to identify. The subject may be known to be in a particular state prior to obtaining the sensor data to be used as input. In such a case, the state may be entered manually into the system. The state of the user may be determined (e.g., determined passively) using sensor data. For example, IMU data may be used to identify the state. In some embodiments, other sensors (e.g., biopotential, ECG, PPG, IMU, combinations of the above) may be used to determine the user state. In some embodiments, the state of the subject may be manually input by the user or by an observer (e.g., healthcare provider, technician performing a study, caregiver).

[0144] Upon the state being determined, the determined state may be applied to label physiological data collected while the user was in the state. At step 1208, if it is determined that the sensor data was collected while the user was not in a desired sleep state, the sensor data may be cleared from memory. In some embodiments, if the user is determined to be awake, the sensor data collected while the user was awake may be cleared from memory. Alternatively, the state analysis step 1204 may be used to gate the sensor data collection step 1202. For example, state analysis 1204 may precede data collection 1202, and only upon determining that the user is in a desired state for data collection (e.g., deep sleep state), may the data collection step 1202 be performed. In some embodiments, only a certain subset of the sensors may be used for the state analysis step 1204, and the other sensors may be used alone or in combination for the data collection step 1202. In this manner, sensor data may be collected only or predominantly in desired sleep windows. In some embodiments, gating sensor data collection in this manner may reduce power consumption and expenditure of computational resources, improve the quality of sleep data collected, and / or improve the sensitivity and selectivity of the generated sleep assessments.

[0145] The system may assign a sleep stage label which may include the name of the sleep stage the user is in. Both the sensor data and assigned label may be sent, for example, to the machine learning model 1200. At step 1208, the system may determine, based on the input sensor data, that the subject is in an undesired sleep state. The system may discard the input sensor data received during this state. In some embodiments, a flag may be received when an undesired sleep state is detected, and the system may transition to an inactive classification state. In some embodiments, sensor data received while the system is in the inactive classification state may be cleared. When subsequent data or inputs indicatePCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 that the user is in a desired sleep state, the system may transition to an active classification state and may resume processing sensor data and generating sleep assessments. The undesired sleep state may be a state for which the machine learning model does not have a corresponding parameter.

[0146] In some embodiments, metrics relating to sleep hygiene or quality of the subjects may also be determined and collected. For example, sleep efficiency, sleep quality, sleep onset latency, number of microarousals during sleep, duration of microarousals during sleep, REM sleep percentage, non-REM sleep percentage, body movements during sleep, heart rate variability during sleep, total sleep time, time spent in each sleep stage, and / or other sleep-related metrics may be obtained. The sleep quality data may be paired with the sensor data collected from each subject. Thus, in some cases, samples of sensor data may be labeled with associated sleep quality data and / or state data relating to a sleep stage the subject was in at the time the sensor data was collected.

[0147] At step 1212, sensor data and associated labels may be used to train a machine learning model 1200. In some embodiments, the machine learning model 1200 may be trained to generate assessments of sleep quality of a user based on received sensor data and, optionally, state data relating to a sleep stage the user is in. For example, by training the model 1200 to recognize correlations between subject sensor data and one or more metrics relating to sleep quality, the model 1200 may be able to receive user sensor data and output a prediction of the corresponding sleep metric(s) for the user.

[0148] The machine learning model 1200 may generate values of the sleep metrics based on the labels and the input sensor data and may use these values when generating the correlations. In order to generate the values, the machine learning model may include a sleep metric classification model. In some embodiments, the machine learning model 1200 may be an encoding model that learns (optionally, during pre-processing) a representation of the data, which may optionally be processed and / or transformed as described in commonly-owned U.S. Patent Application No. 18 / 161,053, filed March 20, 2023 and incorporated by reference herein in its entirety. The learned representations may be categorized into sleep metric classifications at different states, for example, sleep efficiency during deep sleep. The model 1200 may allocate input sensor data into one or more of these classifications and determine a value associated with the sleep metric classification at a given state. For example, the values may include sleep efficiency, total sleep time, sleep latency, number or duration of awakenings or microarousals, time spent in each sleep stage, and / or the like. The model may find that, during a deep sleep state, high sleep efficiency is highly correlated with a low number of awakenings or microarousals. The model 1200 may additionally predict that if a user, while in deep sleep, has both high sleep efficiency and a low number of awakenings or microarousals, the user is likely to have good sleep quality. The classified output may indicate a likelihood of good or poor sleep quality or an assessment of sleep quality trends overtime. In some embodiments, the assessments may be stored in local memory or transmitted to a second device or remote server and stored in memory. Data and / or assessments may be collected over time, and analysis (e.g., time series or longitudinal analysis) may be performed with respect to the stored data to generate assessments of sleep quality, trends, and / or prognosis. The modelPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US11200 may include a deep neural network that may adjust neural network weights associated with each of the sleep values based on input sensor data. The weights may be used to generate the correlations and / or the prediction score described above.

[0149] The model 1200 may include a statistical analysis model. In some embodiments, the statistical analysis model may apply a defined set of computational functions to sensor data to generate outputs. For example, input sensor data may be passed to a regression model which may generate inferences and may generate a value associated with the sleep metric classification. For example, the model 1200 may determine that input sensor data falls into a sleep efficiency category while in a deep sleep state (e.g., which may be determined based on the label). Additional analytics may be executed to determine one or more recommendations for improving sleep quality for the user. In such a case, the one or more recommendations may be included in a notification to the user.

[0150] FIG. 13 shows an exemplary machine learning model 1300 that is trained to generate an assessment of sleep quality based on input sensor data. A user may have been instructed to wear the wearable device described herein during sleep. In some aspects, a user may have been instructed to wear the wearable device on the left wrist while the user sleeps. Wearing the wearable device on the left arm may provide more accurate EMG measurements compared to wearing the device on the right arm, resulting in improved detection of muscle atonia and more precise determination of sleep stages. Sensor data, including biopotential data generated from the wearable device, may be used as input sensor data to a machine learning model 1300 that outputs an assessment of sleep quality, for example, over time. Preparing the input sensor data for the machine learning model 1300, which may be shown in steps 1302 through 1310, may follow the same or similar steps described in steps 1202 through 1210 of FIG. 12. While steps 1202 through 1210 discuss collecting input sensor data from multiple subjects, steps 1202 through 1210 may pertain to collecting input sensor data from a single user over a period of time.

[0151] At step 1312, the model 1300 may be used to monitor the sleep quality of the user. The model 1300 may be fed sensor data as input and output an inference about sleep quality. The model 1300 may categorize the input sensor data into sleep metric classifications using the techniques described with respect to FIG. 12. Likewise, the model 1300 may generate a value associated with a sleep metric, like sleep efficiency, using the techniques described with respect to FIG. 12. The model 1300 may track the generated values over a period of time and perform additional analytics (e.g., or offload the values to another local module or a remote server to perform the analytics) that provide an insight on how sleep quality is changing or improving. The insight along with the values may be outputted by the model and sent via a message to the user. In some embodiments, the insight may be generated at periodic intervals which may be sent by a user and / or healthcare professional. Step 1314 may involve outputting a characteristic relating to the sleep of the user. Additionally, or alternatively, at step 1314, a sleep assessment or score may be generated. The score or assessment may be the same or similar to those described in FIG. 12. For the model described above, additional analytics may be executed to determinePCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 one or more recommendations for improving sleep quality for the user. In such a case, the one or more recommendations may be included in a notification to the user.

[0152] FIG. 14 illustrates a flowchart of an exemplary process 1400 for monitoring sleep using a wearable device. The process 1400 may include multiple steps for acquiring and analyzing data to determine sleep characteristics.

[0153] In step 1402, a wearable device may be worn on a user's arm while sleeping. The wearable device may include the devices described herein and may be designed to be comfortable and nonintrusive, allowing for continuous monitoring throughout the sleep period. The device may be designed to maintain consistent contact with the user's skin to ensure accurate sensor readings. This step may include wearing the wearable device on the left arm while sleeping. Doing so may provide more accurate EMG measurements compared to wearing the device on the right arm, resulting in improved detection of muscle atonia and more precise determination of sleep stages.

[0154] Step 1404 may involve obtaining biopotential signals from the user's arm using electrodes on the device interior, as described herein. These electrodes may be positioned to make contact with the user's skin, enabling the capture of various biopotential signals such as EMG data.

[0155] Step 1406 may involve converting the biopotential signals to biopotential data. This conversion may involve the processes described herein and may include, but are not limited to, analog-to-digital conversion, signal processing, or other data transformation techniques to prepare the raw signals for analysis.

[0156] Step 1408 may include collecting additional sensor data. This additional data may come from various sources such as an accelerometer, gyroscope, or heart rate sensor. These sensors may provide complementary information about the user's movement, position, or physiological state during sleep.

[0157] Step 1410 may involve analyzing the biopotential data and the collected additional sensor data to determine sleep characteristics. This analysis may utilize the machine learning process described herein, such as the training module illustrated in FIG. 12 or FIG. 13. Alternatively, the analysis may employ other methods to process the data and extract sleep-related information. These alternative methods may include, but are not limited to, statistical analysis, rule-based systems, or traditional signal processing techniques. The characteristics may relate to sleep stages, sleep duration, sleep quality, sleep onset latency, number of microarousals during sleep, duration of microarousals during sleep, sleep efficiency, REM sleep percentage, non-REM sleep percentage, body movements during sleep, or heart rate variability during sleep, and / or the like.

[0158] Finally, in step 1412, an output may be generated based on the determined sleep characteristics. This output may take various forms, such as an indication of the determined sleep characteristic(s), a sleep quality score, a breakdown of sleep stages, recommendations for improving sleep, or alerts about potential sleep disorders.

[0159] The process 1400 may be implemented in a continuous or periodic manner throughout the sleep period, allowing for real-time or near-real-time monitoring of sleep. The combination of biopotentialPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 data with other sensor data may provide a comprehensive view of the user's sleep, offering insights that may not be apparent from a single data source alone.

[0160] In some aspects, the process may determine one or more characteristics relating to the sleep of the user by detecting a presence or absence of muscle atonia. Muscle atonia, which refers to the loss of muscle tone or paralysis, is a key feature of REM sleep but does not occur in other sleep stages. The system may analyze the biopotential signals, such as EMG data, obtained from the user's arm to identify periods of reduced muscle activity indicative of muscle atonia. The detection of muscle atonia may involve analyzing the amplitude, frequency, or other characteristics of the EMG signals. In some cases, the system may employ advanced signal processing techniques or machine learning algorithms to accurately identify periods of muscle atonia. This information may be used in conjunction with other sensor data to provide a more comprehensive understanding of the user's sleep patterns and stages.

[0161] Building upon the detection of muscle atonia, the system may further determine specific characteristics related to REM sleep. These characteristics may include the amount, onset, end, duration, or percentage of REM sleep experienced by the user during their sleep period. REM sleep is a critical stage of sleep associated with vivid dreams, memory consolidation, and other important physiological processes.

[0162] The system may utilize the presence of muscle atonia, along with other indicators such as rapid eye movements (which may be detected through other sensors or inferred from the biopotential data), to identify REM sleep periods. By tracking the timing and duration of these periods, the system can provide valuable insights into the user's sleep architecture. For example, it may calculate the total amount of time spent in REM sleep, determine the onset time of the first REM period, identify when REM sleep ends, measure the duration of individual REM episodes, or compute the percentage of total sleep time spent in REM sleep.

[0163] These REM sleep characteristics may be particularly useful for assessing sleep quality and identifying potential sleep disorders. For instance, abnormalities in REM sleep patterns, such as a reduced percentage of REM sleep or delayed REM onset, may be associated with various sleep disorders or other health conditions. By providing this detailed information about REM sleep, the system may enable users and healthcare professionals to gain a deeper understanding of sleep patterns and potentially identify areas for improvement or further investigation.

[0164] In some aspects, the system may be configured to determine one or more characteristics relating to the sleep of the user by detecting a change in one or more of signal quality, noise, or frequency variance of the biopotential signals. This approach may leverage the dynamic nature of biopotential signals during different sleep stages to extract meaningful information about the user's sleep patterns.

[0165] The system may continuously monitor the biopotential signals for changes in their characteristics. For instance, changes in signal quality may be indicative of shifts in the user's sleep state or position. Variations in noise levels within the signal may correlate with different sleep stagesPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 or sleep disturbances. Additionally, changes in frequency variance of the biopotential signals may be associated with transitions between different sleep stages or levels of sleep depth.

[0166] By analyzing these signal characteristics, the system may be able to infer various sleep-related information. For example, a sudden increase in signal noise might indicate movement during sleep, while a shift in frequency content could suggest a transition between sleep stages. The system may employ advanced signal processing techniques or machine learning algorithms, including but not limited to those described herein, to detect and interpret these changes accurately.

[0167] In some implementations, the system may determine whether the user is in REM sleep or non- REM sleep and / or may determine microarousals are occurring by detecting changes in noise, signal amplitude, or frequency content of the biopotential signals. This capability may provide valuable insights into the user's sleep architecture and overall sleep quality. For example, during REM sleep, the biopotential signals may exhibit distinct characteristics compared to non-REM sleep. For instance, there might be an increase in high-frequency components in the signal, reflecting the increased brain activity associated with REM sleep. The signal amplitude may also show characteristic patterns during REM sleep, such as rapid fluctuations corresponding to eye movements. Conversely, non-REM sleep may be characterized by different signal properties. For example, there might be an increase in low-frequency components, particularly during deep sleep stages. The overall noise level in the signal might be lower during non-REM sleep, reflecting the more synchronized brain activity.

[0168] The system may analyze these various signal characteristics in real-time or near-real-time to classify the user's current sleep stage. This information could be used to track the progression of sleep stages throughout the night, measure the duration of REM and non-REM sleep periods, and potentially identify any abnormalities in the sleep cycle. By providing this detailed breakdown of sleep stages, the system may offer users and healthcare professionals valuable insights into sleep patterns and quality. This information could be used to identify potential sleep disorders, assess the effectiveness of sleep interventions, or guide strategies for improving overall sleep health.

[0169] In some aspects, the system may be configured to use a determination of whether the user is asleep or awake for additional analysis, such as to detect or measure microarousals during sleep. Microarousals may take the form of brief awakenings or shifts to lighter sleep stages that may occur throughout the night without the sleeper becoming fully conscious. These events may last for a few seconds to a few minutes and can significantly impact sleep quality and overall restfulness. The system may analyze the biopotential data, along with other sensor data, to identify patterns or changes indicative of microarousals. For instance, sudden changes in muscle tone, heart rate, or movement patterns may signal a microarousal event. By continuously monitoring these parameters, the system may be able to detect both the number of microarousals occurring during a sleep session and their duration.

[0170] In some implementations, the system may employ advanced algorithms or machine learning techniques, including but not limited to those described herein, to distinguish between normal sleepPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 stage transitions and microarousals. This differentiation may be crucial for accurately assessing sleep quality, as frequent microarousals can lead to fragmented sleep even if the total sleep duration appears adequate.

[0171] The ability to detect and measure microarousals may provide valuable insights into sleep architecture and quality. For example, an unusually high number of microarousals might indicate underlying sleep disorders such as sleep apnea or periodic limb movement disorder. Alternatively, environmental factors like noise or temperature fluctuations might be contributing to increased sleep disruptions.

[0172] By quantifying both the number and duration of microarousals, the system may offer a more comprehensive view of sleep quality beyond traditional metrics like total sleep time or sleep efficiency. This information could be particularly useful for healthcare professionals in diagnosing sleep disorders or assessing the effectiveness of sleep interventions.

[0173] In some cases, the system may incorporate this microarousal data into a broader sleep quality score or report. Users may be provided with insights about their microarousal patterns over time, potentially helping them identify factors that contribute to more restful or disrupted sleep. This information could empower users to make informed decisions about their sleep environment, habits, or seek professional advice if persistent sleep disruptions are detected.Computer System

[0174] FIG. 15 depicts an example system that may execute techniques presented herein. FIG. 15 is a simplified functional block diagram of a computer that may be configured to execute techniques described herein, according to exemplary cases of the present disclosure. Specifically, the computer (or “platform” as it may not be a single physical computer infrastructure) may include a data communication interface 1560 for packet data communication. The platform may also include a central processing unit 1520 (“CPU 1520”), in the form of one or more processors, for executing program instructions. The platform may include an internal communication bus 1010, and the platform may also include a program storage and / or a data storage for various data files to be processed and / or communicated by the platform such as ROM 1530 and RAM 1540, although the system 1500 may receive programming and data via network communications. The system 1500 also may include input and output ports 1550 to connect with input and output devices such as keyboards, mice, touchscreens, monitors, displays, etc. Of course, the various system functions may be implemented in a distributed fashion on a number of similar platforms, to distribute the processing load. Alternatively, the systems may be implemented by appropriate programming of one computer hardware platform.

[0175] The general discussion of this disclosure provides a brief, general description of a suitable computing environment in which the present disclosure may be implemented. In some cases, any of the disclosed systems, methods, and / or graphical user interfaces may be executed by or implemented by a computing system consistent with or similar to that depicted and / or explained in this disclosure. Although not required, aspects of the present disclosure are described in the context of computer-PCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 executable instructions, such as routines executed by a data processing device, e.g., a server computer, wireless device, and / or personal computer. Those skilled in the relevant art will appreciate that aspects of the present disclosure can be practiced with other communications, data processing, or computer system configurations, including: Internet appliances, hand-held devices (including personal digital assistants (“PDAs”)), wearable computers, all manner of cellular or mobile phones (including Voice over IP (“VoIP”) phones), dumb terminals, media players, gaming devices, virtual reality devices, multi-processor systems, microprocessor-based or programmable consumer electronics, set-top boxes, network PCs, mini -computers, mainframe computers, and the like. Indeed, the terms “computer,” “server,” and the like, are generally used interchangeably herein, and refer to any of the above devices and systems, as well as any data processor.

[0176] Aspects of the present disclosure may be embodied in a special purpose computer and / or data processor that is specifically programmed, configured, and / or constructed to perform one or more of the computer-executable instructions explained in detail herein. While aspects of the present disclosure, such as certain functions, are described as being performed exclusively on a single device, the present disclosure may also be practiced in distributed environments where functions or modules are shared among disparate processing devices, which are linked through a communications network, such as a Local Area Network (“LAN”), Wide Area Network (“WAN”), and / or the Internet. Similarly, techniques presented herein as involving multiple devices may be implemented in a single device. In a distributed computing environment, program modules may be located in both local and / or remote memory storage devices.

[0177] Aspects of the present disclosure may be stored and / or distributed on non-transitory computer- readable media, including magnetically or optically readable computer discs, hard-wired or preprogrammed chips (e.g., EEPROM semiconductor chips), nanotechnology memory, biological memory, or other data storage media. Alternatively, computer implemented instructions, data structures, screen displays, and other data under aspects of the present disclosure may be distributed over the Internet and / or over other networks (including wireless networks), on a propagated signal on a propagation medium (e.g., an electromagnetic wave(s), a sound wave, etc.) over a period of time, and / or they may be provided on any analog or digital network (packet switched, circuit switched, or other scheme).

[0178] Program aspects of the technology may be thought of as “products” or “articles of manufacture” typically in the form of executable code and / or associated data that is carried on or embodied in a type of machine -readable medium. “Storage” type media include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from aPCT / US25 / 49403 03 October 2025 (03.10.2025)Dkt. No. 4940-144US1 management server or host computer of the mobile communication network into the computer platform of a server and / or from a server to the mobile device. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various airlinks. The physical elements that carry such waves, such as wired or wireless links, optical links, or the like, also may be considered as media bearing the software. As used herein, unless restricted to non- transitory, tangible “storage” media, terms such as computer or machine “readable medium” refer to any medium that participates in providing instructions to a processor for execution.Terminology

[0179] The terminology used above may be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific examples of the present disclosure. Indeed, certain terms may even be emphasized above; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section. Both the foregoing general description and the detailed description are exemplary and explanatory only and are not restrictive of the features, as claimed.

[0180] As used herein, the terms “comprises,” “comprising,” “having,” including,” or other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus.

[0181] In this disclosure, relative terms, such as, for example, “about,” “substantially,” “generally,” and “approximately” are used to indicate a possible variation of ±10% in a stated value.

[0182] The term “exemplary” is used in the sense of “example” rather than “ideal.” As used herein, the singular forms “a,” “an,” and “the” include plural reference unless the context dictates otherwise.

[0183] Other aspects of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

Dkt. No. 4940-144US1Claims1. A system for monitoring sleep, the system comprising: a wearable device configured to be worn on a portion of an arm of a user while the user sleeps, the wearable device comprising: a plurality of electrodes disposed on an interior of the wearable device and configured to obtain biopotential signals from the user's arm; and a processor configured to: analyze biopotential data derived from the biopotential signals to determine one or more characteristics relating to sleep of the user; and generate an output based on the one or more characteristics relating to the sleep of the user.

2. The system of claim 1, wherein the wearable device further comprises: an accelerometer configured to output acceleration data indicating an acceleration of the portion of the user's arm; a gyroscope configured to output angular rate data indicating an angular rate of the portion of the user's arm; and wherein the processor is further configured to: analyze the acceleration data and the angular rate data in combination with the biopotential data to determine the one or more characteristics relating to the sleep of the user.

3. The system of claim 1, wherein the wearable device further comprises: a sensor configured to detect heart rate or heart rate variability of the user, wherein the processor is further configured to: receive heart rate data or heart rate variability data from the sensor; and analyze the heart rate data or heart rate variability data in combination with the biopotential data to determine the one or more characteristics relating to sleep of the user.

4. The system of claim 1, wherein the wearable device further comprises a memory configured to store the biopotential data over multiple sleep sessions, and wherein the processor is further configured to analyze trends in the stored biopotential data across the multiple sleep sessions.

5. The system of claim 4, wherein the processor is further configured to generate a sleep quality report based on the analyzed trends.

6. The system of claim 1, wherein the one or more characteristics relating to the sleep of the user include at least one of: sleep stages; sleep duration; sleep quality; sleep onset latency; number of microarousals during sleep;Dkt. No. 4940-144US1 duration of microarousals during sleep; sleep efficiency; rapid eye movement (REM) sleep percentage; non-REM sleep percentage; body movements during sleep; or heart rate variability during sleep.

7. The system of claim 1, wherein the processor is configured to determine the one or more characteristics relating to the sleep of the user by detecting a presence or absence of muscle atonia.

8. The system of claim 7, wherein the one or more characteristics relating to the sleep of the user is an amount, onset, end, duration, or percentage of rapid eye movement (REM) sleep.

9. The system of claim 1, wherein the processor is configured to determine the one or more characteristics relating to the sleep of the user by detecting a change in one or more of signal quality, noise, or frequency variance of the biopotential signals.

10. The system of claim 1, wherein the one or more characteristics relating to sleep of the user comprises whether the user is in REM sleep or non-REM sleep, and wherein the processor is configured to determine whether the user is in REM sleep or non-REM sleep by detecting a change in noise, signal amplitude, or frequency content of the biopotential signals.

11. The system of claim 1, wherein the processor is further configured to trigger an action based on the one or more characteristics relating to the sleep of the user.

12. The system of claim 11, wherein the action comprises at least one of: adjusting environmental conditions in a sleeping area of the user; providing haptic feedback through the wearable device; sending a notification to a caregiver; or recommending changes in behavior or a sleep routine of the user.

13. The system of claim 1, wherein the processor is further configured to predict cognitive performance of the user based on the one or more characteristics relating to the sleep of the user.

14. A method for monitoring sleep, the method comprising: obtaining, by a plurality of electrodes disposed on an interior of a wearable device worn on a portion of an arm of a user while the user sleeps, biopotential signals from the user's arm; analyzing, by a processor, biopotential data derived from the biopotential signals to determine one or more characteristics relating to sleep of the user; and generating, by the processor, an output based on the one or more characteristics relating to the sleep of the user.

15. The method of claim 14, further comprising wearing the wearable device on a left arm of the user while the user sleeps.Dkt. No. 4940-144US116. The method of claim 14, wherein the one or more characteristics relating to the sleep of the user include at least one of: sleep stages; sleep duration; sleep quality; sleep onset latency; number of microarousals during sleep; duration of microarousals during sleep; sleep efficiency; rapid eye movement (REM) sleep percentage; non-REM sleep percentage; body movements during sleep; or heart rate variability during sleep.

17. The method of claim 14, wherein determining the one or more characteristics relating to the sleep of the user comprises detecting a presence or absence of muscle atonia.

18. The method of claim 17, wherein the one or more characteristics relating to the sleep of the user is an amount, onset, end, duration, or percentage of rapid eye movement (REM) sleep.

19. A system for monitoring sleep, the system comprising: a wearable device configured to be worn on a portion of an arm of a user while the user sleeps, the wearable device comprising: a plurality of electrodes disposed on an interior of the wearable device and configured to obtain biopotential signals from the user's arm; and a processor configured to: analyze biopotential data derived from the biopotential signals to determine whether the user is asleep or awake; and generate an output based on the determination of whether the user is asleep or awake.

20. The system of claim 19, wherein the processor is further configured to use the determination of whether the user is asleep or awake to detect or measure a number or duration of microarousals during sleep.

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