Abstract: The features of physiological signals can be mapped to a latent space in order to draw inferences about activity, health, and age of an individual. For example, heart rate pulses for a population can be acquired as PPG signals and features of these acquired PPG signals can be mapped to a latent space, along with biological age, in order to encode data in the latent space such that location and/or distance within the latent space can be used to infer a corresponding cardiovascular age. Features of a current pulse of PPG data for a user can then be transformed into the latent space with an autoencoder or the like in order to estimate a cardiovascular age for the user, which can also be compared to the user's biological age in order to draw inferences about fitness and/or provide recommendations, coaching, and the like.

Abstract: A wearable physiological monitor is configured through a calibration procedure to provide a calibrated blood pressure measurement based on signals from an optical sensing system. In one aspect, optical (PPG) signals and motion signals are acquired while applying a mechanical stimulus over a range of mechanical frequencies with a haptic actuator. Resulting data is used to create a dynamic model for calculating blood pressure based on motion of the monitor. This blood pressure measurement can also usefully be correlated to the PPG signal for continuous blood pressure estimation. In another aspect, a monitoring device is positioned over a radial artery, and then optical measurements are taken of the radial artery while varying (and measuring) an applied force. Using various techniques, a model can be derived from this data for continuous blood pressure estimation.

Abstract: Sleep need for a user is assessed using continuous physiological data from a wearable monitor. In particular, by calculating a first sleep debt metric based on user strain and a second sleep debt metric based on accumulated sleep debt, an objective metric can be obtained that estimates an amount of sleep needed by the user in a next sleep period. This approach takes advantage of multiple modes of information embedded in the physiological data, such as a sleep and exercise patterns for a user over one or more preceding days.

Abstract: A model of data quality is derived for physiological monitoring with a wearable device by comparing data from the wearable device to concurrent data acquisition from a ground truth device such as a chest strap or electrocardiography (EKG) heart rate monitor. With this comparative data, a machine learning model or the like may be derived to prospectively evaluate data quality based on the data acquisition context, as determined, for example, by other sensor data and signals from the wearable device.

Abstract: A physiological monitor uses a light source and a number of detectors to determine whether a physiological monitor is positioned for acquisition of physiological data. More specifically, an intensity of the light source, as measured at two photodetectors at different distances from the light source, can be used to accurately detect whether the monitor is properly positioned for use. The disclosed methods may advantageously leverage existing physiological monitoring hardware (such as light emitting diodes and photodetectors), and may improve on the accuracy of prior art techniques using, e.g., capacitive sensors and/or other hardware to detect proper device positioning.

Abstract: Tightness of a wearable device can be evaluated through direct observations of how the device responds to a physical stimulus. For example, by applying a varying pattern of vibrations such as a CHIRP signal with a haptic output element or the like to a device strapped to a wrist or other body part, the mechanical and/or optical response of the device can be measured to infer the amount of tension that is retaining the device against the body, or more generally, to evaluate whether the device is properly fitted to a user. Results can then be presented to a user objectively using Newtons or some other metric, or subjectively by providing qualitative assessments of fit. Recommendations for adjustments may also or instead be provided to the user for optimal performance of the wearable device.

Abstract: A model of data quality is derived for physiological monitoring with a wearable device by comparing data from the wearable device to concurrent data acquisition from a ground truth device such as a chest strap or electrocardiography (EKG) heart rate monitor. With this comparative data, a machine learning model or the like may be derived to prospectively evaluate data quality based on the data acquisition context, as determined, for example, by other sensor data and signals from the wearable device.

Abstract: Variations in pulse shape over time can be used to draw inferences about activity, health, and age of an individual. For example, PPG pulses may be mapped to a latent space where variations in shape can be measured directly in terms of distance between pulses. In one aspect, pulse-to-pulse comparisons for an individual can be used to estimate strain, recovery, sleep, and so forth. Longer term measurements (e.g., over weeks, month, or years) can be used to detect changes in health and fitness for the individual. In another aspect, pulse-to-pulse comparisons among different individuals can be used to estimate relative cardiovascular health, age, and the like.

Abstract: A model of data quality is derived for physiological monitoring with a wearable device by comparing data from the wearable device to concurrent data acquisition from a ground truth device such as a chest strap or electrocardiography (EKG) heart rate monitor. With this comparative data, a machine learning model or the like may be derived to prospectively evaluate data quality based on the data acquisition context, as determined, for example, by other sensor data and signals from the wearable device.

Abstract: A physiological monitoring device controls an optical signal acquisition system within a number of discrete operating states, each providing values for controllable parameters such as illumination intensity for a light source and the gain for an optical detector. Using this technique, a small number of operating states may be defined, such as operating states that are known to work well within expected use scenarios. This approach advantageously facilitates optimal or near optimal operation across a range of most likely use cases while avoiding complex or continuous optimization problems. The list of operating states may further be prioritized so that a best operating state can be selected based on, e.g., signal quality or environmental conditions.

Abstract: A model of data quality is derived for physiological monitoring with a wearable device by comparing data from the wearable device to concurrent data acquisition from a ground truth device such as a chest strap or electrocardiography (EKG) heart rate monitor. With this comparative data, a machine learning model or the like may be derived to prospectively evaluate data quality based on the data acquisition context, as determined, for example, by other sensor data and signals from the wearable device.

Abstract: A physiological monitoring device controls an optical signal acquisition system within a number of discrete operating states, each providing values for controllable parameters such as illumination intensity for a light source and the gain for an optical detector. Using this technique, a small number of operating states may be defined, such as operating states that are known to work well within expected use scenarios. This approach advantageously facilitates optimal or near optimal operation across a range of most likely use cases while avoiding complex or continuous optimization problems. The list of operating states may further be prioritized so that a best operating state can be selected based on, e.g., signal quality or environmental conditions.

Abstract: Systems and methods for real-time tracking of photoacoustic sensing are provided. In one aspect, a method for performing in vivo analysis of a subject is provided. The method includes directing an electromagnetic excitation toward a subject to be analyzed, and acquiring, with an ultrasound probe, data about resultant waves caused by the electromagnetic excitation. The method also includes processing the acquired data to extract information related to properties of tissues in the subject, and comparing the information related to the properties of tissues in the subject using a set of criteria. The method also includes generating a report about a condition of the subject based on the comparison of the information related to properties of the tissues in the subject.

Abstract: A physiological signal such as a heart rate acquired from a monitoring device is processed to reduce interference, ambiguity, or artifacts arising during various activities. For example, the system can process a physiological signal to account for motion artifacts in the physiological signal and, thus, reduce the impact of movement on the physiological signal. Additionally, or alternatively, the system can process a physiological signal based on one or more measurement contexts associated with a wearable device. In general, the physiological signal processed as described herein can be useful as a reliable, continuous indication of a physiological parameter and, thus, can serve as the basis for other physiological assessments (e.g., heart rate variability) derived from the physiological parameter.

Abstract: A physiological signal such as a heart rate acquired from a monitoring device is processed to reduce interference, ambiguity, or artifacts arising during various activities. For example, the system can process a physiological signal to account for motion artifacts in the physiological signal and, thus, reduce the impact of movement on the physiological signal. Additionally, or alternatively, the system can process a physiological signal based on one or more measurement contexts associated with a wearable device. In general, the physiological signal processed as described herein can be useful as a reliable, continuous indication of a physiological parameter and, thus, can serve as the basis for other physiological assessments (e.g., heart rate variability) derived from the physiological parameter.

Abstract: A physiological signal such as a heart rate acquired from a monitoring device is processed to reduce interference, ambiguity, or artifacts arising during various activities. For example, the system can process a physiological signal to account for motion artifacts in the physiological signal and, thus, reduce the impact of movement on the physiological signal. Additionally, or alternatively, the system can process a physiological signal based on one or more measurement contexts associated with a wearable device. In general, the physiological signal processed as described herein can be useful as a reliable, continuous indication of a physiological parameter and, thus, can serve as the basis for other physiological assessments (e.g., heart rate variability) derived from the physiological parameter.

Abstract: A physiological signal such as a heart rate acquired from a monitoring device is processed to reduce interference, ambiguity, or artifacts arising during various activities. For example, the system can process a physiological signal to account for motion artifacts in the physiological signal and, thus, reduce the impact of movement on the physiological signal. Additionally, or alternatively, the system can process a physiological signal based on one or more measurement contexts associated with a wearable device. In general, the physiological signal processed as described herein can be useful as a reliable, continuous indication of a physiological parameter and, thus, can serve as the basis for other physiological assessments (e.g., heart rate variability) derived from the physiological parameter.

Abstract: Systems and methods for real-time tracking of photoacoustic sensing are provided. In one aspect, a method for performing in vivo analysis of a subject is provided. The method includes directing an electromagnetic excitation toward a subject to be analyzed, and acquiring, with an ultrasound probe, data about resultant waves caused by the electromagnetic excitation. The method also includes processing the acquired data to extract information related to properties of tissues in the subject, and comparing the information related to the properties of tissues in the subject using a set of criteria. The method also includes generating a report about a condition of the subject based on the comparison of the information related to properties of the tissues in the subject.