Physiological monitoring devices and methods using optical sensors
Inventors
LeBoeuf, Steven Francis • Tucker, Jesse Berkley • Aumer, Michael Edward • Just, Steven Matthew • Felice, Mark Andrew
Assignees
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Publication Number
US-11337655-B2
Publication Date
2022-05-24
Expiration Date
Abstract
A monitoring device configured to be attached to a subject includes a photoplethysmography (PPG) sensor configured to measure physiological information from the subject, and at least one processor configured to process signals from the PPG sensor to determine heart rate and RR-interval (RRi) for the subject, and to determine a heart rate pattern for the subject over a period of time. The at least one processor is configured to change a sampling frequency of the PPG sensor for determining RRi in response to the determined heart rate pattern. The at least one processor is configured to reduce the sampling frequency of the PPG sensor in response to determining a pattern of heart rate below a threshold.
Core Innovation
Wearable monitoring devices include a photoplethysmography (PPG) sensor configured to measure physiological information from a subject and to produce a photoplethysmogram that is processed by at least one processor. The processor generates a biometric parameter in a plurality of time intervals comprising at least three time intervals, and the PPG measurement is adapted across the time intervals by changing the optical emitter polling rate and/or changing the PPG sensor data sampling rate across successive time intervals.
The disclosed monitoring adapts measurement frequency and interrogation power based on detected conditions associated with the subject and the surrounding environment. The detected conditions include heart rate pattern and activity level, subject vital signs such as blood pressure, temperature, and respiration rate, motion, environmental conditions, clock and circadian rhythm, location, and stress level.
The document also describes algorithm switching for signal analysis and supports changing measurement configurations across time intervals, including switching between time-domain and frequency-domain approaches. Wavelength switching and interval-based measurement for different biometrics are also included, together with power-saving strategies.
Claims Coverage
The independent claim set covers three related aspects of the same concept: (i) progressively lower optical emitter polling rates across at least three time intervals, (ii) progressively lower sampling rates where each time interval has sensor data sampled at a different rate, and (iii) monitoring methods that implement these approaches to generate biometric parameters across a plurality of time intervals that include at least three intervals.
Progressively lower optical emitter polling rates across time intervals
A monitoring device configured to be attached to a subject, comprising a photoplethysmography (PPG) sensor configured to measure physiological information and at least one processor configured to process a photoplethysmogram to generate a biometric parameter in a plurality of time intervals comprising at least three time intervals, where the at least one processor causes an optical emitter of the PPG sensor to have a first polling rate in a first time interval, a second polling rate in a second time interval lower than the first polling rate, and a third polling rate in a third time interval lower than the second polling rate.
Different sampling rates for PPG sensor data across time intervals
A monitoring device configured to be attached to a subject, comprising a photoplethysmography (PPG) sensor configured to measure physiological information and at least one processor configured to process a photoplethysmogram to generate a biometric parameter in a plurality of time intervals comprising at least three time intervals, where each time interval is associated with PPG sensor data sampled at a different sampling rate, including a first sampling rate in a first time interval, a second sampling rate in a second time interval lower than the first sampling rate, and a third sampling rate in a third time interval lower than the second sampling rate.
Method of generating biometric parameters with progressively lower optical emitter polling rates
A method of monitoring a subject via a monitoring device attached to the subject, where the monitoring device comprises a photoplethysmography (PPG) sensor and at least one processor, the method comprising processing, via the at least one processor, a photoplethysmogram produced by the PPG sensor to generate a biometric parameter in a plurality of time intervals comprising at least three time intervals, and causing an optical emitter of the PPG sensor to have a first polling rate in a first time interval, a second polling rate in a second time interval lower than the first polling rate, and a third polling rate in a third time interval lower than the second polling rate.
Method of generating biometric parameters with different sampling rates across time intervals
A method of monitoring a subject via a monitoring device attached to the subject, where the monitoring device comprises a photoplethysmography (PPG) sensor and at least one processor, the method comprising processing, via the at least one processor, a photoplethysmogram produced by the PPG sensor to generate a biometric parameter in a plurality of time intervals comprising at least three time intervals, where each time interval is associated with PPG sensor data sampled at a different sampling rate, including a first sampling rate in a first time interval, a second sampling rate in a second time interval lower than the first sampling rate, and a third sampling rate in a third time interval lower than the second sampling rate.
Across the independent claims, coverage centers on generating biometric parameter(s) from a photoplethysmogram in at least three time intervals while adapting PPG measurement by using progressively lower optical emitter polling rates and/or progressively lower sampling rates for the PPG sensor data. The independent method claims correspond to the same adaptive interval-based polling or sampling strategy implemented during monitoring of a subject.
Stated Advantages
Power saving strategies are included for reducing power while maintaining accuracy metrics for RRi.
Experimental/observational support indicates RRi accuracy versus polling/sampling frequencies, supporting maintenance of accuracy under reduced sampling regimes.
Documented Applications
Wearable PPG monitoring that adapts signal sampling frequency/sensor interrogation power for biometric parameters based on detected conditions including heart rate pattern/activity, subject vital signs, motion, environmental conditions, clock/circadian rhythm, location, and stress level.
RRi (RR-interval) monitoring with polling/sampling frequency regimes assessed for accuracy.
Algorithm switching for PPG signal analysis using time-domain versus frequency-domain approaches, optionally along with wavelength switching and interval-based measurement for different biometrics.
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