Circadian Phase Estimation via Activity Level Substitution
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Solution Overview
Problem
Existing methods for estimating a subject's circadian phase often rely on light exposure measurements, which may not be available or reliable, especially in scenarios where subject-specific light exposure information is not suitable.
Innovation Solution
A system and method utilizing a sensor to detect motion and generate activity level signals, which are then used to determine activity parameters and estimate light exposure parameters through a pacemaker oscillator model described by a second-order differential equation, allowing for the estimation of circadian phase without direct light exposure data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light exposure measurements are used to estimate circadian phase, then measurement precision is improved, but reliability deteriorates when light exposure data is unavailable
Solution Approach 1:
The patent introduces activity level measurements as an intermediary substitute for direct light exposure measurements. Activity data serves as a mediator that indirectly reflects circadian phase information when primary light exposure data is unavailable, allowing the system to maintain estimation reliability through alternative measurement pathways
Solution Approach 2:
The system dynamically switches between different measurement parameters based on data availability. When light exposure data is unavailable, the system changes from using light exposure parameters to using activity level parameters, maintaining the ability to estimate circadian phase through parameter substitution and model adaptation
2Reliability
If activity level measurements are used instead of light exposure data, then reliability is improved, but measurement precision may deteriorate
Solution Approach 1:
The patent replaces direct optical measurement (light exposure sensing) with mechanical movement measurement (activity level sensing). This substitution uses motion detection to infer circadian phase information, trading direct optical precision for reliable mechanical measurement that works in all environmental conditions
Solution Approach 2:
The system creates a proxy measurement model where activity level data serves as a copy or surrogate for light exposure data. The activity-based model replicates the circadian phase estimation function using alternative data that correlates with behavioral patterns driven by circadian rhythms
3Adaptability or versatility
If pacemaker oscillator model with activity parameters is used, then adaptability is improved, but device complexity increases
Solution Approach 1:
The pacemaker oscillator model is designed to handle multiple types of input data (both light exposure and activity level measurements). This universal model structure allows the same computational framework to process different data sources, making the system adaptable to various measurement scenarios without requiring separate models for each input type
Data Source
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AI summary
Systems and methods to estimate circadian phase of a subject use one or more sensors to track an activity level of the subject over a period. Actual light exposure need not be tracked nor used to estimate the circadian phase of the subject. One or more estimated light exposure parameters are based on the activity level. The estimated circadian phase is based on the one or more estimated light exposure parameters,possibly derived from activity measurements.