Wearable Sensor Device for Thermogenic and Psychogenic Stress Differentiation

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Solution Overview

Problem

Current wearable sensor devices cannot accurately separate thermogenic and psychogenic stress responses from skin conductance measurements, as both types of stressors activate sweat glands and result in similar skin conductance variations, making it difficult to quantify and distinguish between thermal and emotional stress contributions.

Innovation Solution

A wearable sensor device with multiple electrodes configured to contact different skin areas, utilizing a switching arrangement to measure skin conductance signals in various states, allowing for the differentiation between thermogenic and psychogenic stress responses by analyzing the polarity and resistance changes across glabrous and non-glabrous skin regions, and processing units to determine stress responses based on rising edge heights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If skin conductance is measured at a single location to simplify the device, then device complexity is reduced, but the ability to separate thermogenic and psychogenic stress responses is lost

Engineering Contradiction:
Improvenumber of electrodesVSAvoidstress response differentiation
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the skin measurement into two distinct segments: glabrous skin (e.g., palm) and non-glabrous skin (e.g., back of hand). By placing electrodes on these different skin types, the system can separately measure thermogenic sweating (predominant on non-glabrous skin) and psychogenic sweating (predominant on glabrous skin), enabling differentiation of stress responses while maintaining a relatively simple device structure with only three electrodes.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple electrodes are used to differentiate stress types, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvestress response differentiationVSAvoidnumber of electrodes
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by selecting specific skin locations with different physiological properties. Glabrous skin (palm) and non-glabrous skin (back of hand) have different sweat gland distributions and responses to stimuli. By measuring at these localized regions with distinct characteristics, the system achieves accurate stress differentiation using minimal electrodes, avoiding the need for complex multi-electrode arrays.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If skin conductance measurements are taken simultaneously at multiple locations, then stress separation accuracy improves, but crosstalk between measurements increases

Engineering Contradiction:
Improvestress contribution separationVSAvoidmeasurement crosstalk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic action through time-division multiplexing, where measurements at different electrode locations are taken in alternating time slots rather than simultaneously. The switching arrangement sequentially connects different electrode pairs to the skin conductance sensor, ensuring that at any given moment only one measurement is active. This periodic measurement approach eliminates crosstalk between simultaneous measurements while maintaining the ability to compare results from different skin locations for accurate stress differentiation.

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate quantification and separation of thermogenic and psychogenic stress contributions, improving the assessment of cortisol responses to stressors and providing a more precise measurement of emotional and thermal stress levels.

Implementation Method 1

a skin conductance sensor configured to provide a voltage signal between a positive input terminal and a negative input terminal and to measure a skin conductance signal at an output terminal

Methodology Applied
Scientific EffectElectrical Conductivity: Conduction (electrical)

Data Source

PatentEP4072413B1Wearable sensor device and a sensing method
Publication Date: 2024.02.07 KONINKLIJKE PHILIPS NV
  • EP4072413B1 patent drawingFigure 1~2
  • EP4072413B1 patent drawingFigure 3~4
  • EP4072413B1 patent drawingFigure 5

AI summary

The present invention relates to a wearable sensor device and method for a thermogenic and/or psychogenic stress response of a subject. The wearable sensor device comprises a first electrode (11) configured to contact a first non-glabrous skin part of the subject, a second electrode (12) configured to contact a second non-glabrous skin part of the subject, a third electrode (13) configured to contact a glabrous skin part of the subject, and a skin conductance sensor (14) configured to provide a voltage signal between a positive input terminal (141) and a negative input terminal (142) and to measure a skin conductance signal at an output terminal (143). A switching arrangement (15) switches connections between the first to third electrodes and the positive and negative input terminals of the skin conductance sensor between at least three switching states. A processing unit (15) determines a 10 thermogenic and/or psychogenic stress response from the measured skin conductance signals during the at least three switching states.