Feasibility Study of Using Alternating Current Excitation to Obtain Electrodermal Activity with a Wearable System

Area of Science:

• Biomedical Engineering
• Physiological Measurement

Background:

• Electrodermal activity (EDA) is crucial for assessing physiological responses.
• Traditional direct current (DC) excitation methods for EDA are prone to signal drift caused by electrode-skin polarization.
• Developing stable and reliable EDA measurement techniques is essential for real-time biomechanical applications.

Purpose of the Study:

• To investigate the feasibility of using full-wave alternating current (AC) excitation for wearable electrodermal activity (EDA) measurements.
• To address the signal drift issue commonly encountered with direct current (DC) excitation.
• To evaluate the performance of AC excitation in terms of signal stability and skin response.

Main Methods:

• A portable wearable system utilizing fixed-amplitude, full-wave AC signals for EDA measurement was developed.
• A multilayer model was employed to simulate skin's electrical behavior and analyze current propagation at various frequencies.
• Experiments were conducted on ten healthy participants, comparing DC and AC excitation methods, including signal stability and skin response analysis.

Main Results:

• Full-wave AC excitation demonstrated significantly reduced signal drift compared to DC excitation.
• Measurements using AC excitation exhibited greater temporal stability.
• Enhanced detection of the skin's capacitive response was observed with AC excitation.

Conclusions:

• Full-wave AC excitation is a feasible and advantageous method for electrodermal activity (EDA) measurement.
• The improved reliability and stability of AC excitation support its adoption in wearable and real-time biomechanical monitoring.
• This approach offers a more robust solution for physiological monitoring in ambulatory settings.