A System Based on Photoplethysmography and Photobiomodulation for Autonomic Nervous System Measurement and Adjustment

Area of Science:

• Biomedical Engineering
• Neuroscience
• Traditional Chinese Medicine

Background:

• Autonomic nervous system (ANS) imbalance, characterized by sympathetic hyperactivity (high tension) or parasympathetic hyperactivity (low attention), is a prevalent global health concern.
• Existing methods for assessing and modulating ANS status are often limited, necessitating the development of integrated and accessible systems.

Purpose of the Study:

• To develop and validate a feasible integrated system capable of measuring and influencing autonomic nervous system (ANS) status.
• To investigate the effects of photobiomodulation (PBM) at specific acupoints on heart rate variability (HRV) and ANS modulation.

Main Methods:

• A novel system integrating signal processing, photoplethysmography (PPG) sensors, and an LED stimulation module was developed to analyze heart rate variability (HRV).
• HRV analysis using the developed system was validated against electrocardiogram (ECG) measurements.
• Photobiomodulation (PBM) was applied to Neiguan (PC6) and Shenmen (HT7) acupoints at 10 Hz and 40 Hz frequencies to assess its impact on ANS status.

Main Results:

• The developed system accurately analyzed HRV metrics from PPG data, showing trends consistent with ECG measurements.
• Stimulation at the Neiguan (PC6) acupoint with 10 Hz PBM increased overall HRV (SDNN) and enhanced parasympathetic nervous system (PNS) activity (HF (%)).
• Stimulation at the Shenmen (HT7) acupoint with 40 Hz PBM increased overall HRV (SDNN) and enhanced sympathetic nervous system (SNS) activity (LF (%)).

Conclusions:

• A functional prototype system for measuring and influencing ANS status was successfully developed and demonstrated feasibility.
• Evidence suggests that stimulating Neiguan (PC6) can inhibit SNS activity, while stimulating Shenmen (HT7) can activate SNS activity.
• Further research with varied parameters (pulse rates, dosages, acupoints) is recommended to comprehensively confirm these findings and optimize therapeutic applications.