Multipoint surface electromyography measurement using bull's-eye electrodes for wide-area topographic analysis

Area of Science:

• Biomedical Engineering
• Neuroscience
• Kinesiology

Background:

• Surface electromyography (sEMG) traditionally analyzes limited muscle activity.
• Understanding muscle coordination requires simultaneous measurement of multiple muscles.
• The bull's-eye electrode enables wide-area, multipoint sEMG measurements without directional dependence.

Purpose of the Study:

• Establish a multipoint sEMG measurement system using bull's-eye electrodes.
• Evaluate the system's effectiveness in assessing forearm muscle fatigue during grasping.
• Create topographic maps of muscle activity.

Main Methods:

• Nine healthy adults performed grasping tasks with bull's-eye electrodes recording muscle activity.
• Calculated root mean squares and entropy to analyze muscle activity distribution over time.
• Validated system effectiveness by comparing muscle activity metrics.

Main Results:

• Entropy analysis showed increased muscle uniformity over time, indicating potential fatigue.
• Topographic maps visually represented muscle activity, highlighting intersubject variations.
• The system successfully captured activity from nine muscle points.

Conclusions:

• The bull's-eye electrode system effectively creates topographic muscle activity images.
• Progressive entropy increase suggests adaptive muscle coordination in response to fatigue.
• This novel system offers a promising approach for multichannel sEMG with improved wearability.