Characterization of capacitive electromyography biomedical sensor insulated with porous medical bandages

Charn Loong Ng,Muhammad Enamul Hoque Chowdhury,Maria Liz Crespo,Mamun Bin Ibne Reaz,Andres Cicuttin

doi:10.1038/s41598-020-71709-0

Abstract

A capacitive electromyography (cEMG) biomedical sensor measures the EMG signal from human body through capacitive coupling methodology. It has the flexibility to be insulated by different types of materials. Each type of insulator will yield a unique skin–electrode capacitance which determine the performance of a cEMG biomedical sensor. Most of the insulator being explored are solid and non-breathable which cause perspiration in a long-term EMG measurement process. This research aims to explore the porous medical bandages such as micropore, gauze, and crepe bandage to be used as an insulator of a cEMG biomedical sensor. These materials are breathable and hypoallergenic. Their unique properties and characteristics have been reviewed respectively. A 50 Hz digital notch filter was developed and implemented in the EMG measurement system design to further enhance the performance of these porous medical bandage insulated cEMG biomedical sensors. A series of experimental verifications such as noise floor characterization, EMG signals measurement, and performance correlation were done on all these sensors. The micropore insulated cEMG biomedical sensor yielded the lowest noise floor amplitude of 2.44 mV and achieved the highest correlation coefficient result in comparison with the EMG signals captured by the conventional wet contact electrode.

Highlights

A capacitive electromyography biomedical sensor measures the EMG signal from human body through capacitive coupling methodology
This signal contains useful information for a wide range of applications such as clinical diagnosis of musculoskeletal diseases (MSD), healthcare and rehabilitation, and prothesis controller. This alternating bioelectrical signal appear in a burst form which can be measured with the capacitive coupling methodology
The noise floor characterization test measured the baseline result of the porous medical bandages insulated capacitive electromyography (cEMG) biomedical sensor

Summary

Introduction

A capacitive electromyography (cEMG) biomedical sensor measures the EMG signal from human body through capacitive coupling methodology. This research aims to explore the porous medical bandages such as micropore, gauze, and crepe bandage to be used as an insulator of a cEMG biomedical sensor Most of the insulators are solid and non-breathable material which will cause perspiration after a long-term electromyography (EMG) measurement This phenomenal will change the skin–electrode capacitance value and eventually alter the performance of a cEMG biomedical s ensor[4]. The cEMG biomedical sensor was insulated by these porous medical bandage samples to measure the EMG signals from the bicep brachii muscle of two subjects The performance of these sensors were benchmarked with the conventional wet contact electrode (Ag–AgCl). A 50 Hz digital notch filter is added in the post signal processing process to improve the signal-to-noise ratio of the porous medical bandages insulated cEMG biomedical sensor[5,6]

Objectives

Methods

Results

Conclusion