Multi-Channel Surface Electromyography Electrodes: A Review

This paper is a review of multi-channel surface electromyography (sEMG) electrode used in the research for investigating the properties of muscles. Over 300 papers from five recognized journals were examined from the year 2000 to 2013 with only 64 stating the use of multi-channel electrodes in their research. The review determined that multi-channel electrodes can be classified as linear array or 2D array electrodes. The 2D array is the basis for developing the high-spatial-resolution sEMG (HSR-sEMG) or high density sEMG (HD-sEMG). The important factors considered in this review of the electrodes are: 1) the material used; 2) the inter-electrode distance; and 3) the configuration for the collection of the electromyography signals. The basic configurations of the sEMG electrodes are monopolar, bipolar, and double differential. It was found that the majority of the linear array electrodes were used to collect either bipolar or double differential signals. The 2D array electrodes were used to collect monopolar signals. The HSR-sEMG electrodes used a normal double differentiating filter, referred to as Laplacian configuration. The HD-sEMG has versatility being able to collect all types of signals, such as monopolar, bipolar, double differential, or signals filtered by Laplacian configuration.