Evaluation of electrodes for speech muscle electromyography

A variety of surface and intramuscular EMG electrodes commonly used in speech research, and a silver-silver chloride (Ag-AgCl) miniature surface electrode we have developed for speech EMG were evaluated by quantitatively comparing charcteristics such as impedance, senstivity, bandwidth, noise, and susceptibility to motion artifact. These characteristics were measured periodically to monitor changes with time. Additionally, experimental subjects rated the electrodes for discomfort and obtrusiveness. The results reveal serious difficulties with the “paint-on” (silver metal-film) variety of surface electrode for most speech EMG applications. While the preferred electrode can vary with the application, hooked wire electrodes, particularly those using platinum-iridium wire, consistently demonstrated superior performance. Where hooked wires are contraindicated, a sufficiently miniaturized high quality Ag-AgCl surface electrode, comparable to the design described in this paper, is often the preferred alternative. [Research supported by NINCDS grant.]