Surface Electromyographic Signals Using Dry Electrodes

For many electromyography (EMG) applications, a suitable dry electrode would simplify practical implementation of an EMG recording system. Wearable mobility monitoring is an example of such a system. Therefore, surface EMG signals, from Fraunhofer Institute for Biomedical Engineering (IBMT) flexible dry electrodes and Orbital Research electrodes, were compared to signals from conventional Ag/AgCl electrodes. EMG measurements were performed on the right tibialis anterior for a range of different activities, such as light twitches, isometric contractions, jumping, and walking. Signal feature comparisons, skin preparation effects (i.e., cleaning with isopropyl alcohol), and impedance-noise analyses were performed. Results showed that both dry electrodes had comparable sensitivity to the standard Ag/AgCl electrodes for detecting small unloaded muscle contractions and large loaded contractions. Results also showed that noise content and impedance are weakly correlated and skin preparation methods did not have a positive effect on skin/electrode impedance.