Abstract

The purpose of this work was to design a micro electrical mechanical sensor (MEMS) based system to measure the mechanomyogram of electrically stimulated muscle. The measuring device for the mechanomyography (MMG) system consisted of a dual axis accelerometer and a signal conditioning circuit designed specifically to enhance raw MMG signals . Currently electromyography (EMG) is the standard tool for measuring muscle contraction. During electrical stimulation however, EMG measurements are corrupted with a large stimulus artefact. This obscures any contributions from the much smaller electrical activity of the muscle tissue itself for the first 10ms to 12ms, before disappearing. MMG, being based on kinetic measurements, offers an alternative in such cases. We illustrate this with a dual modality EMG/MMG simultaneous acquisition for a Hoffman-reflex study.