Preprint : Shalaby R, Schauer T, Liedecke W, Raisch J. Amplifier design for EMG recording from stimulation electrodes during functional electrical stimulation leg cycling ergometry. Biomed Tech (Berl)

Functional electrical stimulation leg cycle ergometry (FES-LCE), which is often used as exercise for people with Spinal Cord Injury (SCI) has been recently applied in the motor rehabilitation of stroke patients. Recently completed studies show controversial results, but with a tendency to positive training effects. Technology involved at the moment is identical to the one used in FES-LCE for SCI while the pathology of stroke differs strongly. Most stroke patients with hemiparesis are able to drive an ergometer independently. Depending on the degree of spasticity, the paretic leg will partially support or hinder movements. Electrical stimulation increases muscle force and endurance, which both are per-requisites for restoring gait. However, the effect of FES-LCE on improving impaired motor coordination is unclear. In order to measure motor coordination during FES-LCE, an EMG-amplifier design has been investigated which suppresses stimulation artifacts and allows detection of volitional or reflex induced muscle activity. Direct measurement of EMG from stimulation electrodes between stimulation pulses is an important asset of this amplifier. Photo-MOS switches in front of the pre-amplifier are utilized to achieve this. The technology presented can be used to monitor the effects of FES-LCE to adapt the stimulation strategy or to realize an EMG-biofeedback training.