A basic study on estimation of foot dorsiflexion movement during walking from measurement in sitting position for FES-assisted foot drop correction

Functional electrical stimulation (FES) is effective to correct foot drop. Although electrode position and stimulation intensity to develop appropriate dorsiflexion are determined in sitting position, FES movement during walking may differ from that in sitting position. That is, it is better to determine appropriate electrode position and stimulation parameters by estimating foot movement during walking from measurement in sitting position. In this report, ankle dorsiflexion angle during FES-assisted walking and that developed by electrical stimulation in sitting position were measured on two hemiplegic subjects with inertial sensors. In both subjects, there were some trials that dorsiflexion angle at 95% of gait cycle was different from that in sitting position. In some trials of one subject, effect of drop foot correction decreased during gait. Decrease of dorsiflexion angle may cause falling, thus it is necessary to study reason of decrease of effect of foot drop correction.