Spatially distributed sequential array stimulation of tibial anterior muscle for foot drop correction

Electrode arrays for the ease of electrode placement in the correction of foot drop with surface electrical stimulation have been developed in recent years. However, the configuration and identification of optimal stimulation sites with regard to time efficiency, stimulation comfort, and fatigue resistance is yet to be solved. In this study, the candidate stimulation sites were ranked and selected according to the motor thresholds induced by 1 Hz stimulation trains. Then based on the selected sites, a new stimulation configuration method termed spatially distributed sequential stimulation was tested and compared with traditional single electrode stimulation for foot drop correction in two normal subjects. The preliminary results demonstrated that the motor threshold of spatially distributed sequential stimulation was equal or less than motor thresholds of each stimulus sites. Besides, with the same stimulation parameters, the spatially distributed sequential stimulation induced larger dorsiflexion motion compared with traditional single electrode stimulation. These findings suggest that spatially distributed sequential stimulation on the selected sites might be an effective electrode array configuration method for correcting foot drop with electrical stimulation.