Skin contact forces extracted from human nerve signals--a possible feedback signal for FES-aided control of standing

In this paper, information about stance related skin contact forces was extracted from nerve cuff electrode recordings of human neural signals. Forces measured under the heel during standing were scaled and applied to the innervation area of the sural nerve on the side of the foot using a hand held force probe. The neural response to the stimuli was measured with a cuff chronically implanted around the sural nerve in one hemiplegic person. An artificial neural network was used for extraction of the applied force from the recorded nerve signal. The results showed that it is possible to extract information about absolute skin contact forces from the nerve signal with an average goodness of fit of 69.3% for all trials and 82.2% for the more dynamic trials. This information may be applicable as feedback signal in control of standing.