A closed-loop control system for controlling the key grip of a C6 tetr
aplegic patient was developed. Natural sensors served as the source of
the feedback signal. The neural signals from cutaneous receptors were
picked up by an implanted cuff electrode placed around the radial bra
nch of the median nerve innervating the lateral part of the index fing
er. Mechanical stress applied to the skin, like pressure and slips, re
sulted in an increase in amplitude of the recorded neural signal. The
goal of the study was to determine whether the recorded neural signals
were able to indicate the slip of an object during lateral grasp and
whether the slip could be stopped by increasing the grasp force throug
h functional electrical stimulation of the thumb adductor and flexor.