Comparison of catch responses between a tetraplegic patient using an FES system, and healthy control subjects

A closed loop control FES system was developed to provide a C5-tetraplegic patient with lateral hand grasp. Cutaneous mechanoreceptors, sensitive to slips across the skin, were applied to control the stimulation intensity of the system. The authors investigated the `catch responses´ to slip events during lateral hand grasp tasks and compared them to the responses of five healthy control subjects. Slips of the grasped object were initiated by increasing the tangential pulling force. Different pulling loads and object textures were used in this study, the slip distances increased with higher pulling loads and more slippery surfaces. For the sandpaper surface the authors did not observe significant differences between the SCI-patient and the control subjects with respect to reaction time and slip distances