Sensory Feedback In Prosthetics: Where Do We Go Now?


Absence of a hand involves much more than the loss of prehensile function. Loss of sensory function deserves serious attention. A small-scale clinical evaluation of a prosthesis incorporating cutaneous electrical stimulation as a means of providing feedback of prehensile force involved six unilateral amputees, aged 7-28 years at fitting, with two to ten years follow-up. The results show clearly a need for more robust and reliable equipment: a high repair rate and system unreliability are the predominant disadvantages. Two patients considered the stimulus irritating. Advantages include improved ability to hold light objects without visual attention (4), a feeling that the prosthesis is "More like part of my body" (2) and ease of handling delicate objects (2). One subject still uses the system, four others would like an opportunity to try an improved system and five would recommend feedback to others. More insight is needed into the clinical need. Undue emphasis should not be placed on feedback as a means of improving control of prehension. Technical problems related to sensors and reliable coupling to the body were noted.

*Bio-Engineering Institute, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3 Canada