Ideal Carrier Waveform for Functional Electrical Stimulation in Upper Extremity

ABSTRACT

OBJECTIVE: This study was purposed to find the ideal carrier waveform in burst wave in Functional Electrical Stimulation (FES) for upper limbs after selection of proper site of electrode. METHOD: The 10 healthy men's non-dominant hands were studied. In 5 muscles (adductor pollicis, flexor digitorum sublimis, flexor pollicis longus, extensor digitorum communis and extensor pollicis brevis), the site where electric stimulus induced the best of purposed response was selected. A burst wave contains three carrier waveforms sine, triphasic & rectangular. The amount of mean current was measured during key grip and open motion. Discomfort of subject was scored by three degree and compared among three waveforms. RESULTS: The amount of mean current in key grip and open motion is lowest at triphasic wave (31.3 mA, 50.5 mA) and highest at rectangular wave (79.4 mA, 82.1 mA). For the discomfort, rectangular waveform provoke the greatest discomfort in key grip and open motion. There is no statistical difference between sine and triphasic waveform. CONCLUSION: In FES of upper limbs, triangular wave can be an useful carrier waveform which require less amount of current for performing the same motion and less discomfort than rectangular or sine waveform.