Method: Fifteen rabbits were experimentally spinal cord injured at the T10 or T11 spinal cord level. Three kinds of stimulation frequency (10, 20, 40 Hz) and sham control stimulation were applied to the tibialis anterior muscle of each four group for 1 hour per day, for 2 weeks. Muscle fatigue index and peak torque were measured during electrical stimulation, and proportion of the type I muscle fiber was measured at ATPase (pH 9.4) staining.

Results: Complete paraplegia was obtained in all 12 rabbits. Muscle fatigue index and peak torque were not changed after 2 weeks of electrical stimulation in all four groups. The proportion of the type I muscle fiber was reduced in all four groups after 2 weeks. However, 40 Hz stimulation group showed less decline in proportion of type I muscle fiber than control or 10 Hz group.

Conclusion: High frequency electrical stimulation applied at an early stage of spinal cord injury is more effective in preserving muscle endurance than low frequency stimulation. (J Korean Acad Rehab Med 2003; 27: 410-417)

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.

Objective: The purpose of this study is to evaluate the effect of functional electrical stimulation (FES) on hemiplegic shoulder subluxation in post-acute stroke patients.

Method: Forty-four patients who had shoulder subluxation as a consequence of their first stroke were included and randomly assigned to either a control group (22 subjects) or a study group (22 subjects). Patients in both groups received physiotherapy and used an arm sling. The study group received, FES therapy to shoulder muscles (supraspinatus and posterior deltoid) for 30 minutes, five days a week for 6 weeks. The effect of FES therapy was evaluated by assessment of the severity of subluxation using radiologic measurements before and after treatment.

Results: 1) The severity of subluxation was significantly increased after 6 weeks (p＜0.05) in the control group. In the study group, it was reduced but the difference was not statistically significant (p＞0.05). 2) In the group of patients with early treatment (onset duration, less than 6 months), the control group showed a significant increase in subluxation (p＜0.05), but the study group showed significantly reduced (p＜0.05) shoulder subluxation after treatment period. 3) In the group of patients with mild shoulder subluxation before treatment (less than 1 finger breadth), the control group showed a significant increase in subluxation (p＜0.05), but the study group showed significantly reduced (p＜0.05) shoulder subluxation after treatment period.

Conclusion: The FES therapy is effective in preventing and reducing the severity of hemiplegic shoulder subluxation in post-acute stroke patients, especially if duration since stroke onset was less than six months and the severity of subluxation before treatment was mild.