Abstract
In recent years the effect of biofeedback therapy for wirter's cramp has been evaluated in relation to reduction of EMG and improvement of symptoms, and reports on its effectiveness are being made. However, hardly any reports have been published in detail on the relationship between the clinical effect of biofeedback therapy and physiological responsivity. Biofeedback was conducted for writer's cramp using two-channel EMG of musculus extensor carpi radialis longus and musculus trapezius, and its clinical effect and physiological responsivity were studied. The results of our study showed a relatively high effective rate of 73.9%. In the patients with writer's cramp in whom EMG biofeedback was effective, the EMG was originally high and the symptoms were reflected in the EMG. Furthermore, in these patients, EMG could be reduced during the trial period and session period. In order the enhance the clinical effect, it was found that control of only the musculus extensor carpi radialis longus was insufficient and the propriety and effectiveness of two-channel biofeedback therapy were suggested. In the study of writer's cramp by clinical type, it was confirmed that our classified stiff-tremor type is a unique clinical type which shows a responsivity unlike those of other types. The clinical effect classified by clinical type was the highest for stiff type, followed in decreasing order by stiff-tremor type and tremor type. It was ineffective for dystonia type. However, it was ascertained that the responsivity of EMG classified by clinical effect was not dependent on clinical type. EMG used as index in the present study appropriately reflected the pathophysiology of writer's cramp patients with writing difficulty and when there was room for learning toward the objective direction and there was responsivity to biofeedback, EMG indicated the potential therapeutic effectiveness regardless of clinical type. Furthermore, it was considered possible to speculate the therapeutic effect by the initial EMG value on the first day of therapy and by its responsivity.
