The influence of EMG-initiated electrical muscle stimulation on motor recovery of the centrally paretic hand.

The present study compares the effect of EMG-initiated electrical stimulation of hand extensors and flexors with the influence of a standardized repetitive training of the hand that had been proven to ameliorate arm and hand function significantly. Twenty hemiparetic stroke patients participated in the study. Following a 2 week baseline phase in which conventional inpatient occupational and physiotherapy was applied, all patients received EMG-initiated electrical muscle stimulation twice daily during 20 min periods followed by a third phase with a standardized repetitive training of the hand. Both training procedures were conducted in addition to conventional occupational and physiotherapy. Grip strength, peak force of isometric hand extensions as well as peak acceleration of isotonic hand extensions were measured as indicators of motor performance. Spasticity of hand flexors was assessed by means of the modified Ashworth scale. Motor capacity of the affected arm was scored by means of the Rivermead motor assessment, arm section. Contrary to usual occupational and physiotherapy, both the EMG-initiated stimulation and the repetitive training are appropriate to improve all biomechanical and functional parameters significantly whereas no difference in the efficacy of both methods could be detected. The functional significance of frequent active repetition of identifcal movements and the role of time-locked afferent information about the unfolding movement for motor learning and recovery are discussed.