Abstract

Aim: The effect of electrical somatosensory stimulation on motor performance of the affected hand was investigated in 12 chronic subcortical stroke subjects.

Methods: Subjects performed index finger and hand tapping movements as well as reach-to-grasp movements with both the affected and unaffected hand prior to (baseline conditions) and following (1) 2 h of electrical somatosensory stimulation (trains of five pulses at 10 Hz with 1 ms duration delivered at 1 Hz with an intensity on average 60% above the individual somatosensory threshold) of the median nerve of the affected hand or (2) 2 h of idle time on separate occasions at least 1 week apart. The order of sessions was counterbalanced across subjects.

Results: Somatosensory stimulation of the median nerve of the affected hand, but not a period of idle time, enhanced the frequency of index finger and hand tapping movements and improved the kinematics of reach-to-grasp movements performed with the affected hand, compared with baseline. Somatosensory stimulation did not impact on motor performance of the unaffected hand.

Discussion: The data suggest that electrical somatosensory stimulation may improve motor function of the affected hand after stroke; however, further studies are needed to test if the implementation of somatosensory stimulation in rehabilitation of hand function also impacts on manual activities of daily life after stroke.