Article ID: JJPTF_2023_10
When sensory perception is impaired, motor coordination becomes difficult. Thus, ways to cue with target objects during therapeutic exercise must be devised. This study investigated the effect of thumb motion adjustment on short-latency somatosensory evoked potentials (SEP). Twenty healthy adults participated in this study. Electrical stimulation to evoke the SEP was administrated the right median nerve at the wrist. All the subjects performed tasks involving repetitive palmar abduction movements, in which the right thumb was moved from 0° to 20° at a frequency of 1 Hz. Task 1 had no target (non-target task), while Task 2 had a palpable convex target at 20° (target task). Compared to the other amplitudes, those for the N9 and N13 amplitudes were the same in both tasks. The N20 amplitude was significantly lower in non-target task and target task than in the rest and significantly lower in non-target task than in target task. The absolute error was significantly lower in target task than in non-target task. Somatosensory input was suppressed and the N20 amplitude derived from the primary somatosensory cortex was decreased during voluntary movements. However, target task showed a weakened suppression effect compared to non-target task because the subjects made precise motor adjustments based on tactile stimulation. These findings suggested that motor control based on tactile stimulation might decrease the amount of gating in the thalamus and primary somatosensory cortex.
