Effects of Active Thumb Movements upon Early Component of Somatosensory Evoked Potential
1999 年 11 巻 2 号 p. 113-116
詳細
1999 年 11 巻 2 号 p. 113-116
This study aimed to investigate the effects of thumb movement at three frequencies on early components of SEP. Subjects consisted of eighteen healthy persons whose age ranged from 19 to 30 years old (average age; 22 ± 3). The subjects pressed a counter set on a desk with the right thumb and electric stimulation was simultaneously applied to the median nerve of part of the right wrist joint. SEP was recorded at C3 on the contralateral scalp. The following results were obtained: 1) The latencies of P1, N1 and P2 were significantly prolonged during the counter pushing at a frequency of 1 Hz.citation=2. The peak to peak amplitudes of the P1-N1 and N1-P2 were significantly reduced by about 14% and 38%, respectively, during thumb movement at a frequency of 3 Hz.citation=3. These peak to peak amplitudes were not significantly decreased during counter pushing at a frequency of 0.25 Hz. The amplitude reduction of early components of SEP was observed during the thumb movements at a high frequency. The reduction was thought due to a repression of the sensory area by the ipsilateral motor one. These repressive effects varied with the frequency of movement.
