Twenty normal person were tested as control. Results: Of 31 patients with extramedullary lesions, CMCT to the abductor pollicis brevis (APB) muscles was abnormal in 19 cases (61.3%) and to the Anterior Tibia, (AB) muscles in 21 cases (67.7%).

• 结果 :3 1例髓外病变者 ；19例 ( 61.；3%25 )上肢拇展短肌 ( APB)中枢运动传导速度 ( CMCT)异常；2 1例 ( 67