Carpal tunnel syndrome is induced by median nerve compression at the wrist.Neuropsychological tests are often helpful for diagnosing the disease.During electrophysiological diagnosis of carpal tunnel syndrome,distal latencies of compound muscle action potentials of the median nerve and abductor pollicis brevis are important diagnostic indicators of the disease stage and choice of treatment.Paget (1853) first described median nerve compression at the wrist induced dysfunction in the corresponding innervated area.Phalen (1966) established principles for diagnosing and treating carpal tunnel syndrome.Several recent research advances have been made describing the pathophysiology and electrophysiology of carpal tunnel syndrome.