Sensory palmar stimulation in the diagnosis of carpal tunnel syndrome.

The measurement of motor and sensory latencies of the median and ulnar nerves using conventional techniques in able-bodied subjects and patients with a history compatible with carpal tunnel syndrome (CTS) is described. The results obtained by conventional techniques are compared with measurement of median nerve sensory latency obtained by palmar stimulation and the difference of median-ulnar nerve distal sensory latencies. It is concluded that the use of measurement of median palmar sensory latency under the flexor retinaculum adds to the sensitivity of the nerve conduction studies in the diagnosis of CTS. It is suggested that, in patients with suspected CTS in whom conventional nerve conduction studies are normal, other techniques such as the measurement of palmar sensory latency, difference between median and ulnar nerve distal sensory latency and examination of all the digits should be carried out.