Tethered median nerve stress test in the diagnosis of carpal tunnel syndrome.

The sensitivity of the Median Nerve Stress Test (Stress Test) described by La Ban et al. and performed hyperextending for one minute the supinated wrist and the distal interphalangeal joint of the index finger and looking for pain in the proximal forearm was evaluated in 140 arms with Carpal Tunnel Syndrome confirmed electrophysiologically. The Stress Test was positive in 60 hands (42.8%), the Phalen's sign in 79 (56.4%) and the Tinel's sign in 59 (42.1%). Hypoaesthesia to pinprick in the distribution of the median nerve was found in 45 hands (32.1%) and weakness or hypotrophia of thenar eminence in 17 (12.1%). In spite of his low sensitivity, in some cases the Stress Test was the only clinical positive sign and, in addition to electrophysiological examination, may be helpful in clinical practice.