SENSITIVITIES OF THE ELECTRODIAGNOSTIC TESTS IN IDIOPATHIC MILD CARPAL TUNNEL SYNDROME

Abstract

OBJECTIVE: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy. The diagnosis is based on the history, clinical signs and symptoms of the patient, but electrodiagnostic studies are done to confirm the diagnosis and to manage the treatment. This study aimed to assess sensitivities of clinical symptoms, provocative tests and electrodiagnostic studies (EDS) in patients with idiopathic mild CTS.MATERIAL AND METHODS:The study included 90 hands of 75 patients with idiopathic mild CTS and 30 hands of 15 healthy volunteers. The patients were questioned for symptoms in the innervation area of the median nerve such as pain, paresthesia, weakness in the hand and numbness and pain worsening at night, relief from the symptoms by shaking hands. Tinel and Phalen tests were done. The EDS included; motor, mixed and sensorial (digits 1-2-3-4 and palm) nerve conduction studies (NCS) for median nerve; motor, mixed and sensorial (fifth digit) NCS for ulnar nerve, sensorial NCS (first digit) for radial nerve, median and ulnar F waves. The values for distal latency and nerve conduction velocity (NCV) were calculated for all studied nerves. Sensitivities of median sensory distal latency and NCV to digits 1,2,3,4 and palm-wrist segments and sensitivities of the following comparative tests were detected; median-radial sensory distal latency difference (SDLD) to the first digit, median-ulnar SDLD to the fourth digit, median-ulnar SDLD to the digits 2-5, 3-5, 4-5 and median-ulnar F latency difference.RESULTS: The most common symptoms in patients with idiopathic mild CTS were paresthesia (95.6%) and nocturnal numbness (88.8%). The sensitivity of Phalen’s and Tinel’s tests were 67.8% and 56.7%, respectively. Among the EDS, first digit and palm-wrist sensorial NCV were the most sensitive tests (98.9%). Of the comparative tests, median-ulnar SDLD to digits 4-5 was the most sensitive one (93.3%). Median-ulnar F latency difference had the lowest sensitivity (38.9%).CONCLUSIONS: The most sensitive EDS were first digit and palm-wrist sensorial NCV. Median-ulnar SDLD to digits 4-5 was more sensitive than the other tests. With use of these tests, the diagnostic sensitivity of EDS may be increased in patients with mild CTS.