Automatic carpal tunnel syndrome tester

Objective: A device for automatic testing of sensory latency across the car pal tunnel is described. A fixed bar contains a stimulating electrode dista lly and a bipolar recording set up with the two poles at 7 and 14 cm distan ce proximally. The device is thus based on the so called 14/7 method, using orthodromic testing. Methods: Automatic testing of electrode resistance and muscle relaxation pr ecedes the self triggered start of stimulation. The latencies are analyzed according to a special algorithm. The proximal/distal latency index is incr eased in carpal tunnel syndrome (CTS). Results: Healthy controls (32 hands in 32 subjects) and patients referred w ith suspicion of CTS (258 hands) were studied with the new device, by conve ntional technique and sometimes by inching (centimetering) across the carpa l tunnel. A positive CTS result with the tester was in accordance with the routine test in 94% of the patients. Conversely, routine studies showed CTS in 118 hands. Among those, the tester agreed in 44, showed no signals in 7 0 and indicated normal findings in 4 hands. In cases with a combination of polyneuropathy and CTS, the CTS was detected in 5 out of 6 cases. A complet e test takes about 1 min per hand. Conclusions: The results are very promising. (C) 2000 Elsevier Science Irel and Ltd. All rights reserved.