Diagnosis of carpal tunnel syndrome using ring finger sensory nerve conduction velocity

Objective To investigate the method of diagnosis of carpal tunnel syndrome (CTS) using ring finger sensory nerve conduction velocity(SCV). Methods Eighteen cases (26 hands) with normal latency of wrist sensation action potential were studied. The sensory nerve conduction velocity (SCV) were recorded. The SCV in the median and ulnar nerve in the ring finger, SCV in the median nerve in the middle finger were recorded. Then the results were compared with those in 15 normal men (30 hands). Results The abnormal rate from median nerve in the middle finger was 50%. The abnormal rate of the difference in SCV between median and ulnar nerve in the ring finger was 84.6%. A double-peak wave was recorded in the median nerve at the wrist after stimulation of the affected ring finger in 6 cases (9 hands), but not found in control hands. Conclusion The difference of SCV between the median and ulnar nerve is one of the sensitive indicators for early diagnosis of carpal tunnel syndrome.