Electrophysiological analysis in carpal tunnel syndrome in 22 cases

Objective:To find out the neural electrophysiological features in patients with carpal tunnel syndrome(CTS).Methods: We performed the measurement of motor nerve conduction velocity and sensory nerve conduction velocity on median nerve and ulnar nerve as well as electromyogram of abductor pollcis brevis and abductor digiti minimi in 22 cases of CTS patients.Results: Of the 22 patients,bilateral lesions were found in 7 and unilateral in 15,and totally there were 29 lesions.The latency of 29 median nerves sensory conduction became delayed and the sensory conduction velocity were decreased.Reduced evoked amplitude was seen in 21 median nerves sensory nerves and delayed distal motor latency(DML) in 28 median nerves.In addition,28 median nerves compound muscle action potential(CMAP) were found decreased.The DML and the evoked amplitude remained normal in only 1 median nerve.The neurogenic injury was seen in 19 abductor pollicis brevis controlled by the median nerve.Conclusion: Neural electrophysiological examination has great value in the diagnosis and differential diagnosis of CTS.