Background :To investigate the relationship between clinical grading and electrophysiological parameter in carpal tunnel syndrome.
Materials and Methods:This studies examined 75 outpatients (100 hands) who were diagnosed as carpal tunnel syndrome at neurologic clinic from March to July in 2006. They were divided into three groups by clinical grading and then each groups were compared with sensory nerve conduction velocity (SNCV) and sensory compound nerve action potential (CNAP) amplitude of I-W, F-W, and P-W segments, motor terminal latency (TL), motor compound muscle action potential (CMAP) amplitude of distal segment, and disto-proximal ratio on the third finger.
Results :The first group(mild) was 46 (51 hands) patients, second group(moderate) was 29 (35 hands) patients, and the third group (severe) was 14(14 hands) patients. The mean ages were 55.9, 57.4 and 57.0 years in each group, and there were no statistical differences in age and sex between 3 groups. SNCV of I-W, F-W and P-W segments and motor TL were different significantly between 3 groups, but disto-proximal ratio on the third finger was not different significantly(P<0.05). Motor TL was correlated with clinical grading. And also sensory CNAP amplitude of I-W, F-W, and P-W segments, and motor CMAP amplitude of distal segment were different significantly between 3 groups. Especially, sensory CNAP amplitude of P-W segment and motor TL were correlated with higher clinical grading groups(2, 3 groups)(p<0.05).
Conclusion :SNCV of F-W and P-W segments, motor TL, motor CMAP amplitude of distal segment and sensory CNAP amplitude of each segments were correlated with the clinical grading of carpal tunnel syndrome.
The author studied 20 healthy adults (20 hands) as a control and 30 patients (40 hands) with carpal tunnel syndrome to evaluate the clinical usefulness of measuring nerve conduction velocity after wrist flexion in diagnosis of carpal tunnel syndrome. The median nerve conduction velocity over wrist to finger segment was measured before and after wrist flexion for 1, 2 and 5 minutes, using belly-tendon method for motor nerve distal latency (MNDL) and antidromic method for sensory nerve conduction velocity (SNCV). The results were as follows: 1. In control group, MNDL increased in 1 hand and SNCV decreased in 2 hands after wrist flexion. In patient group, MNDL increased in 2 hands and SNCV decreased in 3 hands after wrist flexion. 2. In both control and patient group, there were no significant changes in mean values of SNCV and MNDL between before and after wrist flexion. 3. Phalen's wrist flexion test was positive in 5 percent of control and 60 percent of patient group. 4. Tinel's sign was present in 10 percent of control and 33 percent of patient group.