Electrophysiological evaluation of 140 hands with carpal tunnel syndrome.

AIM: To study various electrophysiological parameters in clinically suspected carpal tunnel syndrome (CTS). MATERIAL AND METHODS: Electrophysiological (EPS) evaluation of 70 patients (140 hands) of clinically suspected CTS was done as per AAEM recommendation. EPS grading was done as described by Padua, et al. RESULTS: The mean age was 44.21 +/- 10.29 (range 24-66) years with female predominance (M:F 3:11). Sixty four (91.4%) patients had bilateral involvement. The mean EPS grade was 3.18 +/- 1.41. One hundred and six (75.5%) hands had moderate to severe (EPS grade 1-3) CTS. Median distal motor latency (DML) (mean 4.76 +/- 1.4 msec) was prolonged in 92 (65.71%) hands and was not recordable in seven (5%) hands. Median sensory distal latency (SDL) (mean 3.54 +/- 0.82 msec) was prolonged in 38 (27.1%) hands and not recordable in 49 (35%) hands. Sensory median mid-palm latency (MPL) (2.42 +/- 0.56 msec) was commonest EPS abnormality present in 128 (91.4%) hands. EMG was abnormal in 75% hands. CONCLUSION: This study suggests incorporation of median sensory midpalm latency as a screening test for electrophysiological diagnosis of CTS. In addition, bilateral studies are recommended as there is bilateral involvement in 64 patients.