Abstract: Abstract   Objective   To early evaluate the function status of motor fibers in patients with carpal tunnel sydrome (CTS) according to the number of motor units estimated (MUNE), the duration and amplitude of motor unit action potential (MUAP) and the amplitude of compound muscle action potential (CMAP). Methods   We evaluated 40 patients, who had been diagnosed with CTS. There were 20 patients in CMAP normal group and 20 patients in CMAP abnormal group. The control group includes 20 healthy people. We used the Keypoint.net(Medoc Ltd)electromyogram device to record the MUNE，the duration and amplitude of motor unit action potential (MUAP) of the abductor pollicis brevis. Results  The MUNE reduced, the MUAP duration prolonged and amplitude highed in the CTS group, There were significantly different from those found in the control group (P<0.05). In CMAP normal group and control group the MUNE was 142.85±21.51 vs 188.23±23.51,(P<0.05), the duration of MUAP was 12.83±1.39ms vs 10.19±1.28ms,(P<0.05)and amplitude 959.60±92.41μV vs 789.45±70.74μV,(P<0.05). The area under the ROC curve was 0.934 for MUNE, 0.919 for MUAP duration and 0.921 for MUAP amplitude. Conclusion   The MUNE ,the duration and amplitude of the MUAP could early evaluate the function status of motor fibers in patients with CTS compared with the CMAP .

Key words: carpal tunnel syndrome, ROC curves, motor unit number estimation, motor unit action potential, compound muscle action potential