To investigate how sensory symptoms impact the motor control of hands, in this study we examined the differences in conventional sensibility assessments and pinch force control in the pinch-holding-up activity (PHUA) test between carpal tunnel syndrome (CTS) patients and healthy controls. CTS patients (n = 82) with 122 affected hands and an equal number of control subjects were recruited to participate in the threshold, discrimination, and PHUA tests. The patients showed significantly poorer hand sensibility and lower efficiency of force adjustment in the PHUA test as compared with the control subjects. Baseline pinch strength and the percentage of maximal pinch strength for the PHUA were significantly higher for the subgroup of sensory nerve action potential (SNAP) of <16 μV than for the subgroup of SNAP of3 16 μV. Using a PHUA perspective to analyze the efficiency of force-adjustment could assist the clinical detection of sensory nerve dysfunction.
Yen, Chen, Kuan, and Hsu are with the Dept. of Physical Medicine and Rehabilitation, National Cheng Kung University Hospital, Tainan, Taiwan. Y-L Kuo is with the Division of Plastic and Reconstructive Surgery, and L-C Kuo the Dept. of Occupational Therapy, National Cheng Kung University, Tainan, Taiwan.