Feasibility of a Novel Functional Sensibility Test as an Assisted Examination for Determining Precision Pinch Performance in Patients with Carpal Tunnel Syndrome

Abstract

To understand the feasibility of a novel functional sensibility test for determining precision pinch performance in patients with carpal tunnel syndrome, this study investigates the validity, sensitivity and specificity of functional sensibility derived from a pinch-holding-up activity (PHUA) test. Participants include 70 clinically defined carpal tunnel syndrome (CTS) patients with 119 involved hands and 70 age- and gender-matched controls. To examine the discriminating ability of the functional sensibility test, the differences in the ability of pinch force adjustments to the inertial load of handling object between CTS and control subjects are analyzed. The results of functional sensibility are correlated with the severity of CTS to establish concurrent validity. The receiver operating characteristic (ROC) curve is constructed to demonstrate the accuracy of the proposed test. The functional sensibility score significantly discriminates the patients and control groups (respectively, 12.94±1.72 vs. 11.51±1.15N in peak pinch force (FPPeak), p<0.001; 2.92±0.41 vs. 2.52±0.24 in force ratio, p<0.001) and is moderately correlated (r = 0.42–0.54, p<0.001) with the results of traditional sensibility tests (touch-pressure threshold and two-point discrimination test). In addition, there is a statistical difference in the results of functional sensibility (p<0.001) among the subgroups of CTS severity based on electrophysiological study. The sensitivity and specificity are 0.79 and 0.76, respectively, for the functional sensibility test. The areas under the ROC curve are 0.85 and 0.80 for the force ratio and FPPeak, respectively. In conclusion, the functional sensibility test could be feasibly used as a clinical tool for determining both the sensibility and precision pinch performance of hands for the patients with CTS.

Assessment from Functional Perspectives: Using Sensorimotor Control in the Hand as an Outcome Indicator in the Surgical Treatment of Carpal Tunnel Syndrome

“…Different from the traditional sensory evaluations, which focus on submodality-specific perceptions, the PHUA and MTT are used to assess the abilities of sensorimotor control and actively sensing weight, geometry and texture for patients with impaired sensibility. In agreement with previous studies [ 25 , 26 ], the MTT, precision pinch performance, and traditional sensibility tests are all valid tools with high statistical power for detecting differences in hand sensibility from various perspectives. In fact, this work is a pilot study to verify the responsiveness of the MTT and PHUA test with regard to the outcomes of CTS treatment.…”

“…The force ratio between FP Peak and FL Max was used to determine the capacity for adjusting pinch force according to inertial load fluctuations, and this had a high testing reliability [ 28 ]. A score of 2.66 for force ratio is the optimal cutoff point when screening for CTS patients [ 25 ]. In addition, the time lag between T1 and T2 were analyzed to understand the precise temporal coupling between grip and load force profiles after CTR.…”

“…Clinically, the instruments for documenting treatment outcomes for nerve injuries are required to be valid and able to capture valuable information [ 24 ]. The PHUA and MTT can assess subtle changes in the sensorimotor abilities of the hand among patients with various degrees of CTS severity, diagnosed based on the results of electrophysiological studies [ 25 , 26 ]. However, the responsiveness of these two new sensibility tests with regard to CTS treatment has never been analyzed.…”

Impacts of elevated glycaemic haemoglobin and disease duration on the sensorimotor control of hands in diabetes patients

“…The force adjustment ability in the PHUA test has recently been analysed to help clinicians better understand motor control in the precision pinch performance of the hand . For neuropathic hands, the higher pinch force (FP Peak ) and peak force ratio is a compensatory strategy to maintain pinch stability and to prevent an object slipping from the hands during lifting .…”

Effects of Carpal Tunnel Syndrome on Force Coordination and Muscle Coherence during Precision Pinch

“…CTS patients commonly demonstrate lack of dexterity in activities of daily living, such as inexplicably dropping objects. As a potential compensatory strategy to overcome sensorimotor deficits and prevent objects from unintentionally slipping, patients with CTS apply excessive pinch force while lifting objects [10-12]. CTS also impairs digit force accuracy and stability during precision pinch, especially when the force application lacks accompanying visual feedback [13].…”