Diagnostic and clinical value of mixed–sensory nerve conduction velocity differences between wrist–elbow and second finger–wrist segments in carpal tunnel syndrome

Abstract

Background & Objective: This study aimed to evaluate the diagnostic utility of the nerve conduction velocity difference between the mixed (wrist–elbow) and sensory (second finger–wrist) segments of the median nerve (WE–FW).

Methods: This prospective study included 40 CTS patients (61 extremities) and 40 healthy controls (40 extremities). Diagnosis was based on clinical findings. The Visual Analog Scale (VAS) and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire were administered to the CTS group. The WE–FW was derived from orthodromic (WE–FW/O) and antidromic (WE–FW/A) sensory conduction studies in the second finger–wrist segment of the median nerve, using both onset and peak latencies.

Results: There were no significant differences in age or sex between groups (p>0.05). WE–FW/O and WE–FW/A values were significantly higher in CTS patients than controls (p<0.001 for all). Sensitivities of WE–FW/O (onset and peak latency) were 84.1% and 77.3%, with specificities of 85.0% and 77.5%. WE–FW/A sensitivities were 83.3% (onset) and 81.5% (peak), with 82.5% specificity for both. WE–FW/O (peak latency; p=0.044, r=0.306) and WE–FW/A (onset latency; p=0.005, r=0.376) positively correlated with clinical CTS severity. Both parameters also significantly correlated with VAS and DASH scores.

Conclusions: WE–FW shows strong diagnostic potential in CTS. This novel method correlates with clinical and neurophysiological severity, and may serve as valuable adjuncts in diagnosis and follow-up.