Sensitivity of Median Nerve Sensory Conduction Studies in the Digital Branches for the Diagnosis of Carpal Tunnel Syndrome

Aim: To evaluate the diagnostic sensitivity of sensory conduction studies targeting the digital branches and the palm-to-wrist segment of the median nerve in patients with electrophysiologically confirmed mild-to-moderate carpal tunnel syndrome (CTS), and to assess whether combining multiple segments improves diagnostic yield.Materials and Methods: This cross-sectional study included 217 hands from patients referred for electrophysiological evaluation between 2020 and 2022 with a preliminary CTS diagnosis. Orthodromic sensory conduction studies were performed on the first (D1W), second (D2W), and third (D3W) digit-to-wrist segments and the palm-to-wrist (PW) segment. Laboratory-specific reference limits were established from 73 healthy controls. Sensitivity was calculated for each segment individually and in combination.Results: The PW segment demonstrated the highest sensitivity (98.62%), followed by D1W (96.31%), D3W (94.47%), and D2W (92.63%). Combining PW with D1W achieved 100% sensitivity; PW combined with D3W and D2W yielded 99.6% and 99.1%, respectively.Conclusion: Testing a single digital segment alone may miss CTS diagnoses in some patients. Combining the PW segment with any digit-to-wrist segment raises sensitivity above 99%, substantially reducing false-negative rates. To minimize false-negative rates, combining the PW segment with at least one digit-to-wrist segment is recommended in routine CTS electrophysiological evaluation, particularly when digital branch studies yield normal or borderline results.