Affiliation:
1. Department of Neurology, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia
2. Neuromuscular Medicine Unit, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah 21589, Saudi Arabia
3. Department of Internal Medicine, Neurology Division, International Medical Center, Jeddah 23214, Saudi Arabia
Abstract
Background: Appropriate cut-off values and diagnostic accuracy (DA) [sensitivity, specificity, predictive values, positive (PPV) and negative (NPV)] of electrodiagnostic findings for carpal tunnel syndrome (CTS) based on age, gender, and diabetes mellitus (DM) were not reported. Methods: In a retrospective study, we described the latency difference values and DA of comparative latency studies COLS [median to ulnar through palmar difference (palmdiff) and ring difference study (ringdiff), median to radial through thumb difference study (thumbdiff), and combined sensory index (CSI)] among non-CTS and CTS groups based on age, DM, and gender. Results: We included 632 patients (228 without CTS and 404 with CTS). For PPV > 90% and NPV > 50%, the best cut-offs among patients without DM, were 0.5ms, 0.8–1 ms, 1.4 ms, and 2 ms for palmdiff, thumbdiff, CSI (age < 60 years), and CSI (age > 60 years), respectively. The best cut-offs among patients with DM were 0.5 ms, 1.2 ms, 0.8 ms, 1.0–1.2 ms, 1.8 ms, 1–1.2 ms, 3.0 ms, and 3.5 ms for palmdiff (age < 50 years), palmdiff (age > 50 years), thumbdiff (age < 40 years), thumbdiff (age 40–59 years), thumbdiff (age > 60 years), CSI (age < 50 years), CSI (age 50–59 years), and CSI (age > 60 years), respectively. Conclusion: The cut-off values of COLS to confirm CTS and their DA were different according to age and DM.