Median Nerve Symptoms, Signs, and Electrodiagnostic Abnormalities Among Working Adults.

Abstract

Diagnostic screening tests for carpal tunnel syndrome (CTS) have not been rigorously assessed in large populations. This study is a cross-sectional analysis from a prospective cohort study. Participants' (n = 1,194) symptoms and disease prevalence were measured. Sensitivity, specificity, and positive and negative predictive values (NPVs) were calculated. When defining CTS as tingling/numbness in at least two median nerve-served digits and an abnormal median nerve conduction study, the prevalence was 8.9%. The sensitivity of paresthesias with nocturnal awakening was 77.4%. The sensitivity of the Phalen sign was 52.8% and that of the Hoffman-Tinel sign was only 37.7%. The highest sensitivity (77.4%) for a case definition of CTS in this population of workers was for nocturnal tingling/numbness in a median nerve distribution, and the highest specificity (97.5%) was for continuous tingling/numbness. The Phalen sign has a sensitivity of 52.8% and NPV of 95%, suggesting that the NPV is of particular diagnostic value. Hoffman-Tinel signs seem primarily helpful for the NPV (93.7%). Level II diagnostic study.