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

INTRODUCTION

Diagnostic screening tests for carpal tunnel syndrome (CTS) have not been rigorously assessed in large populations.

METHODS

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.

RESULTS

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%.

DISCUSSION: 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 OF EVIDENCE: Level II diagnostic study.