Clinical examination for carpal tunnel syndrome

The clinical update on the utility of the clinical examination for carpal tunnel syndrome1 is a review of a review. The original article highlights the pitfalls of using MEDLINE-based reviews to generate clinical practice guidelines.2 The basic assumption of Kathryn Myers' clinical update is that electrodiagnostic studies represent the gold standard for diagnosis, an assumption the authors of the original article themselves admit is flawed.

Myers extracts the recommendation that “decreased pain sensation in the median nerve distribution is the most helpful finding in making the diagnosis.” This finding will only help to diagnose advanced carpal tunnel syndrome, in which the patient's sensation at rest is impaired. Use of this finding will indeed increase the specificity of the examiner's results but will seriously decrease the sensitivity of the clinical examination. If practitioners follow this guideline they will grossly underdiagnose carpal tunnel syndrome and will exclude many patients who would benefit from treatment.

Recent studies point to the carpal compression test as the most reliable and valid physical examination test for the diagnosis of carpal tunnel syndrome.3^,4^,5 The goal in recommending a clinical examination technique for the diagnosis of a disorder is both high specificity and sensitivity, and the carpal compression test is a markedly better way to achieve this goal than assessment of median nerve pain threshold.