Diagnostic accuracy of sensory and motor tests for the diagnosis of carpal tunnel syndrome: a systematic review

BACKGROUND: Carpal tunnel syndrome (CTS) is the most common entrapment mononeuropathy of the upper extremity. The previous systematic review of the diagnostic tests for CTS was outdated. The objective of this study was to compile and appraise the evidence on the accuracy of sensory and motor tests used for the diagnosis of CTS. METHODS: MEDLINE, CINAHL, and Embase databases were searched on January 20, 2020. Studies assessing at least one diagnostic accuracy property of the sensory or motor tests for CTS diagnosis were selected by two independent reviewers. Diagnostic test accuracy extension of the PRISMA guidelines was followed. Risk of bias and applicability concerns were rated using QUADAS-2 tool. Any reported diagnostic accuracy property was summarized. Study characteristics and any information on the accuracy of the sensory and motor tests for CTS diagnosis were extracted. RESULTS: We included sixteen clinical studies, assessing thirteen different sensory or motor tests. The most sensitive test for CTS diagnosis was the Semmes-Weinstein monofilament test (with 3.22 in any radial digit as the normal threshold) with sensitivity from 0.49 to 0.96. The tests with the highest specificity (Sp) were palmar grip strength (Sp = 0.94), pinch grip strength (Sp from 0.78 to 0.95), thenar atrophy (Sp from 0.96 to 1.00), and two-point discrimination (Sp from 0.81 to 0.98). CONCLUSIONS: The evidence was inconclusive on which sensory or motor test for CTS diagnosis had the highest diagnostic accuracy. The results suggest that clinicians should not use a single sensory or motor test when deciding on CTS diagnosis. TRIAL REGISTRATION: PROSPERO CRD42018109031, on 20 December 2018.