The validity of the upper limb neurodynamic test 2A in women with a clinical diagnosis of carpal tunnel syndrome: a prospective diagnostic accuracy study

INTRODUCTION: the validity of the upper limb neurodynamic tests and especially the upper limb neurodynamic test 1 for diagnosing carpal tunnel syndrome has been the subject of several previous studies. However, the upper limb neurodynamic test 2A, which is also a test designated to assess the mechanosensitivity of the median nerve, has not been sufficiently studied, particularly for the diagnosis of carpal tunnel syndrome. METHODS: we used the upper limb neurodynamic test 2A as the index test and nerve conduction studies as the reference standard. We considered the upper limb neurodynamic test 2A positive according to Nee et al. criteria. Sensitivity, specificity, positive likelihood, and negative likelihood were calculated. In addition, a receiver operating characteristics analysis was carried out. RESULTS: ninety-four women (188 hands) suspected of carpal tunnel syndrome with a mean age of 48.87 years and SD of 12.09 participated in the study. The sensitivity of the upper limb neurodynamic test 2A was estimated at 73.4%, the specificity at 47%, the positive likelihood ratio was 1.38, the negative likelihood ratio was 0.57, and the Kappa agreement was 20.3%, and the area under the curve 60.1%. CONCLUSION: the upper limb neurodynamic test 2A does not seem to have value in the diagnosis of carpal tunnel syndrome when compared to nerve conduction studies. It could be alternatively used to detect an increased mechanosensitivity of the median nerve when the upper limb neurodynamic test 1 cannot be performed in case of a range of motion limitation of the shoulder abduction.