Validity of the Upper Limb Neurodynamic Test 1 for the diagnosis of Carpal Tunnel Syndrome. The role of structural differentiation

• Individuals with suspected CTS were invited to voluntarily participate in the study.
• NCS were considered the Gold Standard for the diagnosis of CTS in this study.
• ULNT1 was positive when patient's symptoms were reproduced and changed during SD.
• The LRs suggested that the ULNT1 generates small shifts in post-test probability.
• Due to imprecision in the CIs ULNT1 alone shouldn't be used to diagnose CTS.

BackgroundSeveral studies have analysed the use of the Upper Limb Neurodynamic Test 1 (ULNT1) for diagnosing Carpal Tunnel Syndrome (CTS) obtaining weak diagnostic accuracy, which could be related to the lack of consensus in the selected diagnostic criteria of ULNT1.ObjectiveTo determine the concurrent validity of ULNT1 in comparison to Nerve Conduction Studies (NCS) for the diagnosis of CTS, considering the structural differentiation (SD) as an essential part of the diagnosis.DesignProspective diagnostic test study.MethodsIndividuals with suspected CTS referred for NCS were invited to voluntarily participate in the study. Each participant was tested with NCS and ULNT1. ULNT1 result was considered positive when the patient's clinical symptoms were reproduced during the test and symptoms changed during contralateral neck side bending (SD).Results58 Participants (17 men, 44 women) with suspected CTS and a total of 95 limbs were examined using the NCS and ULNT1. Sensitivity of the ULNT1 was 57.9%, specificity was 84.2%, and the positive and negative likelihood ratios were 3.67 and 0.50 respectively.ConclusionResults obtained in the study may indicate the ability of the ULNT1 to generate small shifts from pre-test to post-test probability. However, imprecision in the CIs limits interpretation from the data.Level of evidence1b.