Carpal tunnel syndrome diagnosis: validation of a clinic-based nerve conduction measurement device

Abstract

Background: Carpal Tunnel Syndrome (CTS) is the commonest upper limb nerve entrapment syndrome seen in practice. In many centres, nerve conduction studies (NCS) have been adopted as a routine part of the diagnostic process. In the United Kingdom, the time taken to access diagnostic tests has been likened to a “hidden waiting list”, lengthening the time taken for a patient to access treatment. In the current healthcare climate with a centrally driven aim to reduce patient waiting time to a maximum of eighteen weeks, including tests, such waiting is even more unacceptable. Aim. This study was performed in order to evaluate a simple handheld device for quantifying median nerve lesions in CTS. Design of study: A prospective blinded cohort study. Setting: Leicester General Hospital, Carpal Tunnel Service Method: Participants were recruited from the nor-mal referral stream. If the clinical findings were consistent with a diagnosis of CTS, they were for-mally consented to the study in which results from the new handheld device were compared with traditional NCS. Final test group consisted of 63 participants. Results: For the new device the correct positive detection rate for abnormal nerve conduction was 91% (74/81 hands). Of the seven abnormal results not picked up by the new device, four were in asymptomatic hands (positive per cent agree-ment in symptomatic hands 95%). There were no false positives with the new system. (Negative per cent agreement 100%) Conclusion: We conclude that this new device demonstrates a high degree of concordance with currently available traditional NCS. The study suggested ways in which the accuracy could be further improved.