NC-stat as a Screening Tool for Carpal Tunnel Syndrome in Industrial Workers

Abstract

The initial purpose of this study was to establish a normal data set for median nerve studies in industrial workers using NC-stat technology. Sixteen hundred ninety-five persons applying for employment at a single heavy industry plant without symptoms of carpal tunnel syndrome (CTS) were studied. Values for median distal motor latency (DML), amplitude, and F-waves were recorded in the dominant limbs. The DML was 3.81 +/- 0.57 milliseconds, with a 95% cut-off value of 4.75 milliseconds. Amplitude of the compound muscle action potential was 0.95 +/- 0.46 mV, reflecting the use of volume conduction by this technology. Most of the workers who were characterized as having borderline, prolonged, or very prolonged distal motor latencies according to NeuroMetrix automated report actually fell below the 95% cut-off of this independent data analysis. NC-stat technology using DML appears to be no more sensitive or specific than a traditionally performed DML for the diagnosis of CTS. Until recently promoted sensory studies using NC-stat technology are better defined, this technology cannot be recommended for screening or diagnosis of CTS in an industrial population.