PREDICTIVE VALUE OF NERVE-CONDUCTION MEASUREMENTS AT THE CARPAL-TUNNEL

We compared the predictive values of three measurements of sensory con duction of the median nerve at the carpal tunnel (maximum latency diff erence [MLD], 8-cm latency [S8], and 14-cm latency [S14]) in 2334 hand s of industrial workers, workers' compensation patients, and students. The MLD was determined by the centimetric technique. The MLD was the most sensitive and efficient measurement for predicting carpal tunnel syndrome (CTS). An MLD greater-than-or-equal-to 0.40 ms correctly iden tified 86.3% of 753 hands with CTS. The MLD correlated best with CTS a nd with the primary diagnostic category (CAT). MLD was the second fact or selected in stepwise regression analysis for CAT (numbness was firs t and S8 was third). The MLD was the most important factor for predict ing persistent or de novo CTS in a 5-year follow-up of 630 hands. Thus , the MLD was the most reliable nerve conduction study measurement for predicting current or future CTS in these subjects' hands. (C) 1993 J ohn Wiley & Sons, Inc.