Body mass index: A modifying factor of median nerve conduction

Abstract

Background: Nerve conduction studies are important electrophysiological tests used to assess functional status of peripheral nerves. Entrapment of median nerve in carpal tunnel is a possibility in high body mass index (BMI). Aim and Objectives: The objective of this study was to determine BMI as a modifying factor of median nerve conduction. Materials and Methods: Forty-seven healthy male subjects were divided in three study groups, that is, normal, pre-obese, and obese according to BMI. Nerve conduction study was tested to compare different parameters of compound motor action potential (CMAP) and sensory nerve action potential (SNAP). Parameters used for SNAP were peak latency (PL), conduction velocity (CV), and amplitude (Amp). Parameters used for CMAP were distal motor latency (DML), CV, and amplitude (Amp). Results: In the right median nerve, CMAP between various groups represented significant prolongation of DML (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. In the left median nerve, CMAP between various groups represented significant prolongation of DML (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. In the right median nerve, SNAP between various groups represented significant prolongation of PL (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. In the left median nerve, SNAP between various groups represented significant prolongation of PL (P = 0.000) and slowing CV (P = 0.000) with increasing BMI. Conclusion: Our study suggested BMI as the substantial factor to affect median nerve conduction at carpal tunnel. Thus, high BMI plays crucial role to develop carpal tunnel syndrome (CTS).