Effects of anthropometric factors on nerve conduction: an electrophysiologic study of feet

Previous studies have shown that age, sex, and body mass index (BMI) affect the amplitude of sensory nerve action potentials (SNAPs), but the total effects of multiple factors and the most prominently affected nerves have not been elucidated. We systematically investigated the effects of these factors on motor and sensory nerves of the feet.

The amplitude, latency, and conduction velocity of compound muscle action potential (CMAP), SNAP, and mixed nerve action potential (MNAP) of the posterior tibial, calcaneal, distal posterior tibial, medial and lateral plantar, and sural nerves were measured in 30 healthy individuals (60 feet). The effects of age, sex, height, and BMI on each nerve were estimated by correlation and linear regression analyses.

The amplitude of posterior tibial CMAP and distal posterior tibial MNAP decreased with BMI. The amplitude of medial plantar MNAP and sural SNAP decreased with height. The conduction velocity of calcaneal SNAP and distal posterior tibial and lateral plantar MNAP decreased with height and BMI. The conduction velocity of medial plantar MNAP decreased only with height. The latency of posterior tibial CMAP increased with age and height. The latency of lateral plantar CMAP and calcaneal SNAP increased with height. The latency of lateral plantar MNAP increased with BMI.

The effects of age, sex, height, and BMI in foot nerve conduction studies are not identical. Height and BMI were shown to strongly affect motor, sensory, and mixed nerve conduction. Further investigations are needed.