Peripheral motor and sensory nerve conduction studies in normal infants and children.

OBJECTIVE: There are few data on electrophysiological data of motor and sensory fibres during nerve maturation. The aim of this study is to investigate the evolution of nerve conduction in the upper and lower limbs during the first years of life.
METHODS: The study comprised 92 normal infants and children aged from 1 week to 6 years. Using surface electrodes, the investigation included the following data: (1) motor conduction velocity (MCV), corrected distal motor latency (DML) to a standard distance, and F-waves of the median, ulnar, peroneal and tibial nerves; (2) sensory conduction velocity (SCV) of the median and tibial nerves; and (3) amplitude and morphology of the muscle and sensory action potentials.
RESULTS: Maximal MCV and SCV in the neonatal period was about half of adults; there was a steep conduction increase during the first year of life, adult values being reached around age 4. In the neonatal period corrected DML was greater than in adults with a further decrease during the first year. F-wave latencies also decreased during the first year with increase at the end of the study.
CONCLUSIONS: This study corroborates the fact that 'maturation' of MCV and SCV occurs during the first 5 years of life, especially in the former. Evolution of DML is accounted for using correction. F-wave latency changes are explained both by an increase in MCV, and extremity growth.