[Motor nerve conduction velocity in children: normal values and application to a few pathologic cases].

Nerve conduction velocity (NCV), according to age, was studied in normal children. Motor distal ulnar NCV (in 63 children, from 1 day to 4 years of age), motor distal tibial NCV (in 93 children, from birth to 15 years of age), proprioceptive tibial NCV (in 59 children, from birth to 5 years of age) and proximal CV (in 133 children from birth to 15 years of age), as well as VIIth superior branch CV (in 67 children) and XIIth CV (in 56 children) from birth to 3 years of age, were measured. These measurements showed that NCV changes were similar; NCV was 45-50% of the adult value during the first month of life. Then NCV increased very quickly, the progression being 90% of the first month's value during the first 18 months of life. The adult value was reached between 2 and 5 years of age. Proprioceptive NCV was 8-13 m/sec higher than motor NCV; proximal NCV was also 10-13 m/sec higher than distal motor tibial NCV. Ulnar NCV remained higher than tibial NCV, although changes in velocity as a function of age remained parallel. These NCV measurements proved significant in some diseases. The were useful for diagnosis of Krabbe's disease or of metachromatic leucodystrophy and to calculate the degree of disturbance in toxic polyneuritis, polyradiculoneuritis and some cranial nerve injuries; they were also useful in following up children undergoing chronic haemodialysis. In each case, NCV was only one aspect of a more complete neurophysiological study.