[Development of auditory evoked potentials of the brainstem in relation to age]

In order to study the various changes which occur in the waveform, latency and amplitude of the auditory brainstem evoked response (BSER) as a function of age, the authors recorded the BSER from the scalp's surface of 20 newborns and 50 infants, 3 months, 6 months, 1 year and 3 years old as well as from 20 normal adults. The data obtained show that the most reliable waves during the first month of life are waves I, III, V, which is often present even when other vertex-positive peaks are absent. The latencies of the various potential components decreased with maturation. Wave V, evoked by 90 dB sensation level clicks, changed in latency from 7, 12 msec at 1-4 weeks of age to 5,77 msec at 3 years of life. The auditory processes related to peripheral and central transmission were shown to mature at differential rates during the first period of life. By the 6th month, in fact, wave I latency had reached the adult value; in contrast, wave V latency did match that of the adult until approximately 1 year old. One obvious explanation for the age-related latency shift is progressive myelination of the auditory tract in infants, for this is know to occur. The authors conclude that the clinical application of this technique in paediatric patients couldn't provide reliable informations about auditory brain stem activity regardless of evaluation of the relationship between age and characteristics of BSER.