Maturation of the acoustic path-way in brain stem responses (ABR) in neonates.

In a group of 130 tested children, 102 of whom had a property evaluated brain stem responses, we tested the influence of newborn maturation on values of response parameters, their configuration and threshold values. It was shown that newborn maturation lowers in a statistically significant way the threshold values of acoustic stimulus. Also, the configuration of the monitoring changes with age of child tested. Newborn maturation increases the frequency of occurrence of waves II, IV and VI though decreases of incidence IV/V complex. In the group of the youngest pre-term babies IV/V complex were present in 50% of the cases whereas in the group of newborns carried to term its present could be verified only in 5-11% of cases. Newborn maturity also in an essential way shortening the latent time consecutive waves as well as central conduction time determining by interpeak latency I-V. Coefficient correlation values for those parameters shows a negative statistical significance correlation. That is, a decreasing of average values of those parameters with maturation of the newborn. It was also shown that structures of the hearing pathway responsible for generation of early and late components of the brain stem responses mature at different time. Peripheral structure of the hearing pathway are significantly more mature at birth than are central structures.