Central hearing system maturation in normally hearing children.
BACKGROUND
the long latency auditory evoked potentials (LLAEP) provide objective data about the function of hearing cortical structures.


OBJECTIVE
to characterize the maturation of the central hearing system in normally hearing children.


METHODS
record of LLAEP of fifty-six subjects with hearing tresholds within normal limits, of both genders, being 46 children and 10 adults. With the availability of two recording channels, one was directed to register the LLAEP and the other, to record the artifact generated by ocular movement, aiming at its control. The potentials were recorded with subjects in an alert state, through electrodes positioned in Cz (active) and A2 (reference), and the ocular movements, through electrodes in the left supra and infra-orbital positions; the ground electrode was placed in A1. The morphology and the values of latency and of amplitude for components P1, N1 and P2, according to age, were analyzed. In order to verify the reproducibility of the recorded potentials, a double blind study was carried out, by introducing the analysis of another evaluator.


RESULTS
the double blind study did not present statistically significant differences between the analyses. With the increase in age there was an improvement in the morphology and a decrease in the latency values of components P1, N1 and P2. Also there was a decrease in the amplitude of component P1 and no variation in the amplitude values was observed for components N1 and P2. No statistically significant difference was observed between genders.


CONCLUSIONS
the maturational process of the central hearing system occurs gradually, being the greatest changes observed when comparing children and adults.
Ventura
Luzia Maria Pozzobom
LM
Faculdade de Odontologia de Bauru da Universidade de São Paulo. poventi@ig.com.br
Costa Filho
Orozimbo Alves
OA
Alvarenga
Kátia de Freitas
Kde F
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001306:Auditory Pathways / Q000254:growth & development / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D004311:Double-Blind Method; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D011930:Reaction Time / Q000502:physiology*; D015203:Reproducibility of Results