title: Central hearing system maturation in normally hearing children.
abstract: 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.
authors.affiliation: Faculdade de Odontologia de Bauru da Universidade de São Paulo. poventi@ig.com.br
authors.forename: Luzia Maria Pozzobom
authors.initials: LM
authors.lastname: Ventura
authors.forename: Orozimbo Alves
authors.initials: OA
authors.lastname: Costa Filho
authors.forename: Kátia de Freitas
authors.initials: Kde F
authors.lastname: Alvarenga
mesh_terms: 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