title: Electrophysiological characterization of hearing in individuals with Down syndrome.
abstract: BACKGROUND
  Few studies have performed Brainstem (BAEP) and P300 Auditory Evoked Potentials simultaneously to assess central auditory pathways in normal hearing individuals with Down syndrome (DS), mainly because of the difficulty in applying these procedures to this population. Previous studies have suggested that individuals with DS might present different patterns of response compared with those of individuals with typical development; nevertheless, the identification of these potentials would be crucial for the establishment of an accurate audiological diagnosis.
  
  
  OBJECTIVE
  To characterize BAEP and P300 in normal-hearing individuals with DS.
  
  
  METHODS
  BAEP and P300 were analyzed in 17 individuals with DS and in 21 individuals with typical development aged 7 to 15 years. The results were quantitatively and qualitatively analyzed using descriptive measures and hypothesis tests.
  
  
  RESULTS
  In the quantitative analysis, latency values were lower in the BAEP for the DS group, with statistically significant difference for wave V and interpeaks III-V and I-V; there were no significant differences in the P300 latency values. In the qualitative analysis, there were a larger number of individuals with early values for BAEP latencies and late latencies for P300 in the DS group; both comparisons showed statistically significant differences.
  
  
  CONCLUSIONS
  Children and adolescents with DS can present early responses to the components of BAEP, suggesting that their auditory pathway requires less time for the neural transmission of acoustic stimuli to the brainstem. Concerning P300, individuals with DS may present increased latencies, suggesting impairment in the central auditory pathway for the cortical processing of auditory information.
authors.affiliation: Universidade de São Paulo - USP - São Paulo (SP), Brasil.
authors.forename: Hellen Medeiros
authors.initials: HM
authors.lastname: Kazan
authors.affiliation: Universidade de São Paulo - USP - São Paulo (SP), Brasil.
authors.forename: Alessandra Giannella
authors.initials: AG
authors.lastname: Samelli
authors.affiliation: Universidade de São Paulo - USP - São Paulo (SP), Brasil.
authors.forename: Ivone Ferreira
authors.initials: IF
authors.lastname: Neves-Lobo
authors.affiliation: Universidade de São Paulo - USP - São Paulo (SP), Brasil.
authors.forename: Fernanda Cristina Leite
authors.initials: FC
authors.lastname: Magliaro
authors.affiliation: Universidade de São Paulo - USP - São Paulo (SP), Brasil.
authors.forename: Suelly Cecília Olivan
authors.initials: SC
authors.lastname: Limongi
authors.affiliation: Universidade de São Paulo - USP - São Paulo (SP), Brasil.
authors.forename: Carla Gentile
authors.initials: CG
authors.lastname: Matas
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D002648:Child; D004314:Down Syndrome / Q000503:physiopathology*; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006320:Hearing Tests; D006801:Humans; D008297:Male