title: Correlation analysis of the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in children.
abstract: BACKGROUND
  The effects of lead on children's health have been widely studied.
  
  
  OBJECTIVE
  To analyze the correlation between the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in Brazilian children.
  
  
  METHODS
  This retrospective study evaluated 20 children ranging in age from 7 to 14 years at the time of audiological and electrophysiological evaluations. We performed periodic surveys of the lead concentration in the blood and basic audiological evaluations. Furthermore, we studied the auditory evoked potential long latency N2 and cognitive P3 by analyzing the absolute latency of the N2 and P3 potentials and the P3 amplitude recorded at Cz. At the time of audiological and electrophysiological evaluations, the average concentration of lead in the blood was less than 10 ug/dL.
  
  
  RESULTS
  In conventional audiologic evaluations, all children had hearing thresholds below 20 dBHL for the frequencies tested and normal tympanometry findings; the auditory evoked potential long latency N2 and cognitive P3 were present in 95% of children. No significant correlations were found between the blood lead concentration and latency (p = 0.821) or amplitude (p = 0.411) of the P3 potential. However, the latency of the N2 potential increased with the concentration of lead in the blood, with a significant correlation (p = 0.030).
  
  
  CONCLUSIONS
  Among Brazilian children with low lead exposure, a significant correlation was found between blood lead levels and the average latency of the auditory evoked potential long latency N2; however, a significant correlation was not observed for the amplitude and latency of the cognitive potential P3.
authors.affiliation: Speech Therapist; Associate Professor at the Department of Speech Therapy of the College of Dentistry of Bauru/University of São Paulo - FOB/USP, Bauru, São Paulo, Brazil.
authors.forename: Kátia de Freitas
authors.initials: Kde F
authors.lastname: Alvarenga
authors.affiliation: Speech Therapist, Master in Speech Pathology, Bauru Dental School, University of São Paulo, Brazil.
authors.forename: Gabriela Rosito
authors.initials: GR
authors.lastname: Alvarez Bernardez-Braga
authors.affiliation: Speech Therapist; Master in Communication Disorders by the Universidade Tuiuti do Paraná - UTP/PR. PhD student in Applied Dental Sciences Program of Bauru Dental School/University of São Paulo FOB/USP, Bauru, São Paulo, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Zucki
authors.affiliation: Speech Therapist, Master in Speech Pathology, Bauru Dental School, University of São Paulo, Brazil. PhD student in Applied Dental Sciences Program of Bauru Dental School/University of São Paulo FOB/USP, Bauru, São Paulo, Brazil.
authors.forename: Josilene Luciene
authors.initials: JL
authors.lastname: Duarte
authors.affiliation: Speech Therapist; Professor, Doctor, at the Department of Speech Therapy of Bauru Dental School/University of São Paulo FOB/USP, Bauru, São Paulo, Brazil.
authors.forename: Andrea Cintra
authors.initials: AC
authors.lastname: Lopes
authors.affiliation: Speech Therapist; Full Professor for the Speech Therapy Course, Bauru Dental School/University of São Paulo FOB/ USP, Bauru, São Paulo, Brazil.
authors.forename: Mariza Ribeiro
authors.initials: MR
authors.lastname: Feniman
keywords: Auditory; Event-Related Potentials; Evoked Potentials; Lead; Lead Poisoning; P300