title: Atypical sound discrimination in children with ASD as indicated by cortical ERPs.
abstract: BACKGROUND
  Individuals with autism spectrum disorder (ASD) show a relative indifference to the human voice. Accordingly, and contrarily to their typically developed peers, adults with autism do not show a preferential response to voices in the superior temporal sulcus; this lack of voice-specific response was previously linked to atypical processing of voices. In electroencephalography, a slow event-related potential (ERP) called the fronto-temporal positivity to voice (FTPV) is larger for vocal than for non-vocal sounds, resulting in a voice-sensitive response over right fronto-temporal sites. Here, we investigated the neurophysiological correlates of voice perception in children with and without ASD.
  
  
  METHODS
  Sixteen children with autism and 16 age-matched typically developing children heard vocal (speech and non-speech) and non-vocal sounds while their electroencephalographic activity was recorded; overall IQ was smaller in the group of children with ASD. ERP amplitudes were compared using non-parametric statistical tests at each electrode and in successive 20-ms time windows. Within each group, differences between conditions were assessed using a non-parametric Quade test between 0 and 400 ms post-stimulus. Inter-group comparisons of ERP amplitudes were performed using non-paired Kruskal-Wallis tests between 140 and 180 ms post-stimulus.
  
  
  RESULTS
  Typically developing children showed the classical voice-sensitive response over right fronto-temporal electrodes, for both speech and non-speech vocal sounds. Children with ASD did not show a preferential response to vocal sounds. Inter-group analysis showed no difference in the processing of vocal sounds, both speech and non-speech, but significant differences in the processing of non-vocal sounds over right fronto-temporal sites.
  
  
  CONCLUSIONS
  Our results demonstrate a lack of voice-preferential response in children with autism spectrum disorders. In contrast to observations in adults with ASD, the lack of voice-preferential response was attributed to an atypical response to non-vocal sounds, which was overall more similar to the event-related potentials evoked by vocal sounds in both groups. This result suggests atypical maturation processes in ASD impeding the specialization of temporal regions in voice processing.
authors.affiliation: Brain Dynamics and Cognition Team, Lyon Neuroscience Research Center; CRNL, INSERM U1028, CNRS UMR5292, University of Lyon 1, Lyon, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Bidet-Caulet
authors.affiliation: UMR Inserm U930, Université François Rabelais de Tours, Tours, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Latinus
authors.affiliation: UMR Inserm U930, Université François Rabelais de Tours, Tours, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Roux
authors.affiliation: UMR Inserm U930, Université François Rabelais de Tours, Tours, France.|CHRU de Tours, Service de Pédopsychiatrie, Tours, France.
authors.forename: Joëlle
authors.initials: J
authors.lastname: Malvy
authors.affiliation: UMR Inserm U930, Université François Rabelais de Tours, Tours, France.|CHRU de Tours, Service de Pédopsychiatrie, Tours, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Bonnet-Brilhault
authors.affiliation: UMR Inserm U930, Université François Rabelais de Tours, Tours, France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Bruneau
keywords: Auditory; Autism; Development; FTPV; Speech; Voice