title: Mismatch negativity in children with specific language impairment and auditory processing disorder.
abstract: BACKGROUND
  Mismatch negativity, an electrophysiological measure, evaluates the brain's capacity to discriminate sounds, regardless of attentional and behavioral capacity. Thus, this auditory event-related potential is promising in the study of the neurophysiological basis underlying auditory processing.
  
  
  OBJECTIVE
  To investigate complex acoustic signals (speech) encoded in the auditory nervous system of children with specific language impairment and compare with children with auditory processing disorders and typical development through the mismatch negativity paradigm.
  
  
  METHODS
  It was a prospective study. 75 children (6-12 years) participated in this study: 25 children with specific language impairment, 25 with auditory processing disorders, and 25 with typical development. Mismatch negativity was obtained by subtracting from the waves obtained by the stimuli /ga/ (frequent) and /da/ (rare). Measures of mismatch negativity latency and two amplitude measures were analyzed.
  
  
  RESULTS
  It was possible to verify an absence of mismatch negativity in 16% children with specific language impairment and 24% children with auditory processing disorders. In the comparative analysis, auditory processing disorders and specific language impairment showed higher latency values and lower amplitude values compared to typical development.
  
  
  CONCLUSIONS
  These data demonstrate changes in the automatic discrimination of crucial acoustic components of speech sounds in children with specific language impairment and auditory processing disorders. It could indicate problems in physiological processes responsible for ensuring the discrimination of acoustic contrasts in pre-attentional and pre-conscious levels, contributing to poor perception.
authors.affiliation: School of Medicine, Universidade de São Paulo (USP), São Paulo, SP, Brazil. Electronic address: carolrocha@usp.br.
authors.forename: Caroline Nunes
authors.initials: CN
authors.lastname: Rocha-Muniz
authors.affiliation: School of Medicine, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors.forename: Débora Maria
authors.initials: DM
authors.lastname: Befi-Lopes
authors.affiliation: School of Medicine, Universidade de São Paulo (USP), São Paulo, SP, Brazil.
authors.forename: Eliane
authors.initials: E
authors.lastname: Schochat
mesh_terms: D000161:Acoustic Stimulation; D001308:Auditory Perceptual Disorders / Q000150:complications* / Q000503:physiopathology; D016022:Case-Control Studies; D002648:Child; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D007805:Language Development Disorders / Q000150:complications* / Q000503:physiopathology; D008297:Male; D011446:Prospective Studies; D011930:Reaction Time
keywords: Auditory perception; Auditory perceptual disorders; Electrophysiology; Eletrofisiologia; Evoked potentials auditory; Language development disorders; Percepção auditiva; Potenciais evocados auditivos; Transtornos da percepção auditiva; Transtornos do desenvolvimento da linguagem