Physiological arousal in autism and fragile X syndrome: Group comparisons and links with pragmatic language

Jessica Klusek, Gary E. Martin, Molly Losh

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


This study tested the hypothesis that pragmatic (i.e., social) language impairment is linked to arousal dysregulation in autism spectrum disorder (ASD) and fragile X syndrome (FXS). Forty boys with ASD, 39 with FXS, and 27 with typical development (TD), aged 4-15 years, participated. Boys with FXS were hyperaroused compared to boys with TD but did not differ from boys with ASD. Dampened vagal tone predicted pragmatic impairment in ASD, and associations emerged between cardiac activity and receptive/expressive vocabulary across groups. Findings support autonomic dysfunction as a mechanism underlying pragmatic impairment in ASD and suggest that biophysiological profiles are shared in ASD and FXS, which has implications for understanding the role of fragile X mental retardation-1 (FMR1, the FXS gene) in the pathophysiology of ASD.

Original languageEnglish (US)
Pages (from-to)475-495
Number of pages21
JournalAmerican Journal on Intellectual and Developmental Disabilities
Issue number6
StatePublished - Nov 2013


  • ASD
  • Arousal
  • Autism
  • Endophenotype
  • Fragile X syndrome
  • Heart rate
  • Pragmatic language
  • Social communication
  • Vagal tone

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Neuropsychology and Physiological Psychology
  • Developmental and Educational Psychology
  • Arts and Humanities (miscellaneous)
  • Clinical Neurology
  • Psychiatry and Mental health


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