Neurophysiological hyperresponsivity to sensory input in autism spectrum disorders

Yukari Takarae, Savanna R. Sablich, Stormi P. White, John A. Sweeney

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Background: Atypical sensory processing is a common clinical observation in autism spectrum disorder (ASD). Neural hyperexcitability has been suggested as the cause for sensory hypersensitivity, a frequently reported clinical observation in ASD. We examined visual evoked responses to parametric increases in stimulus contrast in order to model neural responsivity of sensory systems in ASD. Methods: Thirteen high-functioning individuals with ASD and 12 typically developing (TD) individuals completed a steady-state visual evoked potential study. Stimuli were vertical circular gratings oscillating at 3.76 Hz at varying contrasts (5, 10, 20,..., 90 % contrast, 10 levels). The average spectral power at the stimulus oscillation frequency was calculated for each contrast level. Results: The magnitude of evoked sensory responses increased at a significantly greater rate and resulted in disproportionately elevated activation with higher contrasts in the ASD group. Approximately 45 % of ASD participants had rates of response increases greater than any TD participant. This alteration was highly associated with parental reports of these participants' sensory difficulties. Conclusions: Greater increases in visual responses over contrast manipulation suggest heightened excitability in the sensory cortex in ASD participants. Heightened neural excitability was observed in a substantial portion but not all of the ASD participants. This pattern suggests that individuals with higher excitability may constitute a neurobiologically distinct subgroup requiring individualized treatment interventions.

Original languageEnglish (US)
Article number29
JournalJournal of neurodevelopmental disorders
Volume8
Issue number1
DOIs
StatePublished - Aug 8 2016

Keywords

  • Autism
  • Contrast sensitivity
  • Heterogeneity
  • Individual differences
  • Sensory hypersensitivity

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Pathology and Forensic Medicine
  • Clinical Neurology
  • Cognitive Neuroscience

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