EEG hyper-connectivity in high-risk infants is associated with later autism.

Elena V Orekhova,Tony Charman,Mayada Elsabbagh,Geraldine Dawson,Mark H Johnson,Emily Jh Jones

doi:10.1186/1866-1955-6-40

Abstract

BackgroundIt has been previously reported that structural and functional brain connectivity in individuals with autism spectrum disorders (ASD) is atypical and may vary with age. However, to date, no measures of functional connectivity measured within the first 2 years have specifically associated with a later ASD diagnosis.MethodsIn the present study, we analyzed functional brain connectivity in 14-month-old infants at high and low familial risk for ASD using electroencephalography (EEG). EEG was recorded while infants attended to videos. Connectivity was assessed using debiased weighted phase lag index (dbWPLI). At 36 months, the high-risk infants were assessed for symptoms of ASD.ResultsAs a group, high-risk infants who were later diagnosed with ASD demonstrated elevated phase-lagged alpha-range connectivity as compared to both low-risk infants and high-risk infants who did not go on to ASD. Hyper-connectivity was most prominent over frontal and central areas. The degree of hyper-connectivity at 14 months strongly correlated with the severity of restricted and repetitive behaviors in participants with ASD at 3 years. These effects were not attributable to differences in behavior during the EEG session or to differences in spectral power.ConclusionsThe results suggest that early hyper-connectivity in the alpha frequency range is an important feature of the ASD neurophysiological phenotype.Electronic supplementary materialThe online version of this article (doi:10.1186/1866-1955-6-40) contains supplementary material, which is available to authorized users.

Highlights

It has been previously reported that structural and functional brain connectivity in individuals with autism spectrum disorders (ASD) is atypical and may vary with age
There were no significant differences between high-risk participants with ASD outcome (HR-ASD) and the comparison groups in percent of time spent (1) looking at the videos, (2) moving, (3) watching the video without movement or negative affect, or (4) displaying affect
To examine the possibility that infants from high risk (HR)-ASD and the comparison groups preferred to attend to different types of stimuli, we tested for an effect of video on the infant’s attention using a repeated measures ANOVA with factors Stimulus-Type and Group

Summary

Introduction

It has been previously reported that structural and functional brain connectivity in individuals with autism spectrum disorders (ASD) is atypical and may vary with age. The early overgrowth of white and gray matter during infancy and toddlerhood in individuals with ASD is followed by normal or decreased growth during later childhood [15,16,17,18]. This pattern of atypical development seems to be a particular feature of the temporal, frontal, and cingulate cortices that play crucial roles in attention, emotions, and social cognition [15,18,19,20,21]. The under-connectivity reported in adolescences and adults with ASD may be linked to the reduced brain growth during later childhood and/or to some compensatory processes

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