International Meeting for Autism Research (May 7 - 9, 2009): EEG Theta Oscillations in Children with Autism

EEG Theta Oscillations in Children with Autism

Thursday, May 7, 2009
Northwest Hall (Chicago Hilton)
1:30 PM
M. Murias , Autism Center, University of Washington, Seattle, WA
S. Faja , Center for Autism Research, The Children's Hospital of Philadelphia, Philadelphia, PA
G. Dawson , Autism Speaks; Department of Psychiatry, UNC Chapel Hill, Chapel Hill, NC
Background: Previous work (Orekhova et al., 2006) has demonstrated narrow band electroencephalographic (EEG) theta rhythms in children are reactive to attentive states, including social engagement.
Objectives:   We tested whether young, high-functioning children with ASD differ in theta band EEG response during viewing of videos that contained different degrees of social content, compared with age and IQ-matched controls.
Methods: 128 channel EEG was continuously recorded as participants watched short (45 second) videos.  Subjects were 21 6 and 7-year-olds with ASD and 21 age and IQ-matched controls. Diagnosis was confirmed with the ADOS, ADI-R and DSM-IV-TR. All children in both groups had cognitive ability in the average to above average range (measured by the Differential Ability Scales).   Participants sat quietly watching three short videos: (1)  story telling in a foreign language (2)  story telling in native (English) language; (3) comparable visual and auditory noise.
Results:   Spectral analysis revealed distinct theta rhythms in most subjects in the 6-7 Hz range, with a widely distributed topography that was maximal in parietal, temporal, and frontal areas.  ASD and typical children did not differ in peak theta frequency.  The typical group had more pronounced theta rhythms peaks.  Theta amplitudes tended to be lower in the ASD group, particularly among frontal electrodes.  
Conclusions: Children with ASD appear to show altered theta range EEG reactivity during viewing of social videos.  Further research is needed to determine if these amplitude reductions observed in ASD are distinct from reductions observed in alpha and mu oscillations.
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