International Meeting for Autism Research (May 7 - 9, 2009): ERP Responses to Faces Are Correlated with Verbal Skills in Toddlers with ASD

ERP Responses to Faces Are Correlated with Verbal Skills in Toddlers with ASD

Thursday, May 7, 2009
Northwest Hall (Chicago Hilton)
12:00 PM
E. J. H. Jones , Autism Center, University of Washington, Seattle, WA
S. J. Webb , Autism Center, University of Washington, Seattle, WA
K. Merkle , Autism Center, University of Washington, Seattle, WA
N. Freed , Autism Center, University of Washington, Seattle, WA
J. Greenson , University of Washington, Seattle, WA
M. Murias , Autism Center, University of Washington, Seattle, WA
G. Dawson , Autism Speaks; Department of Psychiatry, UNC Chapel Hill, Chapel Hill, NC
Background: Event-related potentials (ERPs) have previously indicated that face processing may be atypical in 3- to 4-year-old children with ASD (e.g. Dawson et al., 2002; Webb et al., 2006).  However, little is known about the relationship between face processing and other skills early in the development of ASD.  The present study examined neural responses to faces in 18 to 30-month-old toddlers with ASD in comparison to a group of age-matched typically developing toddlers (TD). 
Objectives: To examine neural responses to familiar and unfamiliar faces in 18- to 30-month-old children with ASD and typically developing children, and their relation to age, IQ and adaptive skills.
Methods: In addition to developmental and diagnostic testing (including the Mullen Scales of Early Learning, the Vineland Adaptive Behavior scales, the ADOS and the ADI-R Toddler), toddlers viewed color photographs of their mother and a stranger in an ERP procedure.   Brain activity was continuously recorded using a 128-electrode Geodesic Sensor Net (Electrical Geodesics, Inc.).  
Offline, artifact-free trials from each category were averaged together, re-referenced to an average reference, and baseline corrected.  Children’s data was only included in the final analyses if they had 10 or more artifact-free trials per condition.  Data were averaged across time windows and electrode groups chosen with reference to the grand average waveform.
Results: Preliminary analyses suggest the Nc amplitude response to both face types was significantly more right lateralized in the ASD group than the TD group over anterior electrodes. 
Preliminary correlation analyses showed that a larger Nc correlated with older age in the TD group, but not the ASD group.  In contrast, a larger Nc correlated with higher verbal ability in the ASD group, but not in the TD group. 
Conclusions: Preliminary results suggest that the lateralization of event-related potential responses to facial stimuli may differ in toddlers with ASD.  Further, neural responses to faces may not show the same developmental trajectory in toddlers with ASD as in typically developing toddlers.  Finally, there may be a relation between verbal and communication skills, and neural responses to faces in toddlers with ASD.  We are currently conducting analyses of data from a group of children with general developmental delays in order to explore whether these findings are specific to toddlers with ASD.
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