32133
Infant ERP Responses and Later Emerging Symptoms of ASD in Etiologically-Distinct High-Risk Groups

Oral Presentation
Thursday, May 2, 2019: 2:42 PM
Room: 517A (Palais des congres de Montreal)
M. Guy1, A. L. Hogan2, J. E. Richards3 and J. E. Roberts4, (1)Loyola University Chicago, Chicago, IL, (2)Department of Psychology, University of South Carolina, Columbia, SC, (3)University of South Carolina, Columbia, SC, (4)Psychology, University of South Carolina, Columbia, SC
Background: Past research has shown that etiologically-distinct groups of 12-month-old infants at high-risk of autism spectrum disorders (ASD), including infant siblings of children with autism (ASIBs) and infants diagnosed with fragile X syndrome (FXS), demonstrate differences in event-related potential (ERP) responses to social and non-social stimuli (Guy, Richards, Tonnsen, & Roberts, 2018). Additionally, ERPs measured in 9-month-old ASIBs in response to faces have been associated with continuous measures of behavioral symptom severity at 36 months of age (Elsabbagh et al., 2011).

Objectives: This study aimed to increase understanding of how ERP responses in ASIBs and infants diagnosed with FXS are associated with ASD outcomes in early childhood, as indicated by continuous scores of symptom severity.

Methods: Fifty participants completed the study. At 12 months of age, 18 ASIBs (15 M), 14 infants with FXS (7 M), and 18 low-risk control (LRC) infants (14 M) viewed photographs of faces and toys while EEG was recorded. At approximately 36 months of age, the Autism Diagnostic Observation Schedule-2nd Edition (ADOS-2) was assessed. In replication and extension of methods utilized in past research (Elsabbagh et al., 2011; Guy et al., 2018), amplitude of the N290, P400, and Nc ERP components were examined in association with Overall, Social Affect (SA), and Repetitive Behavior (RB) calibrated severity scores using ANCOVAs and regressions.

Results: Analyses revealed significant effects of infant risk group and ADOS-2 scores for the N290 and P400 ERP components. There was a significant interaction between group, stimulus type, and Overall score, F(2, 4680) = 11.02, p < 0.0001, as well as SA score, F(2, 4680) = 13.45, p < 0.0001, on N290 amplitude. For ASIBs, more negative amplitude N290 was associated with higher Overall scores and higher SA scores. Participants with FXS showed more negative amplitude N290 to faces associated with higher Overall scores. Participants in the LRC group showed the opposite pattern of results. There was also a significant interaction between participant group, stimulus type, and Overall score, F(2, 3898) = 5.64, p = 0.0036, as well as SA score, F(2, 3898) = 3.57, p = 0.0282, on P400 amplitude. Participants with FXS showed greater P400 responses associated with higher Overall scores and higher SA scores. For ASIBs, decreased P400 responses to toys were associated with higher Overall scores and higher SA scores. In LRC participants, decreased P400 to faces was associated with higher Overall scores.

Conclusions: Results revealed relations between ERP responses at 12 months of age and ADOS-2 scores in early childhood, which differed across groups based on ASD risk as determined in infancy. Research has indicated that infants with FXS show enhanced ERP activity to faces relative to ASIB and LRC groups, while ASIBs showed more muted responses (Guy et al., 2018). The current study reveals that increased ERP amplitude exhibited in infants with FXS may be associated with later emerging ASD symptoms. The relations between infant ASIBs’ ERP responses and later ASD symptoms are less straightforward and do not show the face specificity of the FXS group.

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