Electrophysiological Endophenotypes in Autism Spectrum Disorder: A Family Study

Electrophysiological Endophenotypes in Autism Spectrum Disorder: A Family Study Ann Clawson Department of Psychology, BYU Doctor of Philosophy Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorder associated with altered neural connectivity and deficits in self-monitoring, response inhibition, and planning. One promising avenue of research to improve understanding of the symptoms and heritable nature of ASD may be the identification of neural endophenotypes of ASD. The errorrelated negativity (ERN) and post-error positivity (Pe), scalp-recorded event-related potentials (ERPs), reflect performance monitoring processes and may qualify as candidate endophenotypes of ASD. We collected ERP and behavioral data (error rates, response times) from 18 ASD probands and their families (mother, father, sibling) and 38 control youth and their parents to examine the utility of the ERN and Pe as endophenotypes of ASD. In order to examine differences based on group (ASD vs. control) and kinship (proband, sibling, mother, father), we conducted separate multiple regression analyses on behavioral and ERP data with group and kinship as predictors and families as clusters. We hypothesized that ASD probands would display reduced-amplitude ERN and impaired behavioral performance relative to control youth but no differences in Pe amplitude and that families of ASD probands would display reduced error minus correct (ΔERN) amplitudes and impaired behavioral performance relative to control families but no differences in ΔPe amplitude. We did not observe significant ERN amplitude group differences among ASD probands relative to control youth. Likewise, control youth did not differ from ASD probands on behavioral measures or Pe amplitudes. Analyses by family revealed that group and kinship did not significantly predict ΔERN amplitudes. However, fathers of ASD probands displayed significantly reduced ΔPe amplitudes relative to control fathers and parents displayed significantly larger ΔPe amplitudes and better performance than youth. Together, results do not provide sufficient evidence to support the ERN or Pe as an endophenotype or biomarker of ASD. These findings add to an overall heterogeneous literature on performance monitoring in ASD and point to the need for additional research to understand the state-related or trait-related factors that may contribute to ERN amplitudes in ASD.