Brain and Behavioral Responses to a Flanker Task Differ for Children with Autism Spectrum Disorders

Background: Executive control – the ability to manage complex or conflicting information in the service of a goal – is often impaired among children with autism spectrum disorders (ASD). The ability to inhibit conflicting information is specifically impaired relative to other aspects of inhibition (Christ et al., 2007). A developmentally appropriate flanker task, the Child Attention Network Test (Child ANT), has been used for measuring event-related potential (ERP) responses to conflict monitoring (i.e., the N2) and evaluating conflicting stimuli (i.e., the P3). 

Objectives: To investigate ERPs and behavioral responses of children with and without ASD during the Child ANT task and their relation to executive control.

Methods: Twenty-three seizure-free children with ASD and 34 typically developing (TD) children between the ages of 7-11 years participated. All had IQ > 85 and there were no group differences on verbal, performance, or full scale IQ, age or gender. Diagnosis was confirmed with the ADOS, ADI-R, and DSM-5 criteria. The Behavior Rating Inventory of Executive Function (BRIEF)-Parent Report was obtained as a behavioral correlate of broad executive control skills. Electrophysiological responses were recorded during the Child ANT. Mean amplitude was examined at the P100 (Oz), N2 (Fz), and P3 (Pz). Accuracy and reaction time were also collected. 

Results: Overall, accuracy was lower in the incongruent condition, F(1,53)=24.73, p<.001, and in the group with ASD, F(1,53)=5.00, p=.03. Reaction time was slower for incongruent trials, F(1,53)=40.39, p<.001, and a group x condition interaction was detected, F(1,53)=3.95, p=.05. In terms of ERP response, a significant group by condition interaction was detected at the P100, F(1,55)=4.63, p=.04, suggesting groups perceived and attended to basic visual information in the task differently. For the N2, mean amplitude differed by condition, F(1,55)=10.33, p=.002, and group, F(1,55)=6.89, p=.01. No significant effects were found for the P3. Difference scores (I-C) were calculated for the P1, N2 and P3. Within the TD group, the P1 correlated with accuracy, r(27)= .51, p=.007; N2 correlated with better Parent BRIEF global executive composite scores (GEC), r(28)= -57, p =.002, metacognition (MI), r(28)= -.56, p=.002, and behavioral regulation (BRI), r(28)= -.43, p=.02; and, P3 correlated with better BRIEF GEC, r(28)= .45, p=.017, and MI, r(28)= .48, p=.01.  No correlations were found in the ASD group. Results of time frequency analysis will also be reported.

Conclusions: Consistent with recent work, our results suggest that children with ASD have reduced accuracy and speed on a task measuring the ability to inhibit conflicting information, whereas typical children showed the expected pattern of responses. Children with ASD processed visual information differently across conditions and showed less efficient processing overall as shown by increased P1 and N2 mean amplitudes, respectively. This, along with the lack of behavioral correlations on the BRIEF, potentially suggests a compensatory network for executive control in ASD. Further investigations using a broader region of interest and time frequency analysis are underway to better understand neural responses during the task.