Resting-State Theta Oscillations Predict Executive Functioning Deficits in Children with Autism Spectrum Disorder

Background:  Children with autism spectrum disorder (ASD) often show deficits in executive functioning (EF), the ability to manage complex or conflicting information to achieve a goal. EF deficits in ASD may be associated with impaired prefrontal activity and functional integration with the rest of the brain (O’Hearn et al., 2008). In particular, resting-state theta oscillations have been suggested to play a general integrative role in the organization in brain activity, and are particularly important for EF domains that require a variety of cognitive processes such as working memory and inhibitory control (Sauseng et al., 2010). There is significantly greater resting-state theta power in individuals with ASD in the frontal and parietal regions (Wang et al., 2013; Cornew et al., 2013). Taken together, prior research suggests that resting theta oscillations in children with ASD may be a possible neural system abnormality that underlies EF deficits. To our knowledge, associations between resting theta oscillations and EF deficits within children with ASD have not yet been explored.

Objectives:  To examine whether frontal and parietal resting-state theta oscillations predict EF deficits in children with ASD.

Methods: 28 children with ASD (M = 114 months, SD= 13.53) provided adequate EEG data with data collection still underway. EEG was recorded during both eyes-closed and eyes-open resting conditions. To compute power spectra, 2 minutes of EEG were divided into intervals of 2-seconds. A Hanning window and a Fast Fourier Transformation were applied. Children also completed a Flanker task as a measure of inhibition, and EEG was recorded and analyzed for the N2 event-related potential. Parents completed the Behavioral Rating Inventory of Executive Function (BRIEF), which measures global EF skills as well as specific domains of EF.

Results: Linear regressions controlling for age, gender and IQ examined the relation between theta power and EF deficits. Lower frontal theta power during eyes-open condition predicted worse working memory (β = -0.54, t(16) = -2.20, p = 0.04) and planning/organization (β = -0.56, t(16) = -2.77, p = 0.02) on the BRIEF. With eyes open, reduced parietal theta power predicted increased N2 amplitude during incongruent trials (β = -0.38, t(15) = -3.00, p = 0.01) but faster reaction times during the flanker task (β = -0.55, t(15) = -2.68, p= 0.02).

Conclusions: These results suggest that resting theta oscillations predict EF deficits in children with ASD and provide some preliminary evidence that individual differences in the resting-state neural systems in children with ASD may be associated with task-dependent activation in the brain during EF tasks. However, increased theta in both frontal and parietal regions predict better EF performance. This is surprising given that decreased theta power during resting is correlated with better cognitive performance in a typically developing sample (Klimesch, 1999). The relation between parietal theta and increased N2 amplitude suggests there may be an association between decreased theta power during rest and increased anterior cingulate cortex activation during the flanker task. We plan to examine these associations in a typically developing sample, and compare resting-state theta power between groups.