Age-Related Differences in the Large-Scale Resting State Executive Network and Relationships with Social Communication Impairments in Autism Spectrum Disorder

Poster Presentation
Saturday, May 12, 2018: 11:30 AM-1:30 PM
Hall Grote Zaal (de Doelen ICC Rotterdam)
M. Walsh1, L. C. Baxter2, C. J. Smith3 and B. B. Braden4, (1)Arizona State University, Tempe, AZ, (2)Radiology, Barrow Neurological Institute, Phoenix, AZ, (3)Southwest Autism Research & Resource Center, Phoenix, AZ, (4)College of Health Solutions, Arizona State University, Tempe, AZ
Background: The first children diagnosed with autism spectrum disorder (ASD) are now elderly; yet, there is little research on aging in adults with ASD. Abnormalities observed in resting-state functional connectivity (rs-FC) of large-scale brain networks are thought to underlie ASD symptoms. The rs-FC of these networks also declines with normal aging, most strongly in the executive network (EN). This is concerning for aging adults with ASD, since executive functioning has been postulated as a compensatory domain responsible for ameliorating the core symptom, social communication impairments (SCI), in ASD.

Objectives: We aimed to determine age-related differences in EN rs-FC in adults with ASD versus neurotypical (NT) adults. Additionally, we aimed to determine age-related differences in SCI, and the relationship between EN rs-FC and SCI, in adults with ASD. We hypothesized adults with ASD would experience larger age-related changes in EN rs-FC than NT adults. Further, we hypothesized middle-age adults with ASD would have greater SCI and a stronger relationship between SCI and EN rs-FC, than young-adults with ASD.

Methods: Participants were 24 young adult (YA; 18-25 years) and 25 middle-aged (MA; 40-64 years) adult males with high-functioning ASD, and 15 YA-NT and 21 MA-NT adult males. Differences in SCI (measured by the Social Responsiveness Scale -2; SRS-2) between YA and MA adults with ASD were evaluated with a t-test (p<0.05, one-tailed). We used independent component analysis to generate whole-brain rs-FC maps of the EN for all participants. Whole-brain EN comparisons were made using a two-factorial design in Statistical Parametric Mapping-12 and small-volume correction (p<0.05, false discovery rate) using an EN mask (neurosynth.org). An exacerbated aging trajectory of rs-FC decline in ASD was probed with a contrast matrix modeling reduced rs-FC in ASD participants relative to NT participants, and a larger age-related decline between ASD age groups than NT age groups. Rs-FC of six neo-cortical EN nodes was extracted and correlations with SCI were investigated in MA-ASD and YA-ASD groups separately (p<0.05, family-wise error corrected). IQ was entered as a covariate in all analyses.

Results: Although MA-ASD participants demonstrated higher SCI than YA-ASD, this difference was non-significant (p=.13). The EN demonstrated exacerbated age declines in rs-FC of the bilateral dlPFC, with only the left hemisphere surviving statistical correction. Lastly, there was a significant negative correlation between rs-FC of the right dlPFC and SCI in MA-ASD but not YA-ASD participants.

Conclusions: In one of the first aging rs-FC investigations in adults with high-functioning ASD, our findings suggested exacerbating age-related hypoconnectivity in frontal regions of the EN, relative to NT adults. Further, EN hypoconnectivity was related to increased SCI in middle-age adults with ASD only. Findings provide some of the first insights of brain mechanisms underlying core symptoms in older adults with ASD.