Atypical working memory decline across the adult lifespan in autism spectrum disorder?

Abstract

Whereas working memory (WM) performance in typical development increases across childhood and adolescence, and decreases during adulthood, WM development seems to be delayed in young individuals with autism spectrum disorder (ASD). How WM changes when individuals with ASD grow old is largely unknown. We bridge this gap with a cross-sectional study comparing age-related patterns in WM performance (n-back task: 3 load levels) among a large sample of individuals with and without ASD (N = 275) over the entire adult life span (19-79 years) as well as interindividual differences therein. Results demonstrated that, despite longer RTs, adults with ASD showed similar WM performance to adults without ASD. Age-related differences appeared to be different among adults with and without ASD as adults without ASD showed an age-related decline in WM performance, which was not so evident in adults with ASD. Moreover, only IQ scores reliably dissociated interindividual differences in age-gradients, but no evidence was found for a role of basic demographics, comorbidities, and executive functions. These findings provide initial insights into how ASD modulates cognitive aging, but also underline the need for further WM research into late adulthood in ASD and for analyzing individual change trajectories in longitudinal studies.