Cognitive aging in autism

Autistic individuals experience cognitive difficulties to varying degrees (ranging from none to many), and at various stages of life. However, it is relatively unknown how cognitive functions of autistic adults develop during middle- and late adulthood. Therefore, this thesis focusses on the interaction between the aging brain and autistic cognitive characteristics, aiming to answer three main questions: 1) Do we observe differences in cognitive aging (cross-sectionally and longitudinally) between autistic and non-autistic adults? 2) How do these group-based findings translate to the individual level; and more specifically, are behavioral susceptibilities (e.g., self-reported cognitive or mental health difficulties) associated with more vulnerable cognitive characteristics within autistic adults? 3) Can we identify mechanistic explanations of cognitive differences between autistic and non-autistic adults by studying cognitive strategies?
We observed that autistic adults show (modest) difficulties on theory of mind, verbal fluency and prepotent response inhibition, but not on visual- and verbal memory, working memory and processing speed. Crucially, cross-sectional, and longitudinal age-related effects were similar between our autistic and non-autistic group, indicating parallel patterns of cognitive aging. Individual differences across cognitive profiles were somewhat larger in autistic people compared to non-autistic people, yet smaller than anticipated. Also, these variations were mostly unrelated to behavioral susceptibilities. The use of cognitive strategies was largely similar between autistic and non-autistic adults, with comparable age-related effects. In conclusion, although cognitive differences between autistic and non-autistic people exist, they seem modest in nature and do not seem to result in altered patterns of cognitive aging in autism.