Do Cognitive Challenges of Adults with Autism Persist, Abate or Increase into Old Age?

Background: Although autism spectrum disorder (ASD) is a lifelong condition linked to various cognitive challenges occurring from childhood into young adulthood, hardly any study focused on cognition in late adulthood. This is surprising as healthy aging is associated with age-related decline in several cognitive domains, including memory, fluency, and theory of mind (ToM), and ASD is associated with difficulties in exactly some of these domains. In a small study on cognition in elderly with ASD (aged 51 to 83 years; Geurts & Vissers, 2012), a steeper decline with increasing age was observed for visual memory, while problems with phonemic fluency seemed to abate. However, before firm conclusions can be drawn, these findings need to be replicated in a larger ASD sample. 

Objectives: To replicate findings on the role of age on visual and verbal memory and phonemic fluency and to investigate the role of age on semantic fluency and ToM from young to late adulthood in ASD. 

Methods: One-hundred-eighteen individuals clinically diagnosed with ASD and 118 age, gender, and IQ matched individuals without ASD diagnosis (COM group) between 20 and 79 years (IQ>80) performed a series of neuropsychological tests assessing visual and verbal memory, phonemic and semantic fluency, and ToM.   

Results: Group comparisons revealed that the ASD group had higher scores on visual memory immediate recall, similar scores on visual memory delayed recall, verbal memory immediate and delayed recall, and reduced scores on phonemic (trend) and semantic fluency and ToM. Regression analyses revealed similar age-related patterns on visual and verbal memory delayed recall and on phonemic and semantic fluency. However, a differential effect of age was found on visual memory immediate recall and a trend towards a differential effect was found on ToM and verbal memory immediate recall. Separate regressions per group showed that ToM declined with increasing age in the COM group, whereas it did not in the ASD group. Also visual memory immediate recall was affected by age in the COM group and there was only a trend in the ASD group. Even though both groups showed age-related decline on verbal memory immediate recall, the effect was larger in the COM group. 

Conclusions: These preliminary findings suggest that, at least in the studied cognitive domains, age-related decline characteristic of typical aging is not observed, less pronounced, or parallel, but not increased, in individuals with ASD. Some cognitive problems occurring in adulthood are still present in old age (i.e, fluency) and others become less apparent (i.e, ToM) due to decline in those without ASD. Moreover, we see clear cognitive strengths in some domains (i.e, visual memory) that persist over the years. Hence, in this large cross-sectional study we found, unlike Geurts and Vissers (2012), no evidence for accelerated cognitive decline in intellectually able adults and elderly with ASD.