One size does not fit all: An individualized approach to understand heterogeneous cognitive performance in autistic adults

• Published in: Autism research 2023-04, Vol.16 (4), p.734-744
• Main Authors: Torenvliet, Carolien, Groenman, Annabeth P., Radhoe, Tulsi A., Agelink van Rentergem, Joost A., Geurts, Hilde M.
• Format: Article
• Language: English
• Subjects: Adult; Adults; Autism; Autism Spectrum Disorder - psychology; Autistic Disorder - complications; Autistic Disorder - psychology; Cognition; Cognitive ability; Cognitive Dysfunction - complications; Heterogeneity; Humans; Language; Memory; Memory, Short-Term; Multivariate analysis; multivariate normative comparisons; neuropsychology; Psychological stress; Short term memory
• ISSN: 1939-3792; 1939-3806
• DOI: 10.1002/aur.2878

Cognitive performances of autistic people vary widely. Therefore, previous group‐based comparisons on cognitive aging in autistic adults might have overlooked those autistic adults that are particularly vulnerable for cognitive decline. Multivariate normative comparisons (MNC) statistically assess individual cognitive differences on the entire cognitive profile. Cognitive deviancy as indicated by MNC accurately predicts future cognitive decline, and is therefore sensitive in detecting meaningful cognitive differences. The current study aimed to (1) investigate the applicability of MNC to assess cognitive performance in autism individually, and (2) understand heterogeneous cognitive performance in autistic adults. As pre‐registered, we performed MNC in a sample of 254 non‐autistic adults, and two independent samples of respectively 118, and 86 autistic adults (20–85 years, mean: 50 years). Cognitive performance was measured on 11 outcomes in six domains (verbal/visual memory, working memory, verbal fluency, Theory of Mind, and psychomotor speed). Using MNC, about twice as many autistic individuals had a deviant cognitive profile (i.e., deviated statistically from the multivariate normspace) as compared to non‐autistic individuals. Importantly, most autistic individuals (>80%) did not have a deviant cognitive profile. Having a deviant profile was significantly associated with higher levels of psychological distress in autistic adults specifically, showing the clinical relevance of this method. Therefore, MNC seem a useful tool to individually detect meaningful cognitive differences in autism. These results are consistent with previous cognitive studies suggesting that most autistic adults show fairly similar cognitive profiles to non‐autistic adults, yet highlight the necessity for approaches reflecting the heterogeneity observed in autistic people. Lay Summary Aiming to understand cognitive differences between autistic adults, we applied a new statistical method that assesses cognition in a sensitive, and individual manner. Cognitive profiles of autistic adults, and non‐autistic adults were, therefore, investigated statistically. About twice as many autistic individuals showed a different cognitive profile (20%) as compared to non‐autistic individuals, yet most autistic individuals (80%) did not. Differences were, in part, explained by differences in psychological distress.