Commonalities and Divergences in the Cognitive Profiles of Autism and Dementia: Protocol for a Narrative Literature Review.

Background: Literature has shown an increase in research relating to autism and aging, and more specifically, autism and healthy aging. Within the literature, there is a clear lack of knowledge and understanding of the impacts of dementia and autism as co-occurring experiences. More specifically, there is a lack of clinical knowledge about the ways in which the cognitive profiles of autism and dementia do and do not overlap, and how this overlap might affect dementia assessments for this population. This is likely to result in challenges with diagnosis and may lead to misdiagnosis or a lack of diagnosis for the autistic population. Objective: This paper reports on a narrative literature review that addresses the lack of understanding of potential similarities and differences in the cognitive profiles of autistic people and patients with dementia. It aims to identify the cognitive functions that are sensitive only to dementia and are less likely to be sensitive to autism. This will allow for a deeper understanding of how to grant sensitivity and specificity in the assessment of dementia within the autistic population. Methods: The narrative literature review relies on existing guidelines (eg, PRISMA [Preferred Reporting Items for Systematic Reviews and Meta-Analyses]) to inform a newly developed tool, namely the Quality of Evidence Tool (QoET), used to assess publications identified in relevant databases (eg, PubMed, PsycINFO, and others) that report on cognitive functions in autism. Four main cognitive domains were chosen: memory, executive function, attention, and language, as these are the most commonly impaired in people with dementia due to Alzheimer disease and are known to be affected by autism. The QoET was used to select publications that informed us of cognitive functions that would meet our aim, that is, functions affected by dementia and not by autism. Results: This narrative review will identify cognitive domains and functions affected by dementia, not autism, and the assessment tools that yield these findings. It is expected that the rigorous methodological approach devised will shed light on how existing cognitive assessments should be used to increase the specificity of dementia risk detection among autistic individuals, thereby addressing early concerns raised by individuals or health care practitioners. It is expected that the review will be ready for publication by December 2026. As of April 2026, memory and executive function have been drafted. Conclusions: This narrative review does not seek to give a definitive answer on the cognitive domain, function, and outcome measures or tests used in dementia detection, which can help detect risk in autistic individuals. Instead, it aims to provide a starting point, to pragmatically and efficiently explore and synthesize the broad evidence base, to inform future work and potentially highlight topics (eg, cognitive functions of interest) on which future systematic reviews could specifically focus.