Grant: Project Grant

Approximately 1 in 66 Canadians receives a diagnosis on the autism spectrum, which represents more than 500 000 Canadians, a number constantly on the rise and challenging health services. Individuals with an autism spectrum diagnosis are very different from one another in terms of development, cognitive strengths and weaknesses, as well as underlying brain mechanisms. It makes intervention using a one-size-fits-all approach ineffective. There is an emerging consensus that we need to delineate subgroups among the autism spectrum to overcome the heterogeneity challenge. The subgrouping approach currently most supported is the age of speech onset, as autistic individuals who experienced speech onset delay have distinct cognitive, reasoning and cerebral profiles from those who did not experience a delay in speech onset. We propose to incorporate both the characteristic autistic reasoning profiles and the development of brain mechanisms into the subgrouping process to parse the heterogeneity of the autism spectrum. We will employ computerized tasks and brain imaging techniques to investigate reasoning development and brain mechanisms from 7 to 15 years old in autism spectrum children versus typical children. We aim to understand: 1) the developmental trajectory of reasoning mechanisms in autistic children; 2) whether speech onset helps to define subgroups; 3) how the brain mechanisms supporting reasoning evolve from childhood to adulthood; 4) develop a reasoning signature (abilities combined with brain mechanisms) to optimise subgroupings on the autism spectrum. Combining methods for defining meaningful subgroups among the autism spectrum appears as the most promising way to make significant progress in genetic and neuroimaging models, as well as to develop targeted tools for clinical diagnosis and intervention suitable to autism spectrum children.