Étude de la trajectoire développementale des fonctions attentionnelles et exécutives et de leurs relations avec les symptômes clinique dans le trouble déficitaire de l'attention/hyperactivité (TDA/H)

Authors: Vézina, Pascale
Advisor: Rouleau, Nancie
Abstract: Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by developmentally atypical levels of inattention, hyperactivity and impulsivity. Cognitive impairments are now recognized as an important component of the disorder, which could act as an intermediary between genotype and behavioural phenotype. However, methodological issues limit the conclusions that can be drawn regarding the cognitive profile of patients with ADHD. In addition, very few studies have investigated cognitive development in ADHD, although cognitive impairments are thought to be an important component of this developmental disorder. Many questions thus remain about cognitive evolution of ADHD and its association with changes in clinical symptomatology. To address these issues, four main objectives were pursued in the present thesis: 1) to confirm the presence of a dysfunction of five cognitive functions targeted as potential cognitive markers of ADHD (alertness, vigilance, inhibition, set shifting and working memory) using a methodology guided by theoretical models of cognition, 2) to examine the effect of age on the expression of these cognitive dysfunctions throughout development (6 to 22 years), 3) to document the prospective evolution of these cognitive functions in participants with ADHD over a period of 8.74 years, and 4) to verify the presence of an association between cognitive trajectories of the disorder and symptom evolution. Results have shown that participants with ADHD had lower performances of alertness, vigilance, inhibition and set shifting, while working memory seems to be preserved. These impairments were distinctively influenced by age and multiple cognitive trajectories were identified. Indeed, set shifting was found to be specifically impaired in children with ADHD and tended to normalize with age. Inversely, vigilance performance was found to decline with age, with an impairment that was specific to older participants with ADHD. The other processes, i.e. alertness, inhibition and working memory, were less prone to developmental effects and remained relatively stable over time. There was no clear association between cognitive trajectories and symptom evolution, suggesting that cognitive changes are unlikely to be causally involved in the course of symptoms. The results of the thesis lead to propose three cognitive trajectories of ADHD and to discuss the factors underlying them, as well as their relationship with the clinical manifestations of the disorder. They also have methodological and clinical implications for scientists and clinicians working with clients with ADHD.
Document Type: Thèse de doctorat
Issue Date: 2019
Open Access Date: 13 March 2019
Permalink: http://hdl.handle.net/20.500.11794/34004
Grantor: Université Laval
Collection:Thèses et mémoires

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