Browsing by Author "Kubas, Hanna"
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- ItemOpen AccessExecutive Function Determinants of Attention-Deficit/Hyperactivity Disorder Medication Response(2013-10-02) Kubas, Hanna; Hale, James BradfordFocusing on behavioural criteria for attention-deficit/hyperactivity disorder (ADHD) diagnosis leads to considerable neuropsychological profile heterogeneity among diagnosed children and variable response to methylphenidate (MPH) treatment. Documenting “cool” executive/working memory (EWM) or “hot” self-regulation (SR)neuropsychological impairments could aid in differential diagnosis of ADHD subtypes and may help determine the optimal MPH treatment dose. In this study, children with ADHD Inattentive Type (n = 18) (IT) and Combined (n = 35)(CT) underwent a randomized double-blind placebo-controlled 4-week MPH trial. Neuropsychological, behavioural, and observational data were collected to evaluate medication response. Results from individual neuropsychological tests suggest that performance was not uniform; those with moderate or significant baseline EWM/SR impairment showed robust MPH response, while response for those with lower baseline executive impairment was minimal. Implications for medication titration, academic achievement, and long-term treatment efficacy were examined.
- ItemOpen AccessMeasuring Executive Function Deficits in Children with Attention-Deficit/Hyperactivity Disorder(2016) Kubas, Hanna; Wilcox, Gabrielle; Lemay, Jean-François; Climie, Emma; Graham, Susan; Wiebe, SandraAttention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that often negatively impacts behaviour, cognition, and academic achievement. Children with ADHD also exhibit deficits in executive functioning (EF). Current conceptualizations of ADHD suggest that deficits across multiple cognitive processes, rather than a single core deficit, contribute to the manifestation of the disorder. In the current study, children with ADHD (n = 40) and typical controls (n = 36), ages 8 to 12, were compared on performance-based measures and behaviour ratings of EF, including inhibition, verbal and visuospatial working memory, and set shifting. Children with ADHD demonstrated significantly weaker performance on both the verbal and visuospatial working memory tasks, but no group differences emerged on the inhibition and set shifting tasks. Group differences remained when gender and cognitive scores were statistically controlled, but some differences disappeared when academic scores were entered as covariates. Parent behaviour ratings revealed significantly weaker EF scores for the ADHD group across all measures evaluated; all differences remained with the inclusion of gender, cognitive scores, and academic performance as covariates. Correlational analyses revealed modest, yet significant, associations between performance-based measures and behaviour ratings of EF; however, these associations were not uniquely correlated between performance-based tasks and behaviour ratings of EF hypothesized to measure the same underlying construct. Findings highlight the importance of using a combination of performance-based and behaviour ratings of EF in the assessment and treatment of ADHD. Implications for the clinical and diagnostic utility of EF assessment in ADHD are addressed.