Cognitive Functions in Georgian Children with Dyslexia and Comorbid Dyslexia and Attention-Deficit/Hyperactivity Disorder

Abstract

In spite of the fact that dyslexia and Attention-deficit/hyperactivity disorder (ADHD) are highly comorbid, less studies have investigated cognitive functions during co-occurring of those disorders.  Here we studied such cognitive abilities as attention, memory, and executive functions in children with dyslexia and comorbid dyslexia/ADHD.  Three groups of age- and IQ-match children participated in our study: children with dyslexia (group 1), children having ADHD and dyslexia together (group 2) and typically developing children (group 3). All participants performed the visual search tasks, visual working memory task (visual N-back task) and executive function task (WCST). We found that children with comorbid dyslexia/ADHD showed a strong impairment in performance of search tasks while children with dyslexia showed significant worse performance than typically developing children only when task condition was more complex. However, both dyslexia and dyslexia/ADHD groups showed deficits in visual working memory compare to typically developing children. As for executive function task, only children with comorbid dyslexia/ADHD showed a significant worse performance compare to typically developing children. Here, we concluded that visual attention and visual working memory are impaired in children with either dyslexia or comorbid dyslexia/ADHD and these impairments are stronger in dyslexia/ADHD group. Yet, deficits in executive functions are more specific for children with comorbid dyslexia/ADHD.