VISUAL PROCESSING IN GEORGIAN CHILDREN WITH NEURODEVELOPMENTAL DISORDERS.

Neurodevelopmental disorders are disabilities that cause impairment in learning, language, or behaviour areas. ADHD and learning disabilities, namely dyslexia have the greatest prevalence among these disorders and very often co-occur together. As visual perception is essential for development of academic abilities, it is very important question whether visual processing is affected in children with neurodevelopmental disorders or not. There are controversial scientific evidences whether visual perceptual deficits are related to neurodevelopmental disorders or not. Here we investigated such aspects of visual processing as visual attention and visual working memory. Three groups of Georgian children participated in our study: children with dyslexia, children having ADHD and dyslexia together and typically developing children. Two types of attentions were evaluated with two different tasks: selective attention using visual search task and sustained attention using Go/NoGo tasks; short-term visual working memory was investigated using Visual N-back Test. We found that performances of all tasks were similar for dyslexia and control groups in simple conditions but performance deteriorated for all three groups as soon as task was complex. Children having ADHD and dyslexia together had worse performance. Our results showed no deficits for children with dyslexia in visual working memory or visual selective and sustained attention even when reaction times are prolonged. But we found deficits for children having more than one neurodevelopmental condition (ADHD+dyslexia). There was not found any correlation between performances of different tasks. We conclude that deficits of visual attention and visual working memory might not be related to impairment of reading skills in dyslexic children. Even when children with more than one neurodevelopmental disorders show some deficits in visual attention and visual working memory, those deficits alone cannot be accounted for specific deficits of complex neurobehavioral disorders.