Neuropsychological functioning of children with ADHD or a reading disorder

Attention-deficit/hyperactivity disorder (ADHD) and reading disorder (RD) are two of the most common developmental disorders of childhood. They also co-occur much more often than can be expected by chance. The cause of this comorbidity is not fully understood yet. Insight into group differences and similarities and into the aetiology of this comorbidity is however important to improve differential diagnosis and to select an appropriate treatment for each individual child. The main aim of this doctoral dissertation was to gain more insight into the cognitive and neurobiological factors (endophenotypes) that underlie the behavioural symptoms of ADHD and RD, and in the relationship between both disorders with respect to those endophenotypes. To this end, several studies were conducted in which children with ADHD, RD, and ADHD+RD were compared to typically developing control children and to each other on various neurophychological and neurophysiological measures.