Inhibitory control in children with traumatic brain injury (TBI) and children with attention deficit/hyperactivity disorder (ADHD)

The behavioural and cognitive sequelae of traumatic brain injury (TBI) have features in common with attention deficit/hyperactivity disorder (ADHD), b est characterized by deficits in response inhibition. The performance was, therefore, examined of 27 children with TBI, 31 children with developmental ADHD, and 26 matched controls aged 8-12, on two inhibition tasks: the Stop -Signal Task and a Delayed-Response-Task. Children with TBI and children wi th ADHD showed a pervasive deficit in their inhibitory control processes wi th respect to inhibition of both pre-potent and on-going responses. In addi tion, children with TBI were found to suffer from a general slowing of thei r information processing, which was not correlated with the inhibition defi cit. TBI children with and without a secondary ADHD differed only tendentia lly in their Mean Go-Reaction time in the stop-task. However, subdividing T BI children according to actigraph data into hypo-, hyper- and normokinetic subgroups revealed that the hyperactive TBI children had inhibitory defici t patterns that were similar to children with developmental ADHD. It is con cluded that slowing of information processing speed seems to be a general c onsequence of TBI in childhood, whereas slowing of the stop-processes or in hibitory deficits, specifically, are associated with post-injury hypo- or h yperactivity.