Focal cerebral dysfunction in developmental learning disabilities.

In 24 children with developmental learning disabilities and 15 age-matched controls regional cerebral activity was studied with xenon-133 single photon emission tomography. In the 9 children with pure attention deficit and hyperactivity disorder (ADHD), the distribution of regional cerebral activity was abnormal--low in striatal and posterior periventricular regions and high in occipital regions. Low activity in striatal and posterior periventricular areas was also seen in the 8 children with ADHD in combination with phonologic-syntactic dysphasia. 7 children with dysphasia, but without hyperactive behaviour, had low cerebral activity in left temporofrontal regions.