A neuropsychological study of the association between specific language impairment (SLI) and hyperactivity was conducted on four groups of 6-year-old children (5 boys and 5 girls in each group) at the Department of Psychiatry, University of Cambridge, UK. Cognitive functioning on non-verbal tests was not adversely affected in the SLI group, but a test of attentional set shifting, sensitive to frontostriatal dysfunction, was impaired in the hyperactive group. Hyperactive children also showed reduced spatial spans on a test of spatial working memory that reflects parietal lobe functioning. Psychological measures showed no interactions between hyperactivity and SLI. Children with ADHD have problems in inhibitory control of attentional selection. SLI and ADHD have different cognitive correlates. 
COMMENT. The authors recommend that future studies of SLI and ADHD should include concurrent measures of language, cognition, behavior, and general IQ. To determine differences between the psychological functioning of children with SLI and ADHD subtypes, a larger patient sample is required. ADHD children had both frontostriatal and parietal lobe dysfunction, while SLI patients showed no adverse functioning on non-verbal tests.
Controlled study of Adderall and MPH in ADHD showed that the drugs are comparable in reducing inattention and opposition symptoms in the classroom, but Adderal has a longer duration of action.