Neuropsychological functioning, motor speed, and language processing in boys with and without ADHD

We administered a neuropsychological battery to boys aged 6 to 12 years old diagnosed with attention-deficit hyperactivity disorder (ADHD; n = 51) and to comparison boys of the same age range (n = 31). Boys with ADHD had greater difficulty than comparison youngsters on nonautomated language and motor tasks administered with a fast instructional set and on one of two traditional frontal executive measures (Porteus mazes). When tasks requiring automatic processing were paired with similar tasks requiring greater use of selective attention processes, the latter, controlled processing tasks differentiated groups better than did automated tasks. This differential effect of otherwise similar tasks is interpreted in terms of an output deficit mediated by response organization as detailed in the information processing literature. The ADHD group also exhibited slow gross motor output, measured independently of verbal output. The findings are evaluated in terms of both Luria's (1973) tripartite model of neurocognitive organization and frontal striatal models, with an emphasis on output processes. The observed language deficits could represent frontal lobe processes intricately related to self-monitoring and planning. The utility of controlled processing, self- paced tasks with fast instructional sets in assessing language and motor skills in ADHD is highlighted.