Do children with ADHD and/or PDD-NOS differ in reactivity of alpha/theta ERD/ERS to manipulations of cognitive load and stimulus relevance?

Objective: We examined whether the method of event-related (de-)synchronization (ERD/ERS) revealed differential effects of selective attention and working memory load in children (8-11 years) with pervasive developmental disorder - not otherwise specified (PDD-NOS) or attention-deficit/hyperactivity disorder (ADHD). Methods: Fifteen healthy controls and three equally large groups of children with symptoms of PDD-NOS, ADHD or both (PDD/HD) performed a visual selective memory search task. The EEG was recorded from which occipital alpha and frontal theta were derived. Results: The effects of the overall task manipulations of task load, relevance and target/nontarget were clearly present in the overall analyses of alpha and theta ERD/ERS. However, no significant differences with respect to these manipulations existed between any of the subject groups. Conclusions: The results supply no evidence for a distinction in information processing abilities of selective attention and working memory as reflected by alpha and theta ERD/ERS between children diagnosed with either ADHD, PDD-NOS or healthy controls. Significance: Alpha and theta ERD/ERS are sensitive to manipulations of task load, relevance and target/nontarget, but supply no additional information on possible group differences in comparison to the more frequently used method of event-related potentials. (C) 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved