Mapping brain functions of ADHD children

Abstract

Brain functions underlying inattention and impulsivity can be measured with event-related potentials (ERPs) in the cued continuous performance test (CPT A-X). Children with attention deficit hyperactivity disorder (ADHD) exhibit attenuation of the attentional cue P300 microstate, which reflects relatively pure attention and precedes target (go) and nontarget (no-go) trials. Multicenter studies indicate that this attentional deficit is also present in children with AD/HD of the combined subtype (DSM-IV) and in children with hyperkinetic disorders (HD). Tomographic source solutions converge to posterior cue P300 sources that are attenuated in ADHD or HD children, contrasting with the predominance of frontal deficits in metabolic studies of ADHD. A reanalysis of our data indicated that these posterior deficits remain the most robust ERP marker of ADHD. The posterior tomography of the cue P300 proved robust across different LORETA versions but sensitive to spatial undersampling. After more detailed time segmentation, reduced frontal N2 and central no-go P300, considered to reflect frontal deficits, also became evident in ADHD children. A wide range of ADHD subtypes, thus, suffers from activation deficits of both posterior and anterior attention systems. Resolving them with tomographic ERP imaging requires high-density ERPs.