EEG-defined subtypes of children with attention-deficit/hyperactivity disorder

Objectives: This study investigated the presence of EEG clusters within a s ample of children with the combined type of attention-deficit/hyperactivity disorder (ADHD). Methods: Subject, consisted of 184 boys with ADHD and 40 age-matched contro ls. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and relative power in the delta, theta, alpha and beta bands. and for the theta/beta rat io. Factor analysis was used to group sites into 3 regions, covering fronta l. central and posterior regions. These data were subjected to cluster anal ysis. Results: Three distinct EEG clusters of children with ADHD were found. Thes e were characterized by (a) increased slow wave activity and deficiencies o f fast wave. (b) increased high amplitude theta with deficiencies of beta a ctivity, and (c) an excess beta group. Conclusions: These results indicate that children with ADHD do not constitu te a homogenous group in EEG profile terms. This has important implications for studies of the utility of EEG in the diagnosis of ADHD. Efforts aimed at using EEG as a tool to discriminate ADHD children from normals must reco gnize the variability within the ADHD population if such a tool is to be va lid and reliable in clinical practice. (C) 2001 Elsevier Science Ireland Lt d. All fights reserved.