EEG activity in girls with attention-deficit/hyperactivity disorder

Objective: This study investigated the EEG of girls with Attention-deficit/hyperactivity disorder (ADHD). Methods: Subjects consisted of 100 girls with ADHD between the ages of 8 and 12 years and 40 age- and gender-matched controls. 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. Factor analysis was used to group sites into 3 regions, covering frontal, central and posterior regions. The total ADHD group was compared to the control group as well as the data being subjected to cluster analysis. Results: The ADHD subjects had greater total power, more relative theta, and less relative delta, alpha and beta than controls. Cluster analysis indicated the presence of two distinct EEG clusters of girls with ADHD. These were (a) a large subgroup characterized by increased total power, more relative theta, and less relative delta and beta than control subjects; and (b) a small subgroup with a substantially-increased amount of high amplitude theta activity, with deficiencies in all other bands. Conclusions: These results indicate that girls with ADHD exhibit abnormalities in their EEGs, but there is far less variance in their EEG profiles than is found in boys with the disorder. The results also suggest that there may be distinct groups of girls with ADHD who are not being referred for clinical treatment. Recommendations are made for further research in this population. This study is significant in that it is the first major study to separately investigate the EEG of girls with ADHD.