Girls with attention-deficit/hyperactivity disorder: EEG differences between DSM-IV types.

This study investigated EEG differences between the Combined and Inattentive types of Attention-Deficit/Hyperactivity Disorder (AD/HD) in girls. Thirty girls with AD/HD of the Combined type, 30 girls with the inattentive type, and 30 controls (aged 8-12 years) had a resting eyes-closed EEG recorded from 21 electrodes. The EEG was Fast Fourier Transformed and estimates for total power, and absolute and relative power in the delta, theta, alpha and beta frequency bands, were analyzed in nine cortical regions. Across the scalp, girls with AD/HD had elevated total power, elevated absolute delta and theta, reduced relative delta and beta, and increased relative theta compared with controls. Compared with the Inattentive group, the Combined group had greater right hemisphere absolute theta and greater midline posterior absolute beta activity. The Combined group also had reduced right hemisphere relative delta, greater left hemisphere relative theta, reduced midline posterior relative alpha and reduced central relative beta activity. In conclusion, girls with AD/HD had increased slow wave (delta and theta) activity and reduced beta activity, which are robust results in the predominantly-male AD/HD literature, and exhibited the elevated theta/beta abnormality. The lack of global differences between DSM-IV AD/HD types differs from previous studies of boys and mixed-sex groups. The present results highlight the homogeneity of EEG profiles in AD/HD girls, which could be due to sex-bias in the diagnostic criteria. This study is the first to investigate EEG differences between the Inattentive and Combined types of AD/HD with a purely female sample.