This study investigated EEG differences between
children with two subtypes of Attention-Deficit/Hyperactivity
Disorder (ADHD) and normal control subjects. EEG was recorded
during an eyes-closed resting condition and Fourier transformed
to provide absolute and relative power estimates for the
delta, theta, alpha, and beta bands, and the mean frequency
for each band was calculated. Ratio coefficients were also
calculated between frequency bands. Mean group differences
were found in the theta, alpha, and beta bands between
all three groups. Similarly, differences were found between
all three groups for the theta/alpha and theta/beta ratios
and for the mean frequency of the total EEG. These results
support a model of ADHD resulting from a developmental
deviation rather than a maturational lag in the central
nervous system. Differences between the clinical groups
in frontal activity suggest that different neuroanatomical
systems are involved in the different subtypes of ADHD.