Features of the power spectra of the main EEG rhythms in children with different types of attention deficit hyperactivity disorder

As a result of the examination of a group of 9- to 12-year-old children with the combined type of attention deficit hyperactivity disorder (ADHD), two variants of the clinical picture of ADHD were identified: the residual organic variant (ADHD RO) and the idiopathic variant (ADHD IP). The EEG power spectra in the main frequency ranges were studied with the eyes closed and open. The greatest intergroup differences in the power spectra were observed in the θ-band in the forntocentral and occipital derivations. In the frontocentral divisions of the cortex, the maximal values were observed in the group of ADHD RO children, whereas the highest spectral power values were observed in ADHD IP children in the occipital derivations. No statistically significant differences in the α-band spectral power between healthy subjects and ADHD schoolchildren from either group were obtained. Thus, the studies showed that these two ADHD variants have certain neurophysiological differences, which should be considered when therapeutic modalities are to be selected.