Electrophysiology and intelligence: the electrophysiology of intellectual functions in intellectual disability.

The electroencephalograms (EEGs) of 127 subjects with intellectual disability were analysed with regarding to their correlation to intellectual functions in order to further understand the relationships between EEG and intelligence. The EEG frequency spectrum was subdivided into 15, 2-Hz-wide bands and was recorded from electrodes F1, Fpz, Fp2, F7, F3, Fz, F4, F8, T3, C3, Cz, C4, T4, T5, P3, Pz, P4, T6, O1, Oz and O2. Patterns of acorrelation showed several similarities when compared to other analogous studies with normal subjects. However, the typical finding in the present study was a high number of correlations involving the frontal lobes, mainly the prefrontal portions, which is at variance with the patterns of normal subjects. Frontal lobes, especially the prefrontal regions, seem to be affected, regardless of its aetiology, in subjects with intellectual disability.