EEG asymmetry in educationally handicapped children

Bilaterally homologous parietal and temporal EEGs were recorded from two groups of educationally handicapped children while the subjects (Ss) rested with eyes open or closed or performed in simple tasks designed to differentially activate the two hemispheres (reading by Ss, reading to Ss, draw a picture). A 'dyslexic' but not dysphasic group showed a reversal of theta asymmetry from eyes closed to eyes open (L less than R to L greater than R). This difference between groups was reflected most at the parietal placement. Theta in the parietal lead changed in accordance with expectations from reading to drawing (reduction of the R/L ratio), but that pattern did not occur at the temporal lead in 'dyslexics'. A discriminant analysis on theta power correctly classified 20 of the 22 children.