40 HZ EEG activity in learning disabled and normal children during baseline and verbal task conditions

Measurement of parietal EEG activity was undertaken in fourteen learning disabled boys and fourteen normal controls during baseline and verbal-auditory task conditions. Digitized records then underwent digital band pass filtering into 30 Hz, 40 Hz, 50 Hz, and 70 Hz bands. Epochs displaying significant activity in the 70 Hz band were omitted from the EEG analysis to minimize contamination by muscle artefacts. Control subjects displayed symmetrical parietal activity during baseline and a general left hemisphere activation on task across all three EEG bands. This activation was particularly focused in the 40 Hz band. Learning disabled subjects failed to display task dependent left hemisphere activation in any of the EEG bands. These results are consistent with the view that learning disabled subjects display deficits in attention and arousal.