Attention tasks and EEG power spectra.

The authors attempted to observe differences in alpha and beta hemispheric asymmetry during a task in which attention was directed toward input from the environment (intake task) as opposed to tasks that required that environmental events be excluded from the focus of attention (rejection tasks). In comparison to resting, both attention tasks caused a shift in alpha asymmetry ratios toward increased power on the right, with the greatest effect at temporal leads. The only significant difference between attention tasks was a finding of higher alpha power during intake than during rejection. Some characteristics of the EEG during attention indicate potential clinical utility.