COMPARISON OF EEG ACTIVITY IN THE LEFT AND RIGHT CEREBRAL HEMISPHERES BY POWER-SPECTRUM ANALYSIS DURING LANGUAGE AND NON-LANGUAGE TASKS

In 10 female subjects, power-spectrum analysis was performed on the .alpha. activity elicited during the resting state, 4 right hemispheric tasks, and 3 left hemispheric tasks. The data were treated in 3 ways: approach 1, comparing the right and left hemispheric .alpha. activity; approach 2, comparing the right and left hemispheric .alpha. activity adjusted for the resting state; and approach 3, comparing the right and left hemispheric .alpha. activity adjusted for the previous task. Approach 1 and 2 revealed few significant differences in the .alpha. activity of the hemispheres, but approach 3 provided data that better fit the theory of decreased power spectrum or attenuation of activity in the activated hemisphere. Approach 3 may be useful in developing an EEG test for determining cerebral dominance for language.