Increase in frequency of the alpha rhythm by verbal stimulation.

Abstract

During periods of verbal auditory stimulation as compared with periods of minimal external stimulation the frequency of the a rhythm increased significantly (.57 waves per sec.). In a 30-min. control period (min. external stim.) the frequency of the alpha waves increased significantly during the 1st 20 mins. for the majority of the 12 subjects. During the last 10 mins. no further increase was found. An analysis of the conditions of our expts. supports the conclusion that immediate afferent stimulation or increased mental activity may increase the frequency of the a rhythm.