Relationships Among EEG Alpha Frequency, Reaction Time, and Age: A Biofeedback Study

To examine the relationship between the frequency of the EEG alpha rhythm and reaction time, the biofeedback technique was used to manipulate brain wave frequency in 10 young and 10 old subjects. Subjects first learned to increase the percent time they spent in their modal brain wave frequency, and then they were trained to increase the percent time they spent in brain wave frequencies 2 Hz faster and 2 Hz slower than their modal frequency. Simple auditory reaction time (RT) was measured during biofeedback immediately after subjects reached a set criterion at each biofeedback task. To control for the effect of biofeedback training on RT, groups of 5 old and 5 young subjects heard a pre‐recorded feedback signal which was not contingent upon their brain wave activity. Experimental subjects increased the abundance of alpha activity above baseline levels while control subjects did not. Results indicated that experimental alteration of brain wave frequency affected RT. When the subjects produced fast brain waves their RT was significantly faster than when they produced slow brain waves. Correlations between brain wave period and RT were small. Thus, the data did not provide unequivocal support for the notion that the alpha rhythm serves as a master timing mechanism for behavior, but the relationship between controlled EEG activity and RT was clearly demonstrated.