The Effect of 40 Hz Binaural Beats on Working Memory

Abstract

Binaural beats (BB), in which pure tones are delivered at fixed frequency, seek to influence neural activity during cognitive tasks and induce frequency-following response which can entrain brain rhythms to the frequency of external stimulation. An increasing number of studies have suggested that BB can be used to alter or enhance cognitive processes. This study aimed to explore the effect of 40 Hz binaural beats on working memory. In addition to further verifying whether there was a frequency-following response, changes in microstates were observed, providing new evidence for the effectiveness of binaural beats. 40 healthy volunteers completed visuospatial and verbal working memory tasks when listening to pink noise and 40 Hz binaural beats (R: 440 Hz, L: 400 Hz). The EEG was analyzed in terms of behavioral performance, relative power, Higuchi fractal dimension (HFD) and microstates after BB stimulation. We found that subjects performed better on the working memory task when stimulated by 40 Hz binaural beats, with significantly higher HFD in the temporal and parietal lobes and a significant positive correlation between HFD and relative power in the gamma band, in addition to a significant increase in the duration and coverage of microstate D and a significant decrease in those of microstate A. Our results demonstrate that 40 Hz binaural beats improve working memory, and induce frequency-following responses. Besides, changes in both HFD and microstates are correlated with attention, which may also account for the changes in working memory performance affected by 40 Hz binaural beats.