Effect of inaudible 40 Hz binaural beats on attention.

Binaural beat (BB) is a sound stimulus that produces an auditory phenomenon due to the difference in sounds of slightly different frequencies of two tones. In the present study, we aimed to examine the effects of 40 Hz BB on attention using a 40 Hz BB, with a baseline frequency set in the inaudible range, in order to eliminate any influence of the baseline sound, which may have been ignored in previous studies on BB that used the audible range. The experiment included electroencephalograph (EEG) analysis with a 16-channel EEG and assessment of attention with attention network test (ANT). The results revealed no significant difference in the correct response rates between EEG and ANT; however, the reaction time (RT) of ANT was significantly lower in the BB sessions than in the non-BB sessions. The correlation between power spectrum density and the mean RT of correct answers in ANT showed a significant difference only for the left dorsolateral prefrontal cortex in the theta band.