Changes

Vernon and colleagues applied binaural beats in the alpha (10 Hz) and beta (20 Hz) frequency ranges for 1 min duration over ten trials to evaluate whether a frequency following response (FFR) could be elicited to these frequencies in two separate participant groups. Each trial was interleaved with exposure to a pure tone played at 400 Hz while EEG was recorded from the left and right temporal regions. The authors observed a slight decrease in resting baseline amplitudes for both beat frequencies, from the pre- to post-entrainment and during the experimental session, and participants exhibited reduced alpha activity during the binaural beat on-phase compared to the off-phase (36). In a similar study, Gao et al. (37) investigated the effects of binaural beats applied for a 5 min duration at 1, 5, 10, and 20 Hz. To detect EEG changes due to binaural beats, they analyzed relative power (RP), phase locking values (PLVs), and cross-mutual information (CMI). Relative power in the theta and alpha bands increased during delta and alpha binaural-beat frequency stimulation while it decreased in the beta band. During alpha and delta binaural-beat stimulation, reduction in CMI was detected among right temporal, frontal, and occipital areas 3.5 min after stimulation onset. However, during beta-beat stimulation, an increase and subsequent decrease in CMI was observed – this occurred between the left temporal and frontal areas (increase), and between right temporal and centro-parietal areas (decrease), and in the case of theta beat stimulation, an increase over left temporal and central cortical areas was observed. These data suggest that application of binaural beats in theta, alpha, delta, and beta frequencies is able to alter functional connectivity between brain regions (37).

Vernon and colleagues applied binaural beats in the alpha (10 Hz) and beta (20 Hz) frequency ranges for 1 min duration over ten trials to evaluate whether a frequency following response (FFR) could be elicited to these frequencies in two separate participant groups. Each trial was interleaved with exposure to a pure tone played at 400 Hz while EEG was recorded from the left and right temporal regions. The authors observed a slight decrease in resting baseline amplitudes for both beat frequencies, from the pre- to post-entrainment and during the experimental session, and participants exhibited reduced alpha activity during the binaural beat on-phase compared to the off-phase (36). In a similar study, Gao et al. (37) investigated the effects of binaural beats applied for a 5 min duration at 1, 5, 10, and 20 Hz. To detect EEG changes due to binaural beats, they analyzed relative power (RP), phase locking values (PLVs), and cross-mutual information (CMI). Relative power in the theta and alpha bands increased during delta and alpha binaural-beat frequency stimulation while it decreased in the beta band. During alpha and delta binaural-beat stimulation, reduction in CMI was detected among right temporal, frontal, and occipital areas 3.5 min after stimulation onset. However, during beta-beat stimulation, an increase and subsequent decrease in CMI was observed – this occurred between the left temporal and frontal areas (increase), and between right temporal and centro-parietal areas (decrease), and in the case of theta beat stimulation, an increase over left temporal and central cortical areas was observed. These data suggest that application of binaural beats in theta, alpha, delta, and beta frequencies is able to alter functional connectivity between brain regions (37).