Effect of Binaural Beats on Affective Symptoms and Performance on the Digit Span Test.

Background Binaural beats (BB) are auditory tones perceived in the brain when two sine waves with different frequencies are played into each ear. Previous studies have suggested potential benefits of using BB for improving concentration and reducing anxiety and stress. In this study, we investigated the effect of theta (6 Hz), alpha (10 Hz), and beta (16 Hz) BB on measures of stress, anxiety, and short-term and working memory. Methods Sixty-three healthy participants were recruited. They were randomly allocated to a different sub-study in which they listened to (1) 6 Hz (n=14), (2) 10 Hz (n=14), or (3) 16 Hz (n=14) BB centred around 340 Hz, or a 340 Hz control tone (n=21), with the pink noise set at 60% and the tones at 40%. Before and after the audio, participants had their blood pressure and heart rate measured, completed a digit span task, and completed the Depression, Anxiety, and Stress Scale-21 items (DASS-21). Electrodermal activity (EDA) data was collected before and during the audio. We compared the percentage change between baseline and during audio exposure for all measures between the BB groups and control group using the Wilcoxon signed-rank test. Results There were no significant effects of any BB on blood pressure, heart rate, or skin conductance nor on performance on the digit span test. DASS-21 total scale showed a trend for reduction in alpha frequency only (p<0.1). Post hoc analyses of subscales revealed a reduction in stress with alpha frequency (p=0.022) and a trend for reduction in depression (p=0.09). Theta showed a trend for an increase in stress (p=0.06). Conclusions Further work is required to determine whether the effects of alpha BB on stress ratings are consistently found. It is possible that BB may be useful adjuncts to clinical treatments in the future.