Effects of Inaudible Binaural Beats on Visuospatial Memory

Abstract Background Binaural beats (BB) are a form of auditory beat stimulation that produces sounds and can induce a specific state of brain wave based on the difference in the frequency of auditory stimulation. This study aimed at investigating the effects of inaudible BB on visuospatial memory at 18,000 Hz reference and 10 Hz difference frequencies. Methods Eighteen adult subjects in their twenties were enrolled, including 12 males (mean age: 23.8 ± 1.2) and six females (mean age: 22.8 ± 0.8). An auditory stimulator that could provide 10 Hz BB stimulation via 18,000 Hz to the left and 18,010 Hz to the right ears was used. The experiment consisted of two 5-minute phases, the rest and task phases. The task phase involved two conditions: task performance without BB stimulation (Task-only) and with BB stimulation (Task + BB). A 3-back task was used to measure visuospatial memory. Throughout the experiment, brain waves were measured at a 500 Hz sampling rate. Cognitive ability as measured by task performance (accuracy and reaction time) with and without BB, as well as variations in alpha power across different brain domains were compared using paired t-tests. Results The results show that, compared to the Task-only condition, the Task + BB condition had significantly higher accuracy and significantly shorter reaction time. The electroencephalogram (EEG) analysis showed that a reduction level in alpha power for the task performance under the Task + BB condition was significantly lower in all brain areas except the frontal, compared to that under the Task-only condition. Conclusion The significance of this study lies in having verified the independent effects of BB stimulation without any auditory influence, based on visuospatial memory.