Effects of inaudible binaural beats on visuospatial memory.

Abstract

Binaural beats are auditory beat stimulation that produces sounds and induces a specific state of brain wave based on the difference in the frequency of stimulation. This study aimed to investigate the effects of inaudible binaural beats on visuospatial memory at 18 000 Hz reference and 10 Hz difference frequencies. Eighteen adult subjects in their twenties were enrolled, including 12 males (mean age: 23.8 ± 1.2) and 6 females (mean age: 22.8 ± 0.8). An auditory stimulator providing 10 Hz binaural beats stimulation via 18 000 Hz to the left and 18 010 Hz to the right ears was used. The experiment consisted of two 5-min phases, including a rest phase and a task phase involving task performance without (Task-only) and with binaural beats stimulation (Task+BB). A 3-back task was used to measure visuospatial memory. Cognitive ability measured by task performance (accuracy and reaction time) with and without binaural beats, as well as variations in alpha power across different brain domains, were compared using paired t-tests. Compared to the Task-only condition, the Task+BB condition had significantly higher accuracy and significantly shorter reaction time. The electroencephalogram analysis showed that the 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. The significance of this study lies in having verified the independent effects of binaural beats stimulation without any auditory influence, based on visuospatial memory.