Possible Effect of Binaural Beat Combined With Autonomous Sensory Meridian Response for Inducing Sleep

Abstract

Sleep is important to maintain physical and cognitive functions in everyday life. However, the prevalence of sleep disorders is on the rise. One existing solution to this problem is to induce sleep using an auditory stimulus. When we listen to acoustic beats of two tones in each ear simultaneously, a binaural beat is generated which induces brain signals at a specific desired frequency. However, this auditory stimulus is uncomfortable for users to listen to induce sleep. To overcome this difficulty, we can exploit the feelings of calmness and relaxation that are induced by the perceptual phenomenon of autonomous sensory meridian response (ASMR). In this study, we proposed a novel auditory stimulus for inducing sleep. Specifically, we used a 6 Hz binaural beat corresponding to the center of the theta band (4–8 Hz), which is the frequency at which brain activity is entrained during non-rapid eye movement (NREM) in sleep stage 1. In addition, the “ASMR triggers” that cause ASMR were presented from natural sound as the sensory stimuli. In session 1, we combined two auditory stimuli (the 6 Hz binaural beat and ASMR triggers) at three-decibel ratios to find the optimal combination ratio. As a result, we determined that the combination of a 30:60 dB ratio of binaural beat to ASMR trigger is most effective for inducing theta power and psychological stability. In session 2, the effects of these combined stimuli (CS) were compared with an only binaural beat, only the ASMR trigger, or a sham condition. The combination stimulus retained the advantages of the binaural beat and resolved its shortcomings with the ASMR triggers, including psychological self-reports. Our findings indicate that the proposed auditory stimulus could induce the brain signals required for sleep, while simultaneously keeping the user in a psychologically comfortable state. This technology provides an important opportunity to develop a novel method for increasing the quality of sleep.

Frontal EEG Asymmetry of Emotion for the Same Auditory Stimulus

“…We observed reduced alpha power over all brain regions during the auditory stimulus. Some studies showed a decrease in alpha power not only with natural sounds but also when binaural beats that induce theta power were played [50]. The auditory pathway extends through the parietal region, including the temporal region located in the primary auditory cortex, and eventually to the prefrontal and frontal regions through serial and parallel processing of sensory information [75].…”

“…This was because the effects of auditory stimuli are transmitted to all brain regions when exposed for approximately 10 min [49], [50]. In addition, the experiments were carried out with participants' eyes closed to reduce ocular artifacts and increase concentration [51].…”

“…Specifically, the auditory component consisted of a stimulation condition (STIM) and a sham condition (SHAM), which were randomly assigned to participants. The STIM was randomly selected from five natural sounds (rain, sea waves, waterfall, forest, and river) on YouTube (http://www.youtube.com) [50], as spatial patterns whilst listening to various natural sounds are similar [52]. This sound was delivered through in-ear earphones at 60 dB [53].…”

“…This measure computes the difference in phase synchronization between pairs of channels. Specifically, wPLI was calculated to minimize the impact of volume conduction and the number of artifacts [27], [50]:…”

The Importance of Rigorous Methods in a Growing Research Field: Five Practices for ASMR Researchers

“…Since then, the number of published papers on ASMR has increased year on year (Figure 1), indicating a growing academic interest in the phenomenon. Researchers have subsequently investigated the triggers of ASMR (Barratt et al, 2017), the physiological concomitants (Poerio et al, 2018), personality correlates and co-occurrences with other sensory experiences (Bedwell & Butcher, 2020;Fredborg et al, 2017Fredborg et al, , 2018Keizer et al, 2020;Lee et al, 2019;McErlean & Banissy, 2017McErlean & Osborne-Ford, 2020), underlying brain regions (Lochte et al, 2018;Smith et al, 2017Smith et al, , 2019a, and developed reliable self-report measures (Roberts et al, 2019) and curated stimuli sets (Liu & Zhou, 2019).…”