Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillatory activity, and the implications for psychological research and intervention

Abstract

Binaural beats are an auditory phenomenon that occurs when two tones of different frequencies, which are presented separately to each ear, elicit the sensation of a third tone oscillating at the difference frequency of the two tones. Binaural beats can be perceived in the frequency range of about 1–30 Hz, a range that coincides with the main human EEG frequency bands. The brainwave entrainment hypothesis, which assumes that external stimulation at a certain frequency leads to the brain’s electrocortical activity oscillating at the same frequency, provides the basis for research on the effects of binaural beat stimulation on cognitive and affective states. Studies, particularly in more applied fields, usually refer to neuroscientific research demonstrating that binaural beats elicit systematic changes in EEG parameters. At first glance, however, the available literature on brainwave entrainment effects due to binaural beat stimulation appears to be inconclusive at best. The aim of the present systematic review is, thus, to synthesize existing empirical research. A sample of fourteen published studies met our criteria for inclusion. The results corroborate the impression of an overall inconsistency of empirical outcomes, with five studies reporting results in line with the brainwave entrainment hypothesis, eight studies reporting contradictory, and one mixed results. What is to be noticed is that the fourteen studies included in this review were very heterogeneous regarding the implementation of the binaural beats, the experimental designs, and the EEG parameters and analyses. The methodological heterogeneity in this field of study ultimately limits the comparability of research outcomes. The results of the present systematic review emphasize the need for standardization in study approaches so as to allow for reliable insight into brainwave entrainment effects in the future.

Lightening the Mind with Audiovisual Stimulation as an Accessible Alternative to Breath-Focused Meditation for Mood and Cognitive Enhancement

“…The improvement of most mood measures was very similar between the AVS condition with binaural beats (ELA1) and the AVS control condition without binaural beats (ELA2). This similarity was surprising given prior evidence of neural entrainment and mood improvement from binaural beats 19,33,34 , including our previous discovery of strong entrainment effects from ELA1 but not ELA2 or meditation 16 . One hypothesis is that the mood effects may be independent of the entrainment effects and perhaps dependent on other neuromodulatory effects currently unexplored.…”

“…To more thoroughly investigate this apparent paradox of similar behavioral effects despite different neural effects, we plan to conduct additional analyses combining both data types that would have been outside the purview of this current behaviorally focused investigation. This will be an important contribution to AVS research given that most studies and devices using binaural beats seem to assume that any observed behavioral effects are caused by entrainment or other neural mechanisms without even measuring or testing them 19 .…”

“…These findings, pending further research, position AVS as a new form of noninvasive brain stimulation and neurotherapy. The empirical evidence for the psychological effects of AVS is more mixed, according to recent meta-analyses [1][2][3][4]19 , since many studies have either supported or contradicted the ability of AVS to improve a wide variety of mental phenomena including stress, anxiety, depression, memory, attention and focus, cognitive decline, pain, and sleep. The exciting yet uncertain potential for AVS to enhance the brain and mind is complicated by the relatively few studies on this topic, many of which are under sampled and/or lack rigorous experimental methods of randomization, blinding, and controls.…”

“…A key component of the ELA experience is the embedding of binaural beats tuned to the harmonic progression of the music while simultaneously beating at designated frequencies. Binaural beats were designed as part of the ELA experience for the purpose of enhancing its effects, due to previous evidence of their capacity for neuromodulation and enhancement of mood and cognition 19,33,34 . The ELA experience of audiovisual synchronization with binaural beats represents the AVS condition of primary interest (ELA1).…”

Pentatonic sequences and monaural beats to facilitate relaxation: an EEG study

“…Most of the previous literature on the effects of beats on arousal, cognitive, and motor functions have used oscillations encompassed in the EEG range because the main explication factor was neural entrainment ( Orozco Perez et al, 2020 ; Ingendoh et al, 2023 ). The effects of binaural beats are mainly attributed to their capacity to drive neural oscillations at the beat frequency ( Pratt et al, 2010 ) but also effects of cross-frequency modulations have been reported.…”