I have a collection of binaural beats I listen to daily, including now, as I polish this piece. Recently, I shared my favorite beats with friends. Some loved them. Some were skeptical. It was time to dive into the literature.
Binaural Beats and Brainwave Entrainment
Neurons are sensitive to the frequency of sounds we listen to. A binaural beat happens when we listen to sounds at a different frequency in the left and right ears. The brain’s electrical activity synchronizes its neuronal activity to the difference of frequencies in what is called Frequency Following Response (FFR). For example, when someone listens to a sound in the left ear at a 140 Hz frequency and in the right ear at a 146 Hz frequency, the brain computes the difference of 6 Hz and gets entrained (that’s the technical term) on a 6 Hz brainwave.
Binaural beats and brainwave entrainment are not new. Monks, shamans, and healers have used repetitive drumming and chanting to induce specific states. Meditation can also lead to certain brain states. Binaural beats were first reported by Gerald Oster in 1973.¹ Now, the effect of binaural beats on the brain’s electrical activity can be measured with electroencephalograms (EEG).²
Brainwaves are the measurement of the electrical activity between neurons and are characterized by their frequency- the number of cycles per second in Hertz.
There are five brainwaves:
- Delta brainwaves (1–4 Hz), the slowest brainwaves, are observed when someone is in a deep sleep. These are key for restoration.
- Theta brainwaves (4–8 Hz) are observed when we’re in Rapid Eye Movement (REM) sleep. They’re also observed during hypnosis, when we’re daydreaming, in a flow state, and are completing activities we’ve done a million times on auto-pilot.
- Alpha brainwaves (8–12 Hz) are observed when we’re awake, calm, and present, and the mind is resting, for example, when we’re meditating or immersed in a good book.
- Beta brainwaves (12–38 Hz) are observed when we’re actively engaged in tasks. As opposed to other brainwaves, being in a beta state can drain our energy… wonder why you feel “brain dead” after crunching numbers on excel for a few hours?
- Gamma brainwaves (38 to 42 Hz or even higher) are observed when we’re focused and learning information, with coordination of different brain regions, showing not relaxation but intense concentration. Experienced meditators are often in a gamma state when they meditate on loving-kindness or compassion. These brainwaves have also been observed with musicians.
Binaural Beats to Relax
Binaural beats in the lower alpha and theta range are usually best to induce relaxation. A 2001 study showed that listening to binaural beats in the delta/theta range helped reduce mild anxiety.³ A 2014 study showed that listening to theta binaural beats increased parasympathetic activation, which controls the ability of the body to relax.⁴ A 2022 Randomized Control Trial of patients taking anxiolytics showed that listening to theta binaural beats for 24 minutes reduced somatic anxiety for participants suffering from mild anxiety.⁵
Binaural Beats and Learning and Cognition
Binaural beats have been used to stimulate cognition, and their effect on memory has been studied. Listening to 40 Hz gamma binaural beats led to faster attention processing.⁶ Another study showed that gamma binaural beats enhance training and learning after consolidation during sleep.⁷
Alzheimer’s and Neurodegenerative Diseases
Besides hypnosis, relaxation, and improved cognition, binaural beats could have other applications. Neuromodulation, the alteration of nerve activity, has shown potential for treating neurodegenerative diseases.⁸ An MIT team of scientists showed in the reputable Cell journal that auditory stimulation in the gamma frequency range improved memory and reduced amyloid in Alzheimer’s disease mouse models.⁹
Brainwaves as Biomarkers
The diagnosis of mental “disorders” is not always accurate, leading to treatments that are not as best suited as possible and low treatment efficacy. Measurement of brainwave activity with an EEG, a noninvasive and affordable tool, could be used to diagnose and treat disorders. A study showed that dysregulation in alpha and theta brainwaves were linked to major depressive disorder.¹⁰ Another study observed that increased beta brainwave activity correlated with worsening moods and higher anxiety levels.¹¹ This seems logical when considering we live in a society where we’re increasingly switched on and have less and less time to relax and unwind. REM sleep helps process distressing emotional experiences. A study showed that resilient people who had experienced a trauma but didn’t develop PTSD showed higher theta brainwave activity than people who had experienced trauma and developed PTSD.¹² The measurement of theta brainwave activity during REM sleep could potentially be used as biomarker for PTSD.
A Non-Chemical Approach
Binaural beats and brainwaves are not panaceas. But measuring brainwave activity with EEGs could be an affordable way to get additional information on the brain. When we’re very stressed, telling ourselves to relax doesn’t work. We need tools that act on the parasympathetic nervous system, like breathing and potentially binaural beats.
Binaural beats are not new. As with many other scientific phenomena, science is only now able to measure what humans have experienced for ages. It is important to be able to measure and understand, but I think we also need to trust our inner wisdom.
I believe our body knows what we need. Sometimes I pick binaural beats from their description. Sometimes, I pick some I haven’t listened to for a while. I sense what resonates, the ones I am drawn to, and go with the flow.
1. Oster G. Auditory beats in the brain. Sci Am. 1973;229(4):94–102
2. Karino S, Yumoto M, Itoh K, et al. Neuromagnetic responses to binaural beat in human cerebral cortex. J Neurophysiol. 2006;96(4):1927–1938
3. Le Scouarnec RP, Poirier RM, Owens JE, Gauthier J, Taylor AG, Foresman PA. Use of binaural beat tapes for treatment of anxiety: a pilot study of tape preference and outcomes. Altern Ther Health Med. 2001;7(1):58–63
4. McConnell PA, Froeliger B, Garland EL, Ives JC, Sforzo GA. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal. Front Psychol. 2014;5:1248
5. Mallik A, Russo FA. The effects of music & auditory beat stimulation on anxiety: A randomized clinical trial. PLoS One. 2022;17(3):e0259312
6. Engelbregt H, Meijburg N, Schulten M, Pogarell O, Deijen JB. The Effects of Binaural and Monoaural Beat Stimulation on Cognitive Functioning in Subjects with Different Levels of Emotionality. Adv Cogn Psychol. 2019;15(3):199–207
7. Bernhard Ross, Marc Danzell Lopez, 40-Hz Binaural beats enhance training to mitigate the attentional blink, Nature Scientific Reports, 2020, April 24th, 10(1)
8. Chan D, Suk HJ, Jackson B, et al. Induction of specific brain oscillations may restore neural circuits and be used for the treatment of Alzheimer’s disease. J Intern Med. 2021;290(5):993–1009
9. Martorell AJ, Paulson AL, Suk HJ, et al. Multi-sensory Gamma Stimulation Ameliorates Alzheimer’s-Associated Pathology and Improves Cognition. Cell. 2019;177(2):256–271.e22
10. Fernández-Palleiro P, Rivera-Baltanás T, Rodrigues-Amorim D, et al. Brainwaves Oscillations as a Potential Biomarker for Major Depression Disorder Risk. Clin EEG Neurosci. 2020;51(1):3–9
11. Kirkby LA, Luongo FJ, Lee MB, et al. An Amygdala-Hippocampus Subnetwork that Encodes Variation in Human Mood. Cell. 2018;175(6):1688–1700.e14
12. Cowdin N, Kobayashi I, Mellman TA. Theta frequency activity during rapid eye movement (REM) sleep is greater in people with resilience versus PTSD. Exp Brain Res. 2014;232(5):1479–1485