Sensational Differences of Binaural & Percussive Entrainment Methods
By Brendan Bombaci
The reason binaural beats do not typically work upon EEG coherence in human individuals is this: although binaural beats create extra low frequency tones, they are sine waves (very smooth, without “spikes”) rather than percussion or staccato notes. The effect is exactly the same as hearing a musical chord of two notes separated by stereo. This is exactly why so many university scientists use Audio-Visual Stimulation (AVS) which is a method using flashes or impulses, whereas drone- and-sweep binaural beats have not proven clinically effective: unlike impulses or percussive sound, even though the ELF binaural tone is perceived by the listener, it will not automatically cause EEG coherence to the beat frequency. The main problem with audio brainwave entrainment albums available today, then, is that they are too “soft.” To boot, the binaural tones therein are often muddled with interference patterns caused by concomitant vocal meditation guidance, music, nature sounds, and more. The predominant authorities on binaural brainwave entrainment worldwide, who would say otherwise, have been for-profit businesses with no affiliations to academia or medicine. Their methods have never been properly published, and their results have never been peer reviewed, so result repeatability is nonexistent as yet. Binaural beats are still useful, none the less. They alter brainwave amplitude and are also recognized as relative to the way that blind people “see,” in that they create a sort of rotating or oscillating 3D image in the mind. These facts provide the basis for more promising future research in the psychophysiological effects of binaural beating.
In that binaural beats are ubiquitously reported to have psychological and/or physiological effects, it is important to realize what they actually do. In the most recent clinical study,
“EEG signals were acquired from 13 healthy subjects. Five-minute BBs [binaural beats] with four different frequencies were tested: delta band (1 Hz), theta band (5 Hz), alpha band (10 Hz) and beta band (20 Hz). We observed RP [relative power] increase in theta and alpha bands and decrease in beta band during delta and alpha BB stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified.” [Gao at al. 2014]
So, usefully in their own right, they might increase either calm or energy depending on the frequency utilized. A prior but still recent study found no EEG entrainment effects or personality test changes at all with either Theta or Beta brainwave-relative binaural beat frequencies applied to 31 subjects (Goodin et al. 2012). Perhaps more interestingly then, and veritable as it is generally recognized by the psychoacoustic community as an effect relative to the way that blind people “see,”
"It is easy to see that the location [of the perceived sound…] will depend on the interaural time delay, which in turn depends on the direction of the incoming sound. Two tones, a mistuned interval apart, fed into seperate ears, may "foul up" the crosscorrelator: The gradually shifting phase difference between the two tones...will be interpreted by this mechanism as a changing difference in the time of arrival of the left and right auditory signals, hence signaling to the brain the sensation of a cyclically changing sound direction! This is why two pure tones forming a mis-tuned consonant interval, presented dichotically with headphones, gives the eerie sensation of a sound image that seems to be ‘rotating inside the head...’ [Roederer 1975].” [Moore 1983]
Steady-state (punctuated, not oscillating) patterns in audio, light, touch, or electrical charge, can evoke brainwave responses in human beings. With auditory stimuli, this is proven to work with beat frequencies of 1-40hz, where direct frequency matching occurs between 1-5hz, a peak in the Delta band of 3-4hz occurs with Alpha band stimuli between 6-8hz, and brainwaves rise to between 20 and 26hz when stimuli of 14-44hz are presented – the latter being a brainwave range that also occurs in absence of steady state stimulation (Will and Berg 2007). In as much, Theta and Alpha band responses are difficult to produce. Coherence is the term used to describe the listener’s capacity to become neurologically entrained by these potentials. Studies in “Brainwave Entrainment to External Rhythmic Stimuli,” using percussive beats, have been performed by a research team in Stanford University’s Center for Computer Research in Music and Acoustics (CCRMA), and, according to one report,
“coherence in the eyes-closed baseline reflects the number of synaptic connections between recording sites, and the strength of these connections (Thatcher 1992) […and] coherence has been shown to be lower in Alzheimer patients, comatose subjects, and in brain-injured subjects, while it is higher in mentally retarded persons, during sleep, and during epileptic seizures.” [Frederick et al. 2004:3, emphasis added]
Higher coherence while sleeping, particularly, indicates that conscious mentations and sensory distractions keep the stimuli from working well. So it would seem that to be in good neurological health, and in either a focused state or sleeping, is to be more susceptible to the effects of external rhythmic stimuli. Altogether, we can extrapolate that other sounds, music, or speech added to the audio program/test are likely to disable its effectiveness, in that they would create dissonance in otherwise directed attention. The Rhythmic Entrainment Intervention (REI) program, initiated by the Strong Institute (2015), was cited by Stanford University after the above research for being a credible audio brainwave entrainment program retailer.
Although the Centerpointe Research Institute (CRI), one of two major binaural brainwave entrainment companies in the world, has many sources regarding binaural beat recognition and physics on its website, most of them being non-academic (i.e., without peer review), though some are written by degreed individuals (CRI 2015). An example of dubiousness in their assertions is from their credentials page which states how
“Research by Dr. Lester Fehmi, director of the Princeton Behavioral Medicine and Biofeedback Clinic, and perhaps the foremost authority on hemispheric synchronization in the brain, also confirms that hemispheric synchronization and brain entrainment can be induced by binaural beats.” [Harris 2008]
To some feeling of betrayal, closer observation reveals that this particular ‘clinic’ is but an LLC, and has no affiliation with Princeton University, despite the name. It is actually not an academically or medically affiliated organization at all. No less, Fehmi’s research specialization is on meditative intentionality towards controlling biorhythms (Princeton Biofeedback Center, LLC 2015), which introduces a major confounding variable to studying the effects of binaural beat application. The Monroe Institute offers some seemingly more trustworthy credentials with an article from Brady (1997):
“Originating in the brainstem's superior olivary nucleus, the site of contralateral integration of auditory input (Oster, 1973), the audio sensation of binaural beating is neurologically conveyed to the reticular formation (Swann, Bosanko, Cohen, Midgley & Seed, 1982) and the cortex where it can be observed as a frequency-following response with EEG equipment... The word reticular means 'net-like' and the neural reticular formation itself is a large, net-like diffuse area of the brainstem (Anch, et al. 1988)… The RAS regulates cortical EEG (Swann et al. 1988) and controls arousal, attention, and awareness - the elements of consciousness itself (Tice & Steinberg, 1989; Empson, 1986).” [Monroe Products and Hemi-Sync.com 2015]
This is a well assembled assessment, however the goal of EEG entrainment is ultimately to entrain, and, this declaration is only hypothesizing that the EEG response registers in one part of the brain. They, like the Centerpointe Institute, offer no peer reviewed sources exemplifying repeatable brainwave entrainment results (Monroe Products and Hemi-Sync.com 2015b).
Why tout something as promising as energy modulation and spatial awareness training with binaural entrainment as an EEG entrainment device? If binaural perception is literally introducing into our minds a shape or scene which is unaltered in experience from subject to subject… the investment should be in revealing what exact acoustical waveforms (shapes) are created within those ranges.
“Cymatics, the study of wave phenomena, is a science pioneered by Swiss medical doctor and natural scientist, Hans Jenny (1904-1972)... For 14 years he conducted experiments animating inert powders, pastes, and liquids into life-like, flowing forms, which mirrored patterns found throughout nature, art and architecture... What's more, all of these patterns were created using simple sine wave vibrations (pure tones) within the audible range... So what you see is a physical representation of vibration, or how sound manifests into form through the medium of various materials.” [MACROmedia 2008]
Cymatics has been proven to work on a three-dimensional scale as well as such two-dimensional platforms, of course, but not (publically provided) in such chambered forms as smoke or metal fume. That sort of medium may provide us the answers we are seeking regarding the true nature of what “shape” exactly enters the human brain when binaural beats are heard. It would be interesting if, as with increasing complexity of cymatic formations with increasing frequencies, with more complex the standing acoustic waveforms (given complexity with unique timbre), physiological and psychological evoked responses become more complex (the latter of which could be measure by changes in logical or creative/abstract thought). There is promise in this.
Brady, Brian D.
1997 Binaural-Beat Induced Theta EEG Activity and Hypnotic Susceptibility. Research Papers. American Journal of Clinical Hypnosis 43(1):53-69.
2015 Scientific Research Validates Holosync’s Benefits. http://www.centerpointe.com/articles/articles-research. Accessed 18 September 2015.
Frederick, Jon A., PhD, et al.
2004 EEG coherence effects of audio-visual stimulation (AVS) at dominant and twice-dominant Alpha frequency.” Journal of Neuropathy. http://www.mindmodulations.com/resources/Study-frederick-avs-coherence.html. Accessed 18 September 2015.
Gao, et al.
2014 Analysis of EEG Activity in Response to Binaural Beats with Different Frequencies. International Journal of Psychophysiology (94)3:399-406.
Goodin, P., et al.
2012 A High-Density EEG Investigation into Steady State Binaural Beat Stimulation. PLoS ONE 7(4):e34789.
2003 The Science Behind Holosync and Other Neurotechnologies. Centerpointe Research Institute. http://www.centerpointe.com/about/article_downloads/research.pdf. Accessed 18 August 2008.
2008 Cymatics: Insights into the Invisible Realms of Sound.” http://www.cymaticsource.com/cymaticsbook.html. Accessed 10 September 2008.
Monroe Products and Hemi-Sync.com
2015a Binaural-Beat Induced Theta EEG Activity and Hypnotic Susceptibility. Hemi-Sync, by Monroe Products. http://www.hemi-sync.com/hemi-sync-technology/research-papers-articles/binaural-beat-induced-theta-eeg-activityand-hypnotic-susceptibility/. Accessed 18 September 2015.
2015b Research Papers. Hemi-Sync, by Monroe Products. http://www.hemi-sync.com/hemi-sync-technology/research-papers-articles/. Accessed 18 September 2015.
Moore, Richard F.
1983 A General Model for Spatial Processing of Sounds. Computer Music Journal 7(3):6-15.
Princeton Biofeedback Center, LLC
2015 Publications. http://princetonbiofeedback.com/resources/publications/. Accessed 28 September 2015.
2008 BEERT. Stanford University CCRMA (Center for Computer Research in Music and Acoustics). http://www.stanford.edu/group/brainwaves/2006/research.html. Accessed 15 Aug 2008.
2015 REI Custom Program FAQ. Rhythmic Entrainment Intervention (REI Institute). https://www.stronginstitute.com/rei-custom-program/. Accessed 18 August 2008.
Will, Udo, and Eric Berg
2007 Brain Wave Synchronization and Entrainment to Periodic Acoustic Stimuli. Neuroscience Letters 424:55-60.