Brainwave Entrainment in Sound & Music

Did you know that there are ways to control the fundamental brainwave state of the brain? You probably do it more often than you think! In this article I discuss what Brainwave Entrainment (BWE) is, a little background of existing research and how it can help us all to get some more sleep!...

Altered State

The evidence of music as a means of reaching an altered state is evident across history, from the 1995 discovery of a Neanderthal bear-bone flute dating back 43,000 years, on which was possible to play modern diatonic and pentatonic scales (Boyle, 2013), to the clubs in modern towns and cities; humans’ empathy to music both physically and emotionally is undeniable. In Aristotle’s, Poetics of 335BC, an early literary work partly in critical response to Plato’s view of the moral negativity of art aired in his work Republic, Aristotle discusses the merits of poetry in positive morals and good health, and uses the term psychagogia, which is taken from the literal Latin translation, soul-leading and was contextually applied to the audience, who’s state is described as entranced and transported when captured by the emotional nature of a play (Aristotle, 335BC), an early documented example of how melody and rhythm can be applied to create an altered state.

On a more basic level, many of today’s attention holding and hypnotic past-times and activities all share a common factor, the soothing repetition of sight or sound. Television’s entrancing affect has long been passively observed, as has the mesmerising flicker of a fire and the cyclic rushing of waves crashing on sand or shingle, just to name a few. Although non-BWE relaxation music is widely available and found in varying qualities; can the use of brainwave entrainment (BWE) methods buried in music and soundscapes offer improved sleep for somnipathy sufferers and a form of meditation for the digital age?

Poor Sleep!

Somnipathy, or abnormal sleep and sleep disorders such as insomnia, affect around 30% of the adult UK population on a regular basis (Sleep Matters, 2011) and recent studies such as the Sleep Matters study by the Mental Health Foundation in 2011 have shown that poor sleepers are more prone to poor physical health. The notion of the dangers of sleep deprivation and tiredness has permeated culture in several different guises; tiredness and fatigue is often cited, and previously televised Government campaigns attribute these to being a contributing factor in many road traffic accidents. The UK’s Department for Transport’s, Fatigue and Road Safety: A Critical Analysis of Recent Evidence, probes and analyses patterns in statistical evidence from 2000 to 2010 to determine the extent in which tiredness contributes to road accidents. In summary, it indicated that the implications of tiredness on driver safety does not just result in momentary lapses in concentration and micro-sleep that has previously been contributed to causing accidents, but also the detrimental effect of tiredness on reaction time and alertness (Jackson et al., 2011).

Vas supports this concept further in her 2004 book Meditation, by discussing the means in which observable improvements can be seen in working productivity; reporting of the experiment conducted by a R.W. Montgomery, a chemical factory owner in Detroit asked his employees to meditate for 20 minutes in the morning before work and 20 minutes during the day, 52 of 70 workers agreed and over the course of the next three years sick days taken fell by nearly half, productivity more than doubled and it was reported that profits increased over 500% (Vas, p.52). Could brainwave entrainment in music be used as the meditative medium to improve sleep and its related detrimental effects?

What is Brainwave Entrainment?

Brainwave entrainment is the process of using an external stimulus or stimuli to control the frequency of the brain’s overarching electrical impulse by creating synchronicity between the stimulus frequency and the brain’s frequency (brainwave). This is thought to be directly linked to the states of consciousness experienced by human beings, ranging from the different stages of sleep to hyper-activity.

The three main stimulus methods that have previously been employed to deliver these synchrony-seeking frequencies are auditory, visual and both auditory and visual coincidentally. The first documented case of employing brainwave entrainment was by French Psychologist Pierre Janet, who in 1889 reported that hospital patients experienced “reductions in hysteria and increased relaxation when exposed to flickering lights” (Budzynski, ND). Berger confirmed the physiological effect of external visual stimuli on the brain in 1929, when he demonstrated that the brain emits an electrical impulse in response to the input stimulus. Adrian and Matthews further built upon this in 1934, when they simultaneously used visual and auditory stimuli at the same frequency to demonstrate that the power of the physiological response to the input stimulus grew largely with the combination of impulse sources (Goodin et al., 2011)

More organically occurring examples of this can also seen throughout history, is it a coincidence that the victims of the tragic slave trade used chant and song and unwittingly created a new genre of music, the blues; when they were being subjected to the exhausting hardship and drudgery of their existence through racial persecution? Certainly it could be argued that the repetitive nature of the vocal melodies could have contributed to attaining an altered state, even if just to a minor extent.

The brain’s ability to respond to a sensory input with a sympathetic electrical impulse is the main operation process that allows BWE to function. This has been proven by a number of studies, extensively by Kinney, McKay et al. study 'Visual evoked responses elicited by rapid stimulation 'in 1973 coining the term ‘cortical evoked response’, published in the 34th Journal of Electroencephalography and Clinical Neurophysiology. It also drew a poignant and note-worthy analogy between the brain’s electrical response to visual/auditory stimulus to sympathetic resonance of solid objects and instruments from mechanical air pressure.

The selection of specific frequencies to achieve a desired affect through BWE is well documented and throughout this research a clear pattern has emerged to the specific frequency (Hz) bands and their associated different states of brain activity, they name taken from the Greek alphabet. The below table is complied from existing experimental studies.

Table of Brainwave Entrainment Frequencies
Brainwave Entrainment Frequencies

What is particularly interesting is that the 3 slowest frequency waves align respectively with the four different stages of sleep, which is discussed further into this document.

Shattacharya et al. also proved during the experiment evaluating the effectiveness of gamma band (25-100Hz) stimuli, that when musicians were exposed, they had a stronger synchronicity between stimuli and brain frequency than non-musicians.

In current auditory BWE research practice, there are three methods of practical delivery of the auditory brain training frequency discussed above; binaural beats, monaural beats and isochronic tones.

  • Binaural beats use a method of neural-occurring phase subtraction to achieve the desired programming frequency. This must be delivered through headphones. The phenomenon is purely exists in the brain. For example, a sine wave of 400Hz through the left channel and 407Hz through the right will result in the brain ‘hearing’ a resultant sine frequency of 7Hz, also due to the neural phase modification that fundamentally allows for the phenomenon to occur, the combined frequency of 7Hz will appear to modulate in amplitude by +/- 3dB.

  • In binaural beats the phase subtraction takes place inside the listener’s brain, in monaural beats use two sine waves which are again combined, but playback occurs through a single audio channel and therefore the phase interaction that generates the programming frequency is created in the audio recording - or the real-world.. A common example of monaural beating is in a phenomenon often experienced during the tuning of a stringed instrument such as a guitar; when 2 pitches are very nearly identical, but vary slightly different and creates a beating-like effect as the fundamentals and harmonics interact in the air and through the mass of the instrument. This is the fundamental operating method of this type of auditory BWE.

  • The most recently explored type of BWE method is isochronic tones. In this method, phase interactions are not used, but the repetitive pulsing of a single sound at the desired frequency is used instead, this can be thought in a similar manner to strobe light that emits on/off signal (it is important to note that no research encountered suggests that pulsating sounds have an effect on epilepsy sufferers). When the audio example is observed, it is clear to see why an alternative method is sought to deliver BWE in a user friendly way.

Accessing BWE

Products in this area of BWE training do exist, but they are limited in their application being mainly computer-based such as dedicated software or YouTube; which obviously limits the users’ ability to find a comfortable environment, however more modern solutions such as mobile phone and tablet apps are becoming more and more common place and offer a potential platform for the delivery of BWE to aid sleep.

The rise of media sharing sites such as YouTube have given a new delivery format to connect with new audiences, a search shows there are many channels that specifically cater for monaural and binaural compositions, with many of these tracks with well over 300,000 views (April 2015), which certainly shows that there are users searching and consuming this type of music and a growing potential audience.


Research exists that investigates the effectiveness of different BWE methods, in both light and sound, although there are no current studies that aim to understand the role that auditory BWE could play in increasing the ability to reach the state of sleep.

Recent clinical studies have concluded that BWE is effective in reducing the effects of pain suffered from headaches migraines, PMS and long term stress. Huang and Charyton evaluated the results from 20 studies that dealt with the physiological effects of BWE. The studies analysed used a range of different methods for stimulation, some used only visual light stimulus while others just auditory, and some used a combination of both of these. Also the frequency of the visual/auditory training pulse varied widely, as did the length of sessions, some only 1 20-minute session where other studies focussed on eliciting responses only from long-term studies, all of the research conducted employed isochronic tones due to the large impact that isochronic tones have over monaural beats (Huang Charyton, 2008). The longer-term studies that included multiple sessions proved to be more effective. The results are varied in relation to the range of ailments that were being targeted, migraines had mixed outcomes from different studies and can only be concluded that further long-term studies would be needed. However, nearly all of the 20 studies investigated shows a positive response to BWE in the reduction of the pain and improved cognitive functioning, much in support of Janet and Berger’s findings, in 1889 and 1929 respectively. Ideally, further evaluation of Huang and Charyton’s hypothesis from their findings of their evaluative study to discover whether long-term treatment with BWE could help improve sleep in somnipathy sufferers.

None of these studies sought to incorporate the use of music in delivering the aural BWE methods such as binaural, monaural or isochronic form. The studies that analysed mood showed no impact on the test subjects’ mood at all, one of these conducted extensively; 60-minute sessions over 60 days, and still found no changes or improvement in mood, with in fact a 0% improvement. It did suggest that the use of a progressively decreasing frequency until the desired frequency was met increased the effectiveness of the BWE sessions that used the technique.

The actual environmental conditions during the practical application of BWE offer far less research to which to draw upon. However, Restricted Environmental Stimulation: Theoretical and Empirical Developments in Flotation Rest is a well-controlled study of the physiological effects of flotation rest and concluded that shares much of the same neural output as shown when test subjects in a twilight state are observed. It is shown how the experience of rest is quite functionally similar to a twilight state (Budzynski, 1990). The development of this type of environment would allow for the testing of increased physiological response that would be expected, due to the compounding nature of auditory and visual BWE, in addition to discovering if an encapsulating environment can play a key role in the delivery of effective BWE music.

Several studies have offered evidence to suggest that music can help improve the sleep of students and older adults, most notably Lai and Good’s 2005 study, concluding that use of soothing music did help those sufferers of minor sleep problems. Specifically, the participants experienced “…significantly better components of sleep quality” which were defined as “…better perceived sleep quality, longer sleep duration, greater sleep efficiency, shorter sleep latency, less sleep disturbance and less daytime dysfunction” in older adults (Lai, Good, 2005). The similarly titled Music Improves Sleep in Students, in 2008 showed a “…statistical significant improve in sleep…” (Harmat et al., 2008).

With the additional use of BWE tones incorporated into the effective soothing music, the fundamental sound-bed to which employ the chosen BWE method could be formed. Certainly, it could be argued that if non-BWE music has been proven to help, why does an alternative BWE method need be sought, but the answer is explained when considering the original sleep survey results, in which is was reported that this has not been an effective sleep aid for everyone, although only 37.5% of participants stated they currently use music to try and help sleep, over half of these respondents said they still suffered from sleeping problems.

The types of music that have been in previous studies investigated are quite limited in breadth stylistically and all upbeat music has been previously avoided, attributed to avoiding auditory over-stimulation. Classical music was popular and used in several of the studies, including Lai and Good’s study. Harmat et al.’s study was also very narrow in its approach to music choice, as this was clearly not the aim of the survey; the music cited as being used was from, ‘Baroque to Romantic-The Most Relaxing Classical (2 CD, Edited by Virgin 1999)’ and no more specific information was given to the specific musical pieces used and no data was generated to give an insight to how the actual musical components affect the listener’s physiological response.

Literature in popular culture such as the widely acclaimed and best selling, Your Brain on Music by D Levitin, covers a wide range of scientific topics to enlighten the way that music is processed in the brain. It includes findings about music & memory, musical perception and reasons behind our love of music. It does not reference sleep directly but does discuss the positive mental impact that music does have and the potential to increase focus and learning ability (Levitin, 2006).

Which Type of BWE is Most Effective?

The type of BWE method (binaural, monaural, isochronic) that is used has an impact on the strength of the sympathetic physiological response.

Interestingly, at least 7 studies have conclusively proven that the use of binaural beats are ineffective in achieving brainwave entrainment (Oyster, 1973. Lane et al., 1998. Le Scouarnec, 2001. Stevens et al., 2003. Kennerly, 2004. Ulam, 2006. Wahbeh et al., 2007. Goodin et al., 2012). This is important for a number of reasons, no synchronicity will occur and therefore no BWE will occur either. The research indicates that there is very little change in the output EEG of the test subject from the control sound of white noise and therefore “…[it was] insufficient to generate entrainment” (Goodin et al., 2012), and resultantly would not be suitable for further investigation in this scenario, notwithstanding, that there are still occasionally uses in clinical neurological functioning tests (Entraining Tones and Binaural Beats, N.D).

Further examples of the effectiveness of BWE can be seen in Thomas and Siever’s ‘The Effect of Repetitive Audio/Visual Stimulation in Skeletomotor and Vasomotor Activity’ which used 30 participants, split into 2 groups of 15. The groups were asked to sit and relax, one experiencing auditory and visual BWE in the alpha frequency (8-12Hz) and the other not, the under-skin temperature and muscle tension were measured and the results concluded that the control group with no BWE stimulation actually showed more physiological indicators to suggest an increase in tension levels, whereas the BWE group had a significant drop in their muscle tension and a raise of body temperature, associated with increased relaxation (Hutchinson, 1999). This specific study is important as it indicates that BWE can increase restfulness and relaxation, which is physiologically similar to first stage of sleep, stage 1 NREM (non-random eye movement) (Stages of Sleep, N.D).

During a waking state, the brain’s overarching frequency is in the Beta range (see fig. 1); this is a relatively high frequency and allows the brain to perform the complex neural tasks that are associated with wakeful activity. This then reduces to a slower Alpha wave as sleep approaches and as stage 1 NREM sleep is encountered, Theta frequency brainwaves are prevalent, contin