Creators of Rhythmic Entrainment Intervention™
Articles and Research on Rhythmic Entrainment Intervention (REI)
Rhythmic Entrainment Intervention (REI) and Central Nervous System (CNS) Arousal: An exploration of why REI may improve listener's ability to fall and stay asleep
Sleep is one of the universal effects of REI, the core technique used in BSR music. Here is a study paper exploring CNS arousal, REI and sleep.
by Jeff Strong, Director, Strong Institute
Rhythmic Entrainment Intervention is a musical program based on ancient therapeutic rhythm techniques used to synchronize brainwave patterns through entrainment and stimulate brain activity through novelty and complexity (Strong, 1998). The REI Custom Program consists of custom-created recordings played as background music that contain complex, unusual percussion rhythms chosen to address the specific issues a person faces. Each client receives a custom-made REI Custom Program designed specifically for his/her needs based on a comprehensive intake questionnaire and interview process.
Data from numerous previous case studies, several pilot studies, and two controlled studies have suggested that listening to specific musical rhythms played at 8 beats per second may facilitate improvements in sleep for people that experience difficulties falling or staying asleep (Strong, 1996, 1998, 2008, 2011).
In these studies it has been observed that listening to the REI music often sped the onset of sleep and aided in facilitating a more restful sleep period. One case in particular is of a 52-year-old female, referred to as M.M.
Good, restorative sleep is an essential component in life and contributes to overall health and general alertness and energy levels. Sufficient sleep is also associated with reduced stress levels, improved memory, and increased mood. In contrast chronic sleep deprivation can increase feelings of anxiety, reduce energy levels, and increase susceptibility to depression. These were all issues for M.M. before starting the REI Custom Program.
As a professional with two separate masters degrees working professionally as a psychotherapist, she was well aware of the negative impacts of her sleeplessness and sought many therapies to help her sleep. Up until she began the REI Custom Program nothing worked for her. Because of her education and employment background, she was particularly capable and articulate in being able to describe her condition and symptoms in way that many other clients cannot.
M.M. described herself as "a mildly depressed, moderately anxious person who has problems sleeping". Her symptoms before starting the REI Custom Program CDs included; difficulty falling and staying asleep, trouble concentrating, speech dysfluency, and generalized anxiety. One of her main concerns was that, because of her inability to sleep and her tendency to fidget at night, she and her husband slept in separate rooms. This had a significant negative impact on their relationship.
She also reported that, because of her low energy levels, depressed mood and anxiety, she wasn't interested in social interactions. Her lack of social interest further stressed her marriage as well as contributed to her feeling of isolation from her friends and family.
Despite her efforts at practicing good sleep hygiene, which included taking a bath before bed, going to bed at the same time each night in a dark, quiet room, and avoiding alcohol and large meals before bedtime, she still had difficulty getting to and staying asleep. She also reported that she felt she didn't sleep deeply enough to have dreams and when she used melatonin she reported that she often experienced nightmares when she did finally fall asleep.
Upon starting the REI Custom Program, M.M. described that the CD "was a pleasant experience to listen to" and that for the first few days she experienced a "rush of energy" that was unusual for her and bordered on uncomfortable. This energy rush passed after three days and was replaced by an energy level that was still higher than before starting the REI Custom Program but wasn't uncomfortable for her. She described that she had more energy "just to be" and found herself able to socialize more.
She reported that she began sleeping after three days of listening to the mid-morning CD#1 of the Program. She described that she would fall asleep within 1/2 hour of going to bed and would sleep deeply for 7.5 to 8 hours. She also related that for the first time in her memory she was having pleasant dreams every night.
She found that the listening volume needed to be very low for her, as evidenced by one day playing the CD while in the shower and turning it up loud enough to hear over the water. She was irritable the rest of that day. This is not uncommon for sensitive people, so it was suggested that it would be best to alter the week three protocol to ensure that the transition from CD#1 to CD#2 would not over-stimulate her and cause her mood or sleep to be disrupted. It was recommended that she alternate days (CD#1 day one of week three, CD#2 day two, CD#1 day three, and so on) instead of playing both CDs alternately each day as it typical for the REI Custom Program.
At the end of three weeks, M.M. described that listening to CD#2 gave her more energy during the day and didn't disrupt her new deep sleep patterns. The biggest impact for her aside from consistently having restful sleep, was that she was less anxious and her mood was elevated. She was enjoying more social contact and wasn't tired during the day.
As the REI Custom Program progressed over the ten-week duration of the Program, she continued using CD#2 in mid-morning and continued to have about 8 hours of sleep each night. She described that the CDs "were an important part of my day: A part that I look forward to".
Aside from improvements in her sleep M.M. felt fewer feelings of depression and anxiety. Her concentration also improved, most likely as a result of no longer being sleep-deprived. And probably most importantly, she and her husband we able to sleep in the same bed. This improved their sense of intimacy. She was also more socially connected to her family and friends, which further increased her sense of well-being.
Rhythmic Entrainment Intervention was derived from two traditional therapeutic rhythm techniques that have been employed around the world. One rhythmic technique, termed Shamanic drumming, has been used to alter consciousness for tens of thousands of years. Shamanic drumming is the world's most prevalent rhythmic technique and can be found in nearly every part of the planet. According to anthropologist Michael Harner, this technique is "...strikingly similar the world over, even for peoples whose cultures are quite different in other respects, and who have been separated by oceans and continents for tens of thousands of years." (1990). In some places today, such as Nepal, you are still more likely to be treated by a traditional Shamanic practitioner than a Western-trained medical professional (Cook, 2004).
The shamanic drumming technique uses a simple, repetitive pulse at approximately 4-5 beats per second. This drumming rhythm is used to help the healer enter a specific altered state of consciousness, referred to as the "shamanic state of consciousness (SSC)" by Harner (1990). The SSC is considered a meditative state where the healer "journeys" to an unseen word to diagnose the patient's condition or to facilitate healing through specific rituals.
This simple drumming technique is part of the shamanic practice in nearly all the cultures that employ shamanic healing throughout the world. Cultures that don't use the drum use hallucinogens such a peyote or ayahuasca. According to many anthropologists, including Harner, the altered state of consciousness produced by the drum is similar and every bit as all-encompassing as the effects of the hallucinogenic substances. One advantage to drumming is that a skilled shamanic healer can more easily and predictably control the level of the altered state of consciousness and end it at will.
The second traditional therapeutic rhythm approach that forms the basis of Rhythmic Entrainment Intervention is referred to as rhythm-healing. Rhythm-healing distinguishes itself from shamanic drumming in that the rhythm used is dependent on the patient and his symptoms (Diallo and Hall, 1989). This technique is most prevalent in Africa, but can also be found in places where shamanic drumming was also used including indigenous people in North America (Cook, 2004).
This technique historically uses a similar tempo rhythm (typically between 5 and 6 beats per second), which also is used to alter consciousness through entrainment. This is viewed as spirit possession - the listener enters an altered state of consciousness and is "possessed" by the spirit of an ancestral healer (Wilcken, 1992, Davis, 1998). Another aspect to rhythm-healing is that rhythms used are often unique to each person and are complex and variable in contrast to the steady, repetitive shamanic rhythm (Diallo and Hall, 1989).
Rhythmic Entrainment Intervention relies on two aspects of the nervous system to influence consciousness: 1) auditory rhythm can drive the frequencies of the brain. This is called auditory driving. 2) Novel auditory stimulus can increase neurological activity and to allow the brain to entrain to the alpha state of consciousness.
Research on auditory driving can be divided into three basic categories: drumming, tone bursts, and beat frequencies.
Drumming: Early research into the ability of repetitive drumming to direct consciousness showed an entrainment mechanism (Neher, 1962, Jilek, 1975) but left many questions as to why this was happening. A study conducted in 1993 answered many of the questions still remaining about the ability of repetitive drumming to drive brain wave states (Maxfield, 1994). In this study, Maxfield showed a direct correlation between the tempo of the rhythm played and the brain wave activity in the listener's brain. Maxfield also showed that the rhythm need not be repetitive in order to facilitate this entrainment response. This aspect of drumming for directing consciousness is important because auditory driving mechanisms have been less effective at an alpha tempo than theta due to habituation.
By being able to vary the rhythm, habituation becomes much less of a barrier to initiating auditory driving. A variable rhythm is a crucial component when attempting to drive the brain into an alpha level of activity, because a repetitive pulse in the alpha range causes habituation before entrainment can commence.
Beat Frequencies/binaural beats: Beat frequencies and binaural beats are pulsations that the brain perceives when two dissimilar tones are heard bilaterally. Beat frequencies were the results of research conducted by businessman Robert Monroe in the 1960's and 1970's. Considerable study has been done with beat frequencies and binaural beats (Owens & Atwater 1995; Hiew 1995; Hink, et al, 1980; Foster 1990; Oster, 1973; Sadigh, 1990).
Tone Bursts: Over the last twenty years researchers have been experimenting with computer-generated, repetitive rhythms called tone bursts (Kalluri S, Delgutte B., 2003; Joris, et al, 1994). Tone bursts use the same basic approach as ancient shamanic drum rhythm except the white noise tone used theoretically eliminated any interference caused by the frequencies produced by the drum. This interference was suggested by Jilek but was observed by Maxfield not to be an issue.
Another reason tone bursts have become many researcher's method of choice is that beat frequencies have proven to have limitations, especially at alpha, and using a computer generated white noise rhythm employs a higher technology than using a drum. This makes it more attractive to researchers.
A recent survey of brainwave entrainment (BWE) research concluded that, "Findings to date suggest that BWE is an effective therapeutic tool". (Huang T L, Charyton C., 2008)
Novel Auditory Stimulus
Research on novel auditory stimulus suggests that listener's brain activity increases with the introduction of a novel stimulus are part of the CNS orientation response (Knight, 1996). Familiarity causes a decrease in neuron firing response (Rutishauser et al, 2006). It has also been shown that novel rhythmic stumulican increase brain activity even for people with severe neurological disorders (Parsons, 1996, Rossignol, S.; Melvill Jones, G. 1976, Scartelli, 1987).
Entrainment to the alpha state of conscious has been shown to be difficult with auditory driving techniques when the stimulus is repetitive. Though, Maxfield showed that a drumming rhythm needn't be repetitive in order to entrain the brain. REI Rhythms use an underlying pulse at 8 beats-per-second but also include a complexity of accents, thus creating variable rhythms able to sustain attention long enough for entrainment to alpha to take place (Strong, 2008). Binaural beats and tone bursts can't be varied in the same way as a well-played drum, making them very repetitive, thus causing habituation problems at faster tempos such as those in the alpha tempo (Strong, 2008).
Results that have been observed with improved sleep suggest that listening to REI rhythms synchronizes the listener's nervous system, allowing one to shift states of arousal. REI employs non-repetitive auditory stimulus at an 8 beat-per-second tempo. This tempo correlates with an alpha state of consciousness, often referred to as a pre-sleep state. Synchronizing to the pre-sleep state allows the listener to fall asleep from this state naturally.
The variable, complex rhythms aid the synchronization to the alpha state of consciousness by keeping the brain engaged long enough for entrainment to occur. The complexities of the rhythms seem to have an effect of helping the listener develop better sleep patterns. It is currently unknown how this occurs. Future research will explore this correlation.
Research to date, as well as clinical observations, suggests that listening to 20 minutes of complex, non-repetitive auditory rhythms can have positive effects on the listener's sleep. The mechanisms involved may include auditory driving, but may also be the result of neurological organization.
Future research will attempt to further document the clinical effects and well as explore the outcomes and the mechanisms involved.
David, R. American Voudou: Journey into a hidden world. Denton. University of North Texas Press, 1998.
Diallo, Y. and Hall, M. The Healing Drum: African Wisdom Teachings. Rochester, Vermont: Destiny, 1989.
Cook, P.M (2004) Music Healers of Indigenous Cultures. Bainbridge Island, Open Ear Press, 2004.
Harner, M. The Way of the Shaman. 3rd ed. New York: Harper San Francisco, 1990.
Hiew, C.C. (1995). Hemi-Sync into creativity. Hemi-Sync Journal, XIII(1), pp. iii-vi.
Hink, R.F., Kodera, K., Yamada, O., Kaga, K., & Suzuki, J. (1980). Binaural interaction of a beating frequency following response. Audiology, 19 , pp. 3643.
Huang T L, Charyton C. A comprehensive review of the psychological effects of brainwave entrainment. Alternative Therapies in Health and Medicine 2008; 14(5): 38-50.
Jilek, W.G. Salish Indian Mental Health and Culture Change: Psycho Hygienic and Therapeutic Aspects of the Guardian Spirit Ceremonial. Toronto and Montreal: Holt, Rinehart and Winston of Canada, 1975.
Joris, P. X., Carney, L. H., Smith P. H., and Yin, T. C. (1994), Enhancement of neural synchronization in the anteroventral cochlear nucleus. I. Responses to tones at the characteristic frequency. Journal of Neurophysiology, Vol 71, Issue 3 1022-1036
Kalluri S, Delgutte B., (2003). Mathematical models of cochlear nucleus onset neurons: II. model with dynamic spike-blocking state. J Comput Neurosci. 2003 Jan-Feb;14(1):91-110.
Knight, R.T. 2006. Contributing of Human Hippocampal Regions to Novelty Detection. Nature. Vol 383, 19 September 1996.
Maxfield, M. "The Journey of the Drum". ReVision Vol. 16, No.2, 1994. 157-163.
Neher, A. (1994). "A Physiological Explanation of Unusual Behavior in Ceremonies Involving Drums". Human Biology 34, 1962. 151-160.
Oster G. (1973). "Auditory beats in the brain". Sci. Am. 229 (4): 94–102.
Owens, J.E. & Atwater, F.H. (1995). EEG correlates of an induced altered state of consciousness: "mind awake/body asleep". Referenced in Complementary Concepts on the Effects of Sound on Consciousness, The Second Annual International Symposium on Dolphin-Assisted Therapy, 1995.
Parsons, L.M. (1996). "What Components of Music Enhance Spatial Abilities?" Paper presented at the VIth International MusicMedicine Symposium, Oct. 10-12, 1996, San Antonio.
Rossignol, S.; Melvill Jones, G. (1976). "Audio-spinal Influences in Man Studied by the H-reflex and its Possible Role in Rhythmic Movements Synchronized to Sound". Electroencephalography and Clinical Neurophysiology, 41, 1976. 83-92.
Rutishauser,U., Mamelak, A.N., Schuman, E. M. (2006). Single-Trial Learning of Novel Stimuli by Individual Neurons of the Human Hippocampus-Amygdala Complex. Neuron 49, 805–813, March 16, 2006.
Scartelli, J. "Subcortical Mechanisms in Rhythmic Processing". Paper presented at the meeting of National Association for Music Therapy, November 1987, San Francisco.
Strong, J. (1996, October). "Rhythmic Entrainment Intervention (REI) as applied to childhood autism". Paper presented at the VI International MusicMedicine Symposium.
Strong J. (1998, February) "Rhythmic Entrainment Intervention: A Theoretical Perspective". Open Ear Journal, 2/98.
Strong J. (2008) A Look at Rhythmic Entrainment Intervention by Its Creator. Dallas. S.I. Focus Magazine, Winter 2008.
Strong J. (2011) "Rhythmic Entrainment Intervention For Adults With Autism: A Pilot Study". Santa Fe. Coherence, Spring 2011.
Wilcken L (1992) The Drums of Vodou, Tempe, White Cliffs Media, 1992.