It was not until 1834 - 1835 when an English named Talbot and a Belgian named Plateau demonstrated again the flicker phenomenon.
Sixty years later in 1895 entrainment history took a jump when the illusion of colors produced by flickering light was demonstrated by C. E. Benham through his invention - the "artificial spectrum top."
Few years later (1899), Pierre Marie Félix Janet (1859 - 1945) a French physician, psychiatrist, and philosopher, noticed a change in mental state in his patients. They experienced decreasing hysteria and increasing relaxation when he exposed them to flickering light created by a rotating strobe-wheel illuminated by a lantern behind it.
This is the first known clinical application of brainwave entrainment as a treatment tool in entrainment history.
The 20th century
Entrainment history took a turn 1929 when, Hans Berger, a German psychiatrist, began to publish strange pictures consisting of nothing but wavy lines (he must found Ptolemy's stash) showing the electrical activity - signals - made by the human brain.
The voltage of these signals ranged from 50 to 100 micro volts and at a frequency near 10 cycles per second (Hz). This was called the Berger rhythm (later renamed the alpha rhythm). The signals appeared when the subject was at rest with the eyes closed. The signals disappeared when the eyes were opened or during a task that involved attention. Berger's discovery was initially ignored, but a basic, primitive EEG had been discovered.
Five years later in 1934, E. Adrian and B. Matthews confirmed many of Berger's observations but disagreed with his conclusion of where the rhythm originated.They figured, as had Tonnies in 1933, that this rhythm was associated with mental processes and involved a large number of neurons.
In 1940, James Toman performed a number of simple studies into the effects of flicker stimulation on the electrical potentials of the brain. Toman confirmed the work of Loomis, Harvey and Hobart (1936) which showed that people with strong alpha rhythms responded poorly to entrainment and those with little or no alpha rhythms could be entrained to a wider range of frequencies.
During the 1940's, research was conducted by brain researchers, Adrian and Bartley by implanting electrodes into the brains of animals. They concluded that the system of neurons which generate the alpha rhythm is different from those involved in the evoked brainwave.
Dempsey and Morison (1942) observed the "repetitive sensory response" in response to stimulation of the sciatic nerve . This proved that tactile stimulation also produced entrainment.
In 1946, Walter, Dovey and Shipton introduced the "electronic stroboscope". This produced highly accurate information about the timing of evoked brainwave. They also noted some perceived psychological effects.
In 1959, Dr. William Kroger and Sidney Schneider examined and reported on the unusual effects of the rhythmic flashing coming from radar screens of ships and submarines on radar operators. On several occasions radar operators entered into a relaxed state of mind and others fell into deep hypnotic states while watching signals on the radar screen.
This prompted the construction of the "Brain Wave Synchronizer" by Sidney Schneider. This was a significant step in entrainment history. Kroger stated that between 1957 and 1958, the Synchronizer had been tested on approximately 2,500 patients and subjects, some in groups and some individually.
In 1959, John Barrow, MD, from MIT, studied the effects of random photic stimulation on the EEG output of his subjects. Barrow confirmed Bartley's earlier observations. He deduced that the continuous rhythm of the entrainment frequency is brought about by the brain's system which also generates the alpha rhythm and not the system responsible for the visual evoked response.
During the same year (1959), Robert Ellingson, PhD, of the Nebraska Psychiatric Institute, experimented with the effects of photic stimulation on babies.
In 1959, Chatrian and his colleagues at the Rochester State Hospital, utilized depth-electrode recordings to observe the brain's response to clicks in either or both ears. This study showed with certainty that most of the auditory driving was on the opposite side of the stimulus.
In 1963, for the first time in entrainment history M. S. Sadove, MD, Director of Anesthesiology at the University of Illinois, reported that by using the Brain Wave Synchronizer, he could put over 90% of his patients into a trance, which reduced the amount of anesthesia needed for surgery.
In 1964, Van der Tweel, a researcher at the University of Amsterdam, found that fast on/off changes in the visual stimulus produced harmonics of the base frequency in the brain.
In 1966, Bernard Margolis, DDS, published an report about his use of the Brain Wave Synchronizer to induce hypnosis during dental procedures. He found that patients required less anesthesia, had less bleeding, less fear and anxiety, and a greater control of gagging.
In 1972, Richard Townsend developed a gizmo which produced sine-wave modulation of lights so that the lights turned on and off slowly rather than instantly. He agreed with Van der Tweel's findings that sine-wave modulation of the lamps eliminated the second harmonic of brainwave EEG activity. Townsend is probably the first scientist in the course of entrainment history to use an entrainment system using "goggles" with lights in them.
In 1973 Gerald Oster published an excellent article on the effects of binaural beats. He explained, when tones of different frequencies were presented separately to each ear, pulsation's called binaural beats occurred in the brain.
Also in 1973, Jo Ann Kinney and her colleagues, at the Naval Submarine Research Laboratory in Connecticut, developed a method to determine the visual evoked response (VER) at frequencies of 4 Hz and higher.
In 1975, Williams and West, at the University Hospital in Wales, studied the effects of entrainment on people who meditate and compared that with those who do not meditate. They discovered that subjects who meditate entered an entrainment induced meditative state quicker than subjects who did not meditate.
In 1976, Takahashi and Tsukahara, at the Tohoku University School of Medicine in Japan, published their findings on the influence of color on the photo-convulsive response (PCR). They discovered that the color red at a frequency of 15 Hz was most likely to cause convulsions. They also noted that a convulsion elicited by red stimulation could be prevented by introducing low levels of blue light at the same time.
In the 1980's, Norman Shealy and his colleagues studied the effects of 30 minute sessions of 10 Hz visual stimulation. They measured blood levels of serotonin, endorphin, melatonin and norepinephrine. They saw a drop in the daytime level of melatonin (the hormone that makes you sleep) and large increases in the levels of endorphin, serotonin and norepinephrine (brain chemicals that make you happy).
The increase in norepinephrine and serotonin and the decrease in melatonin meant an increased level of alertness. They also noted that people had better relaxation responses to entrainment than from using self hypnosis, or other methods of relaxation.
During the mid 1980's, Glen Solomon, MD, used an unusual entrainment approach for reducing tension headache using a 'Dzidra Glass'. The maximum "flash" frequency was 3 Hz. Almost all of his muscle tension headache subjects reported complete relief of their symptoms. None of the sinusitis or migraine subjects reported any relief.
Entrainment history shows that research on the effects of audio stimulation continued, but in the course of entrainment history it received little attention. This is probably because visual entrainment could be observed and recorded better than the audio response. So visual stimulation proved to be better at providing a clearer understanding of the brain. The fascination with the visual hallucinations associated with visual entrainment may have also contributed to audio stimulation taking a back seat to visual stimulation.
In 1981, entrainment history turned a corner when Arturo Manns, and others. published a study showing the effectiveness of "isochronic" (evenly-spaced) tones. They discovered that the combination of both biofeedback and isochronic tones produced the deepest relaxation. (Unlike binaural beats - see above.) They saw an overall improvement in their subjects well being. Pain, insomnia and emotional tension were reduced considerably.
The 1980's, saw a flood of many different entrainment devices into the market. This prompted a case study in Neurology by Ruuskanen-Uoti and Salmi.
They documented a case of a woman with no history of seizures, who experienced a visually-induced seizure while using an "Inner Quest" brainwave synchronizer that used red LED's. This was a first in entrainment history.
Entrainment devices aren't the only things that cause visual stimulus induced seizures. Teens and kids playing video games have had seizures, as well.
A 1983 article by Glista and his colleagues documented two cases of teenage boys having seizures while playing video games.
They both had normal EEGs with no history of seizures. The seizures stopped after they quit playing video games.
Once again entrainment history took a different course when in 1986, Joseph Glicksohn at the University of Tel Aviv studied the effects of visual stimulation in relation to altered states of consciousness (ASC). He concluded that an increase in alpha activity from visual stimulation may bring about an ASC, visual imagery or both.
In 1988, D. Siever and Dr. N. Thomas, of the University of Alberta, published research showing that persons with TMJ or chiropractic and muscle tension pain would actually unconsciously increase their muscle tension when asked to relax.
When given brainwave entrainment using an entrainment device, their muscles relaxed deeply and their finger temperature increased, suggesting that subjects entered a meditative or alpha state.
In 1989, D. J. Anderson, of Queen Elizabeth Military Hospital, performed work on the treatment of migraine headaches using entrainment. Of the 50 migraines recorded, 49 were rated by the subjects as being helped and 36 of the 49 were rated as being "stopped." Pre-treatment migraines lasted an average of six hours while post-treatment migraines lasted an average of 35 minutes.
In 1990, the psychologists, Brucato and Abascal, at Mindworks International in Miami, did a study with the Metro-Dade Police department. They discovered that entrainment would produce a reduction in the heart rate, and muscle tension. Another first in entrainment history. In psychological tests, the police showed an improvement in their ability to cope and a reduction in their stress levels - particularly anxiety.
In 1992, Fred Boersma, PhD, and Constance Gagnon, at the University of Alberta, published their study using entrainment devices to treat chronic pain. The study showed a marked decrease in pain.
In 1992, Siever conducted a study to determine the effectiveness of entrainment on jaw relaxation while the jaw was opened. He showed that entrainment would reduce the risk of developing a TMJ (Temporo-Mandibular-Joint) problem (jaw pain) during dental procedures.
In 1992 a paper by Sappey-Mariner and his colleagues from the Department of Veterans Affairs Medical Center in California recorded the effects of visual stimulation on blood flow in the brain and glucose metabolism as observed with MRI (magnetic resonance imaging). They saw an increased cerebral blood flow and deduced that a possible increase in burning of glucose was occurring.
In 1993, Morse and Chow published the results of the effects of using an entrainment device during root-canal procedures.
Data was collected from three groups
(1) a control group (no stimulation);
(2) white light entrainment only; and (visual stimulation only)
(3) white light entrainment and music. (audio and visual stimulation)
The study concluded that using entrainment during a root-canal procedure was an effective method of maintaining a relaxed state.
In 1993, Russell and Carter conducted a blind study on a group of learning disabled boys between 8 and 12 years of age. The children were given 40 sessions of audio visual entrainment stimulation at 10 Hz and 18 Hz. The children showed an average IQ increase of 8 points on the Raven IQ test. For the first time in entrainment history research showed significant improvements in memory, reading and spelling.
In 1994, Siever did an informal study of elementary school children who had ADD. The children were rated by their parents, and the parents reported improvements on all of the questions asked in the study. The impact of entrainment in education is a part of entrainment history that is still being investigated.
In 1995, Rosenfeld, Reinhart, and Srivastava at Northwestern University Did some research on entrainment using visual stimulus. They entrained in the alpha band at 10 Hz and in the beta band at 22 Hz. They found that some people entrained to the stimulus and others didn't. Whether or not the participants entrained depended on their natural baseline alpha and beta activity.
In 1995 and 1996, at the annual conferences of the Association for Applied Psychophysiology and Biofeedback, David Noton, PhD, presented Duncan Anderson's findings of a PMS study.
They note that PMS is a "slow brainwave" disorder and belongs in the group of disorders including Attention Deficit Disorder, Chronic Fatigue Syndrome, depression, and Minor Head Injury. Out of seventeen women who completed the study, 76% experienced a greater than 50% reduction in their PMS symptoms.
Noton concluded that these results reflect that entrainment may be acting mostly by increasing cerebral blood flow and not so much by simply speeding up the brainwaves.
In 1996, Leonard, Telch and Harrington, at the University of Texas observed that a certain entrainment device could easily and effectively generate disassociative states. This device became a tool in studying those with disassociative disorders
In 1996, Russell reported on the effectiveness of using visual and auditory stimulation in helping rehabilitate a four-year post aneurysm hemiplegic.
Improvements were noted in motor control. Feeling and movement improvements were observed in the hands and feet including the improved ability to draw and write.
Russell speculated that entrainment could be stimulating brain cell growth. Russell's study supports the results observed in people with brain injuries.
In 1997, Leonard, Telch and Harrington added to entrainment history by conducting another study - this time to observe the impact of the DAVID Paradise on anxiety produced with by the mental disorder of dissociation.
They observed that after 12 minutes of HemistepTM stimulation, all 101 participants had a reduction in their dissociation anxiety sensitivity and heart rate.
They found that anxiety sensitivity proved to be a better predictor of challenge and dissociation-induced anxiety than dissociation sensitivity.
In 1997, Siever and Twittey completed a preliminary study in treating chronic pain using brainwave entrainment. Of the twelve participants who completed the study, most had pain due to fibromyalgia, lupus, arthritis, TMJ Dysfunction and/or motor vehicle accidents. After eight weeks of therapy, the Visual Analogue Pain scale showed a reduction in pain.
In 1998, Michael Joyce used brainwave entrainment on 30 ADD and eight reading challenged, primary school children. Joyce was able to treat 10 children at a time using a multiple stimulation system. He observed substantial improvements in attention and reaction time and a reduction in impulsivity and variability. In the reading group he observed an 18 month improvement in instructional reading level and a 1/2 year advancement in grade level.
The history of brainwave entrainment is long and the evidence wide. The science behind brainwave entrainment is solid. Thus the field of brainwave entrainment is an growing and developing field.
In fact, there has been over 70 years of research and impressive discoveries in entrainment history. The question that begs to be asked is 'why hasn't it become more well known?'. The truth is that there isn't big money behind brainwave entrainment. It can be utilized with relatively cheap hardware and software. Combine its cost with the idea that something so simple could have such a direct effect on the mind sounds preposterous.
However, most people are skeptical until they experience entrainment for themselves.
Our culture has been convinced that the only answer to life's issues and problems is through expensive drugs. Unlike entrainment there is lots of money to be made creating, marketing and selling drugs. Pharmaceutical giants are evidence of that.
It is inexpensive, easy to use at home and can be a viable solution to a huge variety of problems. Every day more psychologists, mental health clinics, coaches, teachers and professionals are discovering entrainment, and finding it remarkably useful.