Heinrich Wilhelm Dove first discovered binaural beats in 1839. While research about binaural beats continued, the subject remained merely a scientific curiosity until 1973, when Dr. Gerald Oster of Mt. Sinai Medical Center in New York published a paper in Scientific American entitled, “Auditory Beats in the Brain”. Oster had discovered that binaural beats can create any desired electrical pattern in the brain, including those of a meditative state.
Dr. Oster also thought binaural beats could be used as a diagnostic tool, not just for finding and evaluating hearing impairments, but also for general neurological conditions, since binaural beats involve different neurological pathways than ordinary hearing. As an example, Dr. Oster found that his subjects who could not perceive binaural beats suffered from Parkinson’s disease. In one case, Dr. Oster followed a subject through a week’s treatment of Parkinson’s disease; at the beginning, the patient could not perceive binaural beats, but by the end of the treatment, the patient was able to hear them.
Dr. Oster also reported gender differences in the perception of binaural beats. Women experience two separate peaks in their ability to perceive binaural beats- peaks possibly correlated to specific points in the menstrual cycle, one at the onset of menstruation, and another midcycle. This led Dr. Oster to speculate if binaural beats could be used as a tool for measuring levels of estrogen.
During a series of biofeedback experiments conducted in 1970 and 1971 at the Menninger Foundation, Drs. Elmer and Alyce Green found that these Indian yogis could produce various brain waves at will, including theta and delta brainwaves, and still remain aware of the environment. One yogi voluntarily stopped his heart for 17 seconds. There were also demonstrations of telekinetic powers. These studies gave researchers the first peek at the electrical brain wave patterns of meditation.
The effects of binaural beats on consciousness were first studied by physicist Thomas Campbell, and electrical engineer Dennis Mennerich, under the direction of Robert Monroe. They were seeking to reproduce a subjective impression of 4Hz brainwave oscillation they associated with out of body experiences. On the basis of their findings, Robert Monroe created the technology of binaural beat self development, by forming The Monroe Institute.
Binaural beats may influence functions of the brain besides those related to hearing, in a phenomenon called “frequency following response”. If a stimulus is received with a frequency within the range of brain waves, the predominant brain wave frequency is thought to move towards the frequency of the stimulus, in a process called “entrainment”. Additionally, binaural beats have been documented relative to both spatial perception and stereo auditory recognition, and, in line with the frequency following response, activation of various sites of the brain.
Perceived human hearing is limited to a range of frequencies from 20 Hz to 20,000 Hz, although Infrasound (sound below 20Hz) although not readily audible, especially at low volumes, still has scientifically observable effects on humans. Human brain waves generally fall below a frequency 40 Hz. When the binaural beat frequency corresponds to the delta, theta, alpha, beta, or gamma brainwave frequencies, the brain entrains to the beat frequency. For example, if a 400 Hz sound wave is played into the right ear, and a 410 sound wave Hz into the left ear, the brain will entrain to a binaural beat frequency 10 Hz, which is in the alpha range. Since alpha is associated with relaxation and meditation, this will have a relaxing effect on the brain.
Binaural beat brainwave stimulation has been used to induce various states of consciousness, and there has been some studt done as to the effects of binaural beats on relaxation, focus, attention, and states of consciousness. Studies have shown that with repeated training to distinguish close frequency sounds, a plastic reorganization of the brain occurs for the trained frequencies, and is capable of asymmetric hemispheric balancing.