The basis for the study of sound relates to recent scientific advancements, rooted in research conducted in the 1930's and 1940's. It extends much further back as well. Since ancient times, human beings have used sound to enhance altered states of consciousness. In China, with meditation gongs; in Tibet, with metal singing bowls, bells, cymbals and chanting; in India, with tamboura and drums, and through a wealth of musical traditions in numerous other cultures around the globe.
By using a sophisticated intuitive knowledge of how the tuning of the bowls, bells, chanting influence brain function and states of consciousness, the ancients were using the low-tech approach to what is today a rapidly expanding science of sound - the high-tech applications of music and patterned frequencies to expand and control consciousness.
Throughout our lives, we experience many different states of consciousness. Mostly we move through ordinary waking states with varying qualities of mental activity, and into the various levels of sleep. Occasionally, many of us experience extraordinary states in which we are more at peace, particularly alert and aware, or unusually creative. Each of these states has a unique pattern of brainwaves which can be measured and mapped.
Brainwaves are electromagnetic wave forms produced by the electrical and chemical activity of the brain. They can be objectively measured with sensitive electronic equipment - this is the basis for an electroencephalogram, or EEG. The frequencies of these waves are measured in cycles per second, or Hertz (Hz)., Brainwaves change frequencies based on neural activity within the brain.
Some of the most useful and interesting research into the relationship between brainwaves and states of consciousness was done by British researcher C. Maxwell Cade. By using a specially designed EEG brain monitor and an electrical skin resistance meter, he was able to demonstrate a correlation between highly specific states of consciousness and their underlying brainwave patterns. His new type of EEG machine, called the Mind Mirror, mapped brainwaves by measuring the activity of fifteen different frequencies. This detailed picture of brainwave activity was correlated with subjective and objective measurements of the physical and psychological state of the subject.
While Cade demonstrated that mental states reflect a complex blending of various frequencies of brainwaves, it is still quite common, and in some ways useful, to identify and discuss four bands of brainwave frequency:
Beta waves (frequencies ranging from 13 to 30 Hz) are most typically associated with normal waking states in which we are focused on external stimulus. Beta is born out of our basic survival orientation, and is most present when we are computing, arranging, and organizing - sorting out and making sense of the external world. Beta affords the quickest response and allows us to attend to the largest number of things. Beta is increased in moments of stress or anxiety, enabling us to manage situations and solve immediate problems.
Alpha waves (frequencies ranging from 7 to 13 Hz) indicate an alert state with a quiet mind. In this state, attention may be focused outward for problem-solving, or inward to achieve an alert meditative state. Alpha may be dominant in states of focused concentration or in the attainment of a still inner center. Increased alpha is often present in the brainwave patterns of people who practice meditation, yoga and tai chi, for example.
Theta waves (frequencies ranging from 3 to 7 Hz) reflect a mind state that is attuned to visualization, imagery and creative inspiration. These waves tend to be produced during deep meditation and daydreaming. Theta waves are dominant during "rapid eye movement (REM) sleep, when most dreams take place. In their waking appearances, theta waves indicated access to intuitive knowledge and deeply-rooted imagery. Theta is often associated with creativity and artistic endeavors.
Delta waves (frequencies ranging from 0.1 to 3 Hz) are associated with the deepest levels of physical relaxation. The slowest of the brainwave frequencies, delta is the rhythm of dreamless sleep. As such, its presence is usually associated with the processes of physical rejuvenation and healing.
Resonant entrainment is a well understood principal within the physical sciences. In 1665, Dutch scientist Christian Huygens discovered that two pendulum clocks mounted side-by-side on the same wall would gradually come to swing at the same rate. He found that this held true consistently as if they wanted to assume the same rhythm. From his investigations sprung an understanding of what is today termed entrainment. In the case of the two pendulums, one is said to entrain; the other to its frequency.
Similarly, if a tuning fork designed to produce a frequency of 440 Hz, for example, is struck, a second tuning fork in its vicinity (similarly designed to vibrate at 440 Hz) will begin to vibrate. This "sympathetic vibration" is also an example of entrainment. The first tuning fork is said to have entrained the second.
So strong is the natural tendency towards entrainment that in one interesting experiment a researcher set up a wave of a desired frequency in a water bed. When a research subject rested on the bed, the resulting tactile signals were effective in entraining the subject's brain waves to the selected frequency.
This same principal of entrainment can be applied to influence human brainwave patterns. Studies using EEG equipment to measure brainwaves show a clear correlation between brainwave response and external pulses experienced by the subject. Initially, research in this area used pulsing light flashes, but later this effect was found to work with a variety of different pulse phenomena, including sound pulses and even electromagnetic pulses. If pulses at a consistent frequency are introduced into the brain by visual, audio or electrical means, the brain has a natural tendency to follow, or lock on to their frequency. This is called frequency following response.
Dr. Jeffrey Thompson began experimenting with the effects of sound pulse frequency patterns and their effect on brain wave function in his Holistic Health Center in Virginia in 1981. His ground-breaking discoveries in the use of sound frequency patterns built into musical soundtracks for brain entrainment are the result of private session research with hundreds of patients. Dr. Thompson utilizes the process of entrainment, the power of soothing music and sounds of nature. Each recording contains a specific pattern of brainwaves, thus allowing the subject to select the brainwave pattern he wants to stimulate in the brain, and thereby orchestrating a specific state of mind.
During all the imagery experience we do, the use of music is very important. Music should be soft background, and carry a slow rhythm. Utilizing the process of entrainment, the body will begin to relax just by listening to the calming music. Make sure that the piece you select for your imageries has no lyrics, and also does not carry a recognizable melody. Clients can sometimes get lost in trying to recognize a particular piece of music and get distracted.
Remember, music should be used to help the client relax, lowering the brain waves to that Alpha place. The music should not be distracting, or too loud to be disruptive.