vity in the brain that can be replicated through controlled stimulation" (Otis, 1989, p. 32).
The synchronized sound and light machine technology is generally based on the principles and research findings described above (Hooper, 1989, P. 26). Flashing a light in an individual's eye, as an example, will cause the individual's brain to resonate at the same frequency. A flash rate of "8 to 12 Hz will produce alpha brain waves," while a flash rate of "4 to 8 Hz" will produce theta brain waves (P. 26). The synchronized sound and light machines represent a technological advance from earlier biofeedback equipment (Flippin, 1989, p. 32).
Six features are typical of most synchronized sound and light machines. These features are as follows:
1. Flashing lights. This feature is the most widely used (Otis, 1989, p. 32). The lights are used variously to produce patterns and images, and to induce brain wave states.
2. Electrical pulses. These pulses are frequently timed to "harmonize with the resonant frequency of Earth's magnetic field . . ." (Otis, 1989, p. 32). Proponents claim "strong healing effects" for the pulses (p. 32).
3. Sounds. Sounds produced by synchronized sound and light machines are "simulated ocean waves, heartbeats, white noise, or tinkly New Age music . . ." (Otis, 1989, p. 32). Such sounds, it is said, help "make to brain resonate." (p. 33).
4. Spoken words. Spoken words are delivered by synchronized sound and light machines in what have been described as "ultra soothing tones." (Otis, 1989, p. 33). It is claimed that such spoken words "help bring on beneficial alpha and theta waves" (p. 33).
5. Motion. The motions created by the machines include swinging, dancing, rotating, and bobbing (Otis, 1989, p. 33). These motions are said to stimulate "the semicircular canal and cilia of the inner ear to transmit signals to the cerebellum while its gives body fluids a beneficial sloshing" (p. 33)....