The brain is an electrochemical organ, generating a large amount of electrical activity. We have all seen pictures of machines that measure this electical activity in terms of patterns of waves; specifically oscillating at different frequencies. It is known that these frequencies vary according to our different mental and emotional states. It is increasingly easy now to buy bio-feedback devices which can help in achieving relaxation.

Varying brainwave frequencies are generally categorised into 4 types. The highest frequency, fastest, waves are known as Beta waves, oscillating at about 15-40 cycles per second, or Hz. The Beta brainwave state is associated with a heightened state of alertness and focused concentration. When your mind is actively engaged in mental activities, the dominant brainwave state will be Beta. A person in active conversation, playing sports or making a presentation would be in a Beta state.

However, a person in a more reflective mood, awake but possibly day-dreaming, restful and relaxed would be producing slower brain waves in the Alpha range of 8-14 Hz. This condition is more conducive to artistic creativity, lateral thinking. It is said that individuals in this state are open to insight and invention. Theta brainwaves are even slower in frequency and represent a state of deep relaxation, enhanced creativity, stress relief, light sleep and dreaming. The Theta brainwave state corresponds to frequencies ranging from 4Hz to 8 Hz.

Delta brainwaves are the slowest in frequency and represent a state of deep dreamless sleep. This is scientifically well documented. While Delta brainwave states usually only occur in deep sleep, they can also be present when very deeply mentally relaxed, such as when meditating. The Delta brainwave state corresponds to frequencies from 0Hz to 4Hz.

In 1839 the German experimenter H.W.Dove discovered that when 2 separate frequencies of differing wave lengths are presented to the ears, one to each ear, the brain creates a third frequency equal to the difference between the original frequencies and now commonly known as a "Binaural beat". For example, a frequency of 440 Hz ( concert "A") applied to one ear and 430 Hz It may be unsafe to use these products while driving or operating machinery.to the other ear would produce a third frequency in the brain of 10 Hz; an Alpha frequency associated with stress-free relaxation. An even earlier discovery, of isochronic tones, found that short bursts of oscillating sound produce the same effect. Research has proven that introducing a binaural beat will cause the brain to begin resonating in tune with the frequency of that beat. This is called the "Frequency Following Response" and was thoroughly researched and tested in 1973 by biophysicist Gerald Oster at Mount Sinai Hospital in New York City. His research on binaural beats and the frequency following response was published in Scientific American and paved the way for further development in the area of auditory stimulation to enhance brain functioning. To date, an increasing number of products on the market use binaural beats and/or isochronic tones to purposefully produce specific mental and emotional states.