In the late 1960's and 1970's we learned that it was possible to recondition and retrain brainwave patterns. Some of this work began with the training of alpha brainwave activity for relaxation, while other work originating at UCLA focused on uncontrolled epilepsy. This training is called EEG biofeedback or neurofeedback. Brainwaves occur at various frequencies. Some are fast and some are quite slow. The classic names of these EEG bands are delta, theta, alpha, and beta. They are measured in cycles per second or hertz (Hz).
Beta brainwaves are small, faster brainwaves (above 13 Hz) associated with a state of mental, intellectual activity and outwardly focused concentration. This is basically a “bright-eyed, bushy-tailed” state of alertness. Alpha brainwaves (8-12 Hz.) are slower and larger. They are associated with a state of relaxation and basically represent the brain shifting into an idling gear, relaxed and a bit disengaged, waiting to respond when needed. If we merely close our eyes and begin picturing something peaceful, in less than half a minute there begins to be an increase in alpha brainwaves. These brainwaves are especially large in the back third of the head. Theta (4-8 Hz) brainwaves represent a day dreamy, spacey state of mind that is associated with mental inefficiency. At very slow levels, theta brainwave activity is a very relaxed state, representing the twilight zone between waking and sleep. Delta brainwaves (0-3.5 Hz) are the slowest, highest amplitude brainwaves, and are what we experience when we are asleep. In general, different levels of awareness are associated with dominant brainwave states.
Each of us, however, always has some degree of each of these brainwave bands present in different parts of our brain. Delta brainwaves will also occur, for instance, when areas of the brain go “off line” to take up nourishment. If we are becoming drowsy, there are more delta and slow theta brainwaves creeping in, and if we are inattentive to external things and our mind is wandering, there is more theta present. If we are exceptionally anxious and tense, an excessively high frequency of beta brainwaves is often present. Persons with ADD, ADHD, learning disabilities, head injuries, stroke, Tourette’s syndrome, epilepsy, and often chronic fatigue syndrome and fibromyalgia tend to have excessive slow waves (usually theta and sometimes excess alpha) present. When an excessive amount of slow waves are present in the executive (frontal) parts of the brain, it becomes difficult to control attention, behavior, and/or emotions. Such persons generally have problems with concentration, memory, controlling their impulses and moods, or with hyperactivity. They can’t focus very well and exhibit diminished intellectual efficiency. (D.C Hammond, 2004)