What brain wave states are most correlated with deep hypnosis?
Hypnotic states are associated with increased theta wave activity. Hypnotically susceptible participants also exhibit hemispheric beta wave asymmetry, but non-susceptible participants do not (Sabourin, Cutcomb, Crawford and Pribram, 1990).
I am studying hypnotherapy at University and this is what I have learnt.
During the induction stages of hypnosis, the body becomes more and more relaxed and the brain enters changing levels of brain wave pattern. There are five brainwave frequencies, however there are four main different brainwave patterns when looking at hypnosis. These are Beta wave pattern, Alpha wave pattern, Theta wave pattern and Delta wave pattern as measured by an EEG (Electroencephalograph).
In the fully engaged and focused state, the brain will show a Beta wave pattern which is from 15 to 40 cycles per second
In a restful state, the brain will show an Alpha wave pattern which is from 9 to 14 cycles per second
In a deeper state of hypnosis, similar to dreaming and some meditative states, the brain shows a Theta wave pattern which is from 4 to 8 cycles per second
And in the deepest state of hypnosis, the brain shows a Delta wave pattern which is from 1 to 4 cycles per second and it is associated with deep dreamless sleep. The deeper the sleep, the higher the amount of delta waves.
The other brainwave frequency is Gamma (40Hz - 70Hz) associated with Processing of various attended stimuli (visual, auditory, touch) and the grouping of the various features of a given stimulus, particularly visual, into a coherent whole.
An important point is that there is no such thing as a “gamma state” of mind. Gamma waves largely play a supporting – though integral- role in the brain. From an EEG point of view, they will be present mostly while a subject is awake, but they will always be supported by other waves in the beta, alpha, theta, or delta ranges.
Brainwave patterns change in a gradual way. That is to say that it will not switch immediately from say 27Hz (27 cycles per second - Beta Waves) to 2Hz (2 cycles per second - Delta Waves). The frequency of brainwaves gradually decreases and increases as required. The speed of gradual change in brainwave frequency however can be fast or slow depending on the individual and the ability of the hypnotherapist. During reorientation, the brainwave patterns will gradually increase towards the Beta waves bringing the client back to full state of awareness.
All the above mentioned brainwave frequencies are normally present together in the brain. However, the dominant frequency in the EEG pattern determines what shall be called the current state of the brain. If the amplitude of the alpha range frequencies is highest, then the brain is said to be in the alpha stage. Note, that other frequencies still exist and it is impossible to give any "exact frequency your brain is operating on." However, for simplification purpose, it is often assumed that such a single frequency exists.
In general, we are accustomed to using the beta brain rhythm. When we diminish the brain rhythm to alpha, we put ourselves in the ideal condition to learn new information, keep facts, perform elaborate tasks, learn languages and analyse complex situations etc. Meditation, relaxation exercises, and activities that enable the sense of calm, also enable this alpha state. Considered as an integral part of the relaxation process before sleep. The alpha frequency band has been studied extensively in meditations of various kinds (like Zen, TM etc) and in almost all cases an increase in the alpha waves has been noted during meditation.
In the Theta state associated with dreams, deep meditation, sleep, and hypnosis, this is seemed to be involved with short-term memory. It is a state of somnolence with reduced consciousness. The theta-state is described by sleep researchers as stage 1 sleep or the twilight state. In this state, subjects pass out of the alert alpha-state into a theta-state in which they lose their sense of lying in bed, though still being awake.
Subjects can be easily awoken from this stage of sleep, and it has many interesting properties. For a brief time as we lie in bed at night, neither fully awake nor yet asleep, we pass through a twilight mental zone like a state of reverie. Many people associate this drowsy stage with hallucinatory images, more fleeting and disjointed than dreams, and compare it to the viewing of a speeded-up, jerky series of photographic slides. A host of artists and scientists have credited the imagery of this twilight state with creative solutions and inspiration for their work.
Meditative states associated with the increased presence of delta waves seem to occur mostly in very experienced practitioners, possibly because entering a delta state and maintaining consciousness at the same time is tremendously difficult.