As the person relaxes in the hypnotic state, his brain waves decrease in frequency. The lower the frequency of brain waves, the deeper the state, and greater the access to the unconscious. In the hypnotic state it is natural for a person to move from a lighter state to a deeper state and back to again to a lighter state.
Brain waves are very low frequency waves measured in Hertz' (Hz), or number of cycles per second. There are four general categories or levels of brain waves.
BETA (13 and 30 Hz) waves are the highest frequency brain waves. This level of brain activity is considered "normal waking consciousness" and is characterized by rational activity including judgment, analysis, use of language and mathematics, etc.
In Beta, a person is actively thinking and there is usually an inner voice either asking questions or making statements. For example a client may hear their inner voice say: "What is going to happen next?" "Am I relaxed enough?" "I always have anxiety at times like this." "This hurts." "Am I doing this right?" Usually, the more anxiety or pain, the more Beta.
ALPHA (8 and 13 Hz) brain waves are generated when a person is relaxed. Also a normal waking state, Alpha is characterized by relaxation, openness and receptivity. In this state of consciousness a person is able to absorb new information, become more resourceful and at ease, and open to new possibilities.
In Alpha, the conscious mind is closer to the imagination and therefore closer to the unconscious mind. Typical activities where Alpha waves predominate include: listening to music, freeway driving, watching television, walking in nature, and resting with no agenda.
THETA (3 – 8 Hz) is ordinarily considered to be a sleep state characterized by rapid eye movements (REM) and dreaming. In the hypnotic state however, Theta is an awake state where the client can experience vivid inner imagery including sounds, touch and even olfactory perceptions.
In Theta, the client is aware of their surroundings, but not interested in them. Their attention is drawn inward to the dream-like activity in the imagination. In the awake Theta state the client is easily in touch with material that is ordinarily unconscious. The lower range of Theta is particularly rich in imagery.
DELTA (.01 to 3 Hz) is the deep sleep state with no dream activity. Although a person in Delta is ordinarily asleep, it is also possible to be in an awake hypnotic state in Delta. When this happens, the client is unaware of their surroundings, including all body sensations. The client experiences no imagery, and the only sensation is a blissful feeling of peace and contentment.
In trance, the very low frequency of Delta waves is ideal for pain control.