Brain Wave Entrainment

During hypnosis the brain shows a characteristic sequence of brain wave activity. This can now be artificially reproduced through the use of audio tones; a process known as brain wave entrainment.

If you are in a particular state, for example, very anxious, then you will produce a unique 'signature' of brainwaves. This applies equally to other states, such as learning and the focused concentration of competitive sport.

These are states that can take a long time and a lot of physical effort to attain. It is an appealing idea that all that hard work and application could be bypassed and the perfect mental state produced through rapid artificial means.

This page is going to show you how this is done.

• Firstly, we are going to review the different types of brain wave and the states that are generally associated with them.
• Secondly, we will look at hypnosis and the brain wave signatures that have been observed in people while undergoing hypnosis.
• Thirdly we will look at psychoacoustics and brain wave entrainment and how it has been used to produce individual and groups of brain waves to modify peoples' state.
• Fourthly we will look at brain wave entrainment specifically with regard to inducing a hypnotic state.
• Finally there are some links to free and retail software suppliers so you can try it for yourself.

Types of Brain Waves

Brain Waves
Name
Frequency
Characteristics
Lamda
~200Hz
Self awareness, higher levels of insight and information. Tibetan monks that walk barely clothed for days through the snow have exhibited high levels of these. They are difficult to measure and little is known about them. They are carried on the very slow moving Epsilon Waves (<0.5Hz).
Hyper Gamma
~100Hz
Gamma
38 - 90Hz
Important in harmonizing and unifying thoughts processed in different parts of the brain. Combines different perceptions. Suppressed totally by anaesthetic. Found in all parts of the brain. Self awareness and insight.

40Hz
The core frequency. Important in cognition, especially coordinating simultaneous processing in all parts of the brain. Deficiencies exhibit learning difficulties. Produced during hypnotic states.

Beta
12 - 38Hz
Wide awake, alert, focused, analyses and assimilates new information rapidly, complex mental processing, peak physical and mental performance, cannot be sustained indefinitely otherwise exhaustion, anxiety, and tension result.

15Hz-18Hz
Mid Range Beta Neuro-feedback training that produced alert behaviour, useful in depression cases.

12 - 15Hz
Low Beta Also known as Sensory Motor Rhythm (SMR) - vigilance, reduced mobility, shallow breathing, less blinking, fixed attention and eye focus, enhancing through neuro-feedback reduces epileptic symptoms and has a calming effect (ADHD sufferers).

Beta-Alpha
12Hz
Hyper-efficient in processing single tasks as it can focus on the details as well as the overall task at the same time

Alpha
7.5 - 12Hz
Mental coordination and resourcefulness, relaxation, alert but not mentally processing anything, inward focus, calmness, at ease, deep breathing and closed eyes can amplify alpha production, peak around 10Hz.

Alpha-Theta
7.48Hz
Primary ionospheric resonance (Schumann) frequency. Stimulates retrieval of memories from the subconscious.

Theta
4 - 7.5Hz
Memory access, learning, deep meditation, sensations, emotions, the threshold of the subconscious, dreaming.

6.2 - 6.7Hz
Frontal Midline Theta - Cognitive activity, maths problems, sustained attention, extrovert personality, low anxiety

4.5Hz
Shamanic trances, Tibetan mantras, Buddhist chants all use this frequency to access altered states
~4Hz
Object naming

Theta-Delta
~3.5Hz
Long term memory access

Delta
0.5 - 4Hz
Deep sleep, human growth hormone release, low blood pressure, low respiration, low body temperature. No muscle movement - Reticular Activating System (RAS) shuts this down.

Epsilon
<0.5Hz
The state Yogi's go into when they achieve "suspended animation" where no heart beat, respiration or pulse are noticeable.

Brain Waves During Hypnosis
It was thought that alpha wave patterns were characteristic of hypnotic states. It is now understood that it is theta and to some extent delta waves and 40Hz gamma waves that are predominant. Other wave patterns occur, even active beta waves, but these are due to the content of the suggestions and the images created by them.

The sequence seems to run something like this.

• As the you relax and then close your eyes there is a brief build up of alpha waves.
• As the induction (see about hypnosis) develops there is an increase in theta and to a lesser extent delta activity and the alpha activity drops away.
• This continues until the end of the hypnotic deepening.
• During the therapeutic suggestions the brain wave activity can vary depending upon the nature of these suggestions and the effect they are having. Generally during this period the delta and theta wave activity begins to slowly subside.
• Through the whole hypnotic process there is a gradual increase in 40Hz gamma wave activity.
• During termination the alpha activity and finally the normal beta activity returns.
This pattern is especially noticeable in highly hypnotisable subjects.
If you want to read more about this then the following article from the April 2004 issue of the American Journal of Clinical Hypnosis presents some interesting research and a review of previous ideas. See the brain wave research article. 


Psychoacoustics - Binaural Tones
If slightly different audible tones are played to each ear through stereo headphones then as the brain puts these two sounds together it creates brain waves of a frequency equal to the difference of the two tones.

For example, if the left ear was played a 200Hz tone and the right ear a 210Hz tone the brain will respond with a 10Hz brain wave (termed a frequency following response).

If you want to know more about the theory and the research then see the article by Bill Harris at the Centerpointe Research Institute.

Brain Wave Training Hypnotic States
The significance of this is that with a careful choice of frequencies, you can rapidly alter your state.

For example, you can reproduce the patterns of brainwaves associated to falling asleep as the activity descends rapidly through alpha into theta and delta waves.

Many other states have been induced by the method such as learning, meditation and creativity. You can stack and overlap different binaural tones to produce quite complex states. Where somebody shows abnormal brainwave patterns, such as ADHD (Attention Deficit) or psychotic episodes, it is possible to train the brain back into a more normal pattern. The possibilities are enormous, and though research is still in its infancy, you can see how useful this could be both therapeutically and for self improvement.

In the case of hypnosis then you can produce a sequence of tones to mimic the normal course of a hypnotic session. For example:

• A period of alpha waves at the start behind the pre talk, at say 10Hz, a frequency known to stimulate serotonin and produce relaxation
• A gradual build up of theta which will remain the dominant wave pattern, at perhaps a frequency of 4.5Hz. This is the frequency used by Shamanic drummers to induce trance states.
• A gradual build up of delta waves
• Towards and during the reinforcement phase and termination introduce a 'learning' theta frequency at around 4Hz.
• You can try a short period of alpha during termination.
• If the final aim is to feel refreshed and revitalised then end with a beta wave wide awake frequency depending upon the nature of the therapy, for example around 13.8Hz (calming for ADHD) or 17Hz (alert for depression).