Extracted Public Domain Article|
The Theory of Brainwave Entrainment |
EEG and the brain's state
EEG (Electroencephalography) technology is used to measure
brain's electrical vibrations from the surface of the scalp.
The resulting EEG pattern will contain frequency elements
mainly below 30Hz. The frequencies are categorized into four
states as follows:
||State of Mind
||0.5 Hz - 4 Hz
||4 Hz - 8 Hz
||Drowsiness (also first
stage of sleep)
||8 Hz - 14 Hz
||Relaxed but alert
||14 Hz - 30 Hz
||Highly alert and
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, later
references to the brain states use the simplification of
assuming that such a single frequency exists.
Entraining the brain to a desired state
If external stimulus is applied to the brain, it becomes
possible to entrain the brain frequency from one
stage to another. For example, if a person is in beta stage
(highly alert) and a stimulus of 10Hz is applied to his/her
brain for some time, the brain frequency is likely to change
towards the applied stimulus. The effect will be relaxing to
the person. This phenomenon is also called the frequency
When the brain's state is close to the applied stimulus,
entrainment works more efficiently. Thus, when doing a sweep
from one frequency to another, the starting frequency should
be as close to your current brain state as possible. The
sweep speed should be such that your brain's state changes
steadily with it, so that the difference never gets very
large. In practice, it is difficult to determine your brain
state without extra equipment (like EEG devices). However,
you can quite safely assume that during the day your brain
is in the beta stage (about 20Hz) and you can start the
sweep from there. If you are already somewhat relaxed, you
can use a start frequency of 15Hz or a few Hz lower.
Stimulating the brain with binaural beat
The easiest way of applying stimulus to the brain is via
ears. Other senses could be used as well, and vision is
actually used quite often (often in addition to hearing).
However, humans cannot hear sounds low enough to be useful
for brain stimulation, so special techniques must be used.
One such special technique used is called binaural beats.
If the left ear is presented with a steady tone of 500Hz
and the right ear a steady tone of 510Hz, these two tones
combine in the brain. The difference, 10Hz, is perceived by
the brain and is a very effective stimulus for brainwave
entrainment. This 10Hz is formed entirely by the brain. When
using stereo headphones, the left and right sounds do not
mix together until in your brain. The frequency difference,
when perceived by the brain this way, is called a binaural
The effect of the audible frequencies
To get a stimulus of 10Hz, you may use tones of 500Hz and
510Hz, or 400Hz and 410Hz, or 800Hz and 810Hz, or so on. The
only requirements are that the tone is heard well enough and
that it is below about 1000Hz. Below 1000Hz, the wavelength
of the skull is sufficiently small so that the sound waves
curve around it.
Altered brain states
As mentioned above, applying a stimulus to the brain will
eventually bring the brain's state closer to the stimulus
frequency. The following paragraphs describe some possible
effects of this.
Helping in meditation
Meditation is essentially about willingly being able to
alter one's brain frequency to a desired state. While
meditators have traditionally used several years to learn
the techniques of meditation, you can now attain the same
effect with brainwave entrainment. No special training or
great discipline is required. Good meditation frequencies
are in the alpha range, from 8Hz to 13Hz.
When a certain brainwave state is experienced and
practiced over a period of time, the brain will "learn" the
state change and it will become easier to self-produce the
desired brainwave state at will. Thus, using brainwave
entrainment, you can expect to get some of its effects later
even without any entrainment.
Reducing learning time
The theta stage (4hz - 7Hz) has been found to increase
learning capabilities. In fact, children spend more time in
theta stage than adults, which probably explains the
accelerated learning capabilities of children.
Alpha frequencies are also useful for learning purposes.
You can play language cassettes, subliminal tapes, etc.
during an entrainment session for a maximum effect.
Reducing sleep needs
Some people have found that half an hour a day of the Theta
stage can replace up to 4 hours of sleep.
Treatment of certain mental diseasesBrainwave entrainment is used in treatment of depression,
low self-esteem, attention deficit disorder, drug and
alcohol addiction and autism, to name a few.
Brainwave entrainment has also been found helpful in
alleviating headaches and migraines.
Some users have also reported increases in their sex drive
as a result of brainwave entrainment.
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