What is Audio-Visual Entrainment?
Audio-visual entrainment is a form of brainwave training or stimulation that can be used to stabilize and regulate an individual’s level of alertness and wakefulness. One’s alertness and wakefulness are controlled by arousal, and the degree of arousal of a brain dramatically impacts performance across all areas function. When the brain is under-aroused or over-aroused, an individual experiences stress, anxiety, lethargy, cognitive fog, among other things.
The neural pathway responsible for the brain’s ability to change its arousal levels starts in the deeper structures of the brain that are responsible for regulating arousal levels, one of these structures is called the thalamus. The thalamus communicates directly with the higher cortical areas of the brain where information is further processed to create “feeling” states. In order for entrainment to occur, a constant, repetitive stimulus of sufficient strength to “excite” the thalamus must be present. The thalamus then sends the stimuli to the sensory-motor strip in the cortex and associated processing areas such as the visual and auditory cortices in the temporal lobes where the information is processed.
During audio-visual entrainment pulses of light or beats of sound are presented at specific frequencies. The brain receives this frequency information, and then through the process of entrainment, mirrors this information. As the auditory-visual frequencies change, so do the frequencies in the brain. This results in a slow and safe shift in the brainwave patterns. The new brainwave patterns create various brain states. By manipulating the brainwave frequencies, we can boost mood, improve sleep patterns, and sharpen and increase levels of attention or relaxation.
Audio-visual entrainment produces a dissociative state which is a state of deep relaxation. The individual in this state experiences feelings of profound relaxation and contentment as certain beneficial neurotransmitters such as serotonin and dopamine are released into the brain. The result is a release of stress which allows the brain to return to an optimal state of normal function.
The three auditory sounds often used for the auditory portion of the entrainment are clicks, isochronic tones, and binaural beats. Research has shown that “clicks” produce powerful auditory entrainment (Chatrian, Petersen & Lazarte, 1959). Research has demonstrated that clicks produced as powerful of an effect in the auditory region of the brain as light flashes do at the same frequency in the visual region of the brain. Perceptually, many people report that they do not enjoy the “click” sound indicating that it creates a sense of anxiety. The David Delight device, which is the device we use at our clinic for auditory-visual entrainment only includes Isochronic Tones (Pulse Tones), Binaural Beats, and Monaural Beats.
Isochronic tones are evenly spaced tones which turn on and off. They are an effective auditory entrainment method because they elicit a strong auditory evoked response via the thalamus and most people find them more likable than the “click” tone.
The visual component of auditory-visual stimulation consists of wearing glasses that are equipped with several LED lights which are mounted over a silver reflector behind a translucent screen. These light blink or pulse to a specific frequency. The placement of the lights in the glasses allows for the left and right visual fields of each eye to be individually stimulated rather than stimulating the entire eye.
The maximum intensity of the lights is about 800 lux, spread out over two square inches per eye. This provides a well-distributed illumination throughout the entire visual field allowing you to move your eyes in any direction (either up or down, left or right) without interfering with the smoothness of the light in the visual field.
Who Can Benefit from Auditory-Visual Entrainment?
Auditory-visual entrainment has been shown to be beneficial in the treatment of the following conditions:
- Attention Deficit Disorders
- Sleep Disorders and disturbances
- Learning Disabilities
- Executive Dysfunction
- Generalized Impaired Cognition
- Regulation Disorders
Who Should Not Do Auditory-Visual Entrainment
Under the supervision of a qualified healthcare provider who is trained, auditory, visual entrainment is a very safe and effective method for treating a variety of conditions. However, there are precautions which must be taken for certain populations of individuals. It is recommended that a qualified healthcare professional supervise the treatment of the following conditions:
- Individuals with a history of epilepsy, photic epilepsy, or those who have ever had a seizure
- Individuals with a history of brain injury
- Individuals with a history of psychiatric illness or mental disorders.