AVS Technology

How Does the SST Device Work Using Auditory and Visual Stimulation (AVS) in Simple Terms?
Auditory and visual stimulation (AVS) is a method of brain stimulation and brainwave "entrainment" or training, that has evolved from the study of biofeedback (a training procedure that can enable a person to alter bioelectrical and physiological responses) and brainwave activity, as measured by electroencephalography (EEG).

The SST device (also known as Mind Machines) provides stimuli to the brain through the ears and eyes by means of binaural tones (heard through the headphones) and the specially designed glasses inset with white light-emitting diodes (LED’s). The auditory and visual stimulation provided by the programs in the SST device are typically synchronized with each other. The light emitting from the glasses, as well as the rate in which they flicker, affects the brain through the optic nerve and cause the brainwaves to "entrain," or match to the frequency of the various programs provided, depending on the preferred outcome. The method by which this "entrainment" occurs is known as Frequency Following Response (FFR). Unlike EEG biofeedback, where the object is for the user to deliberately try to calm or train brainwave activity, AVS-induced "entrainment" occurs directly to the brain without any conscious effort.

Here is a brief explanation of some of the brainwave states:

  • Beta brainwave frequencies, or brain states, are measured approximately between 13 and 40 hertz (Hz.), or cycles per second. This state represents our "waking" state of excitement or high alertness. This state, when predominant, results in external attention, but when paired with a stressful psychological stimulus, it can also result in feelings of anxiety.
  • Alpha frequencies are measured at approximately 8 to 12 Hz. and represent a relaxed state that is associated with external attention.
  • The Theta state is measured from approximately 4 to 8 Hz. and represent a deeply relaxed state of inward focus.
  • Delta is known as the "sleep" state, and is measured at 0.5 to approximately 3 Hz.


Researchers have found that induction into higher brainwave states can increase brain activity, while the induction of lower brainwave states can reduce anxiety and hyperactivity. Brainwave entrainment within alpha states, for example, may allow for relaxation and a decreased stress response to occur by providing a slower and more relaxed brainwave state. A faster brainwave state produced by faster flickering of the LED lights can induce a higher brainwave state, and is theorized to provide enhanced brain stimulation, resulting in increased cognitive abilities. A recent study found that higher frequencies may decrease symptoms of hyperactivity and impulsivity, theorizing that this phenomenon may be similar to the paradoxical application of neurostimulant medication used by individuals to address hyperactivity.