It has been well established that every thought, feeling, sensation, and level of awareness has a corresponding brain wave pattern, or frequency. If, on the other hand, you want to determine what level of awareness you want to experience, you can do so by controlling your brain waves. This method of controlling brain waves is not new at all! Long ago – in the 1930’s – researchers found that repetitive light stimulation caused brain waves to follow and pulse at the same frequency. For decades now, some “new age gurus” made use of repetitive sound stimulation, usually of the inaudible and subliminal kind, so that they can cause their captive audiences to be more receptive to their preaching.
From this knowledge of the effects of light and sound stimulation it was but a small step to the development of a variety of Light-Sound devices that you find on the market today. These devices give off light flashes through goggles and sound stimuli, usually through earphones, that will cause the brain to adjust to a desired brain wave frequency and consequently generate the corresponding level of awareness.
In principle, the usual Light-Sound device is a pulse generator into which earphones and goggles are plugged. In other words: if you want to access a specific level of awareness and get the benefits of their corresponding brain wave frequencies, you need to do so with earphones and goggles on your head.
A further development was the introduction of devices that delivered weak electric shocks to the brain, usually through attachments on the ear lobes. The pulse generator of that contraption is in principle the same as with the Light-Sound devices.