The brain operates by generating and passing electrical signals between some 100 billion neurons. This electrical activity can be detected and recorded outside the brain. The recording of the brains activity is called an electroencephalogram (EEG). EEG patterns, popularly referred to as "brain waves" appear as irregular, somewhat repetitive waveforms with a dominant frequency measured in cycles per second or Hertz (Hz). Brain wave patterns have been recognized as:

BETA WAVES 13-30 Hz -   Alert state, concentration
ALPHA WAVES 8-12 Hz -  Relaxed wakefulness, stress relief
THETA WAVES 3-7 Hz -    Reverie, imagery, meditation, deep relaxation
DELTA WAVES 0.5-2 Hz - Deep sleep

Pulsating sound and light stimulation can produce an "entrainment" effect in the brain. The term "entrainment" refers to the tendency of the brain waves to synchronize with the external stimulation. Light and Sound Machines provide the rhythmic stimulation in the desired brain wave frequency range via goggles with LED lights and headphones. The resulting entrainment of the electrical activity of the brain leads to different mental states.

Benefits attributed to these devices include: