When you listen to binaural beats/tones, you are actually listening to two slightly different pitched frequencies. Each frequency goes to each of your ears independently. When this happens your brain responds by creating a third tone, making up the difference between the two frequencies. This shift in frequency then shifts your brain’s consciousness and changes your state.
When delta waves are present, our awareness of the external world decreases and shuts off. People with ADD have problems with delta waves occurring when they are trying to focus, and focus and attention become increasingly impossible with stronger delta waves. Studies show a reduction of anxiety, improvements in insomnia, and elimination of headaches when people engage in sessions of delta brainwave entrainment.
Neural oscillations are rhythmic or repetitive electrochemical activity in the brain and central nervous system. Such oscillations can be characterized by their frequency, amplitude and phase. Neural tissue can generate oscillatory activity driven by mechanisms within individual neurons, as well as by interactions between them. They may also adjust frequency to synchronize with the periodic vibration of external acoustic or visual stimuli.