This episode only works with headphones. Binaural beats therapy is an emerging form of soundwave therapy in which the right and left ears listen to two slightly different frequency tones yet perceive the tone as one. Research has shown that when a person listens to binaural beats for a recommended time, their levels of arousal change. The four known categories of frequency pattern include: Delta patterns: Binaural beats in the delta pattern are set at a frequency of between 0.1 and 4 Hz, which is associated with dreamless sleep. Theta patterns: Binaural beats with frequency of between 4 and 8 Hz, which is associated with sleep in the rapid eye movement or REM phase, meditation, and creativity. Alpha pattern: Binaural beats in the alpha pattern are set at a frequency of between 8 and 13 Hz, which may encourage relaxation. Beta pattern: Binaural beats in the beta pattern are set at a frequency of between 14 Hz and 100 Hz, which may help promote concentration and alertness.