The Science Behind Binaural Beats
First discovered in 1839 by scientist Heinrich Wilhelm Dove, Binaural beats use low frequencies of sound to effect changes in the brain. The phenomenon is created when two near identical frequencies of sound are played into each ear, creating a dissonant auditory signal into the brain. The difference is frequency between the two tones creates a pulsating tone at a very low frequency, entraining brainwaves to match the tone. For instance, when a tone of 340hz is played into one ear, while a tone of 330hz is played into the other ear, the resulting binaural beat would be 10hz, entraining brainwaves to match this frequency. Depending on the frequency, brainwaves can be entrained into beta, alpha, theta, or delta frequencies. This range of frequencies represents anywhere from fully awake and alert, to deeply relaxed, and even unconscious states. In order for binaural beats to be effective it is necessary to listen to them on stereo headphones so that each ear receives a different frequency.
The Effects of Different Binaural Beats
Binaural beats are used to create deep meditative states, to relieve tension and anxiety, to increase immune functioning, and to stimulate healing in the body. Binaural beats are marketed as effecting the four different categories of brainwave frequencies: beta, alpha, theta, or delta waves. Beta waves are created in your brain when you are fully awake and alert. Low beta waves are present when you are more deeply focused on a task. Alpha waves are present usually right when you wake up, or right before you fall asleep, and are associated with a relaxed state, increased immune system functioning, and increased mental clarity. Theta waves are created when you are lightly sleeping or in a meditative state. Delta is the lowest of the frequencies, and is generally only present during deep dreamless sleep, or extremely deep meditative states. Delta waves are present when the body is healing and regenerating tissue, and when certain growth hormones are being released in the body. Specific frequencies of binaural beats can be used depending on your health objectives.
Research On Binaural Beats
In a 2005 randomized controlled study conducted at the Sunderland Royal Hospital in England, the effects of binaural beats were observed in patients about to undergo surgery. The research was aimed at studying the possible effects of binaural beats in reducing pre surgery anxiety. The results showed a statistically significant decrease in anxiety among the group of patients who listened to binaural beats before surgery. Decreases in anxiety scores among the binaural beat group were 26%, as compared to the control group, who scored 11%.
In 1998 a study of the efficacy of binaural beats in positively effecting performance and mood was conducted at Duke University Medical Center in North Carolina. The study compared the results of binaural beats on two groups of participants who were alloted the task of completing visual vigilance tasks. While completing the tasks one group of participants listened to pink noise, while the other listened to pink noise with binaural beats. The binaural beats were disguised by the pink noise, keeping participants from identifying which group they were a part of. The results showed that the group receiving the binaural beats experienced an elevation in both mood and performance by the study's conclusion.
Additional Benefits of Binaural Beats
Binaural beats may also increase inter-hemisphere communication between the right and left hemispheres of the brain. In the same way that information from each eye combines in the brain to create one single visual experience, information from each ear is synthesized in the brain to form a single auditory experience. The information from each side of the body is processed in the opposite hemisphere of the brain. For instance, sensory input from the left ear is actually processed in the right hemisphere of the brain, and vice versa. The two hemispheres synthesize one perceptual experience by exchanging information across a band of neural fibers called the corpus callosum. The corpus callosum is the only line of communication between the two hemispheres of the brain.
Because binaural beats create two slightly different frequencies, the brain has difficulty synthesizing one cohesive auditory experience. As auditory information is sent back and forth across the corpus callosum, attempting to make sense of the two similar tones, this connective band of fibers gets strengthened during the process. It is believed that strengthening the corpus callosum may improve memory, mental functioning, and increase mental clarity. More research is needed to verify exactly how binaural beats may increase the functioning of the corpus callosum.
Binaural beats have been shown to reduce anxiety, help reduce insomnia, aid the body in healing, and help people achieve better results during meditation. Binaural beats can be purchased online through any MP3 vendor, and are considered safe for most people. However, if you are prone to seizures, or have been diagnosed with certain psychological conditions such as schizophrenia, you should not listen to binaural beats. Never listen to binaural beats while driving or operating any heavy machinery.
Although first discovered in 1839, it wasn't until the 1970s that binaural beats found their way into popular culture through the published findings of Gerald Oster, entitled, "Auditory Beats in the Brain." Oster's research confirmed previous studies conducted on binaural beats, and found new phenomenon associated with the auditory technology. One interesting finding showed that women who listened to binaural beats were effected differently depending on their menstrual cycle, leading Oster to believe that binaural beats could be used as a tool to gauge levels of estrogen in women.