Wednesday, December 05, 2007

Brain Entrainment: Science or Science Fiction?

In my last two sessions, the topic of the effect of binaural beats on the brain, also called frequency following response or brain entrainment, came up. So I checked into the research and was surprised at what I found. There is no evidence to support the benefits of binaural beats, and one pilot study showed that it was harmful (Wahbeh, Calabrese, Zwickey, and Zajdel, 2007).

First, what is it? Binaural beats refers to hearing a sound at one frequency in the left ear, then hearing a sound of another frequency in the right ear. The brain averages the signal and supposedly entrains itself to the frequency. When the frequency matches that of a particular brain wave, the brain produces more of that wave.

All of the studies I saw were poorly designed. In order to measure this effect, you need several control groups:

--Several groups that hear the binaural beats, then are measured physiologically for relaxation effects. You’d need one group per frequency range. For example, one group should hear binaural beats at 7 Hz, one at 12 Hz, etc.
--One group that did nothing and was measured for relaxation.
--One group that meditated and was measured for relaxation.
--One group that heard silence and was measured for relaxation.
--One group that heard white noise and was measured for relaxation.
--Several groups that listened to various forms of music: Reiki, classical, rock, etc. and was measured for relaxation.

This type of experiment could measure the comparative effectiveness of how the various sounds relax the people in the groups. There were no such study designs like this one.

One study I found that tested subjects at the 7 Hz frequency showed increased depression and poorer immediate memory recall.

The discovery of binaural beats dates back to 1839. The research is dated from the 1960s. My recommendation is to stop wasting your money on meditation aids. You don’t need any commercial gadget to experience the profound effects of meditation. All you need is the will to sit down and shut up for a few minutes each day!