Having trouble sleeping? Try listening to Super Sleep, a CD put out by the Monroe Institute that uses a technology called hemi-sync (short for hemisphere synchronization) to help you generate deeply relaxing delta brain waves. The increasingly popular technology can also be used for everything from staying focused for an exam to calming down and reducing pain before, during, and after surgery

In addition to releasing dozens of hemi-sync CDs, the Monroe Institute works with hundreds of doctors and researchers to look more deeply into how and why the method eases a variety of ills.

The basic premise of hemi-sync is that playing different tones in each ear causes the brain to create something called binaural beats. These beats make brain waves perform in formation at whatever level the sound is telling them to; the level of megahertz dictates whether the listener will relax or become more alert. Most of these CDs are accompanied by a voice that leads you through topic-appropriate guided imagery. Others simply embed the sound into classical or new age music. An article in Duke University’s Undergraduate Journal of Science and Technology, Vertices. explains the phenomenon like this: “…for example, when a 400 Hz tone is played in the right ear, and a 404 Hz tone in the left, the binaural beat produced by the brain is 4 Hz. This is a standing wave which in turn can entrain the brain waves. Binaural beats were required by Hemi-Sync technology because it is not possible to record and play on standard audio technology the low frequencies required to tune the brain.” Got that?

Even if you don’t, these CDs can ease everything from stress to chemotherapy. You can find the products here and learn more about the institute here.