The pain and frustration of chronic insomnia affects one in 10 American adults, most of whom find no relief from current therapies. Now a new study finds that simply cooling the brain area just behind the forehead can help.

In a study presented this summer at the American Academy of Sleep Medicine’s SLEEP 2011 conference, researchers fit 12 insomniacs with caps that use circulating water to cool the prefrontal cortex. The cap helps the insomniacs fall asleep about as fast—and stay asleep about as long—as adults without insomnia.

“When you get into the neurobiology, insomnia is a disorder of hyperarousal,” says Eric A. Nof­zinger, a psychiatrist at the University of Pittsburgh School of Medicine who worked on the study. In adults with normal sleeping patterns, the metab­olism of the prefrontal cortex decreases as they fall asleep. In insomniacs, however, it increases—corresponding with the incessant worrying or brain chatter that many insomniacs report experiencing. Using the cap to perform a cooling process on the brain called cerebral hypothermia, the researchers were able to reduce the brain’s activity and lull the subject to sleep.

The finding is significant because current treatments such as hypnosis and sleeping pills help only about one in four insomniacs. The cooling cap, which had a 75 percent success rate, may soon offer patients a safe, comfortable, nonpharmaceutical way to enjoy a good night’s sleep. Participants reported that wearing the cap was a “soothing, massagelike experience,” Nofzinger says. “Imagine your grandmother putting a cold washcloth on your forehead.” He hopes that the cap may also prove useful to patients with anxiety and mood disorders, which also involve the prefrontal cortex.