During the holiday season -- or any time, really -- solid sleep can be a real gift. The not-so-sound sleepers on your shopping list would undoubtedly appreciate anything that would help them get some needed rest.
You can't exactly gift-wrap warm milk and calm thoughts, but you have another option: a CD that promises to put listeners to sleep.
Several sleep CDs offer more than just soothing sounds. The Harmonic Sleep CD from Sound Health Products Inc. sounds like white noise, but it features subliminal "harmonics" that are said to encourage slow, relaxing sleep waves in the brain even though they are too faint to hear. In a similar vein, the Space Age synthesizer music on the Delta Sleep System CD sold by the Center for Neuroacoustic Research contains tones that supposedly match the frequency of delta sleep waves, in theory cuing the brain to make sleep waves of its own.
Users of Harmonic Sleep are told to listen to the CD for 15 minutes before lying down and, if desired, keep it playing through the night. Users of the Delta Sleep System CD are told to put speakers on either side of the bed. People who tend to wake up in the small hours are encouraged to play it throughout the night.
Both CDs are sold at various sites online. The Harmonic Sleep CD sells for about $20. A two-CD set of the Delta Sleep System also costs about $20.
The Sound Health Products website calls the Harmonic Sleep CD a "breakthrough in sleep enhancement" that will give users a "good night of natural, peaceful and deep sleep." Paul Swingle, a Canadian psychoneurophysiologist (as he terms himself) who developed the CD, says brain wave monitors in his office prove that the CD encourages sleep waves in most of his patients. He says the CD is relaxing -- not sedating -- and can even help people with extreme insomnia.
The site for the Center for Neuroacoustic Research says that the Delta Sleep System CD "has saved many, many lives" by "enhancing one's ability to sleep and receive quality, restorative sleep." Encinitas chiropractor Jeffrey Thompson, who created the CD, says that it works by combining physics with biology. "Most people who sell products like this are just entrepreneurs trying to make a dollar," he says. "Being a scientific-minded person makes me kind of unique in the field. It's up to me to say that there's something to this."
The bottom line
Either one of these CDs could potentially help some people drift off to sleep, says Dr. Ronald Kramer, a fellow of the American Academy of Sleep Medicine and a neurologist with the Colorado Neurological Institute in Denver. Some -- but certainly not all -- people who struggle with sleep problems might find a little nighttime music or white noise to be relaxing, he says.
But, Kramer adds, there's little evidence that particular sound waves or subliminal harmonics have any special powers to encourage sleep. "Until I see it in a medical journal, I won't believe it," he says. And until the claims are proven, he says there's no reason to pay extra for harmonics or pseudo-delta waves when you can get a regular CD of calming music or nature sounds at half the cost.
The CDs are highly unlikely to be any improvement over the basic advice for good sleep, Kramer says. He tells patients to keep a room dark and quiet. They should get out of bed if they're having trouble falling asleep. Then they should sit down and do something calming -- perhaps including listening to relaxing music, if that's their preference -- until they start feeling drowsy enough to go back to bed.
An unpublished study of eight insomniacs conducted at the Royal Ottawa Hospital found that the Delta Sleep System did seem to encourage sleep waves and improve quality of sleep. "The study looks promising, but it's just eight patients, so it's hard to draw conclusions," says Dr. Clete Kushida, a neurologist and the medical director of the Stanford Sleep Disorders Clinic in Redwood City, Calif.
Sleep is complicated, Kushida says. Different people have different types of brain activity and different sleep styles, and brain waves in any one person will change throughout the night. In his view, it's overly simplistic to think that a simple sound on a CD could trigger sleep by creating a specific wave in the brain.
Kushida says people may well feel lulled by these CDs. They just shouldn't expect any bedtime miracles.