The diagnosis and treatment of sleep disorders have come a long way in recent years. In the past, people who snored might be advised to sew a tennis ball onto the back of their pajama top. The “snore ball” would discourage them from sleeping on their back and might quiet their droning. Or a doctor might use the “dog index” to measure poor sleep: If your dog generally sleeps with you but by morning has left the bed more than half the time, it may be because you’re such a loud, restless sleeper that the dog has gone elsewhere for some peace and quiet.

How things have changed. Now, doctors with special training diagnose and treat more than 80 sleep disorders – from obstructive sleep apnea to narcolepsy – at special centers with labs where a patient’s every sleeping moment may be recorded and measured.

Insurance usually covers the diagnosis and treatment of sleep problems, with some exceptions. For example, snoring on its own is not a medical problem and insurance won’t cover its treatment, to the great disappointment of many a snorer’s bed partner.

Obstructive sleep apnea, which occurs in at least 2 to 4 percent of Americans, is another matter entirely. The consequences of untreated sleep apnea can be extremely serious.

Sleep apnea is an obstruction of your airway that’s created when the muscles at the back of your throat relax during sleep. The obstruction partially or completely stops your breathing, sometimes for a minute or longer, until your brain alerts your body to wake up and you start to breathe again. This can lead to fragmented, poor sleep as well as reduced oxygen levels, which can worsen such medical conditions as high blood pressure and diabetes and increase your risk of heart attack and stroke.

As awareness of the problem has increased, so has demand for testing and treatment. Patients with suspected sleep apnea are typically sent to sleep centers where they are evaluated overnight while they sleep. In the past 10 years, the number of accredited sleep centers has grown from 566 to 2,258, according to the American Academy of Sleep Medicine.

Snoring is a common symptom of sleep apnea, but some experts say sleep studies may be overprescribed. “Everybody who snores doesn’t need a sleep test,” says Fred Holt, an ear, nose and throat surgeon in Raleigh, N.C., and an expert on sleep apnea who consults on anti-fraud issues for attorneys, medical auditors and investigators. The risk of developing sleep apnea is higher in people who are overweight, male, middle-aged or older, or smokers.

Medicare payments for sleep lab testing have increased from $62 million in 2001 to $235 million in 2009, according to the Department of Health and Human Services’ Office of the Inspector General, which is conducting a study to review the appropriateness of Medicare payments for them. The study is due next year.

There are home sleep tests for problem sleepers as well, and their use is also on the rise, say experts. Rather than measure more than a dozen body functions while a person spends the night in a sleep lab hooked up to sensors, home sleep tests measure only a few functions while patients sleep in their own beds. Their cost is a few hundred dollars vs. up to $2,000 for a night in the lab.

Insurance will generally cover either type of test if it is prescribed by a physician. But while home sleep tests may mean a smaller bite out of your wallet if you have a co-payment or a high-deductible plan, they’re not the best choice for everyone, sleep experts agree. “Home sleep testing should be reserved for people that are at high risk for sleep apnea and who don’t have a lot of other illnesses like obesity or heart disease that might alter the sensitivity of the test,” says Nancy Collop, director of the Emory Sleep Center in Atlanta and president of the American Academy of Sleep Medicine.

Eli Walker snores and sometimes stops breathing for short times while sleeping. Walker, 63, read that there was a correlation between high blood pressure, for which he took two medications already, and sleep apnea. He went to see an ear, nose and throat specialist who sent him to a sleep lab near his Silver Spring home. Diagnosis: moderate sleep apnea.

Walker was prescribed a continuous positive airway pressure mask, which straps onto a person’s face and directs pressurized air into the airway, keeping it open. But after three months of trying to use it, he gave up. “I hated it,” he says. “I couldn’t breathe naturally, and I didn’t like the air blowing in my nose.”

Walker finally found a good night’s sleep with a specially fitted oral appliance that looks kind of like a sports mouth guard. The appliance, which must be fitted by a dentist with special training in sleep medicine, repositions and stabilizes the lower jaw and soft tissues so that the airways stay open. It typically works best with people with mild to moderate sleep apnea.

Good news for seniors: Private insurers have covered the dental appliances for years, according to Sheri Katz, president of the American Academy of Dental Sleep Medicine. In January, Medicare began covering them, too.