When a patient has trouble sleeping, a sleep study may be recommended to determine whether they have sleep-disordered breathing or even sleep apnea. A sleep study, or polysomnogram, is an overnight test that records brain activity and oxygen levels, eye and body movements, heart rate and blood pressure, and more, while a person sleeps.
In the past, most sleep studies were conducted at sleep centers. There, sensors are applied to the patient’s head and body before they crawl into bed and go to sleep. Then a technologist monitors the patient’s sleep from a separate room. While studies conducted by sleep centers are still the best option for some people, especially those with symptoms that point to severe sleep-disordered breathing issues, there are a number of factors that make them less-than-desirable.
For starters, many people have trouble sleeping in a strange place, especially when they know someone is watching them sleep. The average cost for a sleep center study is around $2,500 to $3,500. While insurance may cover the study, out-of-pocket copays usually apply. The sleep center study does test for restless leg syndrome, an unpleasant condition that can severely disrupt sleep. However, it does not test for bruxism, or the clenching/grinding of teeth that can indicate an obstructed airway. This is also important for the dentist to know if the worn dentition is from currently active Bruxism.
Today, there is another option to test for sleep-disordered breathing—the home sleep study. A home sleep study allows the patient to be tested in the comfort of their own bed, and the cost is typically about one-tenth that of sleep center study. With a home sleep study, the patient takes the unit home, applies the sensors themselves, and then returns the unit to have the results read by a sleep specialist. While the home study does not test for restless leg syndrome or brain wave activity, it does test for bruxism.
While an oral physician can order a sleep study, and can ultimately treat for sleep-disordered breathing, the final diagnosis based on the study results must be made by a board-certified sleep physician.
Among the results the sleep physician reviews are:
Apnea-Hypopnea Index (AHI), which measures the number of disruptions per hour. Apnea is a complete collapse of the airway that causes cessation (stoppage) of airflow for at least 10 seconds, leading to arousal from deep sleep and a drop in oxygen levels. Hypopnea is overly shallow breathing or an abnormally low respiratory rate. An Apnea reading of less than five disruptions is normal, 30 or more is severe. While mild AHI (five to 14 disruptions) or moderate (15 to 29) may recommend treatment, anything 30 or higher typically leads to a recommendation for a CPAP machine.
The downside to the home sleep study is it does not differentiate which of the AHAI is due to an apneic event and which is due to hypopnea. Hypopnea events are determined by a 3-4% reduction in oxygen levels.
ODI (Oxygen Desaturation Index) measures oxygen levels below 97 percent compared to the number of hours slept during the test.
SI (Snore Index) refers to the total duration of time spent snoring during the recording.
BEI (Bruxism Episode Index) refers to the number of clenching/grinding events that occurred while being tested: 0 to 2.5 is normal, 5.0 or more indicates highly destructive bruxism, usually requiring multiple treatment methods.
At the Julian Center, we use the Nox T3 system, which in a pilot study found consistent results with sleep center studies. If the study results recommend treatment, then $225 of the $250 fee is applied toward treatment. Follow-up studies to determine the effectiveness of treatment are $25.