Harry Hawk, 51, of New York City, had his first sleep study in 2008. “I stopped breathing 180 times in six hours,” he said of the study’s findings. He was diagnosed with obstructive sleep apnea and put on a CPAP machine, which has helped reduce his symptoms. But after Hawk recently lost weight, his doctor ordered a new sleep study to reevaluate his condition.
“Before the first test, I can imagine I probably had little to no REM sleep for as many as five years,” Hawk said.
A sleep study, or polysomnogram, is a doctor-ordered test under which patients are monitored while they sleep. According to the Mayo Clinic, most polysomnograms occur in a lab setting, where doctors monitor brain waves, stages of sleep, breathing, chest wall movement and abdominal movement. The test is used to determine whether a person has sleep apnea, including whether his or her airway closes automatically or he or she makes no attempt to breathe at all, said Robert Rosenberg, a board certified pulmonary and sleep medicine physician and medical director of Sleep Disorders Center of Prescott Valley and Flagstaff.
During the study, the patient is hooked to a variety of machines including an electroencephalograph (EEG), which measures the electrical activity in a person’s brain. Although it may sound uncomfortable, Rosenberg noted on average about 80 percent of test subjects do in fact, sleep through the night.
For those who can’t sleep in the lab, portable devices are available for in-home sleep studies. While such devices work in helping diagnose obstructive sleep apnea (OSA), they don’t monitor brain waves and can’t tell whether a person is sleeping or awake—important for diagnosing other sleep disorders.
The sleep study can reveal any pauses in breathing, frequency of sleep arousals and intermittent drops in levels of oxygen in the blood. Based on the results, doctors can determine the type and severity of a person’s sleep disorder and appropriate treatment.
“If the sleep study picks up apnea in the first hour or two, we can then begin treatment on the same night, called a split study,” Rosenberg said. “On the other hand, if the sleep apnea doesn’t show ‘til later in the morning, we have to bring [the patient] back and fit [them] for a CPAP machine then.”
CPAP is the "gold standard treatment for sleep apnea,” Rosenberg added.
Treatment of OSA by CPAP can lower a person’s heart attack risk by 3 percent to 5 percent, as well as reduce the incidence of diabetes, mood disorders and post traumatic stress disorder. What’s more, using a CPAP machine can increase daytime alertness and reduce accidents, noted Rosenberg.
A sleep study is the best way to get an accurate diagnosis of sleep apnea, and for someone suffering from the condition, it can be time well-spent. If you suspect you have or a loved one has sleep apnea, take this online quiz to see if a conversation with your doctor is in order. And if a sleep study is recommended, don’t forget to pack your pajamas!