The Science of Sleep

SLEEP MONITORING: ALL IN A NIGHT’S WORK

The center’s four locations in and around Atlanta have a total of 18 bedrooms where patients can spend a night wired up to measure a wide variety of sleep factors, all under the watchful eye of supervisors such as Kevin Okonkwo. A sleep-disorder technician, Okonkwo monitors everyone’s sleep on computer screens in the control room during their overnight stays.

“I love to monitor patients,” he says. “It can make for a pretty exciting night.”

When patients come in, usually around 8 p.m., they’re hooked up to multiple sensors to measure sleep breathing patterns and airflow, heart rates, oxygen and carbon dioxide levels to determine a patient’s level of sleep.

Collop describes it as “a bunch of sensors with wires on their head and under their chin,” as well as muscle monitors and respiratory belts that measure chest expansion and contraction during breathing along with an EKG to detect cardiac arrhythmias.

Because many patients have a condition called restless leg syndrome that causes an uncontrollable urge to move the legs, another sensor measures leg movement. Additional sensors measure brain waves to determine which stage of sleep patients are in at different times.

Everything is fed to the control room where techs like Okonkwo keep watch.

HOW SLEEP EMERGED AS A PUBLIC HEALTH CRISIS

That complex series of measurements is an indication of how the science of sleep has evolved and come into its own as a medical specialty in recent decades, able to bring multiple perspectives to problems such as sleep apnea that have equally complex origins. Doctors such as the Sleep Center’s David Schulman — who’s a professor of pulmonology, allergy, critical care and sleep medicine — say it’s not a moment too soon. 

“Sleep deprivation — I don’t think it’s an exaggeration — is a public health crisis,” he says.

There can be many sources of sleep deprivation beyond sleep disorders, Schulman adds.

These can include a poor sleeping environment with too much light or noise, irregular work hours, inconsistent sleeping hours and, a particular concern for Schulman, the whole range of modern electronic communication devices now available to everyone.

“When you pair some normal degree of insomnia with the ability to distract yourself with a panoply of activities,” he says, “sleep deprivation is incredibly prevalent. It is incredible to think how many hours of lost productivity come from people who are inefficient at their jobs or even making mistakes as a result of chronic sleep deprivation.”

Many of them don’t even realize why they’re struggling, Schulman says. “They think they’re doing OK.”

As a respiratory specialist, Schulman is an expert at diagnosing breathing-related issues such as sleep apnea, a complex series of interrelated ailments that involve the area from behind your hard palate down to your voice box, all of which are subject to collapse.

But, Schulman adds, while sleep apnea is a common problem, “The Sleep Center has specialists from a wide range of backgrounds, including neurologists and otolaryngologists. So even though each of us can manage almost all sleep-related conditions to some degree, no single one of us is expert at every possible sleep problem. Having a group of partners within the center, we can reach out to our colleagues to ask, ‘Hey, can I run this case by you?’ That’s an extraordinarily valuable resource.”

Part of the value of those multiple specializations lies in being able to precisely diagnose what’s wrong with a patient, when many sleep ailments can be hard to tease out or may superficially resemble each other. Patients like Louis Fiorucci.

“Thank God I had that conclusive, definitive information from Emory,” he says. So many other physicians before had led him astray before he was diagnosed with type 1 narcolepsy.

“Oftentimes patients have gone to a primary care physician and said, ‘Hey doc, I’m sleepy but I don’t know why,’” adds Glenda Keating, a research associate in neurology at the Emory School of Medicine who frequently studies Sleep Center patients.

“And they’re written off as depressed or other things and they get lost to follow-up,” Keating says. “They’ve suffered for years and struggle through high school and college and then finally get a referral to come to Emory and then find out the real root of their sleep issues.”

THE CHALLENGE OF CLASSIFYING DISORDERS

The Sleep Center’s interlocking strengths allow its clinicians not only to be able to recognize what’s causing a patient’s problems but also be able to dig deeper and even classify it by a subtype.

For example, most sleep apneas have complex origins. “There are a lot of muscles in there, like 26 in all, just in the throat area,” Collop says.

Obstructive sleep apnea, the most common kind, occurs when the tongue falls against the soft palate during sleep and causes the airway to collapse. Eventually the brain senses the lack of breathing and wakes the body, at which point the cycle starts again.

In the rarer condition known as central sleep apnea, the brain stops sending signals that control the breathing process, so the sleeper temporarily stops breathing. On occasion, both types of apnea combine in a single patient.

All forms of sleep apnea have both upstream risks including genetics that make people more susceptible and downstream risks that make other problems more likely to happen. “Apnea tends to run in families,” Collop says. “It could be facial structure. It could be obesity.”

In addition, patients who suffer from sleep apnea are at greater risk for heart disease, stroke and hypertension.

Narcolepsy, the disorder that plagued Fiorucci, can occur with cataplexy, known as type 1, or without, type 2. Its most visible symptom is excessive daytime sleepiness. However, when sleep occurs, it’s interrupted by frequent awakenings. Sometimes it’s even accompanied by sleep paralysis, a brief stage between sleep and wakefulness when a person is conscious but unable to move.

“There’s a lot of misinformation, even amongst doctors, people in the medical community,” Fiorucci discovered, making him grateful for the Sleep Center. “Having seen someone who writes the books on this stuff is extremely beneficial.”

Even rarer is idiopathic hypersomnia, a baffling affliction of unknown origins that affects less than 1% of the population, causing an irresistible need to sleep, not only at night but during the day. Hypersomnia patients sleep and sleep but never feel refreshed. They may have difficulty awakening and feel disoriented when they do awake, with memory problems, attention problems and cognitive failures.

“With idiopathic hypersomnia, these are people that are sleeping 10 to 12 hours, waking up unrefreshed,” Keating says. “They have to get disability, they can’t hold jobs because they’re so tired in their daily lives and functioning.”

Like sleep apnea, hypersomnia frequently runs in families but a great deal about it is still unknown. “The heterogeneity is huge,” Keating says of the vast diversity of symptoms that show up in different patients. “What it looks like in person A versus person B versus person C, there’s so many different aspects going on. It’s a huge, huge difference in presentation of hypersomnia across people.”

Partly because of the unknowns, idiopathic hypersomnia is one of the nodes where the Sleep Center’s daily clinical practice connects with the larger community of Emory researchers who seek scientific understanding of sleep, sleep health and sleep disorders. The center’s sophisticated clinical technology for monitoring sleep can also be used for scientific studies, with some patients volunteering as research subjects.

PROBLEMS AFFECT DEMOGRAPHIC GROUPS DIFFERENTLY

Dayna Johnson, an associate professor of epidemiology at Emory’s Rollins School of Public Health, has been examining the connection between sleep and inequalities, one of the less recognized forms of health inequity. When Johnson, who was trained in epidemiology, studied sleep data across different demographic groups, she found minoritized individuals consistently displayed poorer sleep patterns. 

“They’re disproportionately affected by shorter sleep duration, poorer sleep quality,” Johnson says. “We’re seeing more irregular sleep patterns. Going to sleep and waking up at different times across the week. That’s associated with hypertension and other adverse cardiovascular outcomes.”

She continues: “Additionally, it’s not just this higher prevalence, but we’re seeing more severe sleep apnea, more severe insomnia. And this is not just a problem for adults. We see this among children and adolescents.”

What’s behind these poor sleep patterns? Johnson attributes part of it to social patterns that mean individuals from minority populations are more likely to live in disadvantaged neighborhoods and be exposed to more air pollution, bright light and noise. Other patterns are harder to attribute to a single cause.

People living in rough neighborhoods are also more likely to sleep with the TV on. Sometimes that’s used as a safety measure to keep intruders away, but it also adds even more distraction to those trying to sleep. In addition, disadvantaged groups have less access to health care and information about good health. Johnson’s study found even Black and Hispanic individuals with higher incomes and education still tend to have worse sleep patterns overall.

“Sometimes it’s race and sometimes it’s place,” she says. “In disadvantaged environments, it doesn't matter what your race is. Everybody is doing bad. Race comes in because we know that certain racial groups are more likely to live in those environments.”

Johnson thinks sleep needs to be included in public health objectives when health policy is made. That’s a view Nancy Collop shares.

Collop believes it’s important to integrate sleep issues into all aspects of medicine and medical training. “If you take stroke,” she says, “and put sleep in, studies have shown probably 80% of patients that come into a hospital who had a stroke have sleep apnea. But not a lot of people are looking at sleep as part of the management or even prevention of stroke. If you could take those highly impactful disorders and add sleep research as part of it, it would go a long way to expand our understanding of sleep and how it impacts other disorders.”