The Science of Sleep

During her restful night at the Vanderbilt Sleep Disorders Center, Laura Miller experienced five REM cycles, typical for most people when they sleep.

A 'View' writer spends a night at the Vanderbilt Sleep Disorders Center

by Laura Marjorie Miller
photography by Mary Donaldson

Both mysterious and compelling are the signs near Memorial Gym for the Vanderbilt Sleep Disorders Center. Passers-by who struggle with sleep problems, such as snoring, sleep apnea and insomnia, might wonder if the lab can help them (Spoiler alert: It can). A curious bystander without such issues might wonder what exactly goes on in the clinic, which is tucked away in the Marriott Hotel at Vanderbilt.

When I told friends I would be experiencing the sleep lab first-hand, I was impressed by how many told me they or a loved one struggled in their sleeping life. Those who sleep restfully take it for granted. But those who do not can understand the isolation of insomniac nights, the irritation brought on by restless legs and the halting breath and snore of apnea that leave one hagridden with exhaustion.

Sleep is familiar, yet so strange. We spend a third of our lives doing it, but like the ocean – which is 70 percent of Earth’s surface – we know little about it.

To prepare for my stay, I was advised: No caffeine after noon. Bring your pajamas and toiletries and your dinner. Bring a book for when you have to wait. (I brought a novelization of Sleeping Beauty). When I entered the hotel, I felt like I was on a secret mission that the employees of the hotel were tacitly in on. I was received by Pennington Grubb, a registered polysomnographic technologist and the sleep lab’s manager, who did a short intake interview and showed me to my quarters for the night.

The sleep lab’s rooms are like any other hotel room, except for the complicated apparatus near the bed: a softly glowing-green sleep computer secreted in a closet, an infrared camera hovering overhead and the absence of a Gideon Bible in the nightstand. I happened to be in one of the pediatric rooms, which has two beds – one for a child and one for his or her parent.

The sleep lab, I discovered, treats cases of different kinds of apnea as well as restless leg syndrome, insomnia and even narcolepsy, for which it does day studies. Physician Beth Malow, who heads up the Vanderbilt Sleep Disorders Center’s multidisciplinary team of specialists from fields such as neuroscience, pediatric medicine and otolaryngology, told me she became interested in sleep medicine while she was studying epilepsy.

“I saw that the severity of people’s seizures decreased when they were able to sleep well at night,” said Malow, professor of neurology and pediatrics. Sleep studies also have shown that healthy sleep can decrease the chances of having a stroke, decrease the level of anxiety in children with autism spectrum disorder and improve family relationships, she said.

I was assigned my own personal tech, registered polysomnographic technologist Mike Cross, who to me would be like Virgil escorting Dante through the underworld. In the 10-bed lab, each tech oversees the sleep of two different patients per night.

Cross explained everything as he hooked me up to what has become affectionately known as “the machine” – a polysomnogram, which would measure my bodily functions. He attached wires below the outer corner of my right eye and above the outer corner of my left to track my eye movement as I dreamt. He explained as he attached electrodes to my jaw that the muscles in one’s jaw utterly relax when one dips into REM sleep.

To track the activity in the frontal and central lobes of my brain and my occipital lobe, he measured from my nasion (roughly, the depressed area between the eyes and just above the bridge of the nose) to my inion (the lower, back part of the skull) to make sure those electrodes were in the right places. He had me raise my head and hum to find where to place the snore microphone on my throat. He affixed two different nasal monitors to measure air pressure and air flow to my inner nostrils. But we weren’t done yet.

He stuck ECG monitors on my chest and back; actigraphic leg wires to track the movement of my limbs (including the common “hypnic jerk,” the muscle-bursty jump that occurs when you start to fall asleep); an oxygen detector on my finger to read my hemoglobin through my fingernail; and lastly, snug belts around my abdomen and upper chest to relay the volume and rhythm of my breath.

I looked like I was wearing a magnificent headdress. I was a somnonaut, outfitted for exploration in the field.

Cross explained to me that this is the one place in the world where you can’t pretend to be asleep. He told me a story about a child in the lab who pretended to be asleep in the morning when Cross came in to wake him. “‘Shhhhh, he’s sleeping,’ said his mum,” Cross said. “But I took one look at the computer and said, ‘No, he’s not,’ and he opened his eyes – he was found out! I could tell by looking at the monitor,” he said with a smile.

Each wire Cross attached to me corresponded to a line on the monitor. When I lay down to rest, he had me open and close my eyes, look in all directions, take deep breaths, and wiggle my feet as he synched up the lines on the computer and made sure all the hook-ups were working correctly. And then he left and it was
time for bed.

It’s an odd sensation to know the team will be watching you on their monitors all during the night. But by the time Cross had me all wired up, I didn’t care. The rooms at the sleep lab are quiet – optimum nests for sleep. They are kept slightly cool, as perspiration can cause the adhesive holding your wires to loosen.

When I fell asleep, I went down hard. I’d had a full day of work and had taught a yoga class, followed by a cup of chamomile tea. There is a live microphone by the bed, so if I needed to go to the bathroom I could simply call out for the tech – but I didn’t need it. I slept deeply through the night. Cross only interrupted me once to readjust my nose clips and put some new ECG readers on my upper back. “You slept really well,” he said in the morning. “You fell asleep right away.”

The polysomnogram records all the stages of sleep. Stage 1 is the hypnogogic and hypnopompic stages, when you are going into and coming out of sleep, respectively. Stage 2 is deeper, called delta, which adults usually don’t have but children do. It is that heavy teenage sleep, where the young do most of their growing, and it is healing and regenerative. Finally, there’s REM (rapid eye movement), the stage when you dream.

Amazingly, the polysomnograph can show exactly when you begin to dream, as the chin lines settle down on the monitor to a thin thread and the eye lines begin to dance.

When my time was through, Cross let me read the story of my sleep from the charts on the computer screen, the polysomnogram that had been recording all night. I went through five REM cycles, the last being near 5 a.m., which is typical for most of us. Cross showed me, according to the graph, exactly where I began to dream and where I moved. I couldn’t remember much of my dreams – one was about Doctor Who, but the rest are lost. My sleep path was pretty optimal, but if I had a sleep disorder, the graph would indicate exactly where apnea interrupted breathing, where cycles of dreaming were disturbed, or where legs moved erratically.

Watching a recording of myself sleeping in the soft green light of the camera was mysterious and intimate – most people never get to see themselves sleeping. It was like an out-of-body experience on time delay. I had a wave of compassion break over me for this sleeping person, for the vulnerability of sleep in us all.

I’m fortunate to be without a sleep disorder, but if you think you might have one, the Sleep Disorders Center offers therapies ranging from medication to sleep hygiene routines to the legendary CPAP (Continuous Positive Airway Pressure) device worn around the nose, which helps apnea sufferers to breathe clearly and smoothly during the night.

Sleep is the baseline health of so many of our functions and so many of the things we need to do.

“We all know what it is like to not sleep well,” Malow said. “To sleep better improves everything.”

Posted 03/01/11