How Sounds Undermine Sleep

Why can some people sleep through a jackhammer at the window, while others waken with the lightest whisper? Host Rachel Martin speaks to Johns Hopkins Sleep Disorders Center researcher Jeffrey Ellenbogen about his new study on how noises interrupt sleep.

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RACHEL MARTIN, HOST:

We're spending some time this morning thinking about sleep. Do we really need it? How do we get more? And what happens inside our brains when we're doing it? We're going to introduce you now to someone in the trenches of sleep research. His name is Dr. Jeff Ellenbogen.

DR. JEFF ELLENBOGEN: ...the secure entrance that we came in and this whole corridor here is the clinical sleep lab. The technical...

MARTIN: We met up with Dr. Ellenbogen at Johns Hopkins University Medical Center in Baltimore, where he works as a professor and researcher. And within minutes of meeting Dr. Ellenbogen, it is clear this is a man who enjoys his work.

ELLENBOGEN: Ah. Look at this. Just slow waves, riding along. And this is sort of a 30-second window and then there's little buzz of activity at about 10 hertz and then...

MARTIN: Those ways he's describing, they're brain waves. And he's pointing to a computer screen full of them. Ellenbogen's research is all about sound and how it changes our sleep. And as part of his research, Ellenbogen spends a lot of time here in his sleep lab. But he also spends a lot of time just walking around the hospital.

ELLENBOGEN: The stakes are very high because we are in the intensive care unit.

MARTIN: He's here in the ICU, not to treat patients but to listen to what he calls the soundscape of this environment. The phones ringing...

(SOUNDBITE OF A PHONE)

MARTIN: ...machines beeping.

(SOUNDBITE OF BEEPING)

MARTIN: Sounds he says can undermine one of the key components of healing: sleep.

ELLENBOGEN: The last thing that's on people's minds is sleep because it feels kind of like indulgent - we can do without it, you'll make up for it later. Right now, we have some really major medical issues we need to address.

MARTIN: Do you find yourself having conversations with your colleagues where you're, you know, proselytizing about the value of sleep?

ELLENBOGEN: Shamelessly, all the time.

(LAUGHTER)

ELLENBOGEN: It's horrible. But, you know, I think when I talk to people about it they say, oh yeah, sleep is important. But I think it doesn't kind of percolate to the surface of the kind of triage list. I mean, sleep is really in some ways a panacea. It relates to all aspects of physiology and...

MARTIN: But a lot of us don't get good rest at night. Ellenbogen is trying to figure out why some of us can sleep through a jackhammer out the window, while others can wake up if they hear nothing more than a whisper. So he's reproducing certain hospital sounds and playing them back to patients who spend the night in his sleep lab.

ELLENBOGEN: So what we do is go around and record sounds: helicopter landing, toilet flush, people taking, doors slamming, beeps and boops of all kinds of alarms. And then we play them at strategic positions during sleep to see what are the rhythms of the brain that are responsible for protecting sleep. Ah, if we could tap into those elements and understand when sleep is disrupted from a sound and when it isn't, then maybe we can be much more nuanced about the neuro-scientific approach to helping people protect their own sleep in noisy environments.

MARTIN: Ellenbogen's sleep lab is still being built. In the meantime, he's working out of the main Hopkins lab. We sit down in front of a couple of computer terminals showing some patient's brain waves.

So let's describe this.

ELLENBOGEN: Yeah.

MARTIN: We are looking at - I don't know - dozen different lines that indicate one person's night's sleep?

ELLENBOGEN: That's right. One person on this screen represents 30 seconds worth of data across those different parameters. And actually these big, juicy waves are nice so-called slow waves. That is the brain really slow-wo-wo-wo-woo, slowing down. Now you see that riding on top of those, and interspersed in between, are faster signals. Here the brain can have several different frequencies firing simultaneously, almost more like a symphony than an instrument. And so, you can kind of get...

(SOUNDBITE OF BANGING)

MARTIN: So that's what a good night's sleep looks like; a brain that's moving in and out of deep REM sleep cycles all night long. But for a lot of us that is not happening. A recent report by the Centers for Disease Control says close to nine million Americans are using some kind of sleep medication. Ellenbogen says it's an artificial kind of fix.

ELLENBOGEN: So I think that if you think of sleep in a very crude way - that it is either asleep or awake - then the sleeping medications achieve that fairly well. But if you look at the more nuanced symphonic structure and dynamic properties of the brain across sleep, a lot of those changes and evolution are blunted.

MARTIN: And we need all of those changes in the course of a night, and with sleep meds you're not getting the nuance.

ELLENBOGEN: That's exactly right.

MARTIN: Dr. Ellenbogen starts to go deep at this point, talking about the thalamus shell and reticular neurons because sleep is really complicated.

ELLENBOGEN: The shell of the thalamus is an...

MARTIN: But Ellenbogen doesn't mind. In fact, as we walk around the ICU, he tells me that's what keeps drawing him further into this field.

ELLENBOGEN: It's kind of fundamental. It's about understanding what does it mean for sleep to be deep? How does it change from one person to the next?

MARTIN: And have you figured out the answers to all of those questions yet?

ELLENBOGEN: Every single one of them and if we just had a few more minutes I could cover it. No, and that's the beauty of being part science, part physician is that every time we stumble into a problem that's so frustrating on the applied medical side, we could say, hey, that's the basis for a research question.

(SOUNDBITE OF MACHINERY)

MARTIN: Dr. Jeff Ellenbogen of Johns Hopkins University in Baltimore, we're talking about sleep this morning. And in another part of the show, we get Freudian - why do we dream?

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