A neurologist uses carefully-timed pulses of noise to boost the size of brain waves responsible for good-quality sleep—and potentially better memory.
Can Sleep Quality and Quantity be Boosted Using Sound?
Published: March 13, 2020
Phyllis Zee: One of the things that we’re most interested in is how can we boost and enhance sleep quality, sleep quantity by using, you know, not pharmacology, but sound?
Narrator: Eighty-year-old Marion Smith is participating in a sleep study. To track the quality of her slow waves, a single electrode is placed on her forehead. Marion will hear carefully timed pulses of sound through this headband, equipped with tiny speakers.
Ralph: Have a good night. I’ll see you tomorrow.
Zee: Our patient, Ms. Smith, is now clearly sleeping. She is now getting deeper sleep.
Narrator: By examining the brainwaves produced by a single electrode, Phyllis has all the information she needs to assess the quality of Marion’s slow waves.
Zee: These are these big slow waves, but there are very few of them. And this is quite typical of an older person who has low amplitude slow waves, and they don’t occur, like, in a train.
Narrator: Next, a specially designed computer algorithm measures the waves to determine the best time to deliver a particular sound, the pulsing of pink noise.
Zee: We do very brief, like, 50 milliseconds of this very short burst of pink noise. And we do it five on, five off, as long as the person is still in deep sleep.
Narrator: Think of the soundwaves produced by pink noise giving Marion’s brainwaves a little push, like a kid on a swing or the movement of a ball in a balance pendulum.
Matt Walker: And what you try to do is sing in time with these brainwaves. But, by stimulating them, you’re trying to boost the size of those brainwaves.
Zee: It’s beautiful. This is what we want them all to look like, these very large, with strong upstate, waves. Even after you stopped stimulating you can see the increase in these slow waves.
Narrator: Phyllis is finding that a little push goes a long way.
Zee: What we’re seeing here is not only that we can increase the amplitude, that means the height of these slow waves, which is really important, but we can also increase the train. So, we could prolong the amount of slow waves, which is wonderful, because it’s hopeful that the brain, even if you’re old, is capable of boosting the slow waves.
Onscreen: The hope is that boosted slow waves would mean better sleep, and perhaps even better memory.
Mysteries of Sleep
Edited by: Jedd Ehrmann
Produced and Directed by: Terri Randall
Digital Production: Angelica Coleman
© WGBH Educational Foundation 2020