Gary Stix: For Science, fastI’m Gary Stix.
Dreams may say something about the psyche, but they also say something about disease states. Dreams can even be something we can take some control over. To find out all this, Scientific American contacted sleep expert Isabelle Arnoldwho is head of the sleep disorders clinic at Pitié Salpêtrière University Hospital in Paris.
During her career, Arnulf, who is also a professor of neurology at the Sorbonne University in France, has researched a wide variety of sleep disorders. Sleepwalking, rapid eye movement, sleep behavior disorder, lucid dreaming, sleep and Parkinson’s disease and hypersomnia, where hypersomnia is excessive daytime sleepiness. Professor Arnulf is with us now to talk about sleep and dreams.
Hello, Professor Arnulf. Welcome to the podcast.
Isabelle Arnulf: Hello. Thank you.
stix: So REM sleep behavior disorder has been a real focus of your research. Can you tell us what that is and how you discovered it interacts with dreams and also how it can help us understand dreams better?
Arnulf: So behavioral disturbances in REM sleep correspond to people exhibiting violent behaviors during sleep, including boxing, kicking, yelling. This is the most common type of dream behavior we see. And this is a condition that needs to be treated because people hurt themselves or their loved one. Most of them are over 50 years old and can reach up to 80 years old.
So they are not young people. And over the past 15 years, when it occurred in the elderly, this behavior has been found to be a strong predictor of Parkinson’s disease and related conditions. So we started tracking a lot of patient cohorts to track them over time and see if they would get Parkinson’s disease or not.
This is currently the main direction of research, but beyond that was the use of these behaviors as a window into the dreaming process. Because if you think about it, you lose a lot of information during this process of waking up and remembering your dream. In contrast, if you watch people during REM sleep behavior disorder, you see that dream in action the moment it happens. People speak exactly as they would speak when they are awake. They behave as they would when awake. It’s a narrow window, but it’s a very, very capable window into dreams.
stix: Is there a certain content of these dreams? And my understanding is that with some of the neurodegenerative disorders like Parkinson’s that you just mentioned, there are certain themes, there are certain types of dreams that they have. Can you talk about it?
Arnulf: The most recurring themes of these dreams are aggression. They are usually attacked by animals or by other people. Or it’s their loved ones who were attacked, and they fight back to protect their loved ones, to protect themselves. We see that in 80% of dreams, but 20% of them are quite normal.
stix: Can this be used by clinicians for diagnosis?
Arnulf: If someone is acting out dreams, screaming at night, I think these are dreams about being assaulted and portraying them in bed as being in their fifties or sixties, yes, it can really be used in the diagnosis process. You have to think about Parkinson’s disease coming up, but performing part is the most important because all people can have nightmares, but performing it is the main point caused by the onset of Parkinson’s disease.
stix: Another area you study has to do with lucid dreaming. Can you tell us what lucid dreams are and how they can give a better understanding of dream states, and how they can be used in sleep medicine?
Arnulf: Lucid dreaming is being aware of dreaming while you are still dreaming without waking up. Sometimes you realize you’re dreaming and wake up, but a lucid dreamer can stay asleep. And once they realize they are dreaming, many of them can act or change some of their dreams. For example, most of them try to fly and you can also change your dream to make them more pleasant, avoid enemies, or make nice trips around the world, or have sex with big (movie) stars.
So it is a condition that occurs in the normal population, it is more common in children than in adults. And this ability to change your dreams is very useful when you have nightmares. If you realize it’s a bad dream or a nightmare and change it, your nightmares will disappear.
It’s something that we developed with patients who have narcolepsy, another condition where people are sleepy all the time, and they often used it to change their nightmares to make them more pleasant.
stix: So you communicate with the self-conscious patient and try to get them to take certain actions? Is that what you say?
Arnulf: Until our recent work on lucid dreaming, it was thought that you couldn’t communicate with someone who was sleeping and dreaming. But we were able to do that in the series of patients. We could ask them some questions while they slept and they could answer, not with their mouths, but with some gestures of their body, such as pointing or smiling.
So lucid dreamers can not only change their dreams, but also send signals or codes to the researchers. And in this case, they’re just great topics to help us research dreams. Lucid dreaming is also just a scientific tool to explore what happens during our dreams.
For example, it was possible to know if the time was the same during our dreams and doing the reality using some cues observed by the lucid dreamers, such as counting from 0 to 10, during dreaming and doing the same during waking. And it was shown to be the same duration.
And we’re using it more recently to ask our lucid dreamers to send us codes about the emotions they felt in their dreams, and what we saw is that these are the emotions that go extremely fast during lucid REM sleep, and they switch very quickly from smiling to crying like it’s one of the functions of dreams to regulate emotions.
stix: Does it also have any clinical benefit in helping patients?
Arnulf: Yes, it has some clinical use, but you have to be a lucid dreamer, and that’s something… if you’re not spontaneously a lucid dreamer, it can be difficult to acquire. You need three to six months of training to become proficient lucid dreamers. But there are some people who are trying to develop other techniques to accelerate the ability to become aware that you are dreaming when you are dreaming.
stix: What are you most excited about in your future research?
Arnulf: The most exciting things I think are lucid dreaming — such a powerful way to answer a lot of questions that we’ve had about dreams for a long time, and because I found that this patient with narcolepsy was proficient lucid dreamers during naps, during the day, we built a lot of experiments around this idea and it worked really well to answer all the questions we had about dreams. So it comes one paper after another because it takes time to publish, but I’m surprised how effective this model is for understanding dreams.
stix: This is really fascinating. Thank you so much.
Arnulf: Thank you. And goodbye.
stix: Science is quickly produced by Tulika Bose, Jeff DelViscio, Kelso Harper and Carin Leong. The music of our show is composed by Dominic Smith. Please consider supporting independent journalism like this, become a Scientific American subscriber today, and don’t forget to subscribe to the podcast on Apple or Spotify.
For Science, fastI’m Gary Stix.
