Scientists Use Sound to Ease Patients’ Chronic Nightmares

People plagued by frequent nightmares may find relief from hearing a specific sound as they sleep, a new, small study suggests.

It’s estimated that about 4% of adults have nightmares that are frequent and distressing enough to impair their sleep and daily functioning. In some cases, the nightmares are related to an underlying condition, like post-traumatic stress disorder (PTSD), while others are considered “idiopathic,” or having no known cause.

Many nightmare sufferers simply live with them.

“Most people either think it’s normal to have so many nightmares, or they don’t know there’s treatment available,” said Jennifer Mundt, a behavioral sleep medicine specialist at Northwestern Medicine in Chicago.

When it comes to nightmare disorder, as it’s officially known, the treatment with the best evidence is imagery rehearsal therapy (IRT), Mundt said.

With that technique, people work with a therapist to recall their nightmares, change the negative storyline to one with a positive ending, and then rehearse the new script during the day.

Research shows that IRT can start to banish people’s nightmares within two to three weeks.

However, around 30% of patients do not respond, according to the new study’s researchers, from the University of Geneva in Switzerland.

So, they tried to boost the effectiveness of IRT by adding an approach known as targeted memory reactivation — where people learn to associate a cue, like a sound or smell, with something they want to remember. They are then exposed to that cue during sleep, which helps solidify the memory.

The researchers, led by senior study author Lampros Perogamvros, a psychiatrist at the Sleep Laboratory of the Geneva University Hospitals, reasoned that targeted memory activation might help conjure up the positive storylines that people learn and rehearse through IRT.

To test that idea, they recruited 36 young adults with chronic nightmares — more than one per week — and randomly assigned them to one of two groups. One had a standard IRT session, while the other had an IRT session plus targeted memory reactivation. In the latter group, people listened to a specific sound as they imagined their new, positive dream.

After the initial IRT session, people in both groups rehearsed their positive dream scenario every day at home for two weeks; those in the memory reactivation group listened to the sound as they rehearsed.

At night, all participants wore a special wireless headband that monitored their brain-wave activity and emitted the same sound during the REM stages of sleep — when dreams occur. But only one group had learned to associate that sound with their positive dream scenario.

In the end, that made a difference, according to the findings published Oct. 27 in the journal Current Biology.

Within two weeks, people in the memory reactivation group went from an average of three nightmares per week to about 0.2 per week. The group on standard IRT also improved, but to a lesser degree — dropping from an average of just under three nightmares per week to one per week.

And the effects lasted. Although participants wore the headbands for only two weeks, they were still having fewer nightmares three months later. While both groups were faring better, the memory reactivation group still had the edge.

They also showed another benefit: an increase in positive dreams. People in the standard IRT group reported fewer nightmares, but no change in happy dreams.

“This is a really cool study,” said Mundt, who was not involved in the research.

She called the initial results “promising,” and said she’d like to see future studies test the approach in people who have trauma-related nightmares. (People in the latest study all had idiopathic nightmares.)

Christopher Drake, a psychologist specializing in sleep medicine, agreed.

“This is a fascinating study,” said Drake, who heads sleep research at the Henry Ford Health System in Detroit.

It’s promising, he said, that the technique enhanced the “most powerful” therapy available for nightmare disorder.

But, Drake added, larger studies are needed, including ones that involve people with more severe symptoms. This study excluded people with insomnia, severe depression, sleep apnea and other conditions that can cause or worsen nightmares.

Sound therapy is low-risk, but one question, Mundt said, is whether it can disturb sleep.

The sounds, according to the researchers, are low in volume and delivered every 10 seconds after the person has been in REM sleep for five minutes. In this study, they found no signs that the therapy disrupted “REM sleep structure.”

While the sound therapy is not yet available in the real world, Mundt said it’s important that nightmare sufferers know there is already effective treatment out there.

“You don’t have to just live with this,” she said.

More information

The Mayo Clinic has more on nightmare disorder.

SOURCES: Jennifer Mundt, PhD, assistant professor, neurology (sleep medicine) and psychiatry and behavioral sciences, Northwestern University Feinberg School of Medicine, Chicago; Christopher Drake, PhD, section head, sleep research, Henry Ford Health System, and professor, psychiatry and behavioral neuroscience, Wayne State University School of Medicine, Detroit; Current Biology, Oct. 27, 2022