Most people have occasional nightmares — those heart-pounding episodes that rouse you at their most terrifying moments and stay with you even when you are awake. But some others have nightmares frequent enough to seriously disrupt sleep and interfere with quality of life.
A treatment from Perogamvros and his team may help those with chronic nightmares. The experimental method, which combined an established treatment — imagery rehearsal therapy — with a sound, led to fewer nightmares among participants for as long as three months afterward, their study showed.
“There is every indication that it is a particularly effective new treatment for the nightmare disorder,” Perogamvros said. “These results also open up new perspectives for the treatment of other disorders, such as insomnia and post-traumatic stress disorder.”
Two to 8 percent of people suffer from chronic, debilitating nightmares that wreck their sleep, according to the American Academy of Sleep Medicine. While nightmares are common among children — most outgrow them by age 10 — an estimated 50 to 85 percent of adults also have them occasionally, the academy says.
“Nightmare disorder is a serious problem for some people, especially affecting people with PTSD, but others as well,” said Timothy I. Morgenthaler, a sleep medicine specialist at the Mayo Clinic, who was not part of the study. “Occasional nightmares are unwelcome, but when they occur frequently — enough that the person becomes distressed with the prospect of experiencing another nightmare, anticipating stressful images during sleep, sometimes avoiding sleep to avoid yet another nightmare — it affects their sleep, daytime function, and arguably their health.”
The subjects in the study experienced frightening nightmares “ranging from mass killing in their native country, unknown people intruding their house and willing to harm them or kill them, or nightmares during which the dreamer is abandoned by his or her family, or people are severely injured or in great danger,” Perogamvros said.
The scientists modeled their method after an approach known as targeted memory reactivation, or TMR, which uses a specific learning-associated trigger, typically an odor, to enhance memory consolidation when reapplied during sleep.
Their trigger was a sound, described as a “neutral” piano chord, which they added to imagery rehearsal therapy — which takes place when patients are awake — and to rapid eye movement (REM) sleep, the final stage of sleep when nightmares usually occur.
Imagery rehearsal therapy is an established cognitive behavioral technique where subjects try to change the negative storyline of their nightmares into a more positive ending, rehearsing the “rewritten” dream scenario for several minutes each day.
The patients recall a specific nightmare that occurs often and are asked to visualize it, recalling every detail they can remember, Perogamvros explained.
“As an example, we can imagine a nightmare in which the patient is hunted by someone in the forest and cannot find her way out,” he said. “Colors, odors, emotions might be described by the patient, as well as the context of the nightmare. For example, the dreamer was walking in the forest with her family when suddenly everybody disappears, and a tense atmosphere emerges.”
Researchers then instruct the patients to change their nightmares into different versions with happier outcomes. “We let them picture it for a few minutes before asking them verbally what this new scenario is,” Perogamvros said. “To continue with our example, a door pops up during the human hunt. The dreamer opens it and enters a safe, peaceful environment such as her bedroom. The door is then locked to ensure the hunter cannot reach her anymore.”
It is a very effective treatment, but it doesn’t work for everyone. Hoping to boost the success rate, the scientists theorized that adding the piano chord sound to the IRT would heighten the positive daytime experience and create a pleasant memory that subjects would associate with the sound. The goal was to increase the chances that patients, upon hearing the same sound during REM sleep, would experience a positive narrative instead of a nightmare.
All 36 subjects engaged in initial imagery rehearsal therapy in the lab. But only half heard the sound during the initial IRT lab session, meaning only one group formed a positive connection to the sound during therapy. Later, all received the sound while asleep at home via a wireless headband that automatically detected the onset of REM. All the participants also were instructed to practice IRT for five minutes every night at home — no sound included — then wear the headband while sleeping for two weeks. The device delivered the piano sound every 10 seconds.
The results, published in the journal Current Biology, found that both groups experienced a decrease in nightmares, but the half that received the sound during the lab-based IRT session had even fewer nightmares and “more positive dream emotions” for two weeks after the experiment and a sustained decrease in nightmares up to three months later, the researchers said.
Perogamvros said they used the C69 piano chord, but emphasized that the sound itself does not matter in the context of TMR. He added, though, that it would be preferable to “avoid a sound with some strong connotations, like, for example, a negatively connotated sound.”
The study has some limitations, the researchers said, including the lack of a control group of nightmare patients who did not undergo IRT.
Rafael Pelayo, a sleep-medicine specialist at Stanford University who was not involved in the study, called the work “promising,” adding that it could have been even stronger if the researchers had added a third arm where the sound was delivered during non-REM sleep to those who had developed a positive emotional connection it. “That would have shown if the mechanism is specifically through REM after all or it involved non-REM sleep, since non-REM sleep may also play a role in memory consolidation,” he said.
Morgenthaler of the Mayo Clinic also called the study “a promising new avenue,” adding: “The researchers have used a clever design to investigate the effects of adding sound during REM sleep to strengthen the desired emotional effects of the replacement dream. If replicated, this may be an important new approach to the treatment of nightmare disorder.”