"Exploding head syndrome," in which people are awakened by abrupt, loud but nonexistent noises or the sensation of an explosion inside their head, is especially common in young people, researchers say.
Almost one in five students interviewed in a Washington State University study said they had experienced the psychological phenomenon at least once, with some saying is was so bad it had a significant impact on their lives, the researchers say.
The syndrome generally occurs as a person is falling asleep, and scientists say they believe it's the result of a hiccup in the brain's mechanisms as it's turning off.
In the "exploding head" phenomenon, auditory neurons, instead of turning off slowly and gradually, all crash at once and with a bang only the person hears, the researchers suggest in the Journal of Sleep Research.
"That's why you get these crazy-loud noises that you can't explain, and they're not actual noises in your environment," says Brian Sharpless, an assistant professor and director of the university's psychology clinic.
Of the 18 percent of the study participants who said they'd experienced the syndrome at least once, a third of that group also reported occurrences of isolated sleep paralysis, a condition where a person is unable to move or talk after waking, dreaming with eyes wide open.
Scientists say they think the same area of the brain stem, known as the reticular formation, is involved in both phenomena.
In a few cases these sleep issues can be deeply disruptive to people's lives, Sharpless pointed out.
"Unfortunately for this minority of individuals, no well-articulated or empirically supported treatments are available, and very few clinicians or researchers assess for it," he said.
Although it normally lasts just a few second, the experience can make some people think they've had a seizure or a brain hemorrhage, he said.
Some people become so traumatized by the experience they won't even share the fact with their spouses, Sharpless says.
"They may think they're going crazy and they don't know that a good chunk of the population has had the exact same thing," he said.
There have been attempts to treat exploding head syndrome with drugs, but with limited success so far.
"One of the drugs they gave for exploding head syndrome actually didn't make the noises go away," Sharpless said. "It just turned the volume down."
Just getting the condition diagnosed and learning that they're not alone in the bizarre experience can be helpful to people, he said.
"There's the possibility that just being able to recognize it and not be afraid of it can make it better."
