Falling asleep is enough of a challenge, but for some, it also comes with auditory hallucinations — often loud crashes or bangs right before they drift off to dreamland. This phenomenon is called exploding head syndrome (EHS), and we've been hearing a lot about it recently. And, a new study suggests that nearly one fifth of college students have suffered from it at some point — way more than previous estimates.
So, we caught up with Joyce Walsleben, PhD, of the NYU Sleep Disorder Center. She was one of the first researchers to capture the phenomenon back in 1993 when it woke up one of her subjects during an unrelated sleep study. The brain activity left a big spike in the electroencephalography (EEG) data.
What we know about EHS suggests it occurs more frequently when people are dealing with high amounts of stress or fatigue (which explains the college students' susceptibility). However, although the experience can be frightening, Dr. Walsleben says it doesn't usually leave lasting effects. "The name is frightening enough," she adds. Below, she answers our pressing questions about the condition.
What is exploding head syndrome?
"People describe it as a loud noise, sharp bang, or a sense of electricity in the middle of their sleep. We can see it, people can report it, but nothing seems to be aberrant about it... It’s pretty shocking both if you are seeing it and [for the] people experiencing it; they can be very frightened by it. It’s been called a hallucination, but it is real...there is definitely a change in the EEG during that time." If EHS is more of a symptom than a syndrome itself, what do we think is causing it?
"We don’t know. That’s the whole thing. People have looked at it as a seizure, but nobody can really explain what it is. There are folks that want to say it’s a sleep-onset or sleep-offset [disorder], but we’ve had it captured in the middle of a steady stage of sleep. So, I think it is just...a hiccup, and it may just be an oddball thing that happens. I don’t think anybody has been able to capture exactly what it is or what causes it."
"People describe it as a loud noise, sharp bang, or a sense of electricity in the middle of their sleep. We can see it, people can report it, but nothing seems to be aberrant about it... It’s pretty shocking both if you are seeing it and [for the] people experiencing it; they can be very frightened by it. It’s been called a hallucination, but it is real...there is definitely a change in the EEG during that time." If EHS is more of a symptom than a syndrome itself, what do we think is causing it?
"We don’t know. That’s the whole thing. People have looked at it as a seizure, but nobody can really explain what it is. There are folks that want to say it’s a sleep-onset or sleep-offset [disorder], but we’ve had it captured in the middle of a steady stage of sleep. So, I think it is just...a hiccup, and it may just be an oddball thing that happens. I don’t think anybody has been able to capture exactly what it is or what causes it."
Why is it so hard to know how common EHS is?
"A lot of times...folks are not too forthcoming with it. So, they want to be in a safe position or a situation where it’s okay to say, 'Yes, I experience this.' That may be part of why we don’t know how common it is... Perhaps they get used to it and go back to sleep and don’t remember it." Is the brain particularly vulnerable when it’s transitioning from being awake to being asleep?
"Oh yeah, there’s very definite switches in the brain... Then, there are switches as [we] go through different stages of sleep, so the chemistry changes drastically. Cells fire on some stages of sleep and then shut off on others. So, there is this definite switch...in the chemistry and physiology of the brain. We know hallucinations, for instance, could [have elements of being asleep and elements of being awake], but we saw [EHS] during a steady stage of sleep." What was it like when you first saw the "blip?"
"We had been running a research study, and we had one of our technicians actually being a subject so we could get things ironed out. She woke up in the middle of the night after we had seen this monster charge of electricity, and she said, 'Did you get that?' "When we saw it on [the EEG], it was pretty impressive. It was a charge of electricity like a seizure through all of the channels... It was quite profound."
"A lot of times...folks are not too forthcoming with it. So, they want to be in a safe position or a situation where it’s okay to say, 'Yes, I experience this.' That may be part of why we don’t know how common it is... Perhaps they get used to it and go back to sleep and don’t remember it." Is the brain particularly vulnerable when it’s transitioning from being awake to being asleep?
"Oh yeah, there’s very definite switches in the brain... Then, there are switches as [we] go through different stages of sleep, so the chemistry changes drastically. Cells fire on some stages of sleep and then shut off on others. So, there is this definite switch...in the chemistry and physiology of the brain. We know hallucinations, for instance, could [have elements of being asleep and elements of being awake], but we saw [EHS] during a steady stage of sleep." What was it like when you first saw the "blip?"
"We had been running a research study, and we had one of our technicians actually being a subject so we could get things ironed out. She woke up in the middle of the night after we had seen this monster charge of electricity, and she said, 'Did you get that?' "When we saw it on [the EEG], it was pretty impressive. It was a charge of electricity like a seizure through all of the channels... It was quite profound."