Do you ever hear a sudden loud noise just as you’re falling asleep or waking up, maybe accompanied by a flash of light?
But then when you check your house or ask someone else, you find no possible source of the noise?
If so, it could be that you’ve experienced exploding head syndrome (EHS). The good news is that although it can be quite scary, it’s not believed to be physically harmful.
This sleep disturbance was first documented in 1920 by the scientist Armstrong-Jones, who described it as a ‘snapping of the brain’.
Compared to some other sleep disorders, there hasn’t been so much funding for research into EHS in the years since then. But scientists are slowly starting to understand it better.
How common is exploding head syndrome and who experiences it?
In 2014, researchers in Germany reviewed multiple cases and previous research, with some interesting findings:
- They found that the average age of onset was 54.
- More women reported having EHS than men.
- The average frequency of attacks was between once a day and once a week.
- The most common symptoms were noise, fear and sudden sensations of light.
Research shows that many young people experience it
In contrast to the research in Germany, researchers at Washington State University in 2015 discovered that many young people also experience EHS. And they didn’t find that women had it more often than men either.
Some of the main points arising from their research include:
- 18% of the 211 undergraduates they interviewed had experienced it in their lifetime.
- 16.60% had experienced it more than once.
- They didn’t find that women had it more often.
- It was found in 36.89% of people who had a diagnosis of isolated sleep paralysis.
- 2.8% had clinically significant levels of distress or reduced ability to function.
2019 research finds even higher prevalence rates
In 2019, a team of researchers again looked at how common EHS is, finding much higher prevalence rates than the previous two pieces of research:
- Out of 199 female undergraduates, 37.19% had experienced it in their lifetime. 6.54% had it at least once a month.
- Out of 1683 male and female adult participants in a separate study, they found a lifetime prevalence of 29.59%. And 3.89% had monthly episodes.
The team also found associations with other sleep disturbances, such as insomnia, sleep paralysis and nightmares.
2020 research sheds more light
In 2020, a fascinating study into EHS was conducted in a collaboration between the British Broadcasting Company (BBC) and psychologists in the United States and the United Kingdom.
In a survey of 6686 adults, 3286 reported that they had experienced EHS during their lives. 2954 said they had never had EHS.
Interestingly, 446 additional people reported having it, but were excluded due to the likelihood it was a different medical condition or because they reported significant pain during their episodes, which is not typically a diagnostic symptom of EHS.
Of the people who said they did have EHS, 5% said they had it several times a week. 35% had it several times a year, and 40% several times in their lifetime.
And in line with the German study, they also found that women were marginally more likely to have it than men.
It doesn’t cause physical harm
The name exploding head syndrome itself sounds very dramatic, provoking all kinds of violent images in the mind when wondering what the consequences of an episode might be!
The reality is that EHS is seen by organizations such as the American Sleep Association as benign and not associated with pain. However, it can cause a great deal of fear, anxiety and confusion, along with physical symptoms like increased heart rate.
Exploding head syndrome symptoms
There are several possible symptoms commonly reported. They can occur either when falling asleep or waking up:
1. Hearing a sudden and loud noise that isn’t real
The main symptom of EHS is hearing or feeling a loud and sudden sound. It can feel like it’s coming from inside your head, somewhere in your house, or even outside.
The type of sound varies between people, and might include:
- The sound of an exploding bomb
- The sound of a gunshot
- A loud clash of cymbals
- The sound of a door slamming
- A rushing sound
- People screaming or shouting
- An electrical buzzing sound
- Any other loud sound which can’t be described exactly
2. Seeing a flash of light
EHS is sometimes accompanied by a sensation of a flashing light. Like the noise though, there’s no actual light source causing it.
3. Fear and distress
Most people don’t usually report feeling pain with EHS. They may describe it as painful initially, but then reveal it’s just extremely loud.
However, the sudden noise and other symptoms can be very disturbing. So it’s not uncommon to wake up feeling scared or upset by what just happened.
In the BBC collaboration study in 2020, for example, 44.4% of participants reported feeling significant fear during episodes. Interestingly, a smaller number of 25% reported clinically significant distress.
4. Elevated heart rate and breathing
Brian Sharpless Ph.D., who has published several papers on EHS, described in his 2018 research the most common symptoms as:
- Muscle twitches
- Respiration difficulty
Interestingly, he also found that visual phenomenon were reported by 27% of people with EHS – a figure he described as “more common than expected”.
5. Accompanying sleep paralysis
As the research at Washington State University found, EHS is sometimes accompanied by sleep paralysis.
Sleep paralysis itself can also be very frightening, so it’s unsurprising that a combination of the two sleep disturbances can cause distress.
6. Worse sleep?
The 2020 study also found interesting effects on people’s sleep in general.
They found people with EHS typically took longer to fall asleep, had shorter sleep duration and worse sleep efficiency.
However, they do note that the differences were not clinically meaningful. I’ve added it here under the symptoms as I think it was interesting that it came up in the study, but it’s not listed as a symptom in sleep disorder guidelines.
Reader EHS poll
I ran a poll of readers for three months to see how often they felt they experienced EHS.
Out of 7,752 readers who voted, a combined total of 53.5% said they experience it at least once a month. 41.9% said they experience it very rarely.
These numbers should be taken with a pinch of salt though, as I only polled readers of this article. So rather than a random sample, it’s people who were probably inspired by their experiences to look it up online.
Causes of exploding head syndrome
The causes of exploding head syndrome still aren’t properly understood. But several theories have been proposed:
- A neurological condition, such as minor seizures in the temporal lobe.
- A sudden movement in inner ear parts, such as the tympanum (the eardrum), or the tensor tympani (the muscle involved in reducing sound – e.g. the sound of chewing food).
- Related to fear, stress or anxiety.
- Calcium signaling impairment.
In 2010, the researchers Thorpy and Plazzi suggsted that EHS might be a form of hypnic jerks, saying:
The EHS is a benign, usually self-limited, condition that is likely a sensory variant of the hypnic jerk. No testing or medications are necessary when the history is typical. Education and reassurance are the cornerstones of therapy. If the symptoms occur multiple times a night and cause insomnia, a hypnotic may be useful.
Going back to the 2020 BBC study again, they asked the participants what they believed caused their EHS. Here are the main causes reported and the percentage of people that endorsed them:
- Something in the brain – 60.6%
- Stress – 34.7%
- Medication side effects – 7.2%
- Something supernatural – 2.8%
- Electronic equipment – 2.3%
The treatment options for EHS are limited due to the fact that it’s seen as physically harmless, and still not fully understood.
Knowing that it has a name, that you’re not alone in experiencing it, and that it’s not dangerous might be reassuring enough for many people.
However, you might like to consider the following options if you remain concerned:
1. Talk to your primary care provider
Speak to your doctor or physician if you’re concerned by your symptoms and they are causing you distress or loss of sleep.
They might check for other causes, such as headache disorders or seizures. But they can also help reassure you that it’s harmless.
There’s isn’t a cure as such. But one medication which has been used with some success is clomipramine.
3. Reduce stress and anxiety
Stress and anxiety can increase the frequency and intensity of some sleep disorders. If you’re under a lot of stress and/or suffer from anxiety at night, it’s a good idea to find ways to tackle it. This could include exercise, walking, yoga, tai-chi, meditation, mindfulness or simple breathing exercises in bed.
4. Practice good sleep habits
Sleep deprivation, exhaustion, and many lifestyle choices can increase the likelihood of disturbed sleep. Try to stick to a regular sleep schedule, and practice good sleep hygiene.
5. Try not to worry about your sleep
It’s important not to become anxious about falling asleep. Try not to worry that you’ll experience another episode or that something bad will happen to you.
That might be easier said than done, but some positive self-suggestion at night can be helpful.
Prevention strategies reported by people with EHS
One final look at the results of the 2020 study reveals some interesting possible techniques to cope with EHS.
The study participants were asked what prevention strategies work for them, and how effective they thought they were.
Here are the top methods that people say helped them:
- Using or refraining from substances, such as drinking alcohol before bed or taking sleep aids like Ambien. It’s not clear in the published study whether more people had success taking or stopping taking substances. It looks to me like drinking alcohol has a positive effect on reducing EHS, but I can’t be sure from the way the data was published!
- Don’t lie on your back.
- Got to bed earlier and get enough sleep.
- Practice mindfulness techniques/relaxation exercises.
- Get up for a bit if it happens.
- Try to wake yourself up during an episode.
Have you experienced EHS? What symptoms did you have, and how did it make you feel?
Feel free to share your story and thoughts in the comments below.