Waking up with a bang? It could be ‘exploding head syndrome’

What is Exploding Head Syndrome?

Have you ever been drifting off to sleep, only to be jerked awake by the sound of a bomb going off inside your head? If you have, then you have most likely experienced exploding head syndrome, a mysterious and poorly understood sleep disorder. Exploding head syndrome (EHS) belongs to a family of sleep disorders known as parasomnias. Other parasomnias include sleep paralysis and hypnic jerks – the cause of that unpleasant feeling of falling we sometimes experience when drifting off to sleep.

EHS has been known to medical professionals since at least 1876, and apparently the French philosopher and scientist René Descartes experienced it. Despite that, we know surprisingly little about the condition.

Symptoms of Exploding Head Syndrome

A typical episode is characterised by the experience of an abrupt loud noise or a sense of an explosion inside the head that occurs during the transition from wakefulness to sleep. The sounds that are heard during EHS are variable, and include perceptions of gun shots, doors slamming, or nondescript screaming. Importantly, the sounds that are heard are always short (a few seconds or less), very loud and without any obvious external source in the environment.

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Alongside the sounds, some people experience accompanying brief visual hallucinations such as bright flashes. Others have also reported feelings of intense heat, or the sensation of electrical charge flowing through the upper body.

Prevalence of Exploding Head Syndrome

It is hard to estimate exactly many people experience EHS. One reason for this is simply a lack of available data. Only a handful of studies have attempted to survey the prevalence of EHS in the general population.

One early study found that 11% of otherwise healthy adults experienced EHS, while another study in undergraduate students found 17% of participants had experienced multiple episodes in their lifetime. In my own, more recent study, again in undergraduate students, my colleagues and I found that one-third of our sample had experienced at least one episode of EHS in their lifetime, with around 6% experiencing at least one episode a month.

Triggers of Exploding Head Syndrome

The exact cause of EHS is unknown. While many theories of the root cause of EHS have been put forward, the most popular implicates the natural brain processes that are ongoing in the transition from wakefulness to sleep. On a typical night, as we transition from wakefulness into sleep, activity within the reticular formation of the brain is reduced.

The reticular formation is a set of brain structures located primarily in the brainstem and hypothalamus, that acts as an “on-off” switch for the brain. As reticular activity slows down in the transition to sleep, our sensory cortices that govern vision, sound, and motor movement start to shut down.

It has been proposed that the experience of EHS is due to a disruption in this normal switching-off process, which gives rise to delayed and disjointed surge of neuronal activation to sensory networks in the absence of any external stimuli. These brief surges of activation are then perceived as the loud, nondescript sounds that characterise EHS.

Is Exploding Head Syndrome Dangerous?

Despite its provocative name, EHS is harmless. It is however important to distinguish an episode of EHS from other conditions, particularly from various types of headaches. EHS episodes are very short (several seconds) and usually there is no associated pain. If there is, it is mild and transient. In contrast, many headaches are longer-lasting and are associated with significantly higher levels of pain.

Coping with Exploding Head Syndrome

This is not to say that EHS cannot be a scary experience. In a recent survey of over 3,000 participants who had experienced EHS, we found that 45% of respondents reported moderate to severe levels of fear associated with their EHS. A quarter of participants also reported high levels of distress in response to experiencing EHS, with increased levels of distress associated with more frequent episodes.

Unfortunately, there have been no systematic studies investigating potential treatments and coping strategies for those struggling with distressing experiences of EHS. In our survey, participants reported that changing their sleeping position to avoid sleeping on their back, adjusting their sleep patterns and deploying mindfulness techniques were all effective strategies for preventing EHS. Whether any of these techniques prove to be effective in clinical trials remains to be seen.

Conclusion

Exploding head syndrome is a relatively common experience, at least in young adults. While the exact cause of EHS is unknown, research suggests that it may be related to disruptions in normal brain processes during the transition from wakefulness to sleep. Fortunately, EHS is harmless and can be managed with simple techniques such as improving sleep habits and deploying mindfulness strategies. By learning more about EHS and how to cope with it, we can reduce the distress associated with this condition and improve the quality of life for those who experience it.

FAQs

Q: What is exploding head syndrome?
A: Exploding head syndrome is a sleep disorder characterized by the experience of an abrupt loud noise or a sense of an explosion inside the head during the transition from wakefulness to sleep.

Q: How common is exploding head syndrome?
A: The exact prevalence of EHS is unknown, but studies suggest that it may be relatively common, particularly in young adults.

Q: Is exploding head syndrome dangerous?
A: No, EHS is harmless and does not indicate any underlying medical condition.

Q: How can I cope with exploding head syndrome?
A: Simple techniques such as improving sleep habits, changing sleeping position, and deploying mindfulness strategies may be effective in preventing and managing EHS.