Comparatively little is known about exploding head syndrome and sleep paralysis, so were launching the first large-scale survey into both disorders

Of all the sleep disorders, “exploding head syndrome” (EHS) has arguably the most intriguing name. EHS has been described as “a sensory parasomnia characterised by the perception of loud noises and/or a sense of explosion in the head when transitioning to or from sleep. These noises are not associated with significant pain, but lead to abrupt arousal and feelings of fright”.

Although this phenomenon was first described as long ago as 1876, it was not given its colourful title until 1988. Despite its long history, it has received very little systematic research attention, with most of our knowledge being based upon small samples of case histories as opposed to large-scale investigations. We, the authors of this piece, along with the world’s leading authority on EHS, Dr Brian Sharpless of Argosy University, Northern Virginia, are hoping to rectify that situation by carrying out a large-scale survey of EHS. We’re also interested in the equally intriguing phenomenon of sleep paralysis, which involves a temporary period of paralysis occurring between sleep and wakefulness, often accompanied by hallucinations. If you have ever experienced either EHS or sleep paralysis, or even if you haven’t, we would love to hear from you.

In addition to explosions, other types of loud noise perceived during episodes of EHS include gunshots, fireworks, thunder, doors slamming, clapping, shouting, and the clash of cymbals. There can also be beeps, buzzing and video static. This may be accompanied by “electrical” sensations, palpitations, breathing difficulties, sweating, seeing a flash of light, and twitching. Perhaps unsurprisingly, intense fear caused by the belief that something is seriously wrong is often reported. Although episodes of EHS are generally thought to be harmless, in a minority of cases sufferers seek medical attention. There is a real risk of misdiagnosis, with potentially important clinical consequences, given the widespread lack of knowledge amongst medical professionals of this under-researched phenomenon.

Recent research has contradicted the idea that EHS is rare. One study found that 10.7% of healthy subjects, 10% of patients with a sleep disorder and 13.8% of psychiatric patients reported having experienced EHS. In another study, 18% of students reported that they had experienced EHS at least once and the vast majority of those sufferers experienced it repeatedly. The latter study also found equal prevalence in males and females in contrast to earlier studies that had found a greater susceptibility in females.

There has been very little systematic study of treatment options for this disorder. Several small-scale studies have produced promising results using different pharmacological interventions such as the tricyclic antidepressant clomipramine, flunarizine, and nifedipine. What is more, education can be useful. Simply informing sufferers of the nature of EHS, and specifically that it is a fairly benign condition, may sometimes be enough to reassure those affected to the extent that the episodes cease. This could be due to a reduction in anxiety associated with falling asleep.

The survey, led by researchers from Goldsmiths, University of London, and promoted by BBC Focus magazine, is calling for members of the general public to tell us about their own sleep habits and these unusual sleep-related experiences. We’ll ask you about your beliefs and basic demographics too. We are just as keen to get responses from people who have never experienced EHS and/or sleep paralysis as we are interested in possible differences between sufferers and non-sufferers.

Amongst the questions of particular interest to us are the following: What is the relationship between these unusual sleep experiences and other sleep habits? To what extent do such experiences interfere with your life in general? What do you think causes these experiences? What, if anything, do you do to try to prevent the episodes from occurring or deal with them when they occur? And how effective are your attempts?

We hope that the results of our survey will be published in scientific journals, presented at conferences and publicised via the media. In this way we hope to make progress in learning more about the nature of such sleep-related anomalies. Just as importantly we want to help to reassure those who suffer from them that, although such episodes may be terrifying, they are essentially harmless.

Christopher French is a professor of psychology and head of the anomalistic psychology research unit at Goldsmiths, University of London. Alice M Gregory is also a professor of psychology at Goldsmiths. Her book about sleep, Nodding Off, will be published by Bloomsbury Sigma in spring 2018 . Dan Denis is a post-doctoral researcher in the sleep and cognition laboratory at Beth Israel Deaconess Medical Center, Harvard Medical School.

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