Exploding Head Syndrome (EHS), also called episodic cranial sensory shock, is a sensory disorder characterised by the perception of a loud noise or sense of explosion in the head, usually when transitioning into or out of deep sleep. Little is known about the exact cause of EHS and, while it is not dangerous, it can lead to fear, anxiety, and interrupted sleep.
Back in 2017, we launched a survey asking BBC Science Focus readers to share their experience of EHS in collaboration with psychologists at Goldsmiths, University of London, St Mary’s College of Maryland, the University of Notre Dame and the University of Sussex.
Nearly 7000 of you replied with 3,286 reporting experience of EHS episodes. Another 446 people initially reported EHS symptoms, but were excluded from the study due to other medical conditions or excessive pain during episodes.
“I was delighted when the editor of BBC Science Focus Dan Bennett, suggested this collaboration. Dr Brian Sharpless led the first paper on Exploding Head Syndrome – but the dataset we collected was extremely rich and there is more to learn,” said Dr Alice Gregory of Goldsmiths, University of London.
Now, the results of the study have been published in the journalSleep Medicine.
While 5 per cent of sufferers said they experienced EHS several times a week, most said they only experienced it occasionally – 35 per cent reported having an episode several times a year, and 40 per cent having just several episodes in their lifetime.
Nearly 45 per cent of all sufferers said they found the episodes frightening with just over 25 per cent reporting significant levels of distress.
While the exact cause of EHS remains unclear, 60 per cent of sufferers believed the condition to be due to ‘something in the brain’. Nearly 35 per cent of sufferers thought EHS was due to stress while 7 per cent thought it was a side effect of their medication, 2 per cent thought that it was caused by electronic equipment, and 3 per cent thought it could be caused by something supernatural.
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The measures taken by sufferers to combat EHS were varied. Among them were increasing alcohol consumption, which was deemed to be more that 80 per cent effective, avoiding sleeping on the back, also deemed to be 80 per cent effective, going to bed earlier, 50 per cent, and getting more sleep, 50 per cent.
“Exploding Head Syndrome (EHS) is not discussed very much in the media or elsewhere. Consequently, people having this experience may have very little information about what is going on,” said Dr Gregory.
“In our study, we found that those who had experienced EHS reported poorer sleep quality and less sleep than others. In future, we would like to understand more about these associations. For example, could disturbed sleep trigger this experience, or is it that someone who has experienced EHS finds it more difficult to fall asleep at night?”
Reader Q&A: Is it possible to be too tired to sleep?
Asked by: Helen Collins, Manchester
It’s perfectly possible to feel tired and at the same time have trouble dropping off. Certain life stresses and health problems can leave us feeling exhausted, but at the same time make it difficult to relax and get to sleep. Also, missing out on sleep can disrupt our natural rhythms, which can make us feel wide awake when we’d usually be sleeping.
Finally, caregivers sometimes refer to their infants as being ‘too tired to sleep’. This happens when the babyhas been awake for longer than their little bodies can cope with, resulting in stress and difficulties settling.
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