Have you ever been just about to drop off to sleep when you’ve heard a loud sound that seems very close to your ears or even right inside your head? Maybe you’ve been woken up by it just after you drifted off. But then you realize there was no external cause of the sound. It was, in fact, a kind of audio hallucination.
If it has happened to you, you’re not alone. It’s a surprisingly common experience, first mentioned in medical journals as long ago as 1920. It was treated to a full clinical description in the 1980s, in which it was charmingly named Exploding Head Syndrome.
Now a recent survey of students at Washington State University revealed that nearly 20% of them have experienced these
, reporting sounds ranging from an explosive bang (hence the name) to a roar like a passing motorbike to a much more pleasant tinkling sound, like wind chimes.
Most respondents said it shook them momentarily and abruptly from their state of slumber. Nearly all of them said they assumed that it happened only to them, and several admitted they were somewhat worried by it, as if it was a sign of a deeper medical condition, or of mental instability. One or two conspiracy theorists even said they thought the sounds were caused by some sort of government-operated mind control weapon.
As yet, there’s no antidote and no conclusive theory on what causes it. But the Washington State boffins who conducted the survey think it may be simply related to the way our brains switch off for sleep.
Our motor, auditory and visual neurons close down in stages and at different times, and the researchers think our auditory apparatus may cause the sound as a natural part of its pre-sleep routine.
So sleep tight and don’t let the banging bother you.