Déjà vu is often caused by misfiring of neurons in the same region. If you take those retrograde premonitions as signs of divine intervention, as signs of being on your intended path, as messages from a higher power, you are in good company. Dostoevsky, like the bus driver, immediately explained the sensation as a concrete encounter of the sort many intellectuals are skeptical: "I have really touched God. He came into me myself; yes, God exists, I cried. ... Mahomet, in his Koran, said he had seen Paradise and had gone into it. All these stupid clever men are quite sure that he was a liar and a charlatan. But no, he did not lie."
Nor are the people who make no claim to divinity, only to Exploding Head Syndrome, liars. You probably do not have Exploding Head Syndrome, according to the best statistical estimates of sleep researchers. If you did, you would know. Especially after the attention that the condition—known to insiders simply as Exploding Head—has gotten this week.
The name lacks a certain subtlety. But "explosions in my head" is exactly how sufferers tend to describe it: the perception of cacophonies while falling asleep or waking up, jerking a person into consciousness. And by innumerable accounts in news media, the condition may, according to new findings published on Tuesday in the Journal of Sleep Research, affect many more young people than experts previously appreciated.
Exploding Head is named for the sensation it elicits, rather than an actual explosion of the head. Learning that was at once heartening and a little disappointing. If you scour the corners of the Internet, as I tend to do, you'll find plenty of people who say they have Exploding Head. And plenty of sufferers don't believe it's a natural biological phenomenon. Instead they attribute it to the government harassing them, often using microwave technology, essentially torturing them with sleep deprivation through electromagnetic radiation. When outlandish things start happening in our bodies, outlandish explanations start to seem less outlandish.
Among academics, there are a handful of theories as to what causes Exploding Head. Those theories include temporal-lobe seizures and dysfunction among the tiny bones in the middle ear. Institutionalized torture is not among them. Brian Sharpless, a clinical psychologist in Pullman, Washington, who has taken a keen interest in the study of Exploding Head in recent years, favors the colloquial explanation that the auditory bursts amount to "a hiccup of the brain." When you're shutting down for sleep, you have to go through a series of steps, shutting off auditory neurons, motor neurons, visual neurons, et cetera. Explosions happen when, instead of shutting down, auditory neurons fire all at once.
"My gut would tell me that things like anxiety and insomnia, and a general preoccupation with bodily symptoms and fear of them, would make people more likely to have Exploding Head," Sharpless told me. The bursts of noise are usually painless, but also usually accompanied by fear and distress. People who are sleep-deprived are more likely to experience explosions, which leads to a question of what is causing what. And, rarely, to a horrible cycle of worsening insomnia and worsening explosions.