Have you ever been close to falling asleep when all of a sudden you hear an incredibly loud bang, and then you come to find out that there was no actual sound? It can be something as loud as cymbals crashing together, thunder, or even an explosion. You heard it, but you didn't hear it. Does that mean you're losing your mind? No, it means you might have a sleep disorder, or a parasomnia, called Exploding Head Syndrome (EHS). EHS is more common than you might think, and there is a logical scientific explanation behind it.