Exploding Head Syndrome

Exploding head syndrome is a form of hypnagogic auditory hallucination in which the sufferer sometimes experiences a sudden loud noise coming from within their own head. The noise is brief and is usually likened to an explosion, roar, gunshot, door slamming, loud voices or screams, a ringing noise, or the sound of electrical arcing (buzzing).

This noise usually happens at the onset of sleep or within an hour or two of falling asleep, but is not necessarily the result of a dream. Although the sound is perceived as extremely loud, it is usually not accompanied by pain. Attacks appear to change in number over time, with several attacks happening in a space of days or weeks, followed by months of remission. Sufferers often feel a sense of fear and anxiety after an attack, accompanied by elevated heart rate. Attacks may also be accompanied by perceived flashes of light (when perceived on their own, known as a "visual sleep start") or difficulty in breathing. The condition is also known as "auditory sleep starts". The associated symptoms are varied, but the benign nature of the condition is emphasized and neither extensive investigation nor treatment are indicated. Sufferers may experience an inability to vocalize any sound, or mild forms of sleep paralysis during an attack.