Exploding head syndrome (EHS) is an abnormal sensory perception during sleep in which a person experiences auditory hallucinations that are loud and of short duration when falling asleep or waking up.
[3] Potential organic explanations that have been investigated but ruled out include ear problems, temporal lobe seizure, nerve dysfunction, or specific genetic changes.
[5] Individuals with exploding head syndrome hear or experience loud imagined noises as they are falling asleep or are waking up, have a strong, often frightened emotional reaction to the sound, and do not report significant pain; around 10% of people also experience visual disturbances like perceiving visual static, lightning, or flashes of light.
[3] A number of hypotheses have been put forth with the most common being dysfunction of the reticular formation in the brainstem responsible for transition between waking and sleeping.
[2] One study found that 14% of a sample of undergrads reported at least one episode over the course of their lives, with higher rates in those who also have sleep paralysis.
[14] Case reports of EHS have been published since at least 1876, which Silas Weir Mitchell described as "sensory discharges" in a patient.
[15] More recently, Peter Goadsby and Brian Sharpless have proposed renaming EHS "episodic cranial sensory shock"[1] as it describes the symptoms more accurately and better attributes to Mitchell.