<unk>  (EHS) is an abnormal sensory perception during sleep in which a person experiences unreal noises that are loud and of short duration when falling asleep or waking up. The noise may be frightening, typically occurs only occasionally, and is not a serious health concern. People may also experience a flash of light. Pain is typically absent. The cause is unknown. Potential explanations include ear problems, temporal lobe seizure, nerve dysfunction, or specific genetic changes. Potential risk factors include psychological stress. It is classified as a sleep disorder or<unk> ache disorder. People often go undiagnosed. There is no high quality evidence to support treatment. Reassurance may be sufficient. Clomipramine and calcium channel blockers have been tried. While the frequency of the condition is not well studied, some have estimated that it occurs in about 10% of people. Women are reportedly more commonly affected. The condition was initially described at least as early as 1876. The current name came into use in 1988.
Exploding head syndrome
Otodental syndrome
Hypnoid state
Emergence delirium
Diencephalic syndrome
Perisylvian syndrome
Brain herniation
Myxedema coma