Exploding head syndrome (EHS) is an #abnormalSensoryPerceptionDuringSleep in which a person experiences #auditoryHallucinations that are loud and of short duration when falling #asleep or #wakingUp. 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 organic explanations that have been investigated but ruled out include ear problems.