“Exploding head syndrome (EHS) is a type of sleep disorder in which you hear a loud noise or explosive crashing sound in your head. The sound isn’t real or heard by anyone else. The episode typically happens suddenly either when you’re beginning to fall asleep or when you wake up during the night.

Along with the loud sound, EHS can occur along with flashes of light and muscle jerks (myoclonic jerks). Unlike its painful-sounding name, the episode is painless.”

Cleveland Clinic (https://my.clevelandclinic.org/health/diseases/exploding-head-syndrome-ehs)