Exploding Head Syndrome: A Case Series of Underdiagnosed Hypnic Parasomnia.

Exploding head syndrome (EHS) is an under-recognized parasomnia characterized by a complaint of sudden loud noise or a sense of explosion in the head that usually occurs at sleep onset. This paper is a report of 6 patients diagnosed with EHS through a structured clinical interview and video-polysomnography (vPSG) recordings. We also reviewed the available literature that addressed the presentation and clinical and PSG characteristics of EHS. The case series included 4 men and 2 women of a mean age of 44.2 years (between 13 and 77 years). Their episodes were variable in expression, between a sudden firecracker-like explosion to a gun-shot sound, mostly as if happening inside the head. EHS is always associated with distress but never with pain. Five out of 6 patients had other sleep-related problems with a close relationship of EHS symptoms to comorbid sleep disorder manifestations and exacerbations. The vPSG recordings of 5 patients were unremarkable. An attack of EHS was documented in 1 patient, arising during stage N2 of sleep. Three patients responded well to reassurance and treatment for the comorbid sleep disorder. The other 3 patients responded well to amitriptyline (10-50 mg). EHS is a well-characterized, underrecognized hypnic parasomnia with a benign course. Amitriptyline seems to be effective in persistent cases.