Exploding head syndrome: six new cases and review of the literature.

Background: Exploding head syndrome (EHS) is characterized by attacks of a sudden noise or explosive feeling experienced in the head occurring during the transition from wake to sleep or from sleep to wake.

Methods: We present six new cases extending the clinical experience with the syndrome. We also reviewed all available cases from the scientific literature and evaluated the typical features of EHS.

Results: The female to male ratio is 1.5 to 1. The median age at onset is 54. In average, one attack per day to one attack per week occurs. Some patients suffer from several attacks per night. In about half of all patients, a chronic time course can be observed but episodic or sporadic occurrence is also common. The most frequent accompanying symptoms beside the noise are fear and flashes of light. Polysomnographic studies do not reveal any specific sleep pattern associated with EHS. Tricyclic antidepressants are helpful in some patients. However, most patients do not need treatment because of the benign nature of the syndrome.

Conclusion: EHS is a well-defined disease entity with a benign nature.