exploding head syndrome EHS

A benign but distressing and often frightening clinical parasomnia known as "exploding head syndrome" (EHS) was given its provocative name by JM Pearce in 1988. Alternative terms in the medical literature have included "episodic cranial sensory shock." As with all parasomnias, a detailed clinical history is critical to diagnose the condition accurately. This phenomenon is characterized as a perception of loud noises when initiating sleep or awakening. These noises are sudden in onset, typically of very brief duration, and distressing to the person (choice D is correct). The noises are typically without any pain, but they may cause fear; confusion; and, in some cases, panic. The episodes are usually infrequent but can manifest in more chronic forms, resulting in more significant clinical consequences and sleep fragmentation. It may be confused with other entities, but a specific history often cinches the diagnosis.

Hypnic headache syndrome is typically noted in older individuals and may also mimic EHS. However, this headache usually occurs 4 to 6 h after sleep onset, lasts for 30 to 60 min, and is frequently diffuse or bilateral and accompanied by nausea but no autonomic symptoms (choice A is incorrect).

Simple partial seizures may manifest with abnormal sensory alterations such as hearing acuity, visual abnormalities, or disruption in the sense of smell, but episodes associated with these convulsions do not usually arise at sleep onset or at the point of awakening (choice B is incorrect).

Sleep-related headaches, such as migraines and cluster headaches, may be confused with EHS. However, these disorders are painful rather than painless as in EHS episodes. Patients with migraine, cluster headache, and hypnic headache usually wake up with an acute episode more frequently during REM sleep than during other stages of sleep, whereas patients with cluster headache and chronic paroxysmal hemicrania may experience the event around the same time of the night almost every night (choice C is incorrect).