Exploding Head Syndrome

Excerpt

Exploding Head Syndrome (EHS) is a benign parasomnia characterized by the perception of a sudden loud noise during sleep, leading to abrupt awakening. These episodes occur during the transition between wake-sleep and sleep-wake periods and typically last less than a second. Patients often report flashes of light and distress during episodes, although significant pain is not present, which is an essential criterion for diagnosis. Although the perceived sounds are commonly described as explosions, gunshots, or thunder, they can be almost any loud noise. The frequency of episodes varies, with some individuals experiencing prolonged remission between episodes. EHS may be more common when sleeping in the supine position.

EHS was first described in medical literature in 1876 by American neurologist Silas Weir Mitchell, who documented 2 patients experiencing nocturnal sensations of loud sounds, which he termed "sensory shocks." Although EHS had been described in earlier case reports, it was not officially recognized as a sleep disorder until 2005, when it was included in the International Classification of Sleep Disorders, Second Revision (ICSD-2). The term "episodic cranial sensory shock" has also been proposed to describe this phenomenon. Many patients may find the experience frightening, especially if they are unaware of its benign nature. Patients often fear a more serious underlying cause, such as a stroke, brain tumor, or brain hemorrhage, leading them to seek medical evaluation. However, EHS is frequently underdiagnosed and underreported, as patients may feel embarrassed discussing their symptoms, and healthcare providers may be unfamiliar with the condition.

According to the American Academy of Sleep Medicine's International Classification of Sleep Disorders, Third Revision (ICSD-3), the diagnostic criteria for EHS include:

1. A sudden perception of a loud noise or explosive sensation in the head, which occurs during the transition from wakefulness to sleep or upon awakening during the night.

2. An abrupt arousal following the event, which is often accompanied by a sense of fear or distress.

3. The experience is not associated with significant pain.