Exploding head syndrome

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Exploding head syndrome
SynonymsEpisodic cranial sensory shock, [1] snapping of the brain, [2] auditory sleep start [3]
Specialty Sleep medicine
SymptomsHearing loud noises when falling asleep or waking up [2]
DurationShort [2]
CausesUnknown [3]
Differential diagnosis Nocturnal epilepsy, hypnic headaches, nightmare disorder, PTSD [2]
TreatmentReassurance, clomipramine, calcium channel blockers [2]
PrognosisGood [2]
Frequency~10% of people [2]

Exploding head syndrome (EHS) is a condition in which a person experiences unreal noises that are loud and of short duration when falling asleep or waking up. [2] [4] The noise may be frightening, typically occurs only occasionally, and is non serious in nature. [2] A flash of light may also occur. [5] Pain is typically absent. [2]

Hallucination perception in the absence of external stimulation that has the qualities of real perception

A hallucination is a perception in the absence of external stimulus that has qualities of real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. They are distinguishable from several related phenomena, such as dreaming, which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and imagery, which does not mimic real perception and is under voluntary control. Hallucinations also differ from "delusional perceptions", in which a correctly sensed and interpreted stimulus is given some additional significance.


The cause is unknown. [3] Potential explanations include ear problems, temporal lobe seizure, nerve dysfunction, or specific genetic changes. [2] Potential risk factors include psychological stress. [2] It is classified as a sleep disorder or headache disorder. [2] [5] People often go undiagnosed. [5]

Mutation A permanent change of the nucleotide sequence of the genome of an organism

In biology, a mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.

Psychological stress psychological feeling of strain and pressure

In psychology, stress is a feeling of strain and pressure. Stress is a type of psychological pain. Small amounts of stress may be desired, beneficial, and even healthy. Positive stress helps improve athletic performance. It also plays a factor in motivation, adaptation, and reaction to the environment. Excessive amounts of stress, however, may lead to bodily harm. Stress can increase the risk of strokes, heart attacks, ulcers, and mental illnesses such as depression.

Sleep disorder disease of mental health that involves disruption of sleep patterns

A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests commonly ordered for some sleep disorders.

There is no high quality evidence to support treatment. [2] Reassurance may be sufficient. [2] Clomipramine and calcium channel blockers have been tried. [2] While the frequency of the condition is not well studied, some have estimated that it occurs in about 10% of people. [2] Females are reportedly more commonly affected. [5] The condition was initially described at least as early as 1876. [2] The current name came into use in 1988. [5]

Clomipramine chemical compound

Clomipramine, sold under the brand name Anafranil among others, is a tricyclic antidepressant (TCA). It is used for the treatment of obsessive–compulsive disorder, panic disorder, major depressive disorder, and chronic pain. It may decrease the risk of suicide in those over the age of 65. It is taken by mouth.


Exploding head syndrome is classified as a parasomnia and a sleep-related dissociative disorder by the 2005 International Classification of Sleep Disorders and is an unusual type of auditory hallucination in that it occurs in people who are not fully awake. [6]

Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep. Most parasomnias are dissociated sleep states which are partial arousals during the transitions between wakefulness and NREM sleep, or wakefulness and REM sleep.

Dissociative disorders (DD) are conditions that involve disruptions or breakdowns of memory, awareness, identity, or perception. People with dissociative disorders use dissociation as a defense mechanism, pathologically and involuntarily. Some dissociative disorders are triggered by psychological trauma, but dissociative disorders such as depersonalization/derealization disorder may be preceded only by stress, psychoactive substances, or no identifiable trigger at all.

A paracusia, or auditory hallucination, is a form of hallucination that involves perceiving sounds without auditory stimulus.

Signs and symptoms

Individuals with exploding head syndrome hear or experience loud imagined noises as they are falling asleep or waking up, have a strong, often frightened emotional reaction to the sound, and do not report significant pain; around 10% of people also experience visual disturbances like perceiving visual static, lightning, or flashes of light. Some people may also experience heat, strange feelings in their torso, or a feeling of electrical tinglings that ascends to the head before the auditory hallucinations occur. [2] With the heightened arousal, people experience distress, confusion, myoclonic jerks, tachycardia, sweating, and the sensation that feels as if they have stopped breathing and have to make a deliberate effort to breathe again. [4] [7] [8] [9]

Tachycardia heart rate that exceeds the normal resting rate

Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal or abnormal.

The pattern of the auditory hallucinations is variable. Some people report having a total of two or four attacks followed by a prolonged or total remission, having attacks over the course of a few weeks or months before the attacks spontaneously disappear, or the attacks may even recur irregularly every few days, weeks, or months for much of a lifetime. [2]

Some individuals mistakenly believe that EHS episodes are not natural events, but are the effects of directed energy weapons which create an auditory effect. [10] Thus, EHS has been worked into conspiracy theories, but there is no scientific evidence that EHS has non-natural origins.


The cause of EHS is unknown. [3] A number of hypotheses have been put forth with the most common being dysfunction of the reticular formation in the brainstem responsible for transition between waking and sleeping. [2]

Other theories into causes of EHS include:


As of 2018, no clinical trials had been conducted to determine what treatments are safe and effective; a few case reports had been published describing treatment of small numbers of people (two to twelve per report) with clomipramine, flunarizine, nifedipine, topiramate, carbamazepine. [2] Studies suggest that education and reassurance can reduce the frequency of EHS episodes. [4] There is some evidence that individuals with EHS rarely report episodes to medical professionals. [9]


There have not been sufficient studies to make conclusive statements about how common or who is most often affected. [2] One study found that 14% of a sample of undergrads reported at least one episode over the course of their lives, with higher rates in those who also have sleep paralysis. [11]


Case reports of EHS have been published since at least 1876, which Silas Weir Mitchell described as "sensory discharges" in a patient. [11] However, it has been suggested that the earliest written account of EHS was described in the biography of the French philosopher René Descartes in 1691. [12] The phrase "snapping of the brain" was coined in 1920 by the British physician and psychiatrist Robert Armstrong-Jones. [11] A detailed description of the syndrome and the name "exploding head syndrome" was given by British neurologist John M. S. Pearce in 1989. [13] More recently, Peter Goadsby and Brian Sharpless have proposed renaming EHS "episodic cranial sensory shock" [1] as it describes the symptoms more accurately (including the non-auditory elements) and better attributes to Mitchell.

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Dementia with Lewy bodies Type of dementia associated with abnormal clumps of alpha-synuclein protein in neurons

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Sleep paralysis phenomenon

Sleep paralysis is when, during awakening or falling asleep, a person is aware but unable to move or speak. During an episode, one may hallucinate, which often results in fear. Episodes generally last less than a couple of minutes. It may occur as a single episode or be recurrent.

Rapid eye movement sleep behavior disorder sleep disorder that involves abnormal behavior including the acting out of violent or dramatic dreams during the sleep phase with rapid eye movement

Rapid eye movement sleep behavior disorder (RBD) is a sleep disorder in which people act out their dreams. It involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. The major feature of RBD is loss of muscle atonia during otherwise intact REM sleep. REM sleep is the stage of sleep in which most vivid dreaming occurs. The loss of motor inhibition leads to a wide spectrum of behavioral release during sleep. This extends from simple limb twitches to more complex integrated movement. These behaviors can be violent in nature and in some cases will result in injury to either the individual or their bed partner.

Cluster headache

Cluster headache (CH) is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye. There is often accompanying eye watering, nasal congestion, or swelling around the eye on the affected side. These symptoms typically last 15 minutes to 3 hours. Attacks often occur in clusters which typically last for weeks or months and occasionally more than a year.

Visual snow visual impairment

Visual snow, also known as visual static, is a proposed condition in which people see white or black dots in parts or the whole of their visual fields. The problem is typically always present and can last years.

Hypersomnia, or hypersomnolence, is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes and can cause distress and problems with functioning. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders.

Rhythmic movement disorder is a neurological disorder characterized by involuntary, repetitive movements of large muscle groups immediately before and during sleep often involving the head and neck. It was independently described first in 1905 by Zappert as jactatio capitis nocturna and by Cruchet as rhythmie du sommeil. The majority of RMD episodes occur during NREM sleep, although REM movements have been reported. RMD is often associated with other psychiatric conditions or mental disabilities. The disorder often leads to bodily injury from unwanted movements. Because of these incessant muscle contractions, patients’ sleep patterns are often disrupted. It differs from Restless Legs Syndrome in that RMD involves involuntary muscle contractions before and during sleep while Restless Legs Syndrome is the urge to move before sleep. RMD occurs in both males and females, often during early childhood with symptoms diminishing with age. Many sufferers also have other sleep related disorders, like sleep apnea. The disorder can be differentially diagnosed into small subcategories, including sleep related bruxism, thumb sucking, hypnagonic foot tremor, and rhythmic sucking, to name a few. In order to be considered pathological, the ICSD-II requires that in the sleep-related rhythmic movements should “markedly interfere with normal sleep, cause significant impairment in daytime function, or result in self-inflicted bodily injury that requires medical treatment ”.

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Musical hallucinations fall under the category of auditory hallucinations and describe a disorder in which a sound is perceived as instrumental music, sounds, or songs. It is a very rare disorder, reporting only 0.16% in a cohort study of 3,678 individuals.

Synucleinopathy neurodegenerative disease that is characterized by the abnormal accumulation of aggregates of alpha-synuclein protein in neurons, nerve fibres or glial cells

Synucleinopathies are neurodegenerative diseases characterised by the abnormal accumulation of aggregates of alpha-synuclein protein in neurons, nerve fibres or glial cells. There are three main types of synucleinopathy: Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). Other rare disorders, such as various neuroaxonal dystrophies, also have α-synuclein pathologies.

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