Exploding head syndrome

Exploding head syndrome
Other names Episodic cranial sensory shock,[1] snapping of the brain,[2] auditory sleep start[3]
Specialty Sleep medicine
Symptoms Hearing loud noises when falling asleep or waking up[2]
Duration Short[2]
Causes Unknown[3]
Differential diagnosis Nocturnal epilepsy, hypnic headaches, nightmare disorder, PTSD[2]
Treatment Reassurance, clomipramine, calcium channel blockers[2]
Prognosis Good[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 not a serious health concern.[2] People may also experience a flash of light.[5] Pain is typically absent.[2]

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]

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]


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]

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]

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.


  1. ^ a b Goadsby, Peter J.; Sharpless, Brian A. (2016-11-01). "Exploding head syndrome, snapping of the brain or episodic cranial sensory shock?". J Neurol Neurosurg Psychiatry. 87 (11): 1259–1260. doi:10.1136/jnnp-2015-312617. ISSN 0022-3050. PMID 26833175.
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa Sharpless, Brian A. (December 2014). "Exploding head syndrome". Sleep Medicine Reviews. 18 (6): 489–493. doi:10.1016/j.smrv.2014.03.001. PMID 24703829.
  3. ^ a b c d Blom JD (2015). Auditory hallucinations. Handb Clin Neurol. Handbook of Clinical Neurology. 129. pp. 433–55. doi:10.1016/B978-0-444-62630-1.00024-X. ISBN 9780444626301. PMID 25726283.
  4. ^ a b c Frese, A.; Summ, O.; Evers, S. (6 June 2014). "Exploding head syndrome: Six new cases and review of the literature". Cephalalgia. 34 (10): 823–827. doi:10.1177/0333102414536059. PMID 24907167.
  5. ^ a b c d e Ceriani, CEJ; Nahas, SJ (30 July 2018). "Exploding Head Syndrome: a Review". Current Pain and Headache Reports. 22 (10): 63. doi:10.1007/s11916-018-0717-1. PMID 30062616.
  6. ^ Thorpy, Michael J. (2012-10-01). "Classification of Sleep Disorders". Neurotherapeutics. 9 (4): 687–701. doi:10.1007/s13311-012-0145-6. ISSN 1933-7213. PMC 3480567. PMID 22976557.
  7. ^ Blom, Jan Dirk (2009-12-08). A Dictionary of Hallucinations. Springer Science & Business Media. ISBN 9781441912237.
  8. ^ Larner, Andrew J.; Coles, Alasdair J.; Scolding, Neil J.; Barker, Roger A. (2011-01-19). A-Z of Neurological Practice: A Guide to Clinical Neurology. Springer Science & Business Media. ISBN 9781848829947.
  9. ^ a b Sharpless, Brian A (2017-04-06). "Characteristic symptoms and associated features of exploding head syndrome in undergraduates". Cephalalgia. 38 (3): 595–599. doi:10.1177/0333102417702128. PMID 28385085.
  10. ^ A., Sharpless, Brian (2016-11-15). Unusual and rare psychological disorders : a handbook for clinical practice and research. ISBN 9780190245863. OCLC 952152912.
  11. ^ a b c Sharpless BA (2015). "Exploding head syndrome is common in college students". J Sleep Res. 24 (4): 447–9. doi:10.1111/jsr.12292. PMID 25773787.
  12. ^ Otaiku AI (2018). "Did René Descartes have Exploding Head Syndrome?". J Clin Sleep Med. 14 (4): 675–8. doi:10.5664/jcsm.7068. PMC 5886445. PMID 29609724.
  13. ^ Thorpy MJ, Plazzi G (2010). The Parasomnias and Other Sleep-Related Movement Disorders. Cambridge University Press. p. 231. ISBN 978-0-521-11157-7. Retrieved 2011-03-18.

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