Exploding head syndrome
|Exploding head syndrome|
|Classification and external resources|
Exploding head syndrome (EHS) is a condition in which a person hears loud noises (such as a bomb exploding, a gunshot, or a cymbal crash) or experiences an explosive feeling when falling asleep or waking up. These noises have a sudden onset, are typically brief in duration, and are often jarring for the sufferer.
Exploding head syndrome is classified as a parasomnia in 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. Neither the cause nor the mechanism of exploding head syndrome is known. As of 2015, there had not been sufficient studies conducted to make conclusive statements about prevalence nor who tends to suffer EHS. However, it has been previously thought that EHS was a rare syndrome, occurring primarily in older (i.e. 50+ years) individuals, females, and those suffering from sleep paralysis. However, a study in 2015 has shown that EHS affects more younger people than thought, reporting that nearly one in five of college students interviewed experienced EHS at least once. Statistics from the study did not show that EHS was more frequent in females, but instead found that more than one-third of those who had EHS also experienced isolated sleep paralysis. Furthermore, the study found that some subjects experienced Exploding Head Syndrome to such a degree that it significantly impacted their lives.
Case reports of EHS have been published since at least since 1876, which Silas Weir Mitchell described as "sensory discharges" in a patient. The phrase "exploding head syndrome" was coined in a 1920 report by the Welsh physician and psychiatrist Robert Armstrong-Jones. A detailed description of the syndrome was given by British neurologist John M. S. Pearce in 1989.
In addition to noise, some people report fear, distress, confusion, myoclonic jerks, tachycardia, sweating, seeing flashes of light, and the sensation as if they had stopped breathing and had to make a deliberate effort to breathe again. Because the sound seems to occur abruptly and with apparently great force, patients may be so alarmed that they may initially and inaccurately describe the noise as pain. In fact, in a clinical study, some patients reported the sound as an "enormous roar, so loud it could kill me" However, upon closer questioning in several studies, there is no pain associated with the syndrome. These auditory hallucinations may occur for a few weeks or months and then spontaneously disappear, or may recur irregularly every few days, weeks, or months for much of a lifetime 
Though the causes of EHS are not known, there are currently a few theories to explain its causes:
- Experts believe that EHS occurs due to the brain having problems when shutting down areas of the brain in preparation of sleep. Usually, different parts of the brain (such as auditory, motor, and visual neurons) shut off in different stages. With EHS, the auditory neurons may instead be activated all at once instead of shutting down properly, causing the abrupt, and often jarring, auditory hallucination. In addition, it is also postulated that with EHS, there is a delay in selected areas of the reticular formation.
- Minor seizures affecting the temporal lobe
- Sudden shifts in middle ear components
- Sensory variant of a hypnic jerk or sleep start
- Stress and anxiety
Several studies have indicated that EHS is significantly underreported.
As of 2014, 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, Ritalin. However, studies suggest that education and reassurance can reduce the frequency of EHS episodes.
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- 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.
- "Exploding Head Syndrome - American Sleep Association". www.sleepassociation.org. https://plus.google.com/u/0/b/115213926650718696189/115213926650718696189/about/p/pub. Retrieved 2015-11-28.
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- Thorpy MJ, Plazzi G (2010). The Parasomnias and Other Sleep-Related Movement Disorders. Cambridge University Press. p. 231. ISBN 0-521-11157-9. Retrieved 2011-03-18.
- Blom, Jan Dirk (2009-12-08). A Dictionary of Hallucinations. Springer Science & Business Media. ISBN 9781441912237.
- 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.
- Pearce, J.M. (July 1989). "Clinical features of the exploding head syndrome". Journal of Neurology, Neurosurgery, and Psychiatry. Retrieved November 28, 2015.
- Bever, Lindsey (2015-04-02). "That loud bang that startles you awake: It may be ‘exploding head syndrome’". The Washington Post (in en-US). ISSN 0190-8286. Retrieved 2015-11-28.
- "Exploding Head Syndrome - Harmless But Disturbing". Nosleeplessnights.com (in en-US). Retrieved 2015-11-28.
- Feketeova, Eva Feketeova (June 2014). "Exploding head syndrome – a rare parasomnia or a dissociative episode?". Sleep Medicine. Retrieved November 28, 2015.
- American Academy of Sleep Medicine article on the syndrome.
- Loud crash at 3 a.m.? It may be your exploding head.
- Møller, Aage R.; Langguth, Berthold; DeRidder, Dirk; Kleinjung, Tobias (2010-11-16). Textbook of Tinnitus. Springer Science & Business Media. ISBN 9781607611455.