Exploding head syndrome

Exploding head syndrome (EHS) is a benign condition in which a person hears loud imagined noises (such as a bomb exploding, a gunshot, or a cymbal crash) or experiences an explosive feeling when falling asleep or waking up.^[1][2][3] These noises have a sudden onset, are typically brief in duration, and are often jarring for the sufferer.^[4]

Exploding head syndrome is classified as a parasomnia and a sleep-related dissociative disorder by the 2005 International Classification of Sleep Disorders,^[5] and is an unusual type of auditory hallucination in that it occurs in people who are not fully awake.^[6] Neither the cause nor the mechanism of exploding head syndrome is known.^[6] As of 2015 there had not been sufficient studies conducted to make conclusive statements about prevalence nor who tends to suffer EHS.^[7] It was 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 interviewed college students had 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.^[8]

Case reports of EHS have been published since at least 1876, which Silas Weir Mitchell described as "sensory discharges" in a patient.^[7] The phrase "exploding head syndrome" was coined in a 1920 report by the Welsh physician and psychiatrist Robert Armstrong-Jones.^[7] A detailed description of the syndrome was given by British neurologist John M. S. Pearce in 1989.^[9]

Symptoms

Individuals with exploding head syndrome hear or experience loud imagined noises as they are falling asleep or waking up. In his article, "Clinical features of the exploding head syndrome," J. M. Pearce asked individuals with exploding head syndrome to describe what noises they commonly heard during an episode. Examples included a loud bang, explosion, shot gun, thunderclap, loud metallic noise, firecrackers, and "noise as if head will burst open". 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. In some cases, some subjects reported that the sound was mild.^[10]

In addition to noise, some people report fear, distress, confusion, myoclonic jerks, tachycardia, sweating, tinnitus, simultaneously seeing flashes of light, and the sensation that felt as if they had stopped breathing and had to make a deliberate effort to breathe again.^{[2][10][11][12]}

The pattern of these auditory hallucinations is variable. Some patients 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. Some patients reported having up to seven EHS attacks throughout the night.^[10]

Causes

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. It is also postulated that with EHS, there is a delay in selected areas of the reticular formation.^[13]
• Minor seizures affecting the temporal lobe^[3]
• Sudden shifts in middle ear components^[3]
• Sensory variant of a hypnic jerk or sleep start
• Stress and anxiety^[14]
• Variable and broken sleep, associated with a decline in delta sleep^[10]
• Prior repetitive auditory trauma whereupon the victim's brain begins to anticipate the sound

Treatment

Several studies have indicated that EHS is significantly underreported, and in fact, many patients very rarely report it to their doctor because they are ashamed, or because they are met with incredulity or disbelief.

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, methylphenidate.^[1] Studies suggest that education and reassurance can reduce the frequency of EHS episodes.^[2]

References

Further reading

• Møller, Aage R.; Langguth, Berthold; DeRidder, Dirk; Kleinjung, Tobias (2010-11-16). Textbook of Tinnitus. Springer Science & Business Media. ISBN 9781607611455. 

External links

• American Academy of Sleep Medicine article on the syndrome.
• Loud crash at 3 a.m.? It may be your exploding head.