Rare Sleep Disorders


Common sleep disorders are at the heart of sleep medicine and have the greatest impact on overall patient health by virtue of their sheer numbers.

But sleep professionals must also be able to recognize those rare and uncommon sleep disorders that come along, even if only once in that proverbial blue moon. Here are a few of which to be aware:

Exploding Head Syndrome
This condition sounds much more dramatic than the actual name implies. Patients with Exploding Head Syndrome typically experience a sudden imaged loud noise or sensation of a violent explosion as they are falling asleep or waking in the night. A flash of light may also accompany this sensation. The sensation may be startling but is typically painless. The disorder is considered rare and there is no diagnostic testing for it.

A neurological work up may be considered to rule out other factors, such as a seizure disorder. As with a number of other parasomnias, obtaining an adequate amount of sleep on a routine basis would be recommended.

A concern for the patient is that they could develop anxiety about falling asleep because they are fearful of these events. Reassuring the patient that the disorder, though frightening, is generally benign can help relieve the anxiety.

SEE ALSO: First Sleep Apnea App

Sleep-Related Groaning (catathrenia)
This is another rare, typically benign parasomnia. Sleep related groaning typically occurs nightly during REM sleep. Patients with this disorder generally exhibit groaning or moaning sounds during exhalation. These sounds may be disturbing to a bed partner but the patient is typically unaware. Polysomnography would be useful to rule out sleep apnea.

Central Sleep Apnea Associated with High Altitude Periodic Breathing
This is basically what it sounds like. Most people sleeping at elevations above 4,000 meters tend to develop periodic breathing (due to hypoxemia at high altitudes). Luckily most people do not sleep at elevations that high. However, approximately 25% of people will develop this disorder at elevations higher than 2,000 meters.

People suffering from central sleep apnea may actually complain of insomnia (their sleep is disrupted by the periodic breathing but they feel like they have not fallen asleep). The easiest solution to this is to descend to a lower altitude. Alternatively, supplemental oxygen may prove beneficial.

Free Running Type (or non-entrained type)
This is a rare circadian rhythm disorder associated with a long body rhythm. There are cases where patients were found to have body rhythms lasting 30 to 36 hours in duration as opposed to the typical circadian rhythm of about 24 hours. These patients may have difficulty maintaining employment (often due to over sleeping) due to their long body rhythm.

“Sleep professionals must be able to recognize rare and uncommon sleep disorders.”

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Actigraphy and sleep logs (for one to two months) would be the primary tools to aid in diagnosing this disorder, ideally during a time when the patient is able to sleep ad lib. Psychological testing may be beneficial to rule out any contributing psychological factors.These patients find it very difficult to maintain a “normal schedule.” Ideally the patient would find employment that does not restrict them to a specific schedule, which, these days with the internet, may more feasible than in the past.

Mark J. Muehlbach is clinical director at Clayton Sleep Institute in St. Louis, is a Fellow of the American Academy of Sleep Medicine and has more than 33 years experience in sleep and sleep disorders research and treatment. He is an adjunct faculty member in the Department of Internal Medicine at Saint Louis University Medical School and in the Department of Behavioral and Social Sciences at Webster University, where he established a specialized course, “The Psychology of Sleep.”

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