Sleep inversion or sleep-wake inversion is a reversal of
sleep
Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain Sensory nervous system, sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with th ...
ing tendencies. Individuals experiencing sleep-wake inversion exchange
diurnal habits for
nocturnal habits, meaning they are active at night and sleep during the day. Sleep-wake inversion, when involuntary, can be a sign of a serious disorder.
Presentation
Individuals with the delayed sleep phase type of the disorder exhibit habitually late sleep hours and an inability to change their sleeping schedule consistently. They often show sleepiness during the desired wake period of their days. Their actual phase of sleep is normal. Once they fall asleep, they stay asleep for a normal period of time, albeit a period of time that starts and stops at an abnormally late time.
Causes
Sleep inversion may be a symptom of
elevated blood ammonia levels and is often an early symptom of
hepatic encephalopathy
Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stag ...
. Sleep inversion is a feature of
African trypanosomiasis
African trypanosomiasis is an insect-borne parasitic infection of humans and other animals.
Human African trypanosomiasis (HAT), also known as African sleeping sickness or simply sleeping sickness, is caused by the species ''Trypanosoma bru ...
, after which the disease takes its common name, "African sleeping sickness"; sleep-wake cycle disturbances are the most common indication that the disease has reached the stage where infection spreads into the central nervous system.
See also
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Jet lag
Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones (east–west or west–east). ...
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Shift work sleep disorder
Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive Somnolence, sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to ...
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Circadian rhythm
A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the env ...
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Delayed sleep phase disorder
Delayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is the delaying of a person's circadian rhythm (biological clock) compared to those of societal norms. The dis ...
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Encephalitis lethargica
Encephalitis lethargica (EL) is an atypical form of encephalitis. Also known as "von Economo Encephalitis", "sleeping sickness" or "sleepy sickness" (distinct from tsetse fly–transmitted sleeping sickness), it was first described in 1917 by ne ...
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Lethargy
Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overw ...
References
Further reading
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External links
American Sleep Disorders Association
Sleep medicine
Sleep disorders