Sleep Disorders
Christopher M Sinton, University of Texas Southwestern Medical Center, Dallas, Texas, USA
Robert W McCarley, Harvard Medical School, Brockton, Massachusetts, USA
Published online: May 2012
DOI: 10.1002/9780470015902.a0001483.pub2
Abstract
Sleep medicine is an increasingly important specialty as the adverse health consequences of disturbed sleep are recognised
by patients and physicians, and the current classification of sleep disorders, as recognised by the American Academy of Sleep
Medicine (AASM), is summarised. Two primary sleep disorders, narcolepsy with cataplexy and the disorders of arousal, a symptomatic
cluster that includes sleepwalking, confusional arousal and sleep terrors, are reviewed in greater detail. Both disorders
can be summarised as being caused by inappropriate switching between the states of vigilance, although they are very different
in age of onset, severity and impact on health. In narcolepsy the boundary between sleep and wakefulness is uncontrolled but
in the disorders of arousal the boundary between states of sleep is affected. These two disorders also have a genetic predisposition
suggesting that advances in knowledge of the relevant mutations could eventually translate into better understanding of the
possible mechanisms and hence lead to improved treatments.
Key Concepts:
-
The disorders of sleep are primary, for example as a result of pathology in the mechanisms of sleep and wakefulness, or secondary,
for example resulting from a medical condition.
-
Apnoea, interruptions of breathing lasting longer than 10 s that result in arousal from sleep, is the principal presenting
condition at sleep clinics.
-
Polysomnography is used to record physiological parameters such as respiration rate, heart rate and blood oxygen level simultaneously
with data allowing the stage of sleep or wakefulness to be defined.
-
Basic research into the neurophysiology, molecular genetics and neurochemistry of sleep and wakefulness has been critical
for understanding the causes of many sleep disorders.
-
The classification of sleep disorders is continuously evolving and being refined as new disorders are recognised in the clinic
and neurophysiological and neurochemical pathologies are better understood.
Keywords: polysomnography; apnoea; rapid eye movement (REM) sleep; non‐rapid eye movement (non‐REM) sleep; parasomnias; electroencephalogram (EEG)
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