Sleepwalking is Increased By Sleep Deprivation
Abstract & Commentary
By Charles Pollak, MD Professor, Clinical Neurology, Director, Center for Sleep Medicine, Weill-Cornell Medical College. Dr. Pollak reports no financial relationships relevant to this field of study.
Synopsis: Sleep deprivation increases the frequency of episodes in patients with known sleepwalking, and supports the theory that the condition arises during slow-wave sleep.
Source: Zadra A, et al. Polysomnographic diagnosis of sleepwalking: effect of sleep deprivation. Ann Neurol 2008;63:513-519.
Sleepwalking (SW) is a common parasomnia, mainly of childhood, that can result in violence and self-injury; however, it can easily be controlled with benzodiazepines given at bedtime. It affects up to 4% of adults, including those taking hypnotic drugs such as zolpidem as well as those with active behavioral disorders. Clinical reports have suggested that SW is more likely to occur after sleep deprivation, but laboratory investigations of SW must rely on its spontaneous occurrence, which is rare.
Twenty-nine adults and one adolescent sleepwalker were studied. The frequency of SW varied from a few times a year to a few times a week (average, 9.7 episodes a month). The onset of SW was during childhood in most cases (73%). After one night in which their sleep was recorded in the sleep laboratory, they were kept awake for 25 hours and were then permitted to sleep ad libitum. SW episodes were recorded by synchronized video-polysomnography and classified by behavioral complexity, ranging from simple playing with bed sheets to full out-of-bed activity such as walking or running.
Sleep deprivation for 25 hours resulted in a marked increase in slow-wave sleep and a decrease in brief arousals. SW episodes increased as did their complexity, the number of episodes arising from slow-wave sleep, and the ratio of number of episodes arising from slow-wave sleep to the number of awakenings from slow-wave sleep. By increasing the proportion of sleepwalkers experiencing complex episodes, sleep deprivation increased diagnostic specificity.
Sleep disorders other than SW, mainly sleep apnea and periodic limb movements of sleep (PLMS), were not found among the subjects referred for SW, nor did apneas or PLMS closely precede SW episodes.
Although non-SW controls were not included in the study, 25-hour sleep deprivation was not associated with SW in other studies. Therefore, sleep deprivation alone does not cause SW, but it does increase the probability of SW in susceptible individuals.
Commentary
This report is significant for two reasons. First, it establishes sleep deprivation as a potent technique for inducing SW in predisposed individuals. If sleep deprivation can be maintained in the sleep laboratory for 25 hours (no easy task, as continuous observation is required), it may enable SW to be studied at will by direct observation. It would then become possible to make the diagnosis of SW with greater specificity in cases of injurious behavior or other medical-legal situations. For the same reason, patients with SW should be advised to avoid disruptions of sleep, including deviations from regular bedtime schedules. Second, it contributes to our understanding of the pathophysiology of SW. By intensifying slow-wave sleep, it reinforces the long-held view that SW is a phenomenon of slow-wave sleep or dysfunction of the mechanism for maintaining slow-wave sleep. This concept has been the working hypothesis since an early seminal paper by Roger Broughton, which described SW and other parasomnias as "disorders of arousal."1 By this, he meant that arousal was incomplete, did not eventuate in wakefulness, and instead produced a residuum of variably impaired consciousness and recall. What remains obscure is what triggers the disturbance of slow-wave sleep in the first place.
Reference
1. Broughton RJ. Science 1968;159:1070-1078.
Sleep deprivation increases the frequency of episodes in patients with known sleepwalking, and supports the theory that the condition arises during slow-wave sleep.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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