Original ArticleDaytime somnolence in adult sleepwalkers
Introduction
Somnambulism (or sleepwalking) is defined by the American Academy of Sleep Medicine as “a series of complex behaviors that are usually initiated during arousals from slow-wave sleep (SWS) and culminate in walking around with an altered state of consciousness and impaired judgment.” Episodes generally develop from sudden but incomplete arousals from SWS and less often from stage 2 sleep [1], [2], [3], [4]. No major differences in the percentage of sleep stages or in sleep stage distribution have been observed between sleepwalkers and age-matched controls. The main distinguishing findings are the increased number of awakenings and electroencephalographic (EEG) microarousals (MA), specifically occurring in the SWS of sleepwalkers even on nights without episodes [2], [5], [6]. Some studies also found decreased slow-wave activity (SWA) in sleepwalkers’ first sleep cycles of the night [6], [7] and a different time course of their δ activity decay across the night [2].
Despite the documented increase in sleepwalkers’ nocturnal awakenings during SWS and their reduced SWA, there is a paucity of information on sleepwalkers’ daytime functioning. Recently a large survey of the general population reported that somnambulism was associated with sleepiness [8]. Additionally a laboratory study of 10 adults who consulted a sleep clinic for chronic somnambulism revealed that they reported excessive daytime somnolence (EDS) [9], even after a night without sleepwalking episodes. In fact, the sleepwalkers had significantly lower mean sleep latencies on the Multiple Sleep Latency Test (MSLT) than matched control subjects. Moreover, 7 of the 10 sleepwalkers had a mean latency below 8 min, which is the accepted threshold for clinical somnolence [10].
Our study aimed to better document the presence of EDS in a larger sample of subjects consulting for sleepwalking and to use polysomnography to assess the contribution of nocturnal events, nocturnal sleep disruption, and poor sleep depth to sleepwalkers’ EDS.
Section snippets
Subjects
Seventy sleepwalkers (40 women, 30 men; mean age, 33.1 ± 10.1 years; age range, 17–60 years) were included in our study. All subjects were investigated for at least one night in the sleep laboratory and completed the Epworth Sleepiness Scale (ESS) [11]. None of the subjects had sleep-disordered breathing or concomitant neurologic or psychiatric disorders, and none of the subjects were taking psychotropic medications. Seventy control subjects (42 women, 28 men; mean age, 35.5 ± 14.0 years; age range,
Results
The mean ESS score for the 70 sleepwalkers was significantly higher than that of controls (9.1 ± 4.5 vs 5.8 ± 3.4; P = .000003). Thus nearly half (45.7%) of the subjects who consulted a sleep disorders center for sleepwalking without concomitant depression reported EDS, as indexed by a score greater than 10 on the ESS. The distribution of ESS scores per group is shown in Fig. 1.
Discussion
Our study revealed that a significant number of adult sleepwalkers reported EDS. This finding does not apply to childhood somnambulism, which is much more prevalent but usually does not require any intervention, given its transitory and relatively harmless nature. This finding suggests that the widespread notion of adulthood somnambulism as a parasomnia without consequences on daytime functioning should be reconsidered. Moreover, the findings indicate the somnolence associated with somnambulism
Financial disclosures
This study is not industry sponsored.
Dr. Desautels received a research grant from GlaxoSmithKline. Dr. Dauvilliers has received funds for speaking and board engagements with UCB, Cephalon, Jazz, Novartis and Bioprojet. Dr. Montplaisir received research grants/support from Merck and GlaxoSmithKline, served as an advisor for Sanofi-Aventis, Servier, Merck, Jazz Pharmaceutical, Valeant Pharmaceutical, and Impax Laboratories, and received honoraria for speaking engagements from Valeant
Author contributions
Dr. Desautels: data analysis, interpretation, and first draft of the manuscript.1.
Dr. Zadra: study concept and design, interpretation, and critical revision of the manuscript for important intellectual content.
Mr. Labelle: acquisition of data.
Dr. Dauvilliers: critical revision of the manuscript for important intellectual content.
Dr. Petit: acquisition of data, data analysis, and critical revision of the manuscript.
Dr. Montplaisir: study concept and design, critical revision of the manuscript
Conflict of interest
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2013.04.029.
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