Elsevier

Sleep Medicine

Volume 14, Issue 11, November 2013, Pages 1187-1191
Sleep Medicine

Original Article
Daytime somnolence in adult sleepwalkers

https://doi.org/10.1016/j.sleep.2013.04.029Get rights and content

Abstract

Objectives

Sleepwalkers often complain of excessive daytime somnolence (EDS). Our retrospective study aimed to document the presence of EDS in a substantial sample of sleepwalkers and to explore the contribution of other sleep disorders, nocturnal sleep disruption, and sleep depth to the alteration of their daytime vigilance.

Methods

Seventy adult sleepwalkers and 70 control subjects completed the Epworth Sleepiness Scale (ESS). Sleepwalkers also were studied for one night in the sleep laboratory. We compared the sleep profiles of 32 somnolent vs 38 nonsomnolent sleepwalkers and investigated the relationship between ESS scores and sleep-related variables.

Results

No differences were found in polysomnographic (PSG) parameters. Slow-wave activity (SWA) also was similar in the two subgroups. Sleepwalkers’ ESS scores were not correlated with their body mass index (BMI) or periodic limb movements during sleep (PLMS) index, but they tended to be negatively correlated with indices of respiratory events.

Conclusions

The EDS reported by adult sleepwalkers does not appear to be explained by the presence of concomitant sleep disorders or PSG signs of nocturnal sleep disruption. These results raise the possibility that EDS is part of the sleepwalking phenotype and that it is linked to its underlying pathophysiology.

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.

. ICMJE Form for Disclosure of Potential Conflicts of Interest form.

References (20)

There are more references available in the full text version of this article.

Cited by (26)

  • Somnambulism

    2024, Sleep Medicine Clinics
  • Sleepiness in sleepwalking and sleep terrors: a higher sleep pressure?

    2016, Sleep Medicine
    Citation Excerpt :

    The final regression model indicated that the level of sleepiness was determined by the sleep onset latency on night 1, the number of awakenings in N3 on night 1, and the total sleep time on night 2. The high frequency (46.8%) of patients with excessive daytime sleepiness among adult sleepwalkers found here corroborates recent observations in large groups of sleepwalkers, in which 41%–47% of patients had ESS greater than 10 [5,6,8]. This frequency was systematically higher than the frequency in age-matched healthy controls [5,6,8].

  • Idiopathic hypersomnia

    2016, Sleep Medicine Reviews
    Citation Excerpt :

    A consistent daily pattern, documented by a carefully kept sleep log (preferably confirmed by actigraphy) showing ten or more hours of sleep per night over a minimum of two weeks is desirable for the identification of the long sleeper. Recently, emphasis has been put on the frequent presence of fatigue upon awakening and hypersomnolence in sleepwalkers, in the absence of any concomitant sleep disorder [84,85]. Finally, there are conditions such as hypothyroidism [86], iron deficiency [87] or vitamine D storage insufficiency [88] which have been suggested as possible causes of hypersomnolence or fatigue, but still lack comprehensive characterization inclusive of objective measurements of sleep propensity and vigilance.

View all citing articles on Scopus
View full text