Damien Leger

Prevalence and comorbidity of nocturnal wandering in the US adult general population

Objective: To assess the prevalence and comorbid conditions of nocturnal wandering with abnormal state of consciousness (NW) in the American general population. Methods: Cross-sectional study conducted with a representative sample of 19,136 noninstitutionalized individuals of the US general population ≥18 years old. The Sleep-EVAL expert system administered questions on life and sleeping habits; health; and sleep, mental, and organic disorders (DSM-IV-TR; International Classification of Sleep Disorders, version 2; International Classification of Diseases–10). Results: Lifetime prevalence of NW was 29.2% (95% confidence interval [CI] 28.5%–29.9%). In the previous year, NW was reported by 3.6% (3.3%–3.9%) of the sample: 1% had 2 or more episodes per month and 2.6% had between 1 and 12 episodes in the previous year. Family history of NW was reported by 30.5% of NW participants. Individuals with obstructive sleep apnea syndrome (odds ratio [OR] 3.9), circadian rhythm sleep disorder (OR 3.4), insomnia disorder (OR 2.1), alcohol abuse/dependence (OR 3.5), major depressive disorder (MDD) (OR 3.5), obsessive-compulsive disorder (OCD) (OR 3.9), or using over-the-counter sleeping pills (OR 2.5) or selective serotonin reuptake inhibitor (SSRI) antidepressants (OR 3.0) were at higher risk of frequent NW episodes (≥2 times/month). Conclusions: With a rate of 29.2%, lifetime prevalence of NW is high. SSRIs were associated with an increased risk of NW. However, these medications appear to precipitate events in individuals with a prior history of NW. Furthermore, MDD and OCD were associated with significantly greater risk of NW, and this was not due to the use of psychotropic medication. These psychiatric associations imply an increased risk due to sleep disturbance.

In flight automatic detection of vigilance states using a single EEG channel

Sleepiness and fatigue can reach particularly high levels during long-haul overnight flights. Under these conditions, voluntary or even involuntary sleep periods may occur, increasing the risk of accidents. The aim of this study was to assess the performance of an in-flight automatic detection system of lowvigilance states using a single electroencephalogram channel. Fourteen healthy pilots voluntarily wore a miniaturized brain electrical activity recording device during long-haul flights (10 ± 2.0 h, Atlantic 2 and Falcon 50 M, French naval aviation). No subject was disturbed by the equipment. Seven pilots experienced at least a periodofvoluntary(26.8 ± 8.0 min, n = 4)orinvoluntarysleep (N1 sleep stage, 26.6 ± 18.7 s, n = 7) during the flight. Automatic classification (wake/sleep) by the algorithm was made for 10-s epochs (O1-M2 or C3-M2 channel), based on comparison of means to detect changes in α, β, and θ relative power, or ratio [(α + θ)/β], or fuzzy logic fusion (α, β). Pertinence and prognostic of the algorithm were determined using epoch-by-epoch comparison with visual-scoring (two blinded readers, AASM rules). The best concordance between automatic detection and visualscoring was observed within the O1-M2 channel, using the ratio [(α + θ)/β] (98.3 ± 4.1% of good detection, K = 0.94 ± 0.07, with a 0.04 ± 0.04 false positive rate and a 0.87 ± 0.10 true positive rate). Our results confirm the efficiency of a miniaturized single electroencephalographic channel recording device, associated with an automatic detection algorithm, in order to detect low-vigilance states during real flights.

Differential Kinetics in Alteration and Recovery of Cognitive Processes from a Chronic Sleep Restriction in Young Healthy Men.

Chronic sleep restriction (CSR) induces neurobehavioral deficits in young and healthy people with a morning failure of sustained attention process. Testing both the kinetic of failure and recovery of different cognitive processes (i.e., attention, executive) under CSR and their potential links with subject’s capacities (stay awake, baseline performance, age) and with some biological markers of stress and anabolism would be useful in order to understand the role of sleep debt on human behavior. Twelve healthy subjects spent 14 days in laboratory with 2 baseline days (B1 and B2, 8 h TIB) followed by 7 days of sleep restriction (SR1-SR7, 4 h TIB), 3 sleep recovery days (R1–R3, 8 h TIB) and two more ones 8 days later (R12–R13). Subjective sleepiness (KSS), maintenance of wakefulness latencies (MWT) were evaluated four times a day (10:00, 12:00 a.m. and 2:00, 4:00 p.m.) and cognitive tests were realized at morning (8:30 a.m.) and evening (6:30 p.m.) sessions during B2, SR1, SR4, SR7, R2, R3 and R13. Saliva (B2, SR7, R2, R13) and blood (B1, SR6, R1, R12) samples were collected in the morning. Cognitive processes were differently impaired and recovered with a more rapid kinetic for sustained attention process. Besides, a significant time of day effect was only evidenced for sustained attention failures that seemed to be related to subject’s age and their morning capacity to stay awake. Executive processes were equally disturbed/recovered during the day and this failure/recovery process seemed to be mainly related to baseline subject’s performance and to their capacity to stay awake. Morning concentrations of testosterone, cortisol and α-amylase were significantly decreased at SR6-SR7, but were either and respectively early (R1), tardily (after R2) and not at all (R13) recovered. All these results suggest a differential deleterious and restorative effect of CSR on cognition through biological changes of the stress pathway and subject’s capacity (ClinicalTrials-NCT01989741).

Are confusional arousals pathological

Objective: The objective of this study was to determine the extent that confusional arousals (CAs) are associated with mental disorders and psychotropic medications. Methods: Cross-sectional study conducted with a representative sample of 19,136 noninstitutionalized individuals of the US general population aged 18 years or older. The study was performed using the Sleep-EVAL expert system and investigated sleeping habits; health; and sleep, mental, and medical conditions (DSM-IV-TR, ICSD-II, ICD-10). Results: A total of 15.2% (95% confidence interval 14.6%–15.8%) (n = 2,421) of the sample reported episodes of CAs in the previous year; 8.6% had complete or partial amnesia of the episodes and 14.8% had CAs and nocturnal wandering episodes. Eighty-four percent of CAs were associated with sleep/mental disorders or psychotropic drugs. Sleep disorders were present for 70.8% of CAs. Individuals with a circadian rhythm sleep disorder or a long sleep duration (≥9 hours) were at higher risk of CAs. Mental disorders were observed in 37.4% of CAs. The highest odds were observed in individuals with bipolar disorders or panic disorder. Use of psychotropic medication was reported by 31.3% of CAs: mainly antidepressant medications. After eliminating possible causes and associated conditions, only 0.9% of the sample had CA disorder. Conclusions: CAs are highly prevalent in the general population. They are often reported allegedly as a consequence of the treatment of sleep disorders. For the majority of subjects experiencing CAs, no medications were used, but among those who were using medications, antidepressants were most common. Sleep and/or mental disorders were important factors for CAs independent of the use of any medication.