A normative study of the maintenance of wakefulness test (MWT)

Revisiting the maintenance of wakefulness test: from intra-/inter-scorer agreement to normative values in patients treated for obstructive sleep apnea

The Maintenance of Wakefulness Test is widely used to objectively assess sleepiness and make safety-related decisions, but its interpretation is subjective and normative values remain debated. Our work aimed to determine normative thresholds in non-subjectively sleepy patients with well-treated obstructive sleep apnea, and to assess intra- and inter-scorer variability. We included maintenance of wakefulness tests of 141 consecutive patients with treated obstructive sleep apnea (90% men, mean (SD) age 47.5 (9.2) years, mean (SD) pre-treatment apnea-hypopnea index of 43.8 (20.3) events/h). Sleep onset latencies were independently scored by two experts. Discordant scorings were reviewed to reach a consensus and half of the cohort was double-scored by each scorer. Intra- and inter-scorer variability was assessed using Cohen's kappa for 40, 33, and 19 min mean sleep latency thresholds. Consensual mean sleep latencies were compared between four groups according to subjective sleepiness (Epworth Sleepiness Scale score < versus ≥11) and residual apnea-hypopnea index (< versus ≥15 events/h). In well-treated non-sleepy patients (n = 76), the consensual mean (SD) sleep latency was 38.4 (4.2) min (lower normal limit [mean - 2SD] = 30 min), and 80% of them did not fall asleep. Intra-scorer agreement on mean sleep latency was high but inter-scorer was only fair (Cohen's kappa 0.54 for 33-min threshold, 0.27 for 19-min threshold), resulting in changes in latency category in 4%-12% of patients. A higher sleepiness score but not the residual apnea-hypopnea index was significantly associated with a lower mean sleep latency. Our findings suggest a higher than usually accepted normative threshold (30 min) in this context and emphasise the need for more reproducible scoring approaches.

Objective evaluation of excessive daytime sleepiness

Excessive daytime sleepiness (EDS) is multifactorial. It combines, among other things, an excessive propensity to fall asleep ("physiological sleepiness") and a continuous non-imperative sleepiness (or drowsiness/hypo-arousal) leading to difficulties remaining awake and maintaining sustained attention and vigilance over the long term ("manifest sleepiness"). There is no stand-alone biological measure of EDS. EDS measures can either capture the severity of physiological sleepiness, which corresponds to the propensity to fall asleep, or the severity of manifest sleepiness, which corresponds to behavioral consequences of sleepiness and reduced vigilance. Neuropsychological tests (The psychomotor vigilance task (PVT), Oxford Sleep Resistance Test (OSLeR), Sustained Attention to Response Task (SART)) explore manifest sleepiness through several sustained attention tests but the lack of normative values and standardized protocols make the results difficult to interpret and use in clinical practice. Neurophysiological tests explore the two main aspects of EDS, i.e. the propensity to fall asleep (Multiple sleep latency test, MSLT) and the capacity to remain awake (Maintenance of wakefulness test, MWT). The MSLT and the MWT are widely used in clinical practice. The MSLT is recognized as the "gold standard" test for measuring the severity of the propensity to fall asleep and it is a diagnostic criterion for narcolepsy. The MWT measures the ability to stay awake. The MWT is not a diagnostic test as it is recommended only to evaluate the evolution of EDS and efficacy of EDS treatment. Even if some efforts to standardize the protocols for administration of these tests have been ongoing, MSLT and MWT have numerous limitations: age effect, floor or ceiling effects, binding protocol, no normal or cutoff value (or determined in small samples), and no or low test-retest values in some pathologies. Moreover, the recommended electrophysiological set-up and the determination of sleep onset using the 30‑sec epochs scoring rule show some limitations. New, more precise neurophysiological techniques should aim to detect very brief periods of physiological sleepiness and, in the future, the brain local phenomenon of sleepiness likely to underpin drowsiness, which could be called "physiological drowsiness".

A New Screening Tool (BAMSA) for Sleep Apnea in Male Professional Truck Drivers

Obstructive sleep apnea (OSA) is common in professional truck drivers. It is important that OSA is recognized since undiagnosed and/or untreated sleep apnea is a risk factor for sleepiness-related traffic accidents. In this study, we developed a new simple tool to screen for obstructive sleep apnea (OSA) in this population. Altogether, 2066 professional truck drivers received a structured questionnaire. A total of 175 drivers had a clinical examination and were invited to participate in sleep laboratory studies, including cardiorespiratory polygraphy. We studied associations of different risk factors with the presence of sleep apnea. We established a new simple screening tool for obstructive sleep apnea (OSA) that was compared to other existing screening tools. A total of 1095 drivers completed the questionnaire. Successful cardiorespiratory polygraphy was obtained for 172 drivers. Full data were available for 160 male drivers included in the analyses. The following five risk factors for sleep apnea formed the BAMSA score (0 to 5): BMI > 30 kgm-2, age > 50 years, male gender, snoring at least one night per week, and the presence of apnea at least sometimes. BAMSA showed a sensitivity of 85.7% and a specificity of 78.8% in detecting AHI ≥ 15 when using a cut-off point of 4, and the ROC area was 0.823. BAMSA is a sensitive and easy-to-use tool in predicting obstructive sleep apnea in male professional drivers.

Evaluation of hypersomnolence: From symptoms to diagnosis, a multidimensional approach

Hypersomnolence is a major public health issue given its high frequency, its impact on academic/occupational functioning and on accidentology, as well as its heavy socio-economic burden. The positive and aetiological diagnosis is crucial, as it determines the therapeutic strategy. It must consider the following aspects: i) hypersomnolence is a complex concept referring to symptoms as varied as excessive daytime sleepiness, excessive need for sleep, sleep inertia, or drowsiness, all of which warrant specific dedicated investigations; ii) the boundary between physiological and abnormal hypersomnolence is blurred, since most symptoms can be encountered in the general population to varying degrees without being considered as pathological, meaning that their severity, frequency, context of occurrence and related impairment need to be carefully assessed; iii) investigation of hypersomnolence relies on scales/questionnaires as well as behavioural and neurophysiological tests, which measure one or more dimensions, keeping in mind the possible discrepancy between objective and subjective assessment; iv) aetiological reasoning is driven by knowledge of the main sleep regulation mechanisms, epidemiology, and associated symptoms. The need to assess hypersomnolence is growing, both for its management, and for assessing the efficacy of treatments. The landscape of tools available for investigating hypersomnolence is constantly evolving, in parallel with research into sleep physiology and technical advances. These investigations face the challenges of reconciling subjective perception and objective data, making tools accessible to as many people as possible and predicting the risk of accidents.

Assessment of Vigilance and Fatigue

This article summarizes the definitions of vigilance, fatigue, and sleepiness, as well as tools used in their assessment. Consideration is given to the strengths and limitations of the different subjective and objective tools. Future directions for research are also discussed, as well as the public health importance of continued investigation in this subject.

Oral Orexin Receptor 2 Agonist in Narcolepsy Type 1

BACKGROUND

Narcolepsy type 1 is caused by severe loss or lack of brain orexin neuropeptides.

METHODS

We conducted a phase 2, randomized, placebo-controlled trial of TAK-994, an oral orexin receptor 2-selective agonist, in patients with narcolepsy type 1. Patients with confirmed narcolepsy type 1 according to clinical criteria were randomly assigned to receive twice-daily oral TAK-994 (30 mg, 90 mg, or 180 mg) or placebo. The primary end point was the mean change from baseline to week 8 in average sleep latency (the time it takes to fall asleep) on the Maintenance of Wakefulness Test (range, 0 to 40 minutes; normal ability to stay awake, ≥20 minutes). Secondary end points included the change in the Epworth Sleepiness Scale (ESS) score (range, 0 to 24, with higher scores indicating greater daytime sleepiness; normal, <10) and the weekly cataplexy rate.

RESULTS

Of the 73 patients, 17 received TAK-994 at a dose of 30 mg twice daily, 20 received 90 mg twice daily, 19 received 180 mg twice daily, and 17 received placebo. The phase 2 trial and an extension trial were terminated early owing to hepatic adverse events. Primary end-point data were available for 41 patients (56%); the main reason for missing data was early trial termination. Least-squares mean changes to week 8 in average sleep latency on the MWT were 23.9 minutes in the 30-mg group, 27.4 minutes in the 90-mg group, 32.6 minutes in the 180-mg group, and -2.5 minutes in the placebo group (difference vs. placebo, 26.4 minutes in the 30-mg group, 29.9 minutes in the 90-mg group, and 35.0 minutes the 180-mg group; P<0.001 for all comparisons). Least-squares mean changes to week 8 in the ESS score were -12.2 in the 30-mg group, -13.5 in the 90-mg group, -15.1 in the 180-mg group, and -2.1 in the placebo group (difference vs. placebo, -10.1 in the 30-mg group, -11.4 in the 90-mg group, and -13.0 in the 180-mg group). Weekly incidences of cataplexy at week 8 were 0.27 in the 30-mg group, 1.14 in the 90-mg group, 0.88 in the 180-mg group, and 5.83 in the placebo group (rate ratio vs. placebo, 0.05 in the 30-mg group, 0.20 in the 90-mg group, and 0.15 in the 180-mg group). A total of 44 of 56 patients (79%) receiving TAK-994 had adverse events, most commonly urinary urgency or frequency. Clinically important elevations in liver-enzyme levels occurred in 5 patients, and drug-induced liver injury meeting Hy's law criteria occurred in 3 patients.

CONCLUSIONS

In a phase 2 trial involving patients with narcolepsy type 1, an orexin receptor 2 agonist resulted in greater improvements on measures of sleepiness and cataplexy than placebo over a period of 8 weeks but was associated with hepatotoxic effects. (Funded by Takeda Development Center Americas; TAK-994-1501 and TAK-994-1504 ClinicalTrials.gov numbers, NCT04096560 and NCT04820842.).

An overview of the effects of levodopa and dopaminergic agonists on sleep disorders in Parkinson's disease

Sleep disorders are among the most common nonmotor symptoms in Parkinson's disease and are associated with reduced cognition and health-related quality of life. Disturbed sleep can often present in the prodromal or early stages of this neurodegenerative disease, rendering it crucial to manage and treat these symptoms. Levodopa and dopaminergic agonists are frequently prescribed to treat motor symptoms in Parkinson's disease, and there is increasing interest in how these pharmacological agents affect sleep and their effect on concomitant sleep disturbances and disorders. In this review, we discuss the role of dopamine in regulating the sleep-wake state and the impact of neurodegeneration on sleep. We provide an overview of the effects of levodopa and dopaminergic agonists on sleep architecture, insomnia, excessive daytime sleepiness, sleep-disordered breathing, rapid eye movement sleep behavior disorder, and restless legs syndrome in Parkinson's disease. Levodopa and dopaminergic drugs may have different effects, beneficial or adverse, depending on dosing, method of administration, and differential effects on the different dopamine receptors. Future research in this area should focus on elucidating the specific mechanisms by which these drugs affect sleep in order to better understand the pathophysiology of sleep disorders in Parkinson's disease and aid in developing suitable therapies and treatment regimens.

CITATION

Scanga A, Lafontaine A-L, Kaminska M. An overview of the effects of levodopa and dopaminergic agonists on sleep disorders in Parkinson's disease. J Clin Sleep Med. 2023;19(6):1133-1144.

Multiple Sleep Latency Test/Maintenance of Wakefulness Test and Central Hypersomnias: Evolving Diagnostic and Therapeutic Approaches

SUMMARY

Central disorders of hypersomnolence include a spectrum of conditions, such as narcolepsy, idiopathic hypersomnia, and Kleine-Levin syndrome, in which excessive daytime sleepiness is the primary feature. Subjective testing with tools, such as sleep logs and sleepiness scales, are often helpful in the evaluation of these disorders but do not necessarily correlate well with objective testing, such as polysomnography and multiple sleep latency test and maintenance of wakefulness test. The most recent International Classification of Sleep Disorders-Third Edition has incorporated biomarkers, such as cerebrospinal fluid hypocretin level, into the diagnostic criteria and have restructured the classification of conditions based on our evolved understanding of their underlying pathophysiologic mechanisms. Therapeutic approaches largely consist of behavioral therapy, with a focus on optimizing sleep hygiene, optimizing opportunity for sleep, and strategic napping, along with judicious use of analeptic and anticataleptic agents when necessary. Emerging therapy has revolved around hypocretin-replacement therapy, immunotherapy, and nonhypocretin agents, with the goal of better targeting the underlying pathophysiology of these disorders rather than addressing symptoms. The most novel treatments have targeted the histaminergic system (pitolisant), dopamine reuptake transmission (solriamfetol), and gamma-aminobutyric acid modulation (flumazenil and clarithromycin) to promote wakefulness. Continued research is required for a more solid understanding of the biology of these conditions to develop a more robust armamentarium of therapeutic options.

Placebo response in objective and subjective measures of hypersomnia in randomized clinical trials on obstructive sleep apnea. A systematic review and meta-analysis

Sleepiness is one of the outcomes most used in randomized clinical trials (RCT) on the effect of treatments for obstructive sleep apnea (OSA). Furthermore, it is known that there is a placebo effect, especially in subjective measures. Therefore, given that sleepiness is a subjective measure, the objective of this systematic review with meta-analysis and three-level meta-regression was to assess the response to different placebos (pills and sham-CPAP) used in RCTs in OSA, both on subjective (Epworth Sleepiness Scale [ESS]) and objective (Multiple Sleep Latency Test [MSLT], Maintenance Wake Test [MWT], the Osler test and the Psychomotor Vigilance Task [PVT]). We observed a statistically significant placebo effect in both subjective and objective measures of hypersomnia, and in both sham-CPAP and pills. This placebo effect was greater, even clinically significant, in subjective measures (ESS: -2.84 points) and in those RCTs that used pills as a placebo. In the meta-regression, only a higher baseline value of the ESS and Osler test was related to the placebo effect.

Usefulness of the maintenance of wakefulness test in central disorders of hypersomnolence: a scoping review

Study Objectives

To review the Maintenance of Wakefulness Test (MWT) as assessment of daytime sleepiness in the evaluation of treatment effects and driving fitness in central disorders of hypersomnolence (CDH).

Methods

We performed a scoping review of studies using the MWT in patients with CDH (i.e. narcolepsy types 1 and 2, and idiopathic hypersomnia). N = 20 articles were included, comprising 683 patients and 129 controls. MWT effect sizes were compared to the Clinical Global Impression (GCI) scale and the Epworth Sleepiness Scale (ESS). MWT sleep latency was correlated to objective driving performances. The role of motivation was evaluated by comparing MWTs of treatment studies (low motivation) to driving fitness studies (high motivation to stay awake). Healthy controls were compared to norm values.

Results

MWT and CGI were both impacted by the same treatment; however, the MWT has higher effect sizes and was more sensitive to measure these effects. The MWT correlated fairly to moderately (ρ = −0.26 to −0.56; p ≤ .05) to objective driving performance. Motivation played a major role on MWT sleep latencies (d = 0.76 to 1.43; p ≤ .001). Current norm values may not be valid, as sleep latency may be impacted by age.

Conclusions

The MWTs applicability to measure treatment effects in CDH was confirmed, but age-adjusted norm values are needed. For a more complete evaluation of EDS it should be combined with subjective measures. Its reliability for driving fitness evaluation is insufficient, and motivation plays a major role. To predict or monitor driving performance in CDH, valid and easy methods should be developed.

Fatigue, sleepiness and depression in multiple sclerosis: defining the overlaps for a better phenotyping

BACKGROUND AND OBJECTIVES

To define the boundaries and the overlaps between fatigue, sleepiness and depression in patients with multiple sclerosis (MS) by using different tools for each dimension, including instrumental sleep analysis.

METHODS

In this cross-sectional, observational study, 71 MS patients (males/females: 20/51; mean age: 48.9 ± 10.5 years) filled in clinical questionnaires and performed polysomnography followed by maintenance of wakefulness test (MWT). Frequency and reciprocal overlap of sleepiness, fatigue and depression in MS were expressed by Eulero-Venn diagrams; standard multiple regression was used to assess the ability of symptoms to predict each other.

RESULTS

There was a high percentage of fatigued (70%), somnolent (45%) and depressed (27%) patients. Fatigue had the strongest overlap and correlated with both depression (beta: 0.52, p < 0.001) and sleepiness (beta: 0.74, p < 0.001). Somnolence and depression were nearly always accompanied by fatigue and were well differentiated from each other by MWT. Four MS subgroups were identified that had: (1) fatigue only; (2) fatigue and sleepiness (3) fatigue and depression; (4) fatigue, sleepiness and depression.

DISCUSSION

The subjective and objective tools are not able to clearly distinguish fatigue from sleepiness and depression, while only a test of vigilance can be helpful in separating somnolence and depression from each other.

Optimal dose determination of enerisant (TS-091) for patients with narcolepsy: two randomized, double-blind, placebo-controlled trials

BACKGROUND

The histamine H3 receptor has emerged as one of the most promising targets of novel pharmacotherapy for narcolepsy. Studies now aim to investigate the optimal dose of enerisant, a novel H3 antagonist/inverse agonist, for the treatment of excessive daytime sleepiness in patients with narcolepsy.

METHODS

We conducted two phase 2, fixed-dose, double-blind, randomized, placebo-controlled trials in patients with narcolepsy. The first phase 2 study (Study 1) was conducted to investigate the efficacy and safety of enerisant at dosages of 25, 50, and 100 mg/day administered for 3 weeks based on the results of a phase 1 study conducted on healthy volunteers. The primary endpoint was mean sleep latency in maintenance of wakefulness test (MWT), and the secondary endpoint was the total score on the Epworth Sleepiness Scale (ESS). The dosages of enerisant in the second phase 2 study (Study 2) were set at 5 and 10 mg/day based on the simulation of receptor occupancy results from positron emission tomography study.

RESULTS

Forty-six and fifty-three patients were randomized in Study 1 and Study 2, respectively. The efficacy of enerisant was partially confirmed in Study 1 with ESS; however, the doses were not tolerated, and there were many withdrawals due to adverse events (mainly insomnia, headache, and nausea). The doses in Study 2 were well tolerated, with a lower incidence of adverse events in Study 2 than in Study 1, although the efficacy could not be confirmed with MWT and ESS in Study 2.

CONCLUSIONS

The optimal dose of enerisant could not be determined in these two studies. Although enerisant has a favorable pharmacokinetic profile, it is thought to have large interindividual variabilities in terms of efficacy and safety, suggesting the necessity of tailored dosage adjustments.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03267303 ; Registered 30 August 2017 (Study 2). Japic identifier: JapicCTI-142529 ; Registered 7 May 2014 (Study 1) and JapicCTI-173689 ; Registered 30 August 2017, https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?clinicalTrialId=29277 (Study 2).

Revisiting the Concept of Vigilance

Vigilance deficits can be observed after a period of prolonged, continuous wakefulness. In this context there has been extensive research targeting the impact of sleep deficits on different aspects of vigilance, but the underlying concept of vigilance was hardly ever addressed and discussed. One reason for this shortcoming is the unclear and ambiguous definition of the term vigilance, which is commonly used interchangeably with sustained attention and even wakefulness. This confusion is the result of a wide range of misleading definitions, starting in the 1940s, as psychologists redefined the concept of vigilance suggested by British Neurologist, Henry Head, in 1923. Nevertheless, the concept of vigilance is still useful and innovative, especially in treating sleep problems in children and young adults. This paper reviews the current usage of the term vigilance in sleep-wake-research and describes not only the benefits, but even more clearly, its limitations. By re-focusing on the definitions given by Henry Head, the concept of vigilance is an innovative way to gather new insights into the interplay between sleep- and daytime behaviors. In addition, future research on vigilance should consider three perspectives: 1st vigilance perceived as a process to allocate resources, 2nd vigilance associated with compensatory behaviors and 3rd the role of vigilance in human environmental interactions. This approach, understood as a conceptual framework, provides new perspectives by targeting sleep-wake behaviors as a 'real life' outcome measure, reflecting both physical and cognitive performance as well as sleep quality and quantity.

Sleep-Related Breathing Disorders in Multiple Sclerosis: Prevalence, Features and Associated Factors

BACKGROUND

Multiple sclerosis (MS) represents a risk factor for sleep disorders, but there are conflicting results about the prevalence and severity of sleep-related breathing disorders (SRBD) in MS. Most available data come from self-administered questionnaires.

OBJECTIVE

To conduct a polysomnographic study in MS focused on SRBD, compared to a group of healthy controls (HC), also considering the neuroimaging findings. To evaluate the impact of SRBD on vigilance, fatigue and depression in MS.

METHODS

In this cross-sectional, observational, instrumental study, 67 MS patients (men/women: 20/47; mean age: 50.6±8.2 years) underwent PSG and maintenance of wakefulness test. Findings were compared to 67 age-, sex-, BMI-matched HC, by using parametric (Student's t-test) and nonparametric statistics (chi-squared test). A subgroup analysis was then performed, evaluating the influence of brainstem (mesencephalic, pontine and medullary) lesions at neuroimaging on instrumental and clinical data: MS patients with at least one brainstem lesion vs MS patients without vs HC.

RESULTS

The frequency of SRBD was comparable in MS patients and HC. No MS patient had a central apnea index ≥2/h. The respiratory disturbance index (RDI) did not correlate to clinical parameters such as fatigue and depression. Patients with MS were drowsier than HC (47% vs 26%, p = 0.019) and showed a worse sleep pattern, in terms of duration, efficiency and architecture.

CONCLUSION

Our study does not provide evidence of an association between MS-specific symptoms such as fatigue, sleepiness, depression and central or obstructive apneas, even in the presence of brainstem lesions.

High prevalence of pathological alertness and wakefulness on maintenance of wakefulness test in adults with focal-onset epilepsy

BACKGROUND

Excessive daytime sleepiness (EDS) is a common complaint in adults with epilepsy (AWE), but objective evaluation is lacking. We used the maintenance of wakefulness test (MWT) to objectively measure the ability of adults with focal-onset epilepsy to maintain wakefulness in soporific conditions.

METHODS

Adults with epilepsy participating in a study investigating the effects of lacosamide on sleep and wakefulness underwent baseline ambulatory polysomnography (PSG)/EEG followed by MWT. Mean sleep latency (MSL) and mean percent sleep time (MST, mean percentage of non-wake EEG scored in 3-sec bins from lights out to sleep onset averaged over the 4 MWT trials) were quantified. Subjective sleepiness was assessed by the Epworth Sleepiness Scale (ESS). Spearman correlation and linear regression assessed relationships between MWT parameters, ESS and relevant sleep and epilepsy-related variables.

RESULTS

Maintenance of wakefulness test MSL in 51 AWE (mean age 43.5 ± 13 years, 69% female, mean BMI 24.6 ± 11.2 kg/m²) was 21.7 ± 11.9 min; 45.1% had an abnormally short MSL <19.4 min and 15.7% <8 min. MST was 9.3% [3.3, 19.1]. Mean ESS score was 8.8 ± 5.7; 39% had elevated ESS (>10). No correlation between subjective ESS and objective MSL (p = 0.67) or MST (p = 0.61) was found. MSL was significantly shorter in subjects with focal to bilateral tonic-clonic seizures (FBTCS; 7.9 min [13.6, 22.3]) compared to those without (27.4 min [21.2, 33.6], p = 0.013). Younger subjects had shorter MSL; MSL increased 3.2 min for every 10-year increase in age.

CONCLUSION

We found a high prevalence of objective sleepiness/difficulty maintaining wakefulness on the MWT and subjective sleepiness using the ESS in AWE without a correlation between the two. More severe objective sleepiness was found in subjects with a history of FBTCS and younger age. Further research is needed to determine mechanistic underpinnings and optimal measurements of pathological sleepiness in people with epilepsy given the burden of it on quality of life.

Predictors of interindividual differences in vulnerability to neurobehavioral consequences of chronic partial sleep restriction

Interindividual differences in the neurobehavioral response to sleep loss are largely unexplained and phenotypic in nature. Numerous factors have been examined as predictors of differential response to sleep loss, but none have yielded a comprehensive view of the phenomenon. The present study examines the impact of baseline factors, habitual sleep-wake patterns, and homeostatic response to sleep loss on accrued deficits in psychomotor vigilance during chronic partial sleep restriction (SR), in a total of 306 healthy adults that participated in one of three independent laboratory studies. Findings indicate no significant impact of personality, academic intelligence, subjective reports of chronotype, sleepiness and fatigue, performance on working memory, and demographic factors such as sex, ethnicity, and body mass index, on neurobehavioral vulnerability to the negative effects of sleep loss. Only superior baseline performance on the psychomotor vigilance test and ability to sustain wakefulness on the maintenance of wakefulness test were associated with relative resilience to decrements in vigilant attention during SR. Interindividual differences in vulnerability to the effects of sleep loss were not accounted for by prior sleep history, habitual sleep patterns outside of the laboratory, baseline sleep architecture, or homeostatic sleep response during chronic partial SR. A recent theoretical model proposed that sleep-wake modulation may be influenced by competing internal and external demands which may promote wakefulness despite homeostatic and circadian signals for sleep under the right circumstances. Further research is warranted to examine the possibility of interindividual differences in the ability to prioritize external demands for wakefulness in the face of mounting pressure to sleep.

Comparing objective wakefulness and vigilance tests to on-the-road driving performance in narcolepsy and idiopathic hypersomnia

Patients with narcolepsy or idiopathic hypersomnia (IH) are at increased risk of driving accidents. Both excessive daytime sleepiness, i.e. unwanted sleep episodes during the day, and disturbed vigilance are core features of these disorders. We tested on‐the‐road driving performance of patients with narcolepsy or IH coming in for a routine driving fitness evaluation and examined: (1) correlations between driving performance and the Maintenance of Wakefulness Test (MWT), Sustained Attention to Response Task (SART) and Psychomotor Vigilance Test (PVT) as objective tests; (2) the predictive power of the MWT and SART for increased risk of impaired driving; (3) the best set of objective predictors for increased risk of impaired driving. Participants were 44 patients (aged 18–75 years) with narcolepsy type 1 (NT1), type 2 (NT2) or IH. They completed the MWT, SART, PVT, a subjective sleepiness questionnaire, and a standardised on‐the‐road driving test. The standard deviation of the lateral position (SDLP) was used as outcome measure of driving performance. The MWT had low correlation with the SDLP (ρ = −0.41 to −0.49, p < 0.01). The SART and PVT had low correlations with SDLP (ρ = 0.30 and ρ = 0.39, respectively, both p < 0.05). The predictive power of MWT for an increased risk of impaired driving was significant, but low (area under the curve = 0.273, p = 0.012), and non‐significant for SART. We conclude that in our present group, none of the tests had adequate ability to predict impaired driving, questioning their use for clinical driving fitness evaluation in narcolepsy and IH. Real‐time monitoring of sleepiness while driving seems more promising in these patients.

Sleep Measurements in Women

Sleep in women and men have been studied in several studies with higher prevalence of sleep complaints in women compared with men. Several factors can affect sleep and could be argued to contribute to sex and gender differences in general sleep. There are no differences in guidelines when measuring sleep in women but several sleep assessment tools have been validated or compared between sexes. Because there is still a lack of knowledge on sleep measurements in women, the present review aimed to produce an overview of the current knowledge of objective and subjective sleep measurements in women.

How to Design a Relevant Corpus for Sleepiness Detection Through Voice?

This article presents research on the detection of pathologies affecting speech through automatic analysis. Voice processing has indeed been used for evaluating several diseases such as Parkinson, Alzheimer, or depression. If some studies present results that seem sufficient for clinical applications, this is not the case for the detection of sleepiness. Even two international challenges and the recent advent of deep learning techniques have still not managed to change this situation. This article explores the hypothesis that the observed average performances of automatic processing find their cause in the design of the corpora. To this aim, we first discuss and refine the concept of sleepiness related to the ground-truth labels. Second, we present an in-depth study of four corpora, bringing to light the methodological choices that have been made and the underlying biases they may have induced. Finally, in light of this information, we propose guidelines for the design of new corpora.

Microsleep assessment enhances interpretation of the Maintenance of Wakefulness Test

STUDY OBJECTIVES

The Maintenance of Wakefulness Test (MWT) is used to objectively evaluate an individual's ability to remain awake; however, microsleeps are not included in the assessment. We aimed to determine if microsleep data prior to sleep onset assisted in interpretation of ability to maintain wakefulness across a range of typical patient groups.

METHODS

Forty-eight patients referred for overnight polysomnography and subsequent MWT were included. Patients were divided into 3 groups (treated obstructive sleep apnea [OSA], untreated OSA, or treated idiopathic hypersomnia or narcolepsy) based on prior medical diagnosis. Demographics, clinical characteristics, polysomnography, and MWT variables, including frequency, distribution, duration, and latency of microsleeps were compared between groups.

RESULTS

Microsleeps were observed in MWT trials significantly more frequently in patients with treated idiopathic hypersomnia/narcolepsy over the course of the day (0.34 ± 0.06 vs 0.07 ± 0.02 microsleeps/min; P < .001) and in patients with untreated OSA toward the end of the day (0.31 ± 0.06 vs 0.05 ± 0.02 microsleeps/min; P < .001) compared to the group with treated OSA. Microsleeps were often observed in series and earlier in patients with treated idiopathic hypersomnia/narcolepsy (10.9 ± 1.6 minutes) and those with untreated OSA (16.2 ± 2.7 minutes) compared to the group with treated OSA (24.9 ± 3.0 minutes; P < .05), and, if taken into consideration, would increase the proportion of patients demonstrating inability to maintain wakefulness by 33% and 22%, respectively.

CONCLUSIONS

MWT performance varies significantly across patient groups. Microsleep analysis prior to sleep onset may be a more sensitive measure of patient daytime wakefulness than sleep latency alone and should be considered in MWT assessment.

CITATION

Anniss AM, Young A, O'Driscoll DM. Microsleep assessment enhances interpretation of the Maintenance of Wakefulness Test. J Clin Sleep Med. 2021;17(8):1571-1578.

Randomized Controlled Trial of Solriamfetol for Excessive Daytime Sleepiness in OSA: An Analysis of Subgroups Adherent or Nonadherent to OSA Treatment

BACKGROUND

Solriamfetol, a dopamine-norepinephrine reuptake inhibitor, is approved in the United States to improve wakefulness in adults with excessive daytime sleepiness (EDS) associated with OSA (37.5-150 mg/d).

RESEARCH QUESTION

Does solriamfetol have differential effects on EDS based on adherence to primary OSA therapy and does solriamfetol affect primary OSA therapy use?

STUDY DESIGN AND METHODS

Participants were randomized to 12 weeks of placebo or solriamfetol 37.5, 75, 150, or 300 mg/d (stratified by primary OSA therapy adherence). Coprimary end points were week 12 change from baseline in 40-min Maintenance of Wakefulness Test (MWT) and Epworth Sleepiness Scale (ESS) in the modified intention-to-treat population. Primary OSA therapy use (hours per night, % nights) and safety were evaluated.

RESULTS

At baseline, 324 participants (70.6%) adhered to OSA therapy (positive airway pressure use ≥ 4 h/night on ≥ 70% nights, surgical intervention, or oral appliance use on ≥ 70% nights) and 135 participants (29.4%) did not adhere. Least squares (LS) mean differences from placebo in MWT sleep latency (minutes) in the 37.5-, 75-, 150-, and 300-mg/d groups among adherent participants were 4.8 (95% CI, 0.6-9.0), 8.4 (95% CI, 4.3-12.5), 10.2 (95% CI, 6.8-13.6), and 12.5 (95% CI, 9.0-15.9) and among nonadherent participants were 3.7 (95% CI, -2.0 to 9.4), 9.9 (95% CI, 4.4-15.4), 11.9 (95% CI, 7.5-16.3), and 13.5 (95% CI, 8.8-18.3). On ESS, LS mean differences from placebo in the 37.5-, 75-, 150-, and 300-mg/d groups among adherent participants were -2.4 (95% CI, -4.2 to -0.5), -1.3 (95% CI, -3.1 to 0.5), -4.2 (95% CI, -5.7 to -2.7), and -4.7 (95% CI, -6.1 to -3.2) and among nonadherent participants were -0.7 (95% CI, -3.5 to 2.1), -2.6 (95% CI, -5.4 to 0.1), -5.0 (95% CI, -7.2 to -2.9), and -4.6 (95% CI, -7.0 to -2.3). Common adverse events included headache, nausea, anxiety, decreased appetite, nasopharyngitis, and diarrhea. No clinically meaningful changes were seen in primary OSA therapy use with solriamfetol.

INTERPRETATION

Solriamfetol improved EDS in OSA regardless of primary OSA therapy adherence. Primary OSA therapy use was unaffected with solriamfetol.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02348606; URL: www.clinicaltrials.gov; EU Clinical Trials Register; No.: EudraCT2014-005514-31; URL: www.clinicaltrialsregister.eu.

Excessive Daytime Sleepiness in Obstructive Sleep Apnea. Mechanisms and Clinical Management

Many patients with obstructive sleep apnea (OSA) experience excessive daytime sleepiness (EDS), which can negatively affect daily functioning, cognition, mood, and other aspects of well-being. Although EDS can be reduced with primary OSA treatment, such as continuous positive airway pressure (CPAP) therapy, a significant proportion of patients continue to experience EDS despite receiving optimized therapy for OSA. This article reviews the pathophysiology and clinical evaluation and management of EDS in patients with OSA. The mechanisms underlying EDS in CPAP-treated patients remain unclear. Experimental risk factors include chronic intermittent hypoxia and sleep fragmentation, which lead to oxidative injury and changes in neurons and brain circuit connectedness involving noradrenergic and dopaminergic neurotransmission in wake-promoting regions of the brain. In addition, neuroimaging studies have shown alterations in the brain's white matter and gray matter in patients with OSA and EDS. Clinical management of EDS begins with ruling out other potential causes of EDS and evaluating its severity. Tools to evaluate EDS include objective and self-reported assessments of sleepiness, as well as cognitive assessments. Patients who experience residual EDS despite primary OSA therapy may benefit from wake-promoting pharmacotherapy. Agents that inhibit reuptake of dopamine or of dopamine and norepinephrine (modafinil/armodafinil and solriamfetol, respectively) have demonstrated efficacy in reducing EDS and improving quality of life in patients with OSA. Additional research is needed on the effects of wake-promoting treatments on cognition in these patients and to identify individual or disorder-specific responses.

Microsleep versus Sleep Onset Latency during Maintenance Wakefulness Tests: Which One Is the Best Marker of Sleepiness?

The interpretation of the Maintenance Wakefulness Test (MWT) relies on sleep onset detection. However, microsleeps (MSs), i.e., brief periods of sleep intrusion during wakefulness, may occur before sleep onset. We assessed the prevalence of MSs during the MWT and their contribution to the diagnosis of residual sleepiness in patients treated for obstructive sleep apnea (OSA) or hypersomnia. The MWT of 98 patients (89 OSA, 82.6% male) were analyzed for MS scoring. Polysomnography parameters and clinical data were collected. The diagnostic value for detecting sleepiness (Epworth Sleepiness Scale > 10) of sleep onset latency (SOL) and of the first MS latency (MSL) was assessed by the area under the receiver operating characteristic (ROC) curve (AUC, 95% CI). At least one MS was observed in 62.2% of patients. MSL was positively correlated with SOL (r = 0.72, p < 0.0001) but not with subjective scales, clinical variables, or polysomnography parameters. The use of SOL or MSL did not influence the diagnostic performance of the MWT for subjective sleepiness assessment (AUC = 0.66 95% CI (0.56, 0.77) versus 0.63 95% CI (0.51, 0.74)). MSs are frequent during MWTs performed in patients treated for sleep disorders, even in the absence of subjective sleepiness, and may represent physiological markers of the wake-to-sleep transition.

Restless Legs Syndrome and Periodic Limb Movements in 86 patients with Multiple Sclerosis

STUDY OBJECTIVES

To assess the frequency of restless legs syndrome (RLS), periodic limb movements during sleep (PLMS) and their overlap in a large sample of patients with multiple sclerosis (MS). To compare clinical and paraclinical findings among four sub-groups of patients: RLS-/PLMS- (patients without RLS and PLMS), RLS+/PLMS- (patients with RLS and without PLMS), RLS-/PLMS (patients without RLS and with PLMS), RLS+/PLMS+ (patients with both RLS and PLMS).

METHODS

In this cross-sectional, observational, instrumental study, eighty-six patients (M/F: 27/59; mean age 48.0 ± 10.8 years) with a diagnosis of MS underwent a telephone interview assessing the five standard diagnostic criteria for RLS. Seventy-six participants underwent polysomnography (PSG) and maintenance of wakefulness test. Instrumental and clinical findings were subsequently statistically compared to investigate their association with RLS and PLMS index (PLMSI).

RESULTS

RLS and PLMS (PLMSI ≥15/h) frequency in patients with MS was of 31.4% and 31.6% respectively. Among patients with RLS, 37.5% had a PLMSI ≥15/h. RLS-/PLMS+ group showed higher wake after sleep onset (p = 0.01), stage shifts per hour (p = 0.03), increased stage N1 (p = 0.03) and reduction in stage N3 (p = 0.01) compared to RLS-/PLMS-. RLS had no influence on clinical and PSG parameters (p = 0.45).

CONCLUSIONS

RLS is highly frequent in patients with MS. The frequency of PLMS is comparable to the general population. The low percentage of patients with RLS having a high PLMSI, together with the absence of correlation between RLS and female gender and older age, support the existence of a distinct symptomatic form of RLS in MS.

Pitolisant versus placebo for excessive daytime sleepiness in narcolepsy and obstructive sleep apnea: A meta-analysis from randomized controlled trials

Excessive daytime sleepiness is considered as the prominent symptom in narcolepsy and Obstructive Sleep Apnea (OSA). Pitolisant is a novel selective histamine H3 receptor antagonist approved for improving excessive daytime sleepiness. The meta-analysis is conducted to assess the efficacy and safety of pitolisant versus placebo for excessive daytime sleepiness in narcolepsy and OSA. PubMed, Embase and Cochrane Library databases were searched from earliest date to November 2020 for randomized controlled trials (RCTs). The primary outcomes were mean changes in Epworth Sleepiness Scale (ESS), mean sleep latency, European quality-of-life questionnaire (EQ-5D), and risk ratio of treatment-emergent adverse events (TEAEs). We pooled 678 patients from four RCTs and found pitolisant significantly decreased ESS by mean difference (MD) of - 2.86 points (95% CI: -3.75 to -1.96), increased mean sleep latency by MD of 3.14 min (95% CI: 2.18-4.11), and increased EQ-5D by MD of 3.32 points (95% CI: 0.26-6.39) compared with placebo. The risk ratio of TEAE was 1.37 (95% CI: 1.08-1.74). Insomnia was the only TEAE significantly associated with pitolisant treatment. In conclusion, pitolisant showed great efficacy and controllable security versus placebo for excessive daytime sleepiness in narcolepsy and OSA. Compared with narcolepsy, patients with OSA were deemed to benefit more from pitolisant especially in terms of improving mobility and quality of life of patients without continuous positive airway pressure therapy.

Efficacy of pitolisant in patients with high burden of narcolepsy symptoms: pooled analysis of short-term, placebo-controlled studies

STUDY OBJECTIVE

To evaluate the efficacy of pitolisant, a histamine 3 (H₃)-receptor antagonist/inverse agonist, in adult patients with high burden of narcolepsy symptoms.

METHODS

Data were pooled from two randomized, placebo-controlled, 7- or 8-week studies of pitolisant (titrated to a potential maximum dose of 35.6 mg/day) in adults with narcolepsy. Analyses included three independent patient subgroups: Epworth Sleepiness Scale (ESS) baseline score ≥16, Maintenance of Wakefulness Test (MWT) sleep latency ≤8 min, and ≥15 cataplexy attacks per week.

RESULTS

The analysis populations included 118 patients for ESS (pitolisant, n = 60; placebo, n = 58), 105 for MWT (pitolisant, n = 59; placebo, n = 46), and 31 for cataplexy (pitolisant, n = 20; placebo, n = 11). On the ESS, least-squares mean change from baseline was significantly greater for pitolisant (-6.1) compared with placebo (-2.3; P < 0.001). Significantly more pitolisant-treated patients were classified as treatment responders: ESS score reduction ≥3, 69.0% in the pitolisant group versus 35.1% in the placebo group (P = 0.001); final ESS score ≤10, 36.2% versus 10.5%, respectively (P = 0.005). On the MWT, mean sleep latency increased from 3.5 min to 10.4 min with pitolisant and from 3.4 min to 6.8 min with placebo (P = 0.017). Least-squares mean change in the weekly rate of cataplexy was significantly greater for pitolisant (-14.5; baseline, 23.9; final, 9.4) compared with placebo (-0.1; baseline, 23.1; final, 23.0; P = 0.004). Headache was the most common adverse event with pitolisant.

CONCLUSIONS

Pitolisant, at once-daily doses up to 35.6 mg, was efficacious for reducing excessive daytime sleepiness and cataplexy in patients with severe narcolepsy symptom burden.

Prevalence of sleep apnea and daytime sleepiness in professional truck drivers

INTRODUCTION

The prevalence of obstructive sleep apnea (OSA) among professional truck drivers has varied from 28 to 78% in previous studies. In this study we wanted to estimate the prevalence of OSA and OSA with both subjectively measured sleepiness and objectively measured ability to stay awake (ie obstructive sleep apnea syndrome, OSAS) among professional truck drivers in Finland.

SUBJECTS AND METHODS

Altogether 2066 professional truck drivers received a structured questionnaire. 175 drivers had a clinical examination and sleep laboratory studies, which included respiratory polygraphy (RP) and maintenance of wakefulness test (MWT). Three groups were formed: 75 subjects with suspected sleep apnea, 75 healthy controls and a random sample of 25 subjects.

RESULTS

1095 drivers answered the questionnaire. RP was performed on 172 drivers and 167 drivers participated in MWT. The mean age was 40.7 years and the mean BMI was 27.7 kgm^-2. The prevalence of sleep apnea in professional truck drivers using various criteria were: AHI ≥5: 40.1%, AHI≥ 15: 16.2% and, AHI≥ 30: 7.2%. The prevalence depended on clinical history. Prevalence of AHI≥5 varied between 20 and 56.9% and prevalence of AHI≥15 was 4.3-25%. Altogether 4.8% of subjects with AHI ≥15 had abnormally short sleep latency in MWT (<19.4 min).

CONCLUSIONS

Moderate sleep apnea is common among professional truck drivers but significant inability to stay awake, defined as MWT <19.4 min, is found in about one of twenty professional drivers.

Efficacy and safety of modafinil in patients with idiopathic hypersomnia without long sleep time: a multicenter, randomized, double-blind, placebo-controlled, parallel-group comparison study

BACKGROUND

Few treatments are available for patients with idiopathic hypersomnia (IH). Modafinil, an established treatment for narcolepsy, was tested for efficacy and safety in Japanese patients with IH without long sleep time.

METHODS

This multicenter, randomized, double-blind, placebo-controlled, parallel-group comparison study was conducted at 20 institutions in Japan. Patients who met the diagnostic criteria of IH in the International Classification of Sleep Disorders (second edition) were included. The study comprised a ≥17-day observation period and a 3-week treatment period during which modafinil (200 mg) or placebo was administered orally once daily (in the morning). The primary efficacy endpoint was change in mean sleep latency on the Maintenance of Wakefulness Test (MWT). Adverse events (AEs) were also recorded to evaluate safety.

RESULTS

In total, 123 patients were screened and 71 were randomized to receive modafinil (N = 34) or placebo (N = 37). Patients treated with modafinil experienced a significantly prolonged mean sleep latency on the MWT at the end of the study compared with placebo (5.02 min, 95% confidence interval: 3.26-6.77 min; p < 0.001). AEs occurred in 58.8% (20/34) and 27.0% (10/37) of patients in the modafinil and placebo groups, respectively. Frequent AEs in the modafinil group were headache (n = 6), dry mouth (n = 3), and nausea (n = 3); no clinically significant AEs occurred.

CONCLUSION

Modafinil was shown to be an effective and safe treatment for excessive daytime sleepiness in patients with IH without long sleep time.

CLINICAL TRIAL REGISTRATION

JapicCTI; 142539.

Efficacy and safety of solriamfetol for excessive sleepiness in narcolepsy and obstructive sleep apnea: findings from randomized controlled trials

BACKGROUND

Solriamfetol is developed for the treatment of excessive sleepiness in adult patients with narcolepsy and obstructive sleep apnea (OSA). No systematic review of existing literature has been investigated before. Therefore, the meta-analysis is conducted to assess the efficacy and safety of solriamfetol for excessive sleepiness in narcolepsy and OSA.

METHODS

PubMed, Embase and Cochrane Library databases were searched from earliest date to July 2020 for randomized controlled trials (RCTs) and the primary outcomes were change from baseline in mean sleep latency and Epworth Sleepiness Scale (ESS).

RESULTS

We pooled 1177 patients from five RCTs and found solriamfetol led to a significant increment in mean sleep latency (MD = 9.52, 95% CI: 7.60 to 11.44, P < 0.00001) and a reduction in ESS score (MD = -3.74, 95% CI: -4.38 to -3.09, P < 0.00001) compared with placebo. The proportion of patients with at least one adverse event was significantly increased in solriamfetol group (RR = 1.42, 95% CI: 1.24 to 1.64, P < 0.00001), while no statistical differences existed in the risk of at least one serious adverse event between solriamfetol and controlled group (RR = 0.95, 95% CI: 0.24 to 3.77, P = 0.39).

CONCLUSIONS

A dose of 150 mg solriamfetol is proved to be the appropriate and stable dose for excessive sleepiness. In addition, solriamfetol showed good efficacy for excessive sleepiness in narcolepsy and OSA but also significantly increases the risk of adverse events.

Comparison of the Oxford Sleep Resistance Test and the Multiple Sleep Latency Test

OBJECTIVE

The Oxford Sleep Resistance Test (OSLER) consists of four tests over 40 min conducted in a dark and quiet room. If a dim light flashes the patient has to briefly depress a button and then press it again immediately, which indicates that the patient resists sleep. The Maintenance of Wakefulness test (MWT) is another test to assess the ability to maintain wakefulness. Previous studies found a good correlation between the sleep latencies measured with the Osler and the MWT. The most widely used Multiple Sleep Latency Test (MSLT) measures the propensity to fall asleep and not the inability to stay awake. Up to this date there have been no studies comparing the Osler and the MSLT, which is the aim of the study presented here.

APPROACH

After a night of polysomnography we investigated the sleep latencies the following day with the Osler and the MSLT in 43 patients suffering from moderate or severe obstructive sleep apnea (OSA) (33 men and 10 women; median age 59 years; median apnea hypopnea index 30.5 per hour sleep). We analysed the correlation between these two tests and between values in the Epworth Sleepiness Scale (ESS) and the Karolinska Sleepiness Scale (KSS) and these two tests.

MAIN RESULTS

We did not find a correlation between the Osler and the MSLT nor between these two tests and the questionnaires (ESS, KSS). The only significant correlation was found between the mean MSLT latency and the sleep onset latency in the polysomnography the night before. Seven patients stayed awake during the Osler and showed a decreased mean sleep latency in the MSLT.

SIGNIFICANCE

The Osler, the MSLT and the questionnaires measure different objective and subjective aspects of sleepiness. In untreated OSA patients an increased propensity to fall asleep was not automatically associated with the inability to stay awake.

Subjective and Objective Assessment of Hypersomnolence

This article describes clinical approaches to assessing sleepiness. Subjective sleep scales are used in clinical settings but have significant limitations. Likewise, objective tools may have prohibitive expense, and practical administration considerations may prohibit regular use. Gold standard tests include the multiple sleep latency test and maintenance of wakefulness test. These studies are criticized for a variety of reasons but are useful in appropriate clinical context. New tools suggest novel ways to assess sleepiness and will likely be more prominent in clinical assessments over time. This article outlines subjective scales and objective tools and suggests situations where particular instruments may be appropriate.

Mutations in Metabotropic Glutamate Receptor 1 Contribute to Natural Short Sleep Trait

Sufficient and efficient sleep is crucial for our health. Natural short sleepers can sleep significantly shorter than the average population without a desire for more sleep and without any obvious negative health consequences. In searching for genetic variants underlying the short sleep trait, we found two different mutations in the same gene (metabotropic glutamate receptor 1) from two independent natural short sleep families. In vitro, both of the mutations exhibited loss of function in receptor-mediated signaling. In vivo, the mice carrying the individual mutations both demonstrated short sleep behavior. In brain slices, both of the mutations changed the electrical properties and increased excitatory synaptic transmission. These results highlight the important role of metabotropic glutamate receptor 1 in modulating sleep duration.

Correlation between the Epworth Sleepiness Scale and the Maintenance of Wakefulness Test in Obstructive Sleep Apnea Patients Treated with Positive Airway Pressure

BACKGROUND

The Epworth sleepiness scale (ESS) is often used to evaluate the impact of treatment in patients with obstructive sleep apnea hypopnea syndrome (OSA). We aimed to evaluate the correlation between ESS and the Maintenance of Wakefulness Test (MWT) in a population of OSA patients treated with positive airway pressure (PAP).

METHODS

We retrospectively included all patients during a 2-year period who were diagnosed with OSA in our sleep clinic and required PAP therapy. ESS was evaluated at baseline and after PAP therapy for all patients, and all had a concomitant MWT. Correlation between final ESS, change in ESS, and MWT were evaluated using Spearman's correlation. Given that MWT is considered as the gold standard, the diagnostic performance of ESS was evaluated against MWT.

RESULTS

Hundred thirty-four OSA patients were included. At the time of MWT, 89.6% of the patients were compliant (PAP use ≥4hours/night), and only 9 (6.7%) had persistent sleepiness despite PAP treatment (mean sleep latency at MWT<19.4min). Moderate correlation was observed between final ESS and MWT (Spearman's correlation coefficient=-0.42), but no correlation was found between change in ESS and MWT. Diagnostic performance was as follows for final ESS: sensitivity=55.6%, specificity=84.8%, PPV=20.8%, and NPV=96.4%.

CONCLUSIONS

ESS was moderately correlated with MWT in a population of OSA patients compliant with PAP therapy. In this population, ESS showed poor diagnostic performance in identifying patients with persistent excessive daytime sleepiness. CLINICALTRIALS.

GOV IDENTIFIER

NCT03629834.

Solriamfetol for the Treatment of Excessive Daytime Sleepiness in Participants with Narcolepsy with and without Cataplexy: Subgroup Analysis of Efficacy and Safety Data by Cataplexy Status in a Randomized Controlled Trial

BACKGROUND

Solriamfetol, a dopamine/norepinephrine reuptake inhibitor, improved wakefulness and reduced excessive daytime sleepiness (EDS) in studies of participants with narcolepsy with and without cataplexy.

OBJECTIVE

Prespecified subgroup analyses of data from a 12-week randomized, double-blind, placebo-controlled, phase III trial of solriamfetol for EDS in narcolepsy evaluated the efficacy and safety of solriamfetol by cataplexy status.

METHODS

Participants with narcolepsy received solriamfetol (75, 150, or 300 mg/day) or placebo and were stratified by cataplexy status. Coprimary endpoints were change from baseline on Maintenance of Wakefulness Test (MWT) and Epworth Sleepiness Scale (ESS); Patient Global Impression of Change (PGI-C) was the key secondary endpoint. Change in frequency of cataplexy attacks was evaluated in participants reporting cataplexy at baseline. Safety was evaluated. No adjustments were made for multiple comparisons; therefore p values are nominal.

RESULTS

There were 117 participants in the cataplexy subgroup and 114 in the non-cataplexy subgroup. At week 12, least-squares (LS) mean (95% confidence interval [CI]) differences from placebo on change from baseline in MWT for solriamfetol 75, 150, and 300 mg in the cataplexy subgroup were 1.6 (- 3.6 to 6.9), 6.1 (0.7-11.4), and 8.9 (3.5-14.2) minutes, respectively (p < 0.05; 150 and 300 mg), and in the non-cataplexy subgroup were 3.4 (- 1.9 to 8.7), 9.1 (3.8-14.3), and 11.2 (5.8-16.6) minutes, respectively (p < 0.001; 150 and 300 mg). At week 12, LS mean (95% CI) differences from placebo on ESS change from baseline for solriamfetol 75, 150, and 300 mg in the cataplexy subgroup were - 1.3 (- 3.9 to 1.3), - 3.7 (- 6.4 to - 1.1), and - 4.5 (- 7.1 to - 1.9), respectively (p < 0.01; 150 and 300 mg), and in the non-cataplexy subgroup were - 3.0 (- 5.6 to - 0.4), - 3.7 (- 6.3 to - 1.2), and - 4.9 (- 7.6 to - 2.2), respectively (p < 0.05; all doses). For PGI-C at week 12, the mean percentage difference from placebo (95% CI) for solriamfetol 75, 150, and 300 mg in the cataplexy subgroup was 10% (- 15 to 35), 33% (9-57), and 39% (16-61), respectively (p < 0.05; 150 and 300 mg), and in the non-cataplexy subgroup was 48% (25-70), 44% (21-67), and 52% (30-73), respectively (p < 0.001; all doses), with somewhat differential treatment effects for 75 mg by cataplexy status. No changes in the number of cataplexy attacks were observed for solriamfetol compared with placebo (mean ± standard deviation changes: - 3.6 ± 13.3 [combined solriamfetol] and - 3.5 ± 9.8 [placebo]). Common adverse events (headache, nausea, decreased appetite, and nasopharyngitis) were similar between cataplexy subgroups.

CONCLUSIONS

These data strongly indicate that solriamfetol was effective in treating EDS in participants with narcolepsy with or without cataplexy, as indicated by robust effects on MWT, ESS, and PGI-C. The safety profile was similar regardless of cataplexy status.

TRIAL REGISTRATION AND DATE

ClinicalTrials.gov NCT02348593. 28 January 2015.

The economic and societal burden of excessive daytime sleepiness in patients with obstructive sleep apnea

Excessive daytime sleepiness (EDS) is common in patients with obstructive sleep apnea (OSA) and continues to persist in many patients despite adequate OSA treatment. EDS in OSA is associated with decreased quality of life (QOL) as well as increased societal burden, which may impact health care utilization and costs. However, economic burden is often not the primary focus in the treatment of EDS in OSA. This targeted literature review aimed to examine the published literature on the economic burden of EDS in OSA. This review identified available literature using a targeted PubMed search strategy using search terms related to EDS in OSA in adults. Results demonstrate that there are few studies that detailed the direct costs associated with EDS in OSA, though several studies indicated an association between EDS in OSA and indirect economic burdens, including motor vehicle accidents (MVAs), near misses, work productivity, mood, and QOL. Data from the literature confirmed that persistent EDS in OSA following continuous positive airway pressure persists in 12%-65% of patients. Future studies should further describe the direct costs of EDS in OSA, quantify the cost associated with MVAs and lost work productivity, and detail QOL and social impacts of the condition.

Automatically Detected Microsleep Episodes in the Fitness-to-Drive Assessment

Study Objectives: Microsleep episodes (MSEs) are short fragments of sleep (1–15 s) that can cause dangerous situations with potentially fatal outcomes. In the diagnostic sleep-wake and fitness-to-drive assessment, accurate and early identification of sleepiness is essential. However, in the absence of a standardised definition and a time-efficient scoring method of MSEs, these short fragments are not assessed in clinical routine. Based on data of moderately sleepy patients, we recently developed the Bern continuous and high-resolution wake-sleep (BERN) criteria for visual scoring of MSEs and corresponding machine learning algorithms for automatic MSE detection, both mainly based on the electroencephalogram (EEG). The present study aimed to investigate the relationship between automatically detected MSEs and driving performance in a driving simulator, recorded in parallel with EEG, and to assess algorithm performance for MSE detection in severely sleepy participants.

Methods: Maintenance of wakefulness test (MWT) and driving simulator recordings of 18 healthy participants, before and after a full night of sleep deprivation, were retrospectively analysed. Performance of automatic detection was compared with visual MSE scoring, following the BERN criteria, in MWT recordings of 10 participants. Driving performance was measured by the standard deviation of lateral position and the occurrence of off-road events.

Results: In comparison to visual scoring, automatic detection of MSEs in participants with severe sleepiness showed good performance (Cohen’s kappa = 0.66). The MSE rate in the MWT correlated with the latency to the first MSE in the driving simulator (r_s = −0.54, p < 0.05) and with the cumulative MSE duration in the driving simulator (r_s = 0.62, p < 0.01). No correlations between MSE measures in the MWT and driving performance measures were found. In the driving simulator, multiple correlations between MSEs and driving performance variables were observed.

Conclusion: Automatic MSE detection worked well, independent of the degree of sleepiness. The rate and the cumulative duration of MSEs could be promising sleepiness measures in both the MWT and the driving simulator. The correlations between MSEs in the driving simulator and driving performance might reflect a close and time-critical relationship between sleepiness and performance, potentially valuable for the fitness-to-drive assessment.

The Psychomotor Vigilance Test Compared to a Divided Attention Steering Simulation in Patients with Moderate or Severe Obstructive Sleep Apnea

BACKGROUND

Sleepiness at the wheel affects 10% to 15% of drivers and is one major cause of death on highways with one-third of fatal accidents. Obstructive sleep apnea (OSA) is one of the most common sleep disorders leading to sleepiness at the wheel. The aim of this study was to compare the psychomotor vigilance test reaction time (PVT RT) in OSA patients and controls (morning and afternoon) with the results of a divided attention steering simulator (DASS). A second purpose was to compare these results with the mean sleep latencies in the multiple sleep latency test (MSLT), the Epworth Sleepiness Scale (ESS) values and a neurocognitive test (test of attentional performance, TAP).

PATIENTS AND METHODS

Thirty eight OSA patients and 16 age and sex matched healthy controls were investigated by ESS, PVT, TAP, MSLT, and DASS (response time, failed responses, lane deviation, and off-road-events).

RESULTS

With increasing age, the performance in the DASS decreased. There was no correlation between the DASS and the results of the MSLT and ESS. The controls showed a significantly faster DASS response time in the morning compared to OSA patients (median 2.1 versus 3.0; p=0.044) and fewer off-road events (9 versus 37; p=0.042). We found a moderate correlation between the PVT RT and all parameters of the DASS, as well as the TAP "alertness" subtest.

CONCLUSION

The increase of PVT RT as well as the decreased tonic alertness in the TAP in untreated OSA patients correlated with an impairment of simulated driving performance. The PVT and the TAP are both suitable diagnostic tools for measuring impaired driving ability in OSA patients. The MSLT did not correlate with the simulated driving performance. We recommend investigation of a longer version of the PVT in order to increase its sensitivity.

Prevalence and correlates of periodic limb movements in OSA and the effect of CPAP therapy

OBJECTIVE

We sought to assess the prevalence, correlates, and consequences of periodic limb movements of sleep (PLMS) in persons with obstructive sleep apnea (OSA) and the effect (worsening or improvement) of continuous positive airway pressure (CPAP) therapy on PLMS in a large prospective multicenter randomized controlled trial.

METHODS

We performed retrospective analyses of data from the Apnea Positive Pressure Long-term Efficacy Study, a prospective multicenter randomized controlled trial. A total of 1,105 persons with OSA enrolled in this study underwent a polysomnographic investigation at baseline, another one for CPAP titration, and another study 6 months after randomization to either active CPAP or sham CPAP.

RESULTS

Of all participants, 19.7% had PLM index (PLMI) ≥10/hour, 14.8% had PLMI ≥15/hour, 12.1% had PLMI ≥20/hour, 9.3% had PLMI ≥25/hour, and 7.5% had PLMI ≥30/hour. The odds of having a PLMI ≥10 were higher in older participants (odds ratio [OR] 1.03, p < 0.001), men (OR 1.63. p = 0.007), those using antidepressants (OR 1.48. p = 0.048), and those with higher caffeine use (OR 1.01, p = 0.04). After controlling for OSA and depression, PLMS were associated with increased sleep latency, reduced sleep efficiency, and reduced total sleep time. No significant relationships were noted between PLMS frequency and subjective sleepiness (Epworth Sleepiness Scale score) or objective sleepiness (Maintenance of Wakefulness Test). There was no differential effect of CPAP in comparison to sham CPAP on PLMS after 6 months of therapy.

CONCLUSIONS

PLMS are common in patients with OSA and are associated with a significant reduction in sleep quality over and above that conferred by OSA. Treatment with CPAP does not affect the severity of PLMS.

Microsleep episodes in the borderland between wakefulness and sleep

Study objectives

The wake-sleep transition zone represents a poorly defined borderland, containing, for example, microsleep episodes (MSEs), which are of potential relevance for diagnosis and may have consequences while driving. Yet, the scoring guidelines of the American Academy of Sleep Medicine (AASM) completely neglect it. We aimed to explore the borderland between wakefulness and sleep by developing the Bern continuous and high-resolution wake-sleep (BERN) criteria for visual scoring, focusing on MSEs visible in the electroencephalography (EEG), as opposed to purely behavior- or performance-defined MSEs.

Methods

Maintenance of Wakefulness Test (MWT) trials of 76 randomly selected patients were retrospectively scored according to both the AASM and the newly developed BERN scoring criteria. The visual scoring was compared with spectral analysis of the EEG. The quantitative EEG analysis enabled a reliable objectification of the visually scored MSEs. For less distinct episodes within the borderland, either ambiguous or no quantitative patterns were found.

Results

As expected, the latency to the first MSE was significantly shorter in comparison to the sleep latency, defined according to the AASM criteria. In certain cases, a large difference between the two latencies was observed and a substantial number of MSEs occurred between the first MSE and sleep. Series of MSEs were more frequent in patients with shorter sleep latencies, while isolated MSEs were more frequent in patients who did not reach sleep.

Conclusion

The BERN criteria extend the AASM criteria and represent a valuable tool for in-depth analysis of the wake-sleep transition zone, particularly important in the MWT.

Can real-life driving ability be predicted by the Maintenance of Wakefulness Test?

Objective: Drowsy driving is a profound road safety issue. In patients with excessive daytime sleepiness (EDS), the Maintenance of Wakefulness Test (MWT) is commonly used to evaluate driving ability. However, there is little evidence that MWT predicts driving performance, and several sleep latency cutoffs have been suggested. Methods: Based on a retrospective chart analysis of patients with an MWT and a driving ability assessment between January 2006 and November 2014, we identified 63 studies in 60 patients. The driving ability assessment judged the patients as qualified or disqualified for commercial driving. MWT latencies to 3 s of alpha activity, 3 s of drowsiness (microsleep), and sleep onset were compared between qualified and disqualified patients and their validity to identify driving qualification was evaluated. Results: Disqualified patients had shorter alpha, microsleep, and sleep latencies, but the latency distributions were widely overlapping. MWT accuracy to predict driving performance was poor: two thirds of short sleep latencies were false positives. Adding information from alpha and microsleep latencies added little extra accuracy. Conclusions: MWT results correlate poorly with driving performance in a 2-h test irrespective of sleep latency cutoff or added alpha/microsleep latency data. Better diagnostic tools are needed to evaluate driving performance in patients with EDS.

Solriamfetol for Excessive Sleepiness in Obstructive Sleep Apnea (TONES 3). A Randomized Controlled Trial

Rationale: Primary treatment of obstructive sleep apnea can be accompanied by a persistence of excessive sleepiness despite adherence. Furthermore, effectiveness of sleep apnea treatment is limited by poor adherence. Currently available pharmacologic options for the treatment of sleepiness in this population are limited. Objectives: To evaluate the efficacy and safety of solriamfetol (JZP-110), a selective dopamine and norepinephrine reuptake inhibitor with robust wake-promoting effects, for the treatment of excessive sleepiness in participants with obstructive sleep apnea with current or prior sleep apnea treatment. Methods: This was a double-blind, randomized, placebo-controlled, parallel-group, 12-week trial comparing solriamfetol, 37.5, 75, 150, and 300 mg, with placebo. Measurements and Main Results: Of 476 randomized participants, 459 were included in the prespecified efficacy analyses. Coprimary endpoints (Maintenance of Wakefulness Test sleep latency and Epworth Sleepiness Scale score) were met at all solriamfetol doses (P < 0.05), with dose-dependent effects observed at Week 1 maintained over the study duration. All doses except 37.5 mg resulted in higher percentages of participants reporting improvement on Patient Global Impression of Change (key secondary endpoint; P < 0.05). Adverse events were reported in 47.9% of placebo- and 67.9% of solriamfetol-treated participants; five participants experienced serious adverse events (two [1.7%] placebo, three [0.8%] solriamfetol); none were deemed related to study drug. The most common adverse events with solriamfetol were headache (10.1%), nausea (7.9%), decreased appetite (7.6%), anxiety (7.0%), and nasopharyngitis (5.1%). Conclusions: Solriamfetol significantly increased wakefulness and reduced sleepiness in participants with obstructive sleep apnea and excessive sleepiness; most adverse events were mild or moderate in severity. Clinical trial registered with www.clinicaltrials.gov (NCT02348606) and www.eudract.ema.europa.eu (EudraCT 2014-005514-31).

Inside the clinical evaluation of sleepiness: subjective and objective tools

PURPOSE

To critically review the available tools for evaluating excessive daytime sleepiness (EDS) in clinical practice.

METHODS

Objective tests and subjective scales were divided into three groups in accordance with the different dimensions of sleepiness they measure, namely physiological, manifest, and introspective. Strengths, weaknesses, and limitations of each test have been analysed and discussed along with the available recommendations for their use in clinical practice.

RESULTS

The majority of the tests developed for sleepiness evaluation do not have practical usefulness outside the research setting. The suboptimal correlation between different tests mainly depends on the different dimensions of sleepiness they analyse. Most importantly in-laboratory tests poorly correlate with sleepiness in real-life situations and, to date, none is able to predict the risk of injuries related to EDS, especially on an individual level.

CONCLUSIONS

There exists not the one best test to assess EDS, however, clinicians can choose a more specific test to address a specific diagnostic challenge on the individual level. The development of novel performance tests with low cost and easy to administer is advisable for both screening purposes and fitness for duty evaluations in populations at high risk of EDS-related injuries, for example professional drivers.

Sleep-wake functions and quality of life in patients with subthalamic deep brain stimulation for Parkinson's disease

OBJECTIVES

Sleep-wake disturbances (SWD) are frequent in Parkinson's disease (PD). The effect of deep brain stimulation (DBS) on SWD is poorly known. In this study we examined the subjective and objective sleep-wake profile and the quality of life (QoL) of PD patients in the context of subthalamic DBS.

PATIENTS AND METHODS

We retrospectively analyzed data from PD patients and candidates for DBS in the nucleus suthalamicus (STN). Pre-DBS, sleep-wake assessments included subjective and objective (polysomnography, vigilance tests and actigraphy) measures. Post-DBS, subjective measures were collected. QoL was assessed using the Parkinson's Disease Questionnaire (PDQ-39) and the RAND SF-36-item Health Survey (RAND SF-36).

RESULTS

Data from 74 PD patients (62% male, mean age 62.2 years, SD = 8.9) with a mean UPDRS-III (OFF) of 34.2 (SD = 14.8) and 11.8 (SD = 4.5) years under PD treatment were analyzed. Pre-DBS, daytime sleepiness, apathy, fatigue and depressive symptoms were present in 49%, 34%, 38% and 25% of patients respectively but not always as co-occurring symptoms. Sleep-wake disturbances were significantly correlated with QoL scores. One year after STN DBS, motor signs, QoL and sleepiness improved but apathy worsened. Changes in QoL were associated with changes in sleepiness and apathy but baseline sleep-wake functions were not predictive of STN DBS outcome.

CONCLUSION

In PD patients presenting for STN DBS, subjective and objective sleep-wake disturbances are common and have a negative impact on QoL before and after neurosurgery. Given the current preliminary evidence, prospective observational studies assessing subjective and objective sleep-wake variables prior to and after DBS are needed.

Predictors of sleepiness in obstructive sleep apnoea at baseline and after 6 months of continuous positive airway pressure therapy

We evaluated factors associated with subjective and objective sleepiness at baseline and after 6 months of continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnoea (OSA).We analysed data from the Apnoea Positive Pressure Long-term Efficacy Study (APPLES), a prospective 6-month multicentre randomised controlled trial with 1105 subjects with OSA, 558 of who were randomised to active CPAP. Epworth sleepiness scale (ESS) scores and the mean sleep latency (MSL) on the maintenance of wakefulness test at baseline and after 6 months of CPAP therapy were recorded.Excessive sleepiness (ESS score >10) was present in 543 (49.1%) participants. Younger age, presence of depression and higher apnoea-hypopnoea index were all associated with higher ESS scores and lower MSL. Randomisation to the CPAP group was associated with lower odds of sleepiness at 6 months. The prevalence of sleepiness was significantly lower in those using CPAP >4 h·night^-1versus using CPAP ≤4 h·night^-1 Among those with good CPAP adherence, those with ESS >10 at baseline had significantly higher odds (OR 8.2, p<0.001) of persistent subjective sleepiness.Lower average nightly CPAP use and presence of sleepiness at baseline were independently associated with excessive subjective and objective sleepiness after 6 months of CPAP therapy.

Cuadro clínico del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS)

El pilar para el diagnóstico del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) es el cuadro clínico obtenido mediante una historia clínica detallada. Los síntomas son referidos por el paciente o su compañero de cama y se pueden dar durante el sueño o la vigilia; estos últimos se presentan como consecuencia del trastorno del sueño. Los síntomas son consecuencia de la obstrucción de la vía aérea superior, de la hipoxia intermitente o de la fragmentación repetida del sueño.Para el diagnóstico de SAHOS, se deben tener en cuenta los factores agravantes, las comorbilidades, los antecedentes familiares, el examen físico, la obtención de medidas antropométricas, los signos vitales y los hallazgos anatómicos estructurales asociados con este síndrome o con alteraciones congénitas que lo predispongan. Tener conocimiento de estos aspectos clínicos es fundamental para alcanzar una buena aproximación a su diagnóstico.

Subjective and Objective Assessment of Hypersomnolence

This article describes clinical approaches to assessing sleepiness. Subjective sleep scales are used in clinical settings but have significant limitations. Likewise, objective tools may have prohibitive expense, and practical administration considerations may prohibit regular use. Gold standard tests include the multiple sleep latency test and maintenance of wakefulness test. These studies are criticized for a variety of reasons but are useful in appropriate clinical context. New tools suggest novel ways to assess sleepiness and will likely be more prominent in clinical assessments over time. This article outlines subjective scales and objective tools and suggests situations where particular instruments may be appropriate.