Epidemiology of sleep disorders

Repeated polysomnography and multiple sleep latency test in narcolepsy type 1 and other hypersomnolence disorders

BACKGROUND

The diagnosis of narcolepsy is based on clinical information, combined with polysomnography (PSG) and the Multiple Sleep Latency Test (MSLT). PSG and the MSLT are moderately reliable at diagnosing narcolepsy type 1 (NT1) but unreliable for diagnosing narcolepsy type 2 (NT2). This is a problem, especially given the increased risk of a false-positive MSLT in the context of circadian misalignment or sleep deprivation, both of which commonly occur in the general population.

AIM

We aimed to clarify the accuracy of PSG/MSLT testing in diagnosing NT1 versus controls without sleep disorders. Repeatability and reliability of PSG/MSLT testing and temporal changes in clinical findings of patients with NT1 versus patients with hypersomnolence with normal hypocretin-1 were compared.

METHOD

84 patients with NT1 and 100 patients with non-NT1-hypersomnolence disorders, all with congruent cerebrospinal fluid hypocretin-1 (CSF-hcrt-1) levels, were included. Twenty-five of the 84 NT1 patients and all the hypersomnolence disorder patients underwent a follow-up evaluation consisting of clinical assessment, PSG, and a modified MSLT. An additional 68 controls with no sleep disorders were assessed at baseline.

CONCLUSION

Confirming results from previous studies, we found that PSG and our modified MSLT accurately and reliably diagnosed hypocretin-deficient NT1 (accuracy = 0.88, reliability = 0.80). Patients with NT1 had stable clinical and electrophysiological presentations over time that suggested a stable phenotype. In contrast, the PSG/MSLT results of patients with hypersomnolence, and normal CSF-hcrt-1 had poor reliability (0.32) and low repeatability.

Characterization of sleep among deaf individuals

OBJECTIVES

Numerous health disparities are documented in deaf population research, but few empirical sleep assessments exist for this under-served population, despite knowledge that sleep contributes to physical and mental health disparities. We sought to document subjective and objective sleep in deaf adults with cross-sectional and prospective measures.

METHODS

Twenty deaf participants completed validated sleep and mental health questionnaires, 2-weeks of nightly sleep diaries and continuous wrist-worn actigraphy monitoring, and 1-week of nightly, reduced-montage EEG recordings.

RESULTS

Questionnaire data suggest high prevalence of insomnia (70%), poor sleep (75%), daytime sleepiness (25%) and nightmares (20%) among participants. Strong correlations were found between depression and sleep quality, fear of sleep, and insomnia severity (p's < .005). Objective sleep assessments suggest elevated wake after sleep onset and low sleep efficiency and sleep duration.

CONCLUSIONS

The prevalence of sleep disturbance recorded from self-report and objective sleep measures provides preliminary evidence of sleep health disparity among deaf adults.

Keep Your Mask On: The Benefits of Masking for Behavior and the Contributions of Aging and Disease on Dysfunctional Masking Pathways

Environmental cues (e.g., light-dark cycle) have an immediate and direct effect on behavior, but these cues are also capable of “masking” the expression of the circadian pacemaker, depending on the type of cue presented, the time-of-day when they are presented, and the temporal niche of the organism. Masking is capable of complementing entrainment, the process by which an organism is synchronized to environmental cues, if the cues are presented at an expected or predictable time-of-day, but masking can also disrupt entrainment if the cues are presented at an inappropriate time-of-day. Therefore, masking is independent of but complementary to the biological circadian pacemaker that resides within the brain (i.e., suprachiasmatic nucleus) when exogenous stimuli are presented at predictable times of day. Importantly, environmental cues are capable of either inducing sleep or wakefulness depending on the organism’s temporal niche; therefore, the same presentation of a stimulus can affect behavior quite differently in diurnal vs. nocturnal organisms. There is a growing literature examining the neural mechanisms underlying masking behavior based on the temporal niche of the organism. However, the importance of these mechanisms in governing the daily behaviors of mammals and the possible implications on human health have been gravely overlooked even as modern society enables the manipulation of these environmental cues. Recent publications have demonstrated that the effects of masking weakens significantly with old age resulting in deleterious effects on many behaviors, including sleep and wakefulness. This review will clearly outline the history, definition, and importance of masking, the environmental cues that induce the behavior, the neural mechanisms that drive them, and the possible implications for human health and medicine. New insights about how masking is affected by intrinsically photosensitive retinal ganglion cells, temporal niche, and age will be discussed as each relates to human health. The overarching goals of this review include highlighting the importance of masking in the expression of daily rhythms, elucidating the impact of aging, discussing the relationship between dysfunctional masking behavior and the development of sleep-related disorders, and considering the use of masking as a non-invasive treatment to help treat humans suffering from sleep-related disorders.

For what indications are antidepressants being used in adults in Colombia?

INTRODUCTION

Antidepressants are useful in the pharmacological treatment of different depressive and anxiety disorders, as well as being potentially useful in other indications. The aim of the study was to determine the indications for which antidepressants are being prescribed in patients over 18 years of age registered with the Colombian Health System.

METHODS

Retrospective study with data from patients over 18 years old, of either sex, registered with the Colombian Health System, who are prescribed antidepressants. Medical records were reviewed, looking for indications approved and not approved by regulatory agencies. Patients were identified randomly, as well as the sociodemographic, clinical and pharmacological variables that could be associated with prescriptions for unapproved indications.

RESULTS

351 patients were evaluated, with a mean age of 60.4 ± 15.3 years, of whom 72.6% were women. They were attended in 34 cities, with prescriptions mainly by general practitioners (n = 276; 78.6%), and psychiatrists (n = 42; 12.0%). Selective serotonin reuptake inhibitors were the most widely prescribed antidepressants (n = 204; 58.1%), followed by atypicals (n = 76; 21.7%). The most frequent indications were for depression (n = 169; 48.1%), anxiety (n = 48; 13.7%), pain (n = 22; 6.3%) and sleep disorders (n = 17; 4.8%). A total of 188 prescriptions (53.6%) were made for approved indications, and the remaining 163 (46.4%) were classified as unapproved.

CONCLUSIONS

Antidepressants are being prescribed for the treatment of depression, anxiety, pain and sleep disorders, especially in older adult women, but almost half of the formulations were for unapproved indications.

Diagnostic value of actigraphy in hypersomnolence disorders

OBJECTIVE

Differentiating between the central hypersomnias presents a challenge to the diagnosis of patients with hypersomnolence. Actitigraphy may support efforts to distinguish them. We aimed to evaluate: 1) the ability of actigraphy to quantify sleep continuity measures in comparison with polysomnography in patients with hypersomnolence; 2) whether actigraphy can distinguish patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid from patients with narcolepsy type 1 and from sleep-healthy controls; and 3) the distinct activity profiles and circadian rhythms of patients with narcolepsy type 1, patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid, and sleep-healthy controls.

METHOD

Polysomnography, multiple sleep latency tests and actigraphy were conducted in 14 patients with narcolepsy type 1, 29 patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid and 15 sleep-healthy controls.

RESULTS

Actigraphy quantified several sleep continuity measures consistently with polysomnography in all the patients. Actigraphy distinguished patients with hypersomnolence with normal hypocretin-1 in cerebrospinal fluid from patients with narcolepsy type 1 and sleep-healthy controls. Patients with narcolepsy type 1 had poor sleep quality and altered circadian rest-activity rhythm compared with controls.

CONCLUSION

Actigraphy is an adequate tool for establishing the amount of night sleep and supports the differential diagnosis of patients with hypersomnolence.

For What Indications are Antidepressants Being Used in Adults in Colombia?

INTRODUCTION

Antidepressants are useful in the pharmacological treatment of different depressive and anxiety disorders, as well as being potentially useful in other indications. The aim of the study was to determine the indications for which antidepressants are being prescribed in patients over 18 years of age registered with the Colombian Health System.

METHODS

Retrospective study with data from patients over 18 years old, of either sex, registered with the Colombian Health System, who are prescribed antidepressants. Medical records were reviewed, looking for indications approved and not approved by regulatory agencies. Patients were identified randomly, as well as the sociodemographic, clinical and pharmacological variables that could be associated with prescriptions for unapproved indications.

RESULTS

351 patients were evaluated, with a mean age of 60.4±15.3 years, of whom 72.6% were women. They were attended in 34 cities, with prescriptions mainly by general practitioners (n=276; 78.6%), and psychiatrists (n=42; 12.0%). Selective serotonin reuptake inhibitors were the most widely prescribed antidepressants (n=204; 58.1%), followed by atypicals (n=76; 21.7%). The most frequent indications were for depression (n=169; 48.1%), anxiety (n=48; 13.7%), pain (n=22; 6.3%) and sleep disorders (n=17; 4.8%). A total of 188 prescriptions (53.6%) were made for approved indications, and the remaining 163 (46.4%) were classified as unapproved.

CONCLUSIONS

Antidepressants are being prescribed for the treatment of depression, anxiety, pain and sleep disorders, especially in older adult women, but almost half of the formulations were for unapproved indications.

Excessive daytime sleepiness and its predictors among medical and health science students of University of Gondar, Northwest Ethiopia: institution-based cross-sectional study

Background

Excessive daytime sleepiness (EDS) is a condition of sleepiness when a person would not be expected to sleep. University students are prone to EDS due to the competitive learning environment and fragmented night sleep. No study was conducted in Ethiopia on EDS. Therefore, this study aimed to determine EDS and its predictors among University of Gondar (UoG) Medical and Health Science students.

Methods

Institution-based cross-sectional study was carried out on 383 Medical and Health Science students of UoG who were recruited using a computer-generated simple random sampling technique. We used a validated Epworth daytime sleepiness tool to collect data. Epi-Info™ 7 and Stata 14 were used for data entry and analysis, respectively. Bivariable and multivariable binary logistic regression analyses were performed to find out predictors. Odds ratio with 95% uncertainty interval were computed. In the final model, a variable with a p < 0.05 was declared as a predictor of EDS.

Results

Three hundred and eighty-three students completed the questionnaire. Males were 69.97% and the mean age of participants was 20.79 (±1.83) years. In the current study, the prevalence of EDS was 31.07% (95% UI: 26.62–35.91). The odds of getting EDS was 1.83 (AOR = 1.83, 95% UI: 1.14–2.96) and 1.84 (AOR = 1.84, 95% UI: 1.13–3.00) higher among students who reported night sleep behaviour disorders and depression, respectively.

Conclusion

This study revealed that EDS is high and predicted by depression and night sleep behaviour disorders. These findings suggest the need to set preventive strategies such as counselling of students to reduce depression and night sleep behaviour disorders. Further studies particularly qualitative studies are required to find out more factors affecting EDS.

Sleep disturbances in major depressive and burnout syndrome: A longitudinal analysis

Sleep quality (SQ) is considered to be a critical variable in major depressive syndrome (MD) as well as in burnout syndrome (B). Thus far, no study examined the differential influence of these syndromes on SQ. MD and B have been assessed in 4,415 participants at baseline and in 1,396 participants at follow-up based on the Patient Health Questionnaire-9 (PHQ-9) and the Maslach Burnout Inventory-General Survey (MBI-GS). The Pittsburgh Sleep Quality Index was used to measure SQ. Based on the PHQ-9 and MBI-GS at baseline assessment, participants were divided into four groups: a control group, a MD group, a B group, and a comorbid group suffering from MD and B. Multiple regression analyses showed that all groups demonstrate significantly worse SQ than the control group, while individuals with MD showed a lower SQ compared to individuals with B. The comorbid group showed the lowest SQ. Longitudinal analyses showed a significant bidirectional association between major depressive symptoms and SQ, whereas burnout symptoms were predictive for SQ but not vice versa. The study indicates differences between MD and B with regard to SQ, suggesting worse SQ in more severely burdened groups. Major depressive symptoms are bidirectionally linked to SQ, whereas burnout symptoms are only suggested a risk factor for impaired SQ.

Sleep-related movement disorders in a population of patients with epilepsy: prevalence and impact of restless legs syndrome and sleep bruxism

STUDY OBJECTIVES

Sleep disorders are frequent co-occurrences in patients with epilepsy (PWE), but sleep-disordered breathing and insomnia are better studied than others. Our aim was to study sleep-related movement disorders in epilepsy.

METHODS

We interviewed 175 PWE (age range 18-71 years, mean 35.4 years, 47.4% female) and 130 controls (age range 18-72 years, mean 33.6 years, 47.7% females). Restless legs syndrome (RLS) and sleep bruxism (SB) were diagnosed by International RLS Study Group's diagnostic criteria and International Classification of Sleep Disorders, Third Edition criteria respectively. We also used Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Berlin Questionnaire (BQ).

RESULTS

Our findings suggest that RLS and SB are encountered more frequently in PWE than controls: 20.6% versus 6.1% for RLS, and 23.7% versus 5.4% for SB (P < .05). Insomnia was more prevalent in epilepsy (46.2% versus 24.6%, P < .05) while poor sleep hygiene occurred more frequently in controls (28.3% versus 53.8%), (P < .05). PWE had poorer sleep by PSQI 61.7% versus 41.5% (P < .05). Sleepiness (38.7% versus 39.2%) and snoring (42.8% versus 40.8%) were equally distributed in both groups, also ESS and BQ not showing significant differences (P > .05).

CONCLUSIONS

Our study demonstrates that sleep disorders comprise important part of epilepsy comorbidity. We demonstrated that unselected PWE had higher prevalence of RLS. For the first time we show higher prevalence of sleep bruxism in epilepsy population. Also complaints of insomnia are seen more in PWE, while snoring and poor sleep hygiene not.

The use and misuse of exogenous melatonin in the treatment of sleep disorders

PURPOSE OF REVIEW

To explore the evidence for using exogenous melatonin in the treatment of sleep disorders, both primary and secondary, in children and adults.

RECENT FINDINGS

A number of recently published meta-analyses have shown that there is evidence for the efficacy of exogenously administered melatonin in a number of sleep disorders. However, melatonin is likely to be prescribed largely for reasons of perceived minimal side-effect profile and very low cost in situations in which high-quality evidence for its usefulness is not forthcoming.

SUMMARY

There is evidence for the efficacy of melatonin in the management of insomnia and some intrinsic disorders of circadian rhythm in adults and children as well as in reducing sleep onset latency in jet-lag and shift work disorder in adults. Melatonin is used routinely in the treatment of rapid-eye movement sleep-behaviour disorder despite limited trial evidence. Increasingly, dual melatonin receptor agonists are being trialled in a variety of sleep disorders. Long-term adverse effects are currently not fully identified.

The neurophysiological basis of excessive daytime sleepiness: suggestions of an altered state of consciousness

Excessive daytime sleepiness (EDS) is characterized by difficulty staying awake during daytime, though additional features may be present. EDS is a significant problem for clinical and non-clinical populations, being associated with a range of negative outcomes that also represent a burden for society. Extreme EDS is associated with sleep disorders, most notably the central hypersomnias such as narcolepsy, Kleine-Levin syndrome, and idiopathic hypersomnia (IH). Although investigation of these conditions indicates that EDS results from diminished sleep quality, the underlying cause for this impairment remains uncertain. One possibility could be that previous research has been too narrow in scope with insufficient attention paid to non-sleep-related aspects. Here, we offer a broader perspective in which findings concerning the impact of EDS on cortical functioning are interpreted in relation to current understanding about the neural basis of consciousness. Alterations in the spatial distribution of cortical activity, in particular reduced connectivity of frontal cortex, suggest that EDS is associated with an altered state of consciousness.

Restless Legs Syndrome/Willis-Ekbom Disease in Multiple Sclerosis Patients with Spinal Cord Lesions

Introduction

Spinal cord lesions in Multiple Sclerosis (MS) patients are associated with a higher risk of restless legs syndrome (RLS). In this study, we investigated the prevalence of RLS, sleep quality, presence and severity of depression, and the relationship of these parameters with cervical cord lesions in patients with RRMS.

Methods

This study was conducted in the outpatient multiple sclerosis clinic of Marmara University Hospital between October 2013 - February 2014, including 93 patients with the diagnosis of MS. After signing informed consent, demographic data, comorbidities and actual medication of the patients were collected. All patients completed the surveys including Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Beck Depression Inventory (BDI). Prevalence of HBS, sleep quality and depression severity were compared between those with and without cervical cord lesions. Furthermore, the relationship between RLS and sleep quality, depression and expanded disability status scale (EDSS) was assessed.

Results

From overall patients, 72% were women (n=67) and 28% (n=26) were men. From all subjects, 32% (n=30) fulfilled IRLSSG diagnostic criteria. Fifty-seven percent of the patients (n=53) had pathological spinal cord lesions. Patients with RLS had significantly higher prevalence of pathological spinal cord lesions compared to patients without RLS (p=0.04). Sleep quality was found to be poor in both patients with cervical cord lesions and patients with RLS and this was statistically significant (p=0.031, p=0.0001).

Conclusions

In summary, the possibility of RLS development in RRMS patients increases with the presence of lesions in spinal cord. Sleep quality was found to be poor in both patients with cervical cord lesions and patients with RLS. As RLS is a potentially treatable condition, increased awareness of diagnosis of RLS in MS patients may be important for early treatment and improve the comfort of the patient.

Abnormal Global Brain Functional Connectivity in Primary Insomnia Patients: A Resting-State Functional MRI Study

Background: Resting-state functional magnetic resonance imaging (fMRI) studies have uncovered the disruptions of functional brain networks in primary insomnia (PI) patients. However, the etiology and pathogenesis underlying this disorder remains ambiguous, and the insomnia related symptoms are influenced by a complex network organization in the brain. The purpose of this study was to explore the abnormal intrinsic functional hubs in PI patients using a voxel-wise degree centrality (DC) analysis and seed-based functional connectivity (FC) approach.

Methods: A total of 26 PI patients and 28 healthy controls were enrolled, and they underwent resting-state fMRI. Degree centrality was measured across the whole brain, and group differences in DC were compared. The peak points, which significantly altered DC between the two groups, were defined as the seed regions and were further used to calculate FC of the whole brain. Later, correlation analyses were performed between the changes in brain function and clinical features.

Results: Primary insomnia patients showed DC values lower than healthy controls in the left inferior frontal gyrus (IFG) and middle temporal gyrus (MTG) and showed a higher DC value in the right precuneus. The seed-based analyses demonstrated decreased FC between the left MTG and the left posterior cingulate cortex (PCC), and decreased FC was observed between the right precuneus and the right lateral occipital cortex. Reduced DC in the left IFG and decreased FC in the left PCC were positively correlated with the Pittsburgh sleep quality index and the insomnia severity index.

Conclusions: This study revealed that PI patients exhibited abnormal intrinsic functional hubs in the left IFG, MTG, and the right precuneus, as well as abnormal seed-based FC in these hubs. These results contribute to better understanding of how brain function influences the symptoms of PI.

Mediterranean diet pattern and sleep duration and insomnia symptoms in the Multi-Ethnic Study of Atherosclerosis

Sleep duration and sleep quality are important predictors of risk for cardiovascular disease (CVD). One potential link between sleep health and CVD is through lifestyle factors such as diet. To clarify the association between diet and sleep, we assessed the associations of sleep duration and insomnia symptoms with current Mediterranean-style diet (aMed) and with historical changes in aMed score. Actigraphy-measured sleep duration and self-reported insomnia symptoms categorized as insomnia with short sleep (<6 hr/night), insomnia without short sleep, no insomnia with short sleep, and no insomnia or short sleep were obtained from 2068 individuals who also had dietary intake data. A 10-point aMed score, derived from a self-report food frequency questionnaire, was collected concurrently with the sleep assessment and 10 years before. Compared with individuals who currently reported a low aMed score, those with a moderate-high aMed score were more likely to sleep 6-7 vs. <6 hr/night (p < 0.01) and less likely to report insomnia symptoms occurring with short sleep (vs. no insomnia or short sleep alone; p < 0.05). An increase in aMed score over the preceding 10 years was not associated with sleep duration or insomnia symptoms. However, compared with those with decreasing aMed score, individuals with an unchanging score reported fewer insomnia symptoms (p ≤ 0.01). These results suggest that a Mediterranean-style diet is associated with adequate sleep duration, less insomnia symptoms, and less likely to have insomnia accompanied by short sleep. Further research should identify possible mediators through which diet may promote adequate sleep duration and reduce the risk of insomnia.

Sleep staging using nocturnal sound analysis

Sleep staging is essential for evaluating sleep and its disorders. Most sleep studies today incorporate contact sensors that may interfere with natural sleep and may bias results. Moreover, the availability of sleep studies is limited, and many people with sleep disorders remain undiagnosed. Here, we present a pioneering approach for rapid eye movement (REM), non-REM, and wake staging (macro-sleep stages, MSS) estimation based on sleep sounds analysis. Our working hypothesis is that the properties of sleep sounds, such as breathing and movement, within each MSS are different. We recorded audio signals, using non-contact microphones, of 250 patients referred to a polysomnography (PSG) study in a sleep laboratory. We trained an ensemble of one-layer, feedforward neural network classifiers fed by time-series of sleep sounds to produce real-time and offline analyses. The audio-based system was validated and produced an epoch-by-epoch (standard 30-sec segments) agreement with PSG of 87% with Cohen's kappa of 0.7. This study shows the potential of audio signal analysis as a simple, convenient, and reliable MSS estimation without contact sensors.

Incidence of narcolepsy after H1N1 influenza and vaccinations: Systematic review and meta-analysis

An increased incidence of narcolepsy was seen in many countries after the pandemic H1N1 influenza vaccination campaign in 2009-2010. The H1N1 vaccine - narcolepsy connection is based on observational studies that are prone to various biases, e.g., confounding by H1N1 infection, and ascertainment, recall and selection biases. A direct pathogenic link has, however, remained elusive. We conducted a systematic review and meta-analysis to analyze the magnitude of H1N1 vaccination related risk and to examine if there was any association with H1N1 infection itself. We searched all articles from PubMed, Web of Science and Scopus, and other relevant sources reporting the incidence and risk of post-vaccine narcolepsy. In our paper, we show that the risk appears to be limited to only one vaccine (Pandemrix^®). During the first year after vaccination, the relative risk of narcolepsy was increased 5 to 14-fold in children and adolescents and 2 to 7-fold in adults. The vaccine attributable risk in children and adolescents was around 1 per 18,400 vaccine doses. Studies from Finland and Sweden also appear to demonstrate an extended risk of narcolepsy into the second year following vaccination, but such conclusions should be interpreted with a word of caution due to possible biases. Benefits of immunization outweigh the risk of vaccination-associated narcolepsy, which remains a rare disease.

Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders

Melatonin is a physiological hormone involved in sleep timing and is currently used exogenously in the treatment of primary and secondary sleep disorders with empirical evidence of efficacy, but very little evidence from randomised, controlled studies. The aim of this meta-analysis was to assess the evidence base for the therapeutic effects of exogenous melatonin in treating primary sleep disorders. An electronic literature review search of MEDLINE (1950-present) Embase (1980- present), PsycINFO (1987- present), and Scopus (1990- present), along with a hand-searching of key journals was performed in July 2013 and then again in May 2015. This identified all studies that compared the effect of exogenous melatonin and placebo in patients with primary insomnia, delayed sleep phase syndrome, non 24-h sleep wake syndrome in people who are blind, and rapid eye movement-behaviour disorder. Meta-analyses were performed to determine the magnitude of effect in studies of melatonin in improving sleep. A total of 5030 studies were identified; of these citations, 12 were included for review based on the inclusion criteria of being: double or single-blind, randomised and controlled. Results from the meta-analyses showed the most convincing evidence for exogenous melatonin use was in reducing sleep onset latency in primary insomnia (p = 0.002), delayed sleep phase syndrome (p < 0.0001), and regulating the sleep-wake patterns in blind patients compared with placebo. These findings highlight the potential importance of melatonin in treating certain first degree sleep disorders. The development of large-scale, randomised, controlled trials is recommended to provide further evidence for therapeutic use of melatonin in a variety of sleep difficulties.

Sleep as a potential fundamental contributor to disparities in cardiovascular health

Optimal sleep is integral to health but is commonly not obtained. Despite its wide-ranging public health impact, sleep health is considered only rarely by policy makers, employers, schools, and others whose policies and structures can adversely affect sleep. An inadequate duration of sleep and poor-quality sleep are prevalent in minority and low-income populations, and may be fundamental to racial and socioeconomic status inequities that contribute to a range of health conditions, including cardiovascular disease (CVD). This review examines the relationship between sleep and disparities in CVD. We describe the public health importance of sleep and the role of sleep duration, as well as the two most common disorders (sleep apnea and insomnia) as risk factors for a number of chronic diseases. We use a multilevel model focused on population health and health disparities, which is based on the notion that individual behaviors, such as sleep, are influenced by complex and dynamic interrelations among individuals and their physical and social environments. We also describe modifiable factors that contribute to insufficient sleep and circadian misalignment, propose potential interventions in various sectors (e.g., neighborhoods, schools, workplaces) that can address social structures that contribute to disparities, and recommend areas for future research. Integrating sleep into public health research will identify novel approaches for closing gaps in health disparities.

Daytime sleepiness and Parkinson's disease: the contribution of the multiple sleep latency test

Background. Sleep disorders are major nonmotor manifestations of patients with Parkinson's disease (PD), and excessive daytime sleepiness (EDS) is one of the most common symptoms. Objective. We reviewed a current literature concerning major factors that influence EDS in PD patients, using Multiple Sleep Latency Test (MSLT). Methods. A Medline search found 23 studies. Results. The presence of EDS was observed in 12.7% to 47% in patients without complaints of daytime sleepiness and 47% to 66.7% with complaints of daytime sleepiness. Despite being recognized by several authors, major factors that influence EDS, such as severity of motor symptoms, use of dopaminergic medications, and associated sleep disturbances, presented contradictory data. Conclusions. Available data suggest that the variability of the results may be related to the fact that it was conducted with a small sample size, not counting the neuropathological heterogeneity of the disease. Thus, before carrying out longitudinal studies with significant samples, careful analysis should be done by assigning a specific agent on the responsibility of EDS in PD patients.