ABC of sleep disorders. Impact and epidemiology of sleep disorders

The socio-economics of insomnia: the materials and the methods

Insomnia affects about one-third of the population, and is associated with increased morbidity and mortality, reduced production and higher rates of accidents. This suggests that insomnia may burden society with significant cost. However, a precise economic analysis of insomnia is a challenge. Insomnia is part of a very complex interplay of physical and psychological illness, functioning both as a cause and as a consequence. In this paper, some of the methodological issues related to an economic analysis of insomnia are discussed. Data is presented using an economic analysis as an organizer, thus illustrating what conclusions can be drawn, and where further research is needed.

Non-alcoholic fatty liver disease among patients with sleep disorders: a Nationwide study of Taiwan

Background

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases. Studies have shown that sleep apnea is associated with NAFLD. However, studies on the association between sleep disorders in general and NAFLD are limited. We conducted a nationwide population-based longitudinal study to evaluate this potential association.

Methods

We identified patients diagnosed with sleep disorders in the years 2000 through 2005 in Taiwan using the National Health Insurance Research Database and selected an equal number of patients without sleep disorders from the same database as the comparison cohort. The patients were followed from the index date to the diagnosis of NAFLD or the end of 2013. We used Cox proportional hazards models to estimate the risk of NAFLD associated with sleep disorders.

Results

A total of 33,045 patients with sleep disorders were identified. The incidence of NAFLD was 14.0 per 10,000 person-year in patients with sleep disorders and 6.2 per 10,000 person-year in the comparison cohort. The adjusted hazard ratio (AHR) of NAFLD associated with sleep disorders was 1.78 (95% confidence interval [95%CI]: 1.46–2.16), and other independent risk factors included male sex (AHR = 1.31, 95%CI: 1.12–1.54), age 40–59 years (AHR = 1.49, 95%CI: 1.21–1.82), and dyslipidemia (AHR = 2.51, 95%CI: 2.08–3.04). In the subgroup analyses, both patients with (AHR = 2.24, 95%CI: 1.05–4.77) and without (AHR = 1.77, 95%CI: 1.46–2.15) sleep apnea had an increased risk of NAFLD.

Conclusions

Sleep disorders are associated with NAFLD, even in patients without sleep apnea. Further studies are warranted to explore the mechanisms of the association.

The mobile sleep lab app: An open-source framework for mobile sleep assessment based on consumer-grade wearable devices

BACKGROUND

Sleep disorders have a prevalence of up to 50% and are commonly diagnosed using polysomnography. However, polysomnography requires trained staff and specific equipment in a laboratory setting, which are expensive and limited resources are available. Mobile and wearable devices such as fitness wristbands can perform limited sleep monitoring but are not evaluated well. Here, the development and evaluation of a mobile application to record and synchronize data from consumer-grade sensors suitable for sleep monitoring is presented and evaluated for data collection capability in a clinical trial.

METHODS

Wearable and ambient consumer-grade sensors were selected to mimic the functionalities of clinical sleep laboratories. Then, a modular application was developed for recording, processing and visualizing the sensor data. A validation was performed in three phases: (1) sensor functionalities were evaluated, (2) self-experiments were performed in full-night experiments, and (3) the application was tested for usability in a clinical trial on primary snoring.

RESULTS

The evaluation of the sensors indicated their suitability for assessing basic sleep characteristics. Additionally, the application successfully recorded full-night sleep. The collected data was of sufficient quality to detect and measure body movements, cardiac activity, snoring and brightness. The ongoing clinical trial phase showed the successful deployment of the application by medical professionals.

CONCLUSION

The proposed software demonstrated a strong potential for medical usage. With low costs, it can be proposed for screening, long-term monitoring or in resource-austere environments. However, further validations are needed, in particular the comparison to a clinical sleep laboratory.

To Assess Sleep Quality among Pakistani Junior Physicians (House Officers): A Cross-sectional Study

Background:

Sleep deprivation among junior physicians (house officers) is of growing concern. In developed countries, duty hours are now mandated, but in developing countries, junior physicians are highly susceptible to develop sleep impairment due to long working hours, on-call duties and shift work schedule.

Aim:

We undertook the study to assess sleep quality among Pakistani junior physicians.

Subjects and Methods:

A cross-sectional study was conducted at private and public hospitals in Karachi, Pakistan, from June 2012 to January 2013. The study population comprised of junior doctors (house physicians and house surgeons). A consecutive sample of 350 physicians was drawn from the above-mentioned study setting. The subject underwent two validated self-administered questionnaires, that is, Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS).

Results:

A total of 334 physicians completely filled out the questionnaire with a response rate of 95.4% (334/350). Of 334 physicians, 36.8% (123/334) were classified as “poor sleepers” (global PSQI score > 5). Poor sleep quality was associated with female gender (P = 0.01), excessive daytime sleepiness (P < 0.01), lower total sleep time (P < 0.001), increased sleep onset latency (P < 0.001), and increased frequency of sleep disturbances (P < 0.001). Abnormal ESS scores (ESS > 10) were more prevalent among poor sleepers (P < 0.01) signifying increased level of daytime hypersomnolence.

Conclusion:

Sleep quality among Pakistani junior physicians is significantly poor. Efforts must be directed towards proper sleep hygiene education. Regulations regarding duty hour limitations need to be considered.

Isolated sleep paralysis and hypnic hallucinations in schizophrenia

BACKGROUND

Usually remembered in the context of Narcolepsy-Cataplexy syndrome, isolated sleep paralysis (SP) and hypnic hallucination are widely prevalent and because of the overlap of symptoms with schizophrenia, their identification is important but unrecognized.

AIMS

To determine the presence of SP and hypnic hallucinations (HH) in people with schizophrenia and schizoaffective disorder.

STUDY DESIGN

Cross-sectional survey.

METHODS

Participants were patients receiving follow-up care for schizophrenia from Assertive Community Treatment Team. A screening questionnaire was administered during their routine follow-up visits.

RESULTS

Of 71 respondents (49 males, 22 females) only 11 (10 males and 1 female), that is, 15% reported SP, and 12 (7 males and 5 females), that is, 16.9% reported HH, a considerably low prevalence.

CONCLUSION

It is difficult to study the presence of SP and HH in patients with active or residual symptoms of schizophrenia, and more refined studies and appropriate questionnaires are required. The possibility of SP and HH confounding or being misdiagnosed as psychotic symptoms needs to be borne in mind.

Evaluation of Sexual Function and Its Contributing Factors in Men With Spinal Cord Injury Using a Self-Administered Questionnaire

Sexual activity is an important aspect of life in patients with spinal cord injury (SCI), rated as one of the top priorities for recovery of function. This study was conducted to establish an understanding of the severity of erectile dysfunction (ED), a major component of male sexual activity, and its correlates in patients with SCI in our community. In a cross-sectional study, 37 male veterans with SCI admitted for regular follow-up at our center were recruited. Demographic and SCI-related descriptive information was gathered through a self-administered questionnaire. Sexual Health Inventory for Men was used to assess the presence and severity of ED. Euro Quality of Life questionnaire and General Health Questionnaire (GHQ-12) were also administered. The mean age of the participants was 45.7 ± 6.5 years with injury duration of 24.7 ± 6.2 years. Mean GHQ-12 score of 3.65 ± 3.38 and mean Sexual Health Inventory for Men score of 11.57 ± 5.28 were measured. All participants had ED, and 27% were suffering from severe ED. Sleep deprivation, worse GHQ-12 score, and hypertension were significantly associated with higher risk of much severe ED ( p < .05). In conclusion, ED is a common problem in veterans with SCI and is inversely associated with their general health status.

Valerian: no evidence for clinically relevant interactions

In recent popular publications as well as in widely used information websites directed to cancer patients, valerian is claimed to have a potential of adverse interactions with anticancer drugs. This questions its use as a safe replacement for, for example, benzodiazepines. A review on the interaction potential of preparations from valerian root (Valeriana officinalis L. root) was therefore conducted. A data base search and search in a clinical drug interaction data base were conducted. Thereafter, a systematic assessment of publications was performed. Seven in vitro studies on six CYP 450 isoenzymes, on p-glycoprotein, and on two UGT isoenzymes were identified. However, the methodological assessment of these studies did not support their suitability for the prediction of clinically relevant interactions. In addition, clinical studies on various valerian preparations did not reveal any relevant interaction potential concerning CYP 1A2, 2D6, 2E1, and 3A4. Available animal and human pharmacodynamic studies did not verify any interaction potential. The interaction potential of valerian preparations therefore seems to be low and thereby without clinical relevance. We conclude that there is no specific evidence questioning their safety, also in cancer patients.

Differences between patients' and clinicians' report of sleep disturbance: a field study in mental health care in Norway

BACKGROUND

The aims of the study was to assess the prevalence of diagnosed insomnia and the agreement between patient- and clinician-reported sleep disturbance and use of prescribed hypnotic medication in patients in treatment for mental disorders.

METHODS

We used three cross-sectional, multicenter data-sets from 2002, 2005, and 2008. Data-set 1 included diagnostic codes from 93% of all patients receiving treatment in mental health care in Norway (N = 40261). Data-sets 2 (N = 1065) and 3 (N = 1181) included diagnostic codes, patient- and clinician-reported sleep disturbance, and use of prescribed hypnotic medication from patients in 8 mental health care centers covering 10% of the Norwegian population.

RESULTS

34 patients in data-set 1 and none in data-sets 2 and 3 had a diagnosis of insomnia as a primary or comorbid diagnosis. In data-sets 2 and 3, 42% and 40% of the patients reported sleep disturbance, whereas 24% and 13% had clinician-reported sleep disturbance, and 7% and 9% used hypnotics. Patients and clinicians agreed in 29% and 15% of the cases where the patient or the clinician or both had reported sleep disturbance. Positive predictive value (PPV) of clinicians' evaluations of patient sleep disturbance was 62% and 53%. When the patient reported sleep disturbance as one of their most prominent problems PPV was 36% and 37%. Of the patients who received hypnotic medication, 23% and 29% had neither patient nor clinician-rated sleep disturbance.

CONCLUSION

When patients meet the criteria for a mental disorder, insomnia is almost never diagnosed, and sleep disturbance is imprecisely recognized relative to the patients' experience of sleep disturbance.

Women sleep objectively better than men and the sleep of young women is more resilient to external stressors: effects of age and menopause

The aims of this study were to: (i) assess gender differences of objective sleep patterns in a general population sample; (ii) evaluate the effects of menopause and hormone treatment (HT) on the sleep of the same cohort; and (iii) examine gender differences in sleep resilience towards external stressors. The participants were (i) 1324 subjects without sleep complaints, recruited from the general population of Central Pennsylvania that spent one night in the sleep laboratory and (ii) 66 young, healthy volunteers whose sleep was disturbed during night four by an external stressor, i.e. 24-h blood drawing (average of nights 2 and 3 versus night 4). Women compared with men in the general population sample had significantly higher percentage of sleep time, lower percentage of stage 1, and higher percentage of slow wave sleep. Also, menopause, in the absence of HT, was associated with prolonged sleep latency and decreased deep sleep. Finally, young, healthy women compared with men experienced less sleep disturbance because of blood draws as indicated by a significantly smaller change in per cent sleep time, and percentage of stage 1 sleep. These findings suggest that women without sleep complaints sleep objectively better across age than men and the sleep of young women is more resistant to external stressors. Also, gonadal hormones exert a beneficial effect on women's sleep. This gender dimorphism in sleep regulation may have been to protect women from the demands of infant and child care, and in part, might contribute to women's lower cardiovascular risks and greater longevity.

The Effect of Sleep Disturbances on Major Depressive Disorder

Sleep disturbances not only commonly occur in major depressive disorder, but constitute one of the symptom criteria. Importantly, there is growing inference that sleep disturbances may be more than a symptomatic byproduct of depression; poor sleep may play a role in the development or clinical course of depression, or both. This article reviews the prevalence of the two major classes of sleep disorders, the insomnias and the sleep-disordered breathing disorders, as they pertain to depression. Beyond prevalence, the empirical evidence reviewed suggests that insomnia is a risk factor for depression and that obstructive sleep apnea (OSA) is highly associated with depression. Preliminary evidence indicates that OSA may also be a risk factor for this disorder. The implications of these findings for the treatment of sleep disturbances either prior to or in the context of depression are discussed.

Evaluation and treatment of sleep complaints: patients' subjective responses

BACKGROUND

This study set out to evaluate whether patients' expectations affected their responses to treatment of a sleep disorder.

METHODS

Fifty consecutive patients attending a sleep clinic for the first time and who had different diagnoses of sleep disorders were included in this study. The patients completed a set of 6 questionnaires on 7 occasions as they progressed through the process of a sleep clinic referral, assessment and treatment. Self-report questionnaires were used to assess their sleepiness, fatigue and alertness. Predictor measures included mental health and individual items assessing expectation regarding the seriousness of the sleep problem. A battery of questions dealt with mental health issues, patients' expectation and their commitment to the sleep investigation and treatment process. Each patient's responses were examined over a period of 6 months.

RESULTS

Immediately following their interview with the sleep consultant, the patients' concern regarding their sleep problem was higher than the first measures obtained at baseline. Compared to prior to their first consultation with a sleep specialist, while on treatment they directed more attention to their sleep problem when problems associated with fatigue were reduced. Although there was a lessening in fatigue with treatment, subjectively rated sleepiness (Epworth Sleepiness Scale) did not vary over the study. Contact with a sleep center and the diagnosis and treatment of individual sleep problems also resulted in improved satisfaction with life.

CONCLUSIONS

Contact with and treatment at a sleep clinic was found to be beneficial. The fatigue levels were reduced and the patients had greater life satisfaction regardless of the diagnosis and treatment of their sleep disorder, although subjective sleepiness did not change. Patient expectations were not critical in determining the outcome of the sleep clinic assessment.

Eszopiclone, a Nonbenzodiazepine Sedative-Hypnotic Agent for the Treatment of Transient and Chronic Insomnia

OBJECTIVE

This paper reviews the pharmacologic and pharmacokinetic properties, clinical efficacy, and safety profile of the nonbenzodiazepine cyclopyrrolone agent eszopiclone in the management of adult patients with insomnia.

METHODS

Recent studies, abstracts, reviews, and consensus statements published in English were identified through searches of MEDLINE (1966-December 2005), International Pharmaceutical Abstracts (1970 December 2005), and PharmaProjects (1990-December 2005) using the search terms eszopiclone, cyclopyrrolone, insomnia, nonbenzodiazepine, and zopiclone enantiomer. Selected information provided by the manufacturer of eszopiclone was included, as were all pertinent clinical trials.

RESULTS

Eszopiclone is rapidly absorbed after oral administration, with Tmax achieved within approximately 1 hour and a terminal-phase elimination half-life of approximately 6 hours. Approximately 52% to 59% of a dose is weakly bound to plasma protein. Eszopiclone is extensively metabolized by oxidation and demethylation. In vitro studies have indicated that the cytochrome P450 (CYP) isozymes CYP3A4 and CYP2E1 are involved in the biotransformation of eszopiclone; therefore, drugs that induce or inhibit these CYP isozymes may affect the metabolism of eszopiclone. Eszopiclone is excreted in the urine as racemic zopiclone at <10% of the orally administered dose. Six Phase III clinical trials were identified that evaluated the safety profile and efficacy of eszopiclone, 1 in healthy subjects with transient insomnia and 5 in patients with primary chronic insomnia (3 in younger adults and 2 in the elderly). In the trials in younger adults, eszopiclone significantly improved sleep efficiency, sleep latency, wake time after sleep onset, number of awakenings, number of nights awakened weekly, total sleep time, and quality and depth of sleep compared with placebo (P<0.05). In the trials in elderly patients, who received eszopiclone 2 mg or placebo for 2 weeks, eszopiclone was associated with significantly shorter sleep latency compared with placebo (P<0.004), as well as a significant decrease in the cumulative number of naps (P<0.05). The most commonly reported drug-related, dose-responsive adverse event in clinical trials of eszopiclone 2 and 3 mg was bitter taste (17% and 34%, respectively), followed by dizziness (5% and 7%) and dry mouth (5% and 7%). Somnolence occurred at an incidence of 4% to 9% with both doses. Tolerance or rebound insomnia was not reported.

CONCLUSIONS

Eszopiclone represents an effective and well-tolerated option for the treatment of insomnia. In the absence of published studies comparing eszopiclone with similar hypnotic agents (eg, zolpidem, zaleplon, zopiclone), it is not yet possible to evaluate its efficacy relative to other agents used for insomnia.

Relevance of sleep paralysis and hypnic hallucinations to psychiatry

OBJECTIVE

To describe a patient who presented with psychopathology in the wake of sleep paralysis and hypnopompic hallucinations, and to discuss the importance of these phenomena to psychiatric diagnoses.

METHODS

Case report.

RESULTS

A 25-year-old black South African woman developed paranoid beliefs and a sad and anxious mood in the wake of her first experience of sleep paralysis and hypnic hallucinations. She had no history of other sleep-related events. Reassurance, explanation of the physiological basis of her experience, and a short course of low-dose diazepam were provided. Her mood and sleep improved promptly and she no longer held paranoid beliefs. She did not experience further episodes of sleep paralysis or hypnic hallucinations and improvement was sustained at 6 months.

CONCLUSIONS

It pays to probe for the core experiences or events that patients may be explaining by devising "delusions". Acute, nocturnal-onset, first-time psychopathology warrants inquiry for sleep paralysis and hypnic hallucinations. Sleep-related side-effects of psychotropic medications need to be studied more closely.

The nose and sleep-disordered breathing: what we know and what we do not know

The relationship between sleep-disordered breathing (SDB) and nasal obstruction is unclear. In order to better understand, we performed an extensive computer-assisted review and analysis of the medical literature on this topic. Data were grouped into reports of normal control subjects, patients with isolated nasal obstruction, and those with SDB. We conclude that SDB can both result from and be worsened by nasal obstruction. Nasal breathing increases ventilatory drive and nasal occlusion decreases pharyngeal patency in normal subjects. Nasal congestion from any cause predisposes to SDB. Although increased nasal resistance does not always correlate with symptoms of congestion, nasal congestion typically results in a switch to oronasal breathing that compromises the airway. Moreover, oral breathing in children may lead to the development of facial structural abnormalities associated with SDB. We postulate that the switch to oronasal breathing that occurs with chronic nasal conditions is a final common pathway for SDB.

Effects of melatonin on the quality of life in patients with delayed sleep phase syndrome

OBJECTIVE

The purpose of this study was to compare health-related quality of life of delayed sleep phase syndrome (DSPS) patients with a random Dutch sample and four samples of patients with other chronic conditions. We also investigated the effectiveness of treatment with 5 mg of melatonin on the quality of life of DSPS patients.

METHODS

Forty-three DSPS patients completed a quality-of-life questionnaire (Medical Outcome Study Short Form-36 [MOS SF-36] health survey) just before and 2-9 months after participation in a clinical trial involving the administration of melatonin. Scores were compared with responses to the same survey by a random Dutch sample and by patients with sleep apnea, clinical depression, migraine, and osteoarthritis.

RESULTS

MOS SF-36 scales scores were significantly lower in DSPS patients relative to age- and gender-adjusted norms for the Dutch sample. Some health dimensions were more affected, and others less affected, by DSPS compared with the other chronic conditions. Melatonin treatment improved all scales except the scale "role due to emotional problems."

CONCLUSION

DSPS has a unique significant quality-of-life burden that seems to be improved by treatment with melatonin.

The Epworth Sleepiness Scale: can it be used for sleep apnoea screening among snorers?

Snoring is a common disorder and may lead to the development of Obstructive Sleep Apnoea (OSA) with its associated hazards. Differentiation of patients with OSA from patients with simple snoring is crucial to the ENT surgeon before selecting treatment. This study aimed to assess the reliability of the Epworth Sleepiness Scale (ESS) to screen for OSA among snorers. Forty-six patients referred for treatment of snoring were studied. Each patient completed the ESS questionnaire and subsequently underwent a hospital sleep study. The ESS scores did not correlate with the apnoea/hypopnoea indices calculated from the sleep studies (correlation coefficient 0.12). The lack of correlation is mainly because simple snorers can also suffer from excessive daytime sleepiness, due to an unclear mechanism. The ESS is a useful questionnaire for assessing disability as a result of snoring but it is of no value in distinguishing simple snorers from patients with OSA.

Cerebral circulation in sleep: vasodilatory response to cerebral hypotension

Little is known of the factors that regulate CBF in sleep. We therefore studied 10 lambs to assess the vasodilatory processes that underlie cerebral autoregulation during sleep. Lambs, instrumented to measure CBF (flow probe on the superior sagittal sinus), sleep state, and cerebral perfusion pressure (CPP), were rapidly made hypotensive by inflating a cuff around the brachiocephalic artery to reduce CPP to 30 mm Hg in each state. During control periods, cerebral vascular resistance (CVR in mm Hg/mL/min) was lower in active sleep (2.8 +/- 0.3, mean +/- SD, P < or = 0.001) than in wakefulness (3.9 +/- 0.6) and quiet sleep (4.3 +/- 0.6). The CVR decreased promptly in each state as CPP was lowered. The time (seconds) required for maximal cerebral vasodilation to occur was longer in active sleep (35 +/- 11) than in quiet sleep (20 +/- 6, P < or = 0.001) and wakefulness (27 +/- 11, P < or = 0.05). The CVR decreased less in active sleep (0.6 +/- 0.3, P < or = 0.001) than in quiet sleep (1.5 +/- 0.3), although the changes in CPP induced with brachiocephalic occlusion were equal in each state. In conclusion, our studies provide the first evidence that the vasoactive mechanisms that underlie autoregulation of the cerebral circulation function during sleep. Moreover, our data reveal that the speed and the magnitude of the vasodilatory reserves available for autoregulation are significantly less in active sleep than in quiet sleep.

The socioeconomic impact of insomnia. An overview

Insomnia is an extremely common symptom both de novo and in the context of other medical and psychiatric disorders. The impact of insomnia is often ignored both by the individual and by society in terms of its clinical and socioeconomic ramifications. Insomnia is therefore under-appreciated and almost certainly under-treated, thus making it a serious health concern. It is estimated that more than 60 million Americans suffer from insomnia annually, and this figure is expected to grow to 100 million by the middle of the 21st century. Whether it be difficulty initiating or maintaining sleep, the disruption of nocturnal sleep will invariably impact on daytime activities and often results in daytime fatigue, performance deficits (including memory and other cognitive deficits), an increase in the number of sick days taken by an individual and accidents (some catastrophic). This review examines the costs directly related to insomnia in various sectors of healthcare, the indirect costs associated with accidents, sick days and decreased work productivity, and related costs resulting from insomnia but which meet neither the criteria of direct nor indirect cost categories. The total direct, indirect and related costs of insomnia are conservatively estimated at $US30 to 35 billion annually in the US (1994 dollars). Economic gains can be made by treating patients on an outpatient basis in sleep centres.

An acoustic screening test for obstructive sleep apnoea

Third-octave sound analysis was performed on the snoring sounds of nine subjects with obstructive sleep apnoea (OSA) and 18 with simple snoring. Both groups demonstrated a large low frequency peak in linear sound levels at around 80 Hz. However, the OSA group displayed a substantially larger high frequency sound component. We utilized this fact in the development of an acoustic index (Hawke Index: HI) which describes the ratio between the overall A-weighted and linear sound levels for the recorded snoring sound of each subject [HI = dB(A)/dB(SPL) for Lmax]. There was a significant positive correlation between the apnoea/hypopnoea index and the HI (r = 0.73, t = 5.3, 25df, P < 0.001). If a value of 0.90 or greater was taken as diagnostic of OSA, the HI exhibited 67% sensitivity, 100% specificity, 100% positive and 86% negative predictive accuracy. With further development, we believe this acoustic phenomena may have a role as a screening test in the diagnosis of OSA.

Prevalence of sleep disturbances in diabetes mellitus

We studied the prevalence of sleep disturbances in 184 persons with diabetes, and 99 controls matched for age and sex. Sleep disorders were more common in diabetics (33.7% vs. 8.2% in controls; P < 0.01). Patients with sleep disturbances were younger than those with normal sleep, and had onset of diabetes at a younger age. There was a significant association of sleep disturbances with the presence of cough, dyspnea, nocturnal cramps, paresthesia and burning of soles. Sleep disturbances may be due to physical discomfort, psychosocial factors, fluctuations in metabolic control and perhaps also hypoinsulinemia. Quality of life is affected and coping with the disease is made difficult by sleep disorders. Thus, physicians caring for persons with diabetes must be able to recognize, diagnose and manage sleep disturbances in their patients, when they occur.