Nonrestorative sleep

Sleep Difficulties and Insomnia Symptoms in Norwegian Musicians Compared to the General Population and Workforce

Sleep problems are reported as common among performing artists and musicians. However, epidemiological research comparing musicians to different groups of the general population is lacking. For this study, 4,168 members of the Norwegian Musician's Union were invited to an online survey regarding work and health. Of the 2,121 (51%) respondents, 1,607 were active performing musicians. We measured prevalence of insomnia symptoms using the Bergen Insomnia Scale (BIS), and compared this sample to a representative sample of the general Norwegian population (n = 2,645). Overall, musicians had higher prevalence of insomnia symptoms compared to the general population (Prevalence Difference 6.9, 95% Confidence Interval 3.9-10.0). Item response analysis showed that this difference was mainly explained by nonrestorative sleep and dissatisfaction with sleep among musicians. An additional analysis, comparing musicians to the general Norwegian workforce (n = 8,518) on sleep difficulties, confirmed this tendency (Prevalence Difference 6.2, 95% Confidence Interval 4.3-8.1). Musicians performing classical, contemporary, rock, and country music reported the highest prevalence of insomnia, and these genres might be of special interest when developing preventative measures, treatment strategies, and further research on sleep difficulties among musicians.

Relationships Between Questionnaire Ratings of Sleep Quality and Polysomnography in Healthy Adults

This study aimed to examine the association between polysomnographic sleep and subjective habitual sleep quality and restoration from sleep. Thirty-one normal sleepers completed the Karolinska Sleep Questionnaire and multiple home polysomnography recordings (n = 2-5). Using linear regression, sleep quality and restoration were separately analyzed as functions of standard polysomnography parameters: sleep efficiency, total sleep time, sleep latency, stage 1 and 2 sleep, slow-wave sleep, rapid eye movement sleep, wake time after sleep onset, and awakenings (n), averaged across recordings. Stage 2 and slow-wave sleep predicted worse and better sleep quality, respectively. Also, slow-wave sleep predicted less subjective restoration, although adjustment for age attenuated this relation. Our findings lend some physiological validity to ratings of habitual sleep quality in normal sleepers. Data were less supportive of a physiological correlate of ratings of restoration from sleep.

The Neurological Sleep Index: A suite of new sleep scales for multiple sclerosis

Objective

The objective of this study was to develop patient-reported outcome measures for sleep dysfunction and sleepiness in multiple sclerosis (MS), since there are currently no MS-specific measurement tools for these clinically important entities.

Methods

Items were generated from semi-structured interviews followed by cognitive debrief. A 42-item pool was administered to patients with MS at three neuroscience centres in the UK. Comparator scales were co-administered. Constructs were validated by Rasch analysis, guided by initial exploratory factor analysis.

Results

There were two supraordinate qualitative themes of diurnal sleepiness and non-restorative nocturnal sleep. Rasch analysis on 722 records produced three scales, which corresponded to diurnal sleepiness, non-restorative nocturnal sleep and fragmented nocturnal sleep. All had excellent fit parameters, were unidimensional and were free from differential item functioning. A summed raw score cut-point of 31/48 in the Diurnal Sleepiness Scale equated to the standard cut-point of 10 on the Epworth Sleepiness Scale (ESS).

Conclusion

Three high-quality measurement scales were developed, and together they compose the Neurological Sleep Index for MS (NSI-MS). The Diurnal Sleepiness Scale might provide an alternative to the ESS. The Non-Restorative Nocturnal Sleep Scale and the Fragmented Nocturnal Sleep Scale appear to be the only such measures for use in MS.

Regional Patterns of Elevated Alpha and High-Frequency Electroencephalographic Activity during Nonrapid Eye Movement Sleep in Chronic Insomnia: A Pilot Study

STUDY OBJECTIVES

To examine nonrapid eye movement (NREM) sleep in insomnia using high-density electroencephalography (EEG).

METHODS

All-night sleep recordings with 256 channel high-density EEG were analyzed for 8 insomnia subjects (5 females) and 8 sex and age-matched controls without sleep complaints. Spectral analyses were conducted using unpaired t-tests and topographical differences between groups were assessed using statistical non-parametric mapping. Five minute segments of deep NREM sleep were further analyzed using sLORETA cortical source imaging.

RESULTS

The initial topographic analysis of all-night NREM sleep EEG revealed that insomnia subjects had more high-frequency EEG activity (> 16 Hz) compared to good sleeping controls and that the difference between groups was widespread across the scalp. In addition, the analysis also showed that there was a more circumscribed difference in theta (4-8 Hz) and alpha (8-12 Hz) power bands between groups. When deep NREM sleep (N3) was examined separately, the high-frequency difference between groups diminished, whereas the higher regional alpha activity in insomnia subjects persisted. Source imaging analysis demonstrated that sensory and sensorimotor cortical areas consistently exhibited elevated levels of alpha activity during deep NREM sleep in insomnia subjects relative to good sleeping controls.

CONCLUSIONS

These results suggest that even during the deepest stage of sleep, sensory and sensorimotor areas in insomnia subjects may still be relatively active compared to control subjects and to the rest of the sleeping brain.

Chronic fatigue syndrome and sleep disorders: clinical associations and diagnostic difficulties

INTRODUCTION

Chronic fatigue syndrome (CFS) is characterised by the presence of intractable fatigue and non-restorative sleep, symptoms which are also very prevalent in multiple diseases and appear as side effects of different drugs. Numerous studies have shown a high prevalence of sleep disorders in patients with CFS. However, non-restorative sleep and fatigue are frequently symptoms of the sleep disorders themselves, so primary sleep disorders have to be ruled out in many cases of CFS.

DEVELOPMENT

This review was performed using a structured search of the MeSH terms ([Sleep]+[Chronic fatigue syndrome]) in the PubMed database.

CONCLUSION

Identifying primary sleep disorders in patients meeting diagnostic criteria for CFS will allow for a more comprehensive treatment approach involving new diagnostic and therapeutic strategies that may improve quality of life for these patients.

Sleep quality and the treatment of intestinal microbiota imbalance in Chronic Fatigue Syndrome: A pilot study

Chronic Fatigue Syndrome (CFS) is a multisystem illness, which may be associated with imbalances in gut microbiota. This study builds on recent evidence that sleep may be influenced by gut microbiota, by assessing whether changes to microbiota in a clinical population known to have both poor sleep and high rates of colonization with gram-positive faecal Streptococcus, can improve sleep. Twenty-one CFS participants completed a 22- day open label trial. Faecal microbiota analysis was performed at baseline and at the end of the trial. Participants were administered erythromycin 400 mg b.d. for 6 days. Actigraphy and questionnaires were used to monitor sleep, symptoms and mood. Changes in patients who showed a clinically significant change in faecal Streptococcus after treatment (responders; defined as post-therapy distribution<6%) were compared to participants who did not respond to treatment. In the seven responders, there was a significant increase in actigraphic total sleep time (p=0.028) from baseline to follow up, compared with non-responders. Improved vigour scores were associated with a lower Streptococcus count (ρ=-0.90, p=0.037). For both the responders and the whole group, poorer mood was associated with higher Lactobacillus. Short term antibiotic treatment appears to be insufficient to effect sustainable changes in the gut ecosystem in most CFS participants. Some improvement in objective sleep parameters and mood were found in participants with reduced levels of gram-positive gut microbiota after antibiotic treatment, which is encouraging. Further study of possible links between gut microorganisms and sleep and mood disturbances is warranted.

Cross-cultural and comparative epidemiology of insomnia: the Diagnostic and statistical manual (DSM), International classification of diseases (ICD) and International classification of sleep disorders (ICSD)

OBJECTIVE

To compare the prevalence of insomnia according to symptoms, quantitative criteria, and Diagnostic and Statistical Manual of Mental Disorders, 4th and 5th Edition (DSM-IV and DSM-5), International Classification of Diseases, 10th Revision (ICD-10), and International Classification of Sleep Disorders, 2nd Edition (ICSD-2), and to compare the prevalence of insomnia disorder between Hong Kong and the United States by adopting a similar methodology used by the America Insomnia Survey (AIS).

METHODS

Population-based epidemiological survey respondents (n = 2011) completed the Brief Insomnia Questionnaire (BIQ), a validated scale generating DSM-IV, DSM-5, ICD-10, and ICSD-2 insomnia disorder.

RESULTS

The weighted prevalence of difficulty falling asleep, difficulty staying asleep, waking up too early, and non-restorative sleep that occurred ≥3 days per week was 14.0%, 28.3%, 32.1%, and 39.9%, respectively. When quantitative criteria were included, the prevalence dropped the most from 39.9% to 8.4% for non-restorative sleep, and the least from 14.0% to 12.9% for difficulty falling asleep. The weighted prevalence of DSM-IV, ICD-10, ICSD-2, and any of the three insomnia disorders was 22.1%, 4.7%, 15.1%, and 22.1%, respectively; for DSM-5 insomnia disorder, it was 10.8%.

CONCLUSION

Compared with 22.1%, 3.9%, and 14.7% for DSM-IV, ICD-10, and ICSD-2 in the AIS, cross-cultural difference in the prevalence of insomnia disorder is less than what is expected. The prevalence is reduced by half from DSM-IV to DSM-5. ICD-10 insomnia disorder has the lowest prevalence, perhaps because excessive concern and preoccupation, one of its diagnostic criteria, is not always present in people with insomnia.

The nature of stable insomnia phenotypes

STUDY OBJECTIVES

We examined the 1-y stability of four insomnia symptom profiles: sleep onset insomnia; sleep maintenance insomnia; combined onset and maintenance insomnia; and neither criterion (i.e., insomnia cases that do not meet quantitative thresholds for onset or maintenance problems). Insomnia cases that exhibited the same symptom profile over a 1-y period were considered to be phenotypes, and were compared in terms of clinical and demographic characteristics.

DESIGN

Longitudinal.

SETTING

Urban, community-based.

PARTICIPANTS

Nine hundred fifty-four adults with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition based current insomnia (46.6 ± 12.6 y; 69.4% female).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

At baseline, participants were divided into four symptom profile groups based on quantitative criteria. Follow-up assessment 1 y later revealed that approximately 60% of participants retained the same symptom profile, and were hence judged to be phenotypes. Stability varied significantly by phenotype, such that sleep onset insomnia (SOI) was the least stable (42%), whereas combined insomnia (CI) was the most stable (69%). Baseline symptom groups (cross-sectionally defined) differed significantly across various clinical indices, including daytime impairment, depression, and anxiety. Importantly, however, a comparison of stable phenotypes (longitudinally defined) did not reveal any differences in impairment or comorbid psychopathology. Another interesting finding was that whereas all other insomnia phenotypes showed evidence of an elevated wake drive both at night and during the day, the 'neither criterion' phenotype did not; this latter phenotype exhibited significantly higher daytime sleepiness despite subthreshold onset and maintenance difficulties.

CONCLUSIONS

By adopting a stringent, stability-based definition, this study offers timely and important data on the longitudinal trajectory of specific insomnia phenotypes. With the exception of daytime sleepiness, few clinical differences are apparent across stable phenotypes.

Pharmacotherapeutic failure in a large cohort of patients with insomnia presenting to a sleep medicine center and laboratory: subjective pretest predictions and objective diagnoses

OBJECTIVE

To measure the frequency of pharmacotherapeutic failure and its association with the diagnosis of sleep-disordered breathing among patients with chronic insomnia disorder.

PATIENTS AND METHODS

In a retrospective review of medical records from January 1, 2005, through December 31, 2012, we identified an inclusive, consecutive series of 1210 patients with insomnia disorder, 899 (74.3%) of whom used sleep aids either occasionally (168 [18.7%]) or regularly (731 [81.3%]). Patients presented to a community-based sleep medicine center in Albuquerque, New Mexico, with typical referral patterns: 743 (61.4%) were referred by primary care physicians, 211 (17.4%) by specialists, 117 (9.7%) by mental health professionals, and 139 (11.5%) by self-referral. Pharmacotherapeutic failure was assessed from subjective insomnia reports and a validated insomnia severity scale. Polysomnography with pressure transducer (an advanced respiratory technology not previously used in a large cohort of patients with insomnia) measured sleep-disordered breathing. Objective data yielded accuracy rates for 3 pretest screening tools used to measure risk for sleep-disordered breathing.

RESULTS

Of the total sample of 1210 patients, all 899 (74.3%) who were taking over-the-counter or prescription sleep aids had pharmacotherapeutic failure. The 710 patients taking prescription drugs (79.0%) reported the most severe insomnia, the fewest sleep-associated breathing symptoms, and the most medical and psychiatric comorbidity. Of the 942 patients objectively tested (77.9%), 860 (91.3%) met standard criteria, on average, for a moderate to severe sleep-associated breathing disorder, yet pretest screening sensitivity for sleep-disordered breathing varied widely from 63.7% to 100%. Positive predictive values were high (about 90%) for all screens, but a tool commonly used in primary care misclassified 301 patients (32.0% false-negative results).

CONCLUSION

Pharmacotherapeutic failure and sleep-disordered breathing were extremely common among treatment-seeking patients with chronic insomnia disorder. Screening techniques designed from the field of sleep medicine predicted high rates for sleep-disordered breathing, whereas a survey common to primary care yielded many false-negative results. Although the relationship between insomnia and sleep-disordered breathing remains undefined, this research raises salient clinical questions about the management of insomnia in primary care before sleep center encounters.

Development and evaluation of a measure to assess restorative sleep

BACKGROUND

There are validated measures assessing insomnia and disturbed sleep, but few psychometrically sound instruments to assess perceptions of the restorative or inadequate properties of sleep are available.

STUDY OBJECTIVES

To develop and evaluate a new instrument, the Restorative Sleep Questionnaire (RSQ).

DESIGN AND SETTING

Focus groups were conducted using participants with and without nonrestorative sleep complaints. Questions were designed to elicit the feelings and experiences people have about their sleep and their view of daytime consequences of sleep. Expert panels confirmed the importance of nonrestorative sleep (NRS) as a frequently encountered problem either with or without other sleep complaints. The resulting RSQ was administered in three studies: (1) a telephone interview with healthy controls and individuals with sleep problems; (2) a randomized clinical trial of patients with primary insomnia assessed by polysomnography (PSG); (3) a PSG study of subjects with NRS complaints.

MEASUREMENT AND RESULTS

Across all studies, the new measures were shown to be significantly correlated with health-related quality of life (HRQL) domains hypothesized to be related to NRS. The RSQ had good psychometric properties (α > 0.90; rtest-retest > 0.80), and factor analysis confirmed the unidimensionality of the measure. The RSQ was able to distinguish between healthy controls, patients with primary insomnia, and insomnia patients with isolated NRS complaints but without PSG defined sleep onset, duration, or maintenance problems. Normal sleepers reported sleep that was about a standard deviation more restorative than that of those with NRS on the RSQ.

CONCLUSIONS

The results of the study provide support for the reliability and validity of the RSQ as a measure of NRS in subjects with and without self-reported or PSG confirmed sleep initiation and maintenance difficulties.

CLINICALTRIALSGOV IDENTIFIERS

NCT00655369; NCT00705601.

Development and validation of the Nonrestorative Sleep Scale (NRSS)

STUDY OBJECTIVES

Nonrestorative sleep (NRS) is defined as the subjective feeling that sleep has been insufficiently refreshing, often despite the appearance of physiologically normal sleep. While NRS has been shown to be associated with a variety of cognitive, affective, and medical complaints, there is currently no valid, reliable instrument available in the public domain for its assessment. The purpose of this study was to develop and validate the nonrestorative sleep scale (NRSS).

PARTICIPANTS

The scale was administered to a sample of 226 (age: 46.7 ± 14.9 years; gender: 48% female) consecutive sleep clinic patients and to 30 control participants (age: 36.9 ± 12.5; gender: 53% female).

RESULTS

Data screening led to a final instrument of 12 items, and factor analysis resulted in 4 factors accounting for 73.2% of total variance. The scale demonstrated excellent internal reliability (α = 0.88) and good test-retest reliability (r = 0.72). Preliminary evaluations of construct validity found that certain subscales correlated reasonably well with previously validated sleep, alertness, and affective scales. Comparisons between global NRSS scores and objective polysomnographic variables revealed a few very small but significant correlations.

CONCLUSIONS

Based on these findings, the NRSS was confirmed to be a valid and reliable tool for the assessment of nonrestorative sleep.

Subjective health perception in healthy young men changes in response to experimentally restricted sleep and subsequent recovery sleep

Sleep and subjective health are both prospectively related to objective indices of health and health care use. Here, we tested whether five days with restricted sleep and subsequent recovery days affect subjective health and is related to increased levels of circulating IL-6 and TNF-α and fatigue. Nine healthy men (23-28 ears) went through a 6-week sleep protocol with subjects as their own controls in a repeated measures design with a total of 11 nights in a sleep laboratory. The experimental part of the protocol included three baseline days (sleep 23-07 h), five days with sleep restriction (03-07 h) and three recovery days (23-07 h) in the sleep laboratory. Subjective health and fatigue was recorded daily. Eight blood samples were drawn each day (every third hour) on 8 days of the protocol and analyzed with respect to IL-6 and TNF-α. Subjective health deteriorated gradually during restricted sleep (p=.002) and returned to baseline levels after three days of recovery. IL-6 and TNF-α did not change significantly. Fatigue increased gradually during sleep restriction (p=.001), which significantly contributed to the association between restricted sleep and subjective health. The study is the first to show that subjective health is directly responsive to changes in sleep length and related to increased fatigue. Thus, subjective health is differently appraised after manipulation of one of its presumed determinants. Larger experimental studies would be beneficial to further distinguish causation from association regarding the underpinnings of subjective health.

Insomnia with Short Sleep Duration: Nosological, Diagnostic, and Treatment Implications

The diagnosis of insomnia is based solely on subjective complaints. This has contributed to the low reliability and validity of the current nosology of insomnia as well as to its lack of firm association with clinically relevant outcomes such as cardiometabolic and neurocognitive morbidity. We review evidence that insomnia with objective short sleep duration is associated with physiological hyperarousal, higher risk for hypertension, diabetes, neurocognitive impairment, and mortality as well as with a persistent course. It also appears that objective short sleep duration in poor sleepers is a biological marker of genetic predisposition to chronic insomnia. In contrast, insomnia with objective normal sleep duration is associated with cognitive-emotional and cortical arousal and sleep misperception but not with signs of physiological hyperarousal or medical complications. Thus, short sleep duration in insomnia may be a reliable marker of the biological severity and medical impact of the disorder. We propose that (a) objective measures of sleep be included in the diagnosis of insomnia and its subtypes, (b) objective measures of sleep obtained in the home environment of the patient would become part of the routine assessment and diagnosis of insomnia in a clinician's office setting, and (c) insomnia with short sleep duration may respond better to biological treatments, whereas insomnia with normal sleep duration may respond primarily to psychological therapies.

Sleep-wake activity rhythm and health-related quality of life among patients with coronary artery disease and in a population-based sample--an actigraphy and questionnaire study

The aim of this study was to explore whether there are gender differences in sleep and health-related quality of life in patients with coronary artery disease (CAD) and a matched population-based sample and to see how subjectively rated sleep is associated with actigraphy. Secondly, to explore whether factors that predict patients' sleep quality could be identified. Fifty-seven patients with stable CAD and 47 participants from a population-based sample were included. All participants completed the Uppsala Sleep Inventory (USI), the Epworth Sleepiness Scale and the SF-36. Actigraphy recordings and a sleep diary were performed for seven 24-h periods. Multiple stepwise regression analysis showed that sleep duration, sleep onset latency, nocturnal awakenings, vitality (SF-36) and body mass index explained 60% of the sleep quality outcome (USI). Sleep duration, sleep efficiency and fragmentation index assessed with actigraphy and sleep diary accounted for 36% of the sleep quality outcome (diary). The result can form the basis for a non-pharmacological, self-care programme supported and led by nurses.

Differentiating nonrestorative sleep from nocturnal insomnia symptoms: demographic, clinical, inflammatory, and functional correlates

STUDY OBJECTIVES

Recent studies have suggested that nonrestorative sleep (NRS) symptoms may be distinct from nocturnal insomnia symptoms (NIS). However, there is limited information on the demographic, medical, and biologic correlates of NRS independent from NIS in the general population. This report presents the sociodemographic correlates, patterns of comorbidity with other sleep and physical disorders, C-reactive protein (CRP) levels, and general productivity associated with NIS and NRS in a nationally representative sample of US adults.

DESIGN

National Health and Nutrition Examination Survey (NHANES).

SETTING

The 2005-2008 surveys of the general population in the United States.

PARTICIPANTS

There were 10,908 individuals (20 years or older).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Respondents were classified by the presence or absence of NIS and NRS. Compared with those without insomnia symptoms, respondents with NIS were older and had lower family income and educational levels than those with NRS. In addition, there was a significant association between NIS and cardiovascular disease, whereas NRS was associated with other primary sleep disorders (including habitual snoring, sleep apnea, and restless legs syndrome), respiratory diseases (emphysema and chronic bronchitis), thyroid disease, and cancer as well as increased CRP levels. In addition, the study participants with NRS only reported poorer scores on the Functional Outcomes of Sleep Questionnaire (FOSQ) than those without insomnia symptoms or those with NIS only.

CONCLUSIONS

These findings suggest that there are substantial differences between NIS and NRS in terms of sociodemographic factors, comorbidity with other sleep and physical disorders, increased CRP level, and functional impairment. An inflammatory response might play a unique role in the pathogenesis of NRS.

Relationship between sleep and pain in adolescents with juvenile primary fibromyalgia syndrome

STUDY OBJECTIVES

To investigate sleep quality in adolescents with juvenile primary fibromyalgia syndrome (JPFS) and determine whether sleep abnormalities, including alpha-delta sleep (ADS), correlate with pain intensity. We hypothesized that successful treatment for pain with exercise therapy would reduce ADS and improve sleep quality.

DESIGN

Single-center preintervention and postintervention (mean = 5.7 ± 1.0 weeks; range = 4.0-7.3 weeks) observational study.

PATIENTS

Ten female adolescents (mean age = 16.2 ± 0.65 SD yr) who met criteria for JPFS and completed treatment.

INTERVENTIONS

Multidisciplinary pain treatment, including intensive exercise therapy.

MEASUREMENTS AND RESULTS

Pain and disability were measured by a pain visual analog scale (VAS) and the functional disability inventory. Subjective sleep measures included a sleep VAS, an energy VAS, and the School Sleep Habits Survey. Objective sleep measures included actigraphy, polysomnography (PSG), and the Multiple Sleep Latency Test. Baseline PSG was compared with that of healthy age- and sex-matched control patients. At baseline, patients had poorer sleep efficiency, more arousals/awakenings, and more ADS (70.3% of total slow wave sleep [SWS] versus 21.9% SWS, P = 0.002) than controls. ADS was unrelated to pain, disability, or subjective sleep difficulty. After treatment, pain decreased (P = 0.000) and subjective sleep quality improved (P = 0.008). Objective sleep quality, including the amount of ADS, did not change.

CONCLUSIONS

Although perceived sleep quality improved in adolescents with JPFS after treatment, objective measures did not. Our findings do not suggest exercise therapy for pain improves sleep by reducing ADS, nor do they support causal relationships between ADS and chronic pain or subjective sleep quality.

Associations between non-restorative sleep, short sleep duration and suicidality: findings from a representative sample of Korean adolescents

AIMS

This study clarifies the associations among sleep duration, non-restorative sleep, suicidal ideation and suicide attempts in a representative sample of Korean adolescents.

METHODS

Analyses are based on data from the 2007 Korean Youth Risk Behavior Web-based Survey. The survey used a cross-sectional, national and representative sample consisting of 78 843 students (grades 7-12) who were selected using a stratified, clustered, multistage sampling method. Logistic regression analysis was conducted to test the association between sleep and suicide variables while controlling for demographic characteristics and other potential risk factors of suicide.

RESULTS

Fewer than 4 h of sleep and a lack of feeling refreshed after sleeping increased the likelihood of suicidal ideation but not of suicide attempts.

CONCLUSIONS

Non-restorative sleep as well as short sleep duration are significantly associated with suicidal ideation in adolescents. This finding highlights the need to assess for both non-restorative sleep and short sleep duration when screening suicide risk in adolescents. Future research should examine the moderating or mediating effects of individual and environmental characteristics on the association between sleep and actual suicide attempt.

DSM-IV psychiatric comorbidity according to symptoms of insomnia: a nationwide sample of Korean adults

PURPOSE

The diagnosis of insomnia is based on the presence of four different symptoms: difficulty in initiating sleep (DIS), difficulty in maintaining sleep (DMS), early morning awakening (EMA), and non-restorative sleep (NRS). This study investigated the differences in sociodemographic correlates and psychiatric comorbidity between the four symptoms of insomnia in the general population of South Korea.

METHODS

A sample of the population aged 18-64 (N = 6,510) was questioned using a face-to-face interview. Insomnia was defined as having at least one of the four following symptoms three or more times per week: DIS, DMS, EMA, and NRS. Psychiatric disorders were evaluated using the Korean version of Composite International Diagnostic Interview. Logistic regression analysis was used to test each of the sleep outcomes (DIS, DMS, EMA, or NRS) for an association with sociodemographic and clinical variables.

RESULTS

The prevalence of DIS, DMS, EMA, and NRS were 7.9 % (95 % CI 6.6-9.5 %), 7.9 % (95 % CI 6.5-9.6 %), 4.9 % (95 % CI 3.9-6.0 %), and 14.8 % (95 % CI 12.6-17.4 %), respectively. The overall prevalence of insomnia was 19.0 % (95 % CI 16.1-22.2 %). Being separated, divorced, or widowed, being single, having a part-time job, having a psychiatric illness, and having a physical illness were all significantly related to insomnia. Older age also increased the risk of DMS and EMA, and younger age was a risk factor for NRS. The presence of most psychiatric disorders was significantly related to insomnia. However, the relationship between the psychiatric illness and each insomnia symptom varied and was dependent on the insomnia symptom.

CONCLUSIONS

Most psychiatric disorders were significantly associated with each insomnia symptom in different ways. Differences in sociodemographic and clinical correlates between the four insomnia symptoms implied the heterogeneous characteristics of insomnia as defined by the current diagnostic criteria.

Pharmacotherapy of insomnia

INTRODUCTION

Insomnia is one of the most prevalent sleep disorders in developed countries, being surpassed only by chronic sleep deprivation. Patients with insomnia tend to have an altered quality of life, impaired daytime functioning and an increased risk of work accidents and motor vehicle crashes. Insomnia is commonly associated with chronic medical conditions, metabolic illnesses and mental disorders (such as depression and anxiety), with which there is a dual, reciprocal relationship.

AREAS COVERED

This paper focuses on current pharmacotherapy options for the treatment of insomnia, particularly benzodiazepine receptor agonists, which nowadays represent the mainstay of hypnotic therapy. The melatonin receptor antagonist, ramelteon, is reviewed (an alternative for some patients with only sleep-onset difficulty), as are sedating antidepressants, which are commonly used 'off-label' to treat insomnia, despite limited efficacy data and potential significant safety concerns. Orexin (OX) antagonists are also discussed, especially those that block OX2 or both OX1 and OX2 receptors, as these are the most promising new agents for the treatment of insomnia, with encouraging results in preliminary clinical trials.

EXPERT OPINION

Research to evaluate and formulate treatments for insomnia is often complicated by the fact that insomnia is usually of multifactorial etiology. Understanding the molecular and receptor mechanisms involved in promoting sleep in varied disorders could provide future approaches in new drug development. In the long term, more randomized controlled trials are needed to assess both short-term and long-term effects of these medications and their efficacy in comorbid diseases that affect sleep quality or quantity.

Nonrestorative sleep: symptom or unique diagnostic entity?

Nonrestorative sleep (NRS) refers to the subjective experience of sleep as insufficiently refreshing, often despite the appearance of normal sleep according to traditionally assessed objective parameters. This has led researchers to pursue alternative physiological markers of nonrestorative or unrefreshing sleep, though much of this research remains controversial and inconclusive. This review summarizes the recent findings on NRS in the literature and discusses some of the issues inherent in current efforts to define and measure NRS. We offer a summary of recommended clinical approaches to NRS and discuss a new potential paradigm for the assessment of NRS-an approach modelled on current diagnosis of insomnia.

Insomnia, sleep quality, pain, and somatic symptoms: sex differences and shared genetic components

This study investigated the sex differences, and the shared genetic and environmental factors underlying the associations of sleep disturbances (insomnia and sleep quality) with pain and somatic symptoms in both adolescents and middle-aged adults. We recruited 259 adolescents (69 with current insomnia) and their parents (256 middle-aged adults, 78 with current insomnia). Insomnia severity and sleep quality were measured by the Insomnia Severity Inventory (ISI) and Pittsburgh Sleep Quality Index (PSQI), respectively. Pain and somatic symptoms were measured by the Somatic Symptom Inventory and Visual Analogue Scale for overall pain. Subjects with insomnia scored higher on all measures of pain and somatic symptoms than non-insomnia patients, in both adolescents and adults (P<.001). Both pain and somatic measures were associated with ISI and PSQI scores after controlling for age, sex, depressive and anxiety symptoms. There was an interaction effect between insomnia and female sex on pain and somatic symptoms (P<.05), especially in adults. Pain and somatic symptoms ran in family with moderate heritability (range h(2)=0.15-0.42). The phenotypic associations of ISI and PSQI with pain and somatic measures were both contributed by genetic (range p(G)=0.41-0.96) and environmental (range p(E)=0.27-0.40) factors with a major genetic contribution. In summary, insomnia and poor sleep quality are closely associated with pain and somatic symptoms. Insomnia seems to modulate the sex differences in pain and somatic symptoms, especially in the adult population. A shared genetic predisposition might underlie the associations of insomnia and sleep quality with pain and somatic symptoms.

Cross-lagged relationships between workplace demands, control, support, and sleep problems

STUDY OBJECTIVES

Sleep problems are experienced by a large part of the population. Work characteristics are potential determinants, but limited longitudinal evidence is available to date, and reverse causation is a plausible alternative. This study examines longitudinal, bidirectional relationships between work characteristics and sleep problems.

DESIGN

Prospective cohort/two-wave panel.

SETTING

Sweden.

PARTICIPANTS

3065 working men and women approximately representative of the Swedish workforce who responded to the 2006 and 2008 waves of the Swedish Longitudinal Occupational Survey of Health (SLOSH).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Bidirectional relationships between, on the one hand, workplace demands, decision authority, and support, and, on the other hand, sleep disturbances (reflecting lack of sleep continuity) and awakening problems (reflecting feelings of being insufficiently restored), were investigated by structural equation modeling. All factors were modeled as latent variables and adjusted for gender, age, marital status, education, alcohol consumption, and job change. Concerning sleep disturbances, the best fitting models were the "forward" causal model for demands and the "reverse" causal model for support. Regarding awakening problems, reciprocal models fitted the data best.

CONCLUSIONS

Cross-lagged analyses indicates a weak relationship between demands at Time 1 and sleep disturbances at Time 2, a "reverse" relationship from support T1 to sleep disturbances T2, and bidirectional associations between work characteristics and awakening problems. In contrast to an earlier study on demands, control, sleep quality, and fatigue, this study suggests reverse and reciprocal in addition to the commonly hypothesized causal relationships between work characteristics and sleep problems based on a 2-year time lag.

Sleep habits in German athletes before important competitions or games

Sleep is generally regarded as a valuable resource for psychological and physiological well-being. Although the effects of sleep on athletic performance have been acknowledged in sport science, few studies have investigated the prevalence of sleep problems and their effects on elite athletes before a sport event. In this study, 632 German athletes from various sports were asked about their sleep habits during the night(s) before an important competition or game. The findings indicate that 65.8% of the athletes experienced poor sleep in the night(s) before a sports event at least once in their lives and a similarly high percentage (62.3%) had this experience at least once during the previous 12 months. Athletes of individual sports reported more sleep difficulties than athletes of team sports. The main sleep problem was not being able to fall asleep. Internal factors such as nervousness and thoughts about the competition were rated highest for causing sleep problems. Most athletes stated that disturbed sleep had no influence on their athletic performance; however, athletes also reported effects such as a bad mood the following day, increased daytime sleepiness, and worse performance in the competition or game. The differences between individual and team sports indicate that athletes in some sports need more help than those in other sports in managing sleep problems.

Nighttime insomnia symptoms and perceived health in the America Insomnia Survey (AIS)

STUDY OBJECTIVES

To explore the distribution of the 4 cardinal nighttime symptoms of insomnia-difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), early morning awakening (EMA), and nonrestorative sleep (NRS)-in a national sample of health plan members and the associations of these nighttime symptoms with sociodemographics, comorbidity, and perceived health.

DESIGN/SETTING/PARTICIPANTS

Cross-sectional telephone survey of 6,791 adult respondents.

INTERVENTION

None.

MEASUREMENTS/RESULTS

Current insomnia was assessed using the Brief Insomnia Questionnaire (BIQ)-a fully structured validated scale generating diagnoses of insomnia using DSM-IV-TR, ICD-10, and RDC/ICSD-2 inclusion criteria. DMS (61.0%) and EMA (52.2%) were more prevalent than DIS (37.7%) and NRS (25.2%) among respondents with insomnia. Sociodemographic correlates varied significantly across the 4 symptoms. All 4 nighttime symptoms were significantly related to a wide range of comorbid physical and mental conditions. All 4 also significantly predicted decrements in perceived health both in the total sample and among respondents with insomnia after adjusting for comorbid physical and mental conditions. Joint associations of the 4 symptoms predicting perceived health were additive and related to daytime distress/impairment. Individual-level associations were strongest for NRS. At the societal level, though, where both prevalence and strength of individual-level associations were taken into consideration, DMS had the strongest associations.

CONCLUSIONS

The extent to which nighttime insomnia symptoms are stable over time requires future long-term longitudinal study. Within the context of this limitation, the results suggest that core nighttime symptoms are associated with different patterns of risk and perceived health and that symptom-based subtyping might have value.

Impaired sleep in chronic fatigue syndrome: how is it best measured?

The goal was to examine comparative efficacy of polysomnography, actigraphy, and self-report in evaluating the sleep/wake experience of individuals with chronic fatigue syndrome (CFS). Sleep parameters were evaluated by the three measurement modalities for the same night in 49 participants with CFS. Psychological and daytime functioning were measured by self-report. Results indicate that: (a) objectively measured nocturnal sleep time effectively approximated subjective experience although nocturnal wakefulness did not; (b) total sleep time and sleep efficiency differentiated individuals with and without insomnia complaints; (c) daytime sleepiness, fatigue, and non-refreshing sleep were not reflected by the objective sleep-related measures (polysomnography and actigraphy).

Nonrestorative sleep as a distinct component of insomnia

STUDY OBJECTIVES

Explore characteristics of nonrestorative sleep (NRS) in prospectively defined subgroups of individuals with NRS symptoms, investigate whether NRS can occur independently of difficulties initiating and maintaining sleep (DIS/DMS), and determine its effect on waking function.

DESIGN

Cross-sectional and longitudinal population-based study comparing patterns of daytime symptoms, and their persistence, in cohorts of subjects with NRS symptoms grouped according to presence or absence of DIS and DMS.

SETTING

28 sleep centers in the US.

PARTICIPANTS

Subjects reporting awakening unrestored or unrefreshed at least 3 times weekly over the previous 3 months were classified, based on self-reported sleep problems, to DIS (n = 138), DMS (n = 44), DIS+DMS (n = 125), and NRS-only (no DIS or DMS; n = 192) cohorts. Eighty healthy volunteers formed a control group.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Polysomnography confirmed DIS and/or DMS in 56/138 (41%), 18/44 (41%), and 37/125 (30%) subjects in DIS, DMS, and DIS+DMS cohorts, respectively; and absence of DIS or DMS in 115/192 (60%) NRS-only subjects and 52/80 (65%) healthy volunteers. Multiple subject-reported endpoints including the Endicott Work Productivity Scale, Pittsburgh Insomnia Rating Scale, Restorative Sleep Questionnaire, and SF-36, showed that NRS-only subjects had significantly impaired daytime function relative to healthy volunteers, comparable to impairment affecting subjects with DIS and/or DMS. Symptoms persisted over 3 months.

CONCLUSIONS

This study confirms that NRS can occur independently of other components of insomnia. Daytime symptoms were as severe in individuals with NRS-only as those whose NRS symptoms were combined with DIS or DMS.

Light sleep and sleep time misperception - relationship to alpha-delta sleep

OBJECTIVE

We investigated the association of alpha-delta sleep (A-DS) with: (1) perception of light sleep and (2) discrepancy between subjective and objective sleep duration.

METHODS

We analyzed data from 5764 individuals who underwent polysomnography (PSG) and replied questions about quantity and quality of sleep, including sleep depth. The difference between objectively recorded sleep time and subjectively estimated sleep time was calculated. Alpha-delta sleep (A-DS) was visually scored in a scale from 1 to 4, based on the density and overnight duration of alpha activity and confirmed using spectral array of the electroencephalographic activity.

RESULTS

A-DS scores 1-4 occurred in, respectively, 37.9%; 31.3%; 20.5%; and 6.2% of the cases. ANOVA showed significant difference of light sleep sensation (p<0.001) and sleep time underestimation (p<0.001) among the four A-DS categories. Regression to explain both light sleep and sleep time underestimation, controlling for confounders, confirmed A-DS as a significant regressor.

CONCLUSIONS

This study of a large prospective sample provides evidence for the association of alpha-delta sleep with subjective sensation of light sleep and with sleep time underestimation.

SIGNIFICANCE

Alpha-delta sleep may be a marker of the physiological disorder underlying light sleep and sleep state misperception.