Sleep, its subjective perception, and daytime performance in insomniacs with a pattern of alpha sleep

Does providing feedback and guidance on sleep perceptions using sleep wearables improve insomnia? Findings from "Novel Insomnia Treatment Experiment": a randomized controlled trial

STUDY OBJECTIVES

Insomnia is a disorder diagnosed based on self-reported sleep complaints. Differences between self-reported and sensor-based sleep parameters (sleep-wake state discrepancy) are common but not well-understood in individuals with insomnia. This two-arm, parallel-group, single-blind, superiority randomized-controlled trial examined whether monitoring sleep using wearable devices and providing support for interpretation of sensor-based sleep data improved insomnia symptoms or impacted sleep-wake state discrepancy.

METHODS

A total of 113 (age M = 47.53; SD = 14.37, 64.9% female) individuals with significant insomnia symptoms (Insomnia Severity Index(ISI) ≥10) from the community were randomized 1:1 (permuted block randomization) to receive 5 weeks (1) Intervention (n = 57): feedback about sensor-based sleep (Fitbit and EEG headband) with guidance for data interpretation and ongoing monitoring, and (2) Control (n = 56): sleep education and hygiene. Both groups received one individual session and two check-in calls. The ISI (primary outcome), sleep disturbance (SDis), sleep-related impairment (SRI), depression, and anxiety were assessed at baseline and post-intervention.

RESULTS

In total, 103 (91.2%) participants completed the study. Intention-to-treat multiple regression with multiple imputations showed that after controlling for baseline values, compared to the Control group (n = 51), the Intervention group (n = 52) had lower ISI (p = .011, d = 0.51) and SDis (p = .036, d = 0.42) post-intervention, but differences in SRI, depression, anxiety, and sleep-wake state discrepancy parameters (total sleep time, sleep onset latency, and wake after sleep onset) were not meaningful (P-values >.40).

CONCLUSIONS

Providing feedback and guidance about sensor-based sleep parameters reduced insomnia severity and sleep disturbance but did not alter sleep-wake state discrepancy in individuals with insomnia more than sleep hygiene and education. The role of sleep wearable devices among individuals with insomnia requires further research.

CLINICAL TRIAL REGISTRATION

The Novel Insomnia Treatment Experiment (NITE): the effectiveness of incorporating appropriate guidance for sleep wearables in users with insomnia. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378452, Australia New Zealand Clinical Trials Registry: ACTRN12619001636145.

Manipulating sleep duration perception changes cognitive performance - An exploratory analysis

OBJECTIVES

To test the effect of perceived sleep duration on cognitive performance.

METHODS

Sixteen healthy individuals [8F; mean age (± SD): 24.2 ± 3.0 years)] received an 8-h sleep opportunity followed by a 5-h opportunity on two consecutive nights. Upon waking, they were randomized to being informed that they received either an 8-h or 5-h sleep opportunity, via a clock that ran either fast, slow or normally. Cognitive performance was assessed using 10-min auditory psychomotor vigilance tests and subjective sleepiness ratings. Homeostatic and circadian sleep drive was assessed using waking electroencephalography (EEG).

RESULTS

Reaction time was significantly quicker when individuals thought that they had slept for 8 h but given a 5-h sleep opportunity. Conversely, reaction times were significantly slower when individuals thought they had 5 h of sleep but given an 8-h sleep opportunity. EEG delta power (1.0-4.5 Hz) during wake increased significantly when sleep was restricted to 5 h, and individuals thought they slept for 5 h, but this increase was attenuated with a perceived sleep duration of 8 h following a 5-h opportunity. EEG delta power did not increase, however, with perceived sleep restriction. EEG high-alpha activity (10.5-11.5 Hz) was consistently higher when participants thought that they had an 8-h sleep opportunity, regardless of the actual duration.

CONCLUSIONS

These results suggest that perceived sleep duration may modulate psychosomatic responses. Additional studies with predefined outcomes and analyses are necessary to confirm these findings, which may have important implications for understanding how sleep affects cognition and psychosomatic responses.

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.

Sleep Perception and Misperception in Chronic Cocaine Users During Abstinence

Study Objectives

During abstinence, chronic cocaine users experience an objective worsening of sleep that is perceived as qualitatively improving. This phenomenon has been termed "occult insomnia." The objective of this study was to determine whether chronic cocaine users experience positive sleep state misperception during abstinence.

Methods

Forty-three cocaine-dependent persons were admitted to an inpatient research facility for 12 days and 11 nights to participate in a treatment study of modafinil. Polysomnographic sleep recordings were performed on study nights 3, 4, 10, and 11, when participants were on average 1 and 2 weeks abstinent from cocaine. Participants also completed sleep diary questionnaires every evening before bed and every morning upon awakening. Polysomnographic and sleep diary measurements of total sleep time, sleep latency, time awake after sleep onset, and time in bed after final awakening were compared.

Results

Chronic cocaine users accurately reported total sleep time after 1 week of abstinence but overreported total sleep time by an average of 40 min after 2 weeks of abstinence. Underestimating sleep latency and time spent awake after sleep onset were responsible for this difference.

Conclusions

Positive sleep state misperception is revealed in chronic cocaine users after 2 weeks of abstinence and is consistent with the previously identified "occult insomnia" in this population.

Sleep Fragmentation Does Not Explain Misperception of Latency or Total Sleep Time

STUDY OBJECTIVES

Perception of sleep-wake times may differ from objective measures, although the mechanisms remain elusive. Quantifying the misperception phenotype involves two operational challenges: defining objective sleep latency and treating sleep latency and total sleep time as independent factors. We evaluated a novel approach to address these challenges and test the hypothesis that sleep fragmentation underlies misperception.

METHODS

We performed a retrospective analysis on patients with or without obstructive sleep apnea during overnight diagnostic polysomnography in our laboratory (n = 391; n = 252). We compared subjective and objective sleep-wake durations to characterize misperception. We introduce a new metric, sleep during subjective latency (SDSL), which captures latency misperception without defining objective sleep latency and allows correction for latency misperception when assessing total sleep time (TST) misperception.

RESULTS

The stage content of SDSL is related to latency misperception, but in the opposite manner as our hypothesis: those with > 20 minutes of SDSL had less N1%, more N3%, and lower transition frequency. After adjusting for misperceived sleep during subjective sleep latency, TST misperception was greater in those with longer bouts of REM and N2 stages (OSA patients) as well as N3 (non-OSA patients), which also did not support our hypothesis.

CONCLUSIONS

Despite the advantages of SDSL as a phenotyping tool to overcome operational issues with quantifying misperception, our results argue against the hypothesis that light or fragmented sleep underlies misperception. Further investigation of sleep physiology utilizing alternative methods than that captured by conventional stages may yield additional mechanistic insights into misperception.

COMMENTARY

A commentary on this article appears in this issue on page 1211.

Nonrestorative Sleep, Musculoskeletal Pain, Fatigue in Rheumatic Disorders, and Allied Syndromes: A Historical Perspective

This chapter provides a historical perspective of the notion that the sleeping–waking brain is intimately related to complaints of unrefreshing sleep, widespread musculoskeletal pain, fatigue, and suffering. Such a constellation of symptoms extend from the remote biblical past, and involve various religious and cultural belief systems up to the recent evolution in Western medicine application of scientific methods for classification of illness. The contemporary application of scientific principles is directed to the etiology of diseases and to derive procedures for the management of such ill-understood illnesses. Historically, this constellation of rheumatic pain and fatigue symptoms have been given ever-changing medical and psychiatric labels that have been devoid of satisfactory medical understanding. In this chapter, the hypothesis that the sleeping/waking brain is integral to the somatic and behavioral symptoms of these disabling rheumatic chronic illness, termed fibromyalgia and various allied disorders, that are being examined and treated by a variety of health care professionals. Contemporary advances in mechanisms of how the sleeping–waking brain connects to these somatic and behavioral symptoms are reviewed. Potential avenues for further scientific understanding are described. Advances in such understanding are influencing current pharmacological and behavioral management of these suffering patients.

Sleep-wake misperception in sleep apnea patients undergoing diagnostic versus titration polysomnography

OBJECTIVE

Insomnia is commonly co-morbid with obstructive sleep apnea. Among patients reporting insomnia symptoms, sleep misperception occurs when self-reported sleep duration under-estimates objective measures. Misperception represents a clinical challenge since insomnia management is based entirely on patient self-report. We tested the hypothesis that misperception occurring in sleep apnea patients would improve with subsequent treatment.

METHODS

We compared subjective sleep-wake reports with objective sleep in adults with obstructive sleep apnea (n=405) in two nights of polysomnography (diagnostic and treatment) within a median interval of 92 days.

RESULTS

Sleep latency was generally over-estimated, while wake after sleep onset and number of awakenings were under-estimated. None of these estimations differed between diagnostic and treatment polysomnograms. We observed a large spectrum of total sleep time misperception values during the diagnostic polysomnogram, with one third of the cohort under-estimating their total sleep time by at least 60 min. Of those with >60 minute misperception, we observed improved total sleep time perception during treatment polysomnography. Improved perception correlated with improvements in self-reported sleep quality and response confidence. We found no polysomnogram or demographic predictors of total sleep time misperception for the diagnostic polysomnogram, nor did we find objective correlates of improved perception during titration.

CONCLUSION

Our results suggest that misperception may improve with treatment of obstructive sleep apnea in patients who also exhibit misperception. Within subject changes in misperception are consistent with misperception being, at least to some extent, a state characteristic, which has implications for management of patients with comorbid insomnia and sleep apnea.

The subjective-objective mismatch in sleep perception among those with insomnia and sleep apnea

The diagnosis and management of insomnia relies primarily on clinical history. However, patient self-report of sleep-wake times may not agree with objective measurements. We hypothesized that those with shallow or fragmented sleep would under-report sleep quantity, and that this might account for some of the mismatch. We compared objective and subjective sleep-wake times for 277 patients who underwent diagnostic polysomnography. The group included those with insomnia symptoms (n = 92), obstructive sleep apnea (n = 66) or both (n = 119). Mismatch of wake duration was context dependent: all three groups overestimated sleep latency but underestimated wakefulness after sleep onset. The insomnia group underestimated total sleep time by a median of 81 min. However, contrary to our hypothesis, measures of fragmentation (N1, arousal index, sleep efficiency, etc.) did not correlate with the subjective sleep duration estimates. To unmask a potential relationship between sleep architecture and subjective duration, we tested three hypotheses: N1 is perceived as wake; sleep bouts under 10 min are perceived as wake; or N1 and N2 are perceived in a weighted fashion. None of these hypotheses exposed a match between subjective and objective sleep duration. We show only modest performance of a Naïve Bayes Classifier algorithm for predicting mismatch using clinical and polysomnographic variables. Subjective-objective mismatch is common in patients reporting insomnia symptoms. We conclude that mismatch was not attributable to commonly measured polysomnographic measures of fragmentation. Further insight is needed into the complex relationships between subjective perception of sleep and conventional, objective measurements.

Deciphering the temporal link between pain and sleep in a heterogeneous chronic pain patient sample: a multilevel daily process study

OBJECTIVES

Because insomnia is a common comorbidity of chronic pain, scientific and clinical interest in the relationship of pain and sleep has surged in recent years. Although experimental studies suggest a sleep-interfering property of pain and a pain-enhancing effect of sleep deprivation/fragmentation, the temporal association between pain and sleep as experienced by patients is less understood. The current study was conducted to examine the influence of presleep pain on subsequent sleep and sleep on pain reports the next day, taking into consideration other related psychophysiologic variables such as mood and arousal.

DESIGN

A daily process study, involving participants to monitor their pain, sleep, mood, and presleep arousal for 1 wk. Multilevel modeling was used to analyze the data.

SETTING

In the patients' natural living and sleeping environment.

PATIENTS

One hundred nineteen patients (73.9% female, mean age = 46 years) with chronic pain and concomitant insomnia.

MEASUREMENT

An electronic diary was used to record patients' self-reported sleep quality/efficiency and ratings of pain, mood, and arousal at different times of the day; actigraphy was also used to provide estimates of sleep efficiency.

RESULTS

Results indicated that presleep pain was not a reliable predictor of subsequent sleep. Instead, sleep was better predicted by presleep cognitive arousal. Although sleep quality was a consistent predictor of pain the next day, the pain-relieving effect of sleep was only evident during the first half of the day.

CONCLUSIONS

These findings challenge the often-assumed reciprocal relationship between pain and sleep and call for a diversification in thinking of the daily interaction of these 2 processes.

(Mis)perception of sleep in insomnia: a puzzle and a resolution

Insomnia is prevalent, causing severe distress and impairment. This review focuses on illuminating the puzzling finding that many insomnia patients misperceive their sleep. They overestimate their sleep onset latency (SOL) and underestimate their total sleep time (TST), relative to objective measures. This tendency is ubiquitous (although not universal). Resolving this puzzle has clinical, theoretical, and public health importance. There are implications for assessment, definition, and treatment. Moreover, solving the puzzle creates an opportunity for real-world applications of theories from clinical, perceptual, and social psychology as well as neuroscience. Herein we evaluate 13 possible resolutions to the puzzle. Specifically, we consider the possible contribution, to misperception, of (1) features inherent to the context of sleep (e.g., darkness); (2) the definition of sleep onset, which may lack sensitivity for insomnia patients; (3) insomnia being an exaggerated sleep complaint; (4) psychological distress causing magnification; (5) a deficit in time estimation ability; (6) sleep being misperceived as wake; (7) worry and selective attention toward sleep-related threats; (8) a memory bias influenced by current symptoms and emotions, a confirmation bias/belief bias, or a recall bias linked to the intensity/recency of symptoms; (9) heightened physiological arousal; (10) elevated cortical arousal; (11) the presence of brief awakenings; (12) a fault in neuronal circuitry; and (13) there being 2 insomnia subtypes (one with and one without misperception). The best supported resolutions were misperception of sleep as wake, worry, and brief awakenings. A deficit in time estimation ability was not supported. We conclude by proposing several integrative solutions.

Sleep misperception and chronic insomnia in the general population: role of objective sleep duration and psychological profiles

OBJECTIVE

To examine the role of objective sleep duration, a novel marker in phenotyping insomnia, and psychological profiles on sleep misperception in a large, general population sample. Sleep misperception is considered by some investigators a common characteristic of chronic insomnia, whereas others propose it as a separate diagnosis. The frequency and the determinants of sleep misperception in general population samples are unknown.

METHODS

A total of 142 insomniacs and 724 controls selected from a general random sample of 1,741 individuals (aged ≥20 years) underwent a polysomnographic evaluation, completed the Minnesota Multiphasic Personality Inventory-2, and were split into two groups based on their objective sleep duration: "normal sleep duration" (≥6 hours) and "short sleep duration" (<6 hours).

RESULTS

The discrepancy between subjective and objective sleep duration was determined by two independent factors. Short sleepers reported more sleep than they objectively had, and insomniacs reported less sleep than controls with similar objective sleep duration. The additive effect of these two factors resulted in underestimation only in insomniacs with normal sleep duration. Insomniacs with normal sleep duration showed a Minnesota Multiphasic Personality Inventory-2 profile of high depression and anxiety and low ego strength, whereas insomniacs with short sleep duration showed a profile of a medical disorder.

CONCLUSIONS

Underestimation of sleep duration is prevalent among insomniacs with objective normal sleep duration. Anxious-ruminative traits and poor resources for coping with stress seem to mediate the underestimation of sleep duration. These data further support the validity and clinical utility of objective sleep measures in phenotyping insomnia.

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.

A computer method for identifying patterns in electroencephalogram signals

A computer method is developed for identifying patterns in electroencephalogram (EEG) signals. An EEG numerical signal is transformed into a symbolic series. The simple transformation used here studies the variations between two successive values of the signal. Then, this series is analysed with a symbolic correlation function based on probabilities without bias. The use of large windows, e.g. 1 hour, allows the identification of weak signals hidden by the specific ones. An application of this method to the sleep analysis of a healthy adult shows a periodicity modulo 10 in all derivations. A possible neurophysiological meaning is presented in the discussion.

The effect of mood on sleep onset latency and REM sleep in interepisode bipolar disorder

The present study investigates whether interepisode mood regulation impairment contributes to disturbances in sleep onset latency (SOL) and rapid eye movement (REM) sleep. Individuals with interepisode bipolar disorder (n = 28) and healthy controls (n = 28) slept in the laboratory for 2 baseline nights, a happy mood induction night, and a sad mood induction night. There was a significant interaction whereby on the happy mood induction night the bipolar group exhibited significantly longer SOL than did the control group, while there was no difference on the baseline nights. In addition, control participants exhibited shorter SOL on the happy mood induction night compared to the baseline nights, a finding that was not observed in the bipolar group. On the sad mood induction night, participants in both groups had shorter SOL and increased REM density when compared to the baseline nights. Bipolar participants exhibited heightened REM density compared to control participants on both nights. These results raise the possibility that regulation of positive stimuli may be a contributor to difficulties with SOL, while hyperactivity may be characteristic of REM sleep.

Disagreement between subjective and actigraphic measures of sleep duration in a population-based study of elderly persons

Sleep duration is an important concept in epidemiological studies. It characterizes a night's sleep or a person's sleep pattern, and is associated with numerous health outcomes. In most large studies, sleep duration is assessed with questionnaires or sleep diaries. As an alternative, actigraphy may be used, as it objectively measures sleep parameters and is feasible in large studies. However, actigraphy and sleep diaries may not measure exactly the same phenomenon. Our study aims to determine disagreement between actigraphic and diary estimates of sleep duration, and to investigate possible determinants of this disagreement. This investigation was embedded in the population-based Rotterdam Study. The study population consisted of 969 community-dwelling participants aged 57-97 years. Participants wore an actigraph and kept a sleep diary for, on average, six consecutive nights. Both measures were used to determine total sleep time (TST). In 34% of the participants, the estimated TST in the sleep diaries deviated more than 1 h from actigraphically measured TST. The level of disagreement between diary and actigraphic measures decreased with subjective and actigraphic measures of sleep quality, and increased with male gender, poor cognitive function and functional disability. Actigraphically measured poor sleep was often accompanied by longer subjective estimates of TST, whereas subjectively poor sleepers tended to report shorter TST in their diaries than was measured with actigraphy. We recommend, whenever possible, to use multiple measures of sleep duration, to perform analyses with both, and to examine the consistency of the results over assessment methods.

Asymptomatic insomnia

BACKGROUND

A syndrome of daytime consequences of insomnia and objectively severe sleep disturbance, which is not perceived by the patients, has recently been described. The present study aimed at retrospectively analyzing data on a group of such asymptomatic insomniacs.

METHOD

Twenty-seven middle-aged target patients who presented with daytime symptoms but denied sleep problems underwent polysomnography (PSG) and filled out a morning questionnaire. For classifying objective insomnia, sleep onset latency or wake after sleep onset (WASO) of more than one hour was required. In addition to PSG, alpha sleep and sleep time, overestimation was calculated.

RESULTS

Comorbidity, mostly multiple (organic, psychiatric, functional, and sleep), was present in all patients. All had severe sleep maintenance disturbance (WASO>100 min), whereas sleep onset was partly normal. Overestimation of sleep was >2.5 h. Alpha sleep was present in 44%, but not related to higher overestimation than non-alpha sleep.

DISCUSSION

Non-perception of intermittent waking times is crucial for this syndrome. Possible causative factors are discussed. A specific insomnia treatment, carried out in 14 patients, was able to reduce daytime symptoms significantly. Thus, recognition of this syndrome is clinically relevant. Studies are needed to elucidate the nature of asymptomatic insomnia.

Positive sleep state misperception – A new concept of sleep misperception

OBJECTIVES

To better define the concept of sleep misperception and analyse a category of patients who overestimate their sleep. At present, a condition of underestimation of sleep is classified as paradoxical insomnia. Overestimation of sleep has also been reported in the past, with no clear reference to corresponding polysomnographic (PSG) findings or its clinical significance.

PATIENTS AND METHODS

Patients were recruited from the general population undergoing a PSG assessment for a cross-sectional retrospective study in a sleep clinic affiliated with a tertiary health center.

RESULTS

A group of patients who overestimated their sleep had mostly non-discriminating PSG findings when compared to patients who underestimated their sleep, and correct estimators. The only parameters that were significantly different were objective sleep duration and efficiency, and, importantly, respective multiple sleep latency test (MSLT) results. The patients who overestimated their sleep had a mean MSLT result of 7.8 min, which indicates moderate daytime sleepiness. Patients who underestimated their sleep and correct estimators had the respective MSLT results of >10 min, making a statistically significant difference.

CONCLUSION

The authors identified a condition opposite the previously described sleep underestimation, and named it 'positive sleep state misperception' (PSSM). The condition is characterised by a gross overestimation of sleep. Inadequate sleep results in a clinically significant excessive daytime sleepiness, which patients were not able to predict. The authors propose a new model that incorporates both ends of the sleep misperception spectrum.

The effect of psychosocial stress on sleep: a review of polysomnographic evidence

This systematic review examines the effect of diverse psychosocial stressors on polysomnographic measures of sleep. Sixty-three articles were located and categorized in terms of the types of stressors imposed. Experimental stress resulted in fairly consistent changes: decreases in slow wave sleep, REM sleep, and sleep efficiency (SE), as well as increases in awakenings. Data were limited in terms of response to non-experimental stressors, except for the case of post-traumatic stress disorder (PTSD) on sleep, where a number of reports suggest that PTSD patients have increased awakenings and decreased SE. Future research needs to define stress more precisely in terms of duration and severity and to measure its impacts on sleep in populations that differ in terms of age, comorbid illness, gender, and so forth. Without such fine-grained analyses, it is difficult to draw definitive conclusions about this important area.

Daytime functioning in primary insomnia: does attentional focus contribute to real or perceived impairment?

A study was conducted to test the proposal that self-focused attention or monitoring exacerbates the perception of poor daytime functioning in the absence of objective deficits among individuals with insomnia. Fifty-one participants meeting Diagnostic and Statistical Manual of Mental Disorders (4th ed.) criteria for primary insomnia were randomly assigned to a self-focus group (viewing themselves on a TV monitor), a monitoring group (instructed to focus on their thoughts, body sensations, mood, and performance), or a no instruction group while completing a battery of neuropsychological tests. The results indicated that all participants performed within published normative ranges on all tests. The groups did not differ on their objective test performance, but the self-focus group perceived their performance on the tests as significantly worse than the no instruction group. These findings suggest that self-focused attention may contribute to perceived impairment in daytime functioning in primary insomnia.

Misperception of sleep can adversely affect daytime functioning in insomnia

This experiment was designed to investigate the relationship between subjective perception of sleep and daytime processes in primary insomnia. Twenty-two individuals with primary insomnia received positive or negative feedback about their sleep, immediately on waking, on three consecutive mornings. The positive feedback was that last night's sleep was good quality. The negative feedback was that last night's sleep was poor quality. Objective sleep on each of the three nights was estimated by actigraphy and did not differ across the three nights or the two feedback conditions. Negative feedback (based on 32 nights of data) was associated with more negative thoughts, sleepiness, monitoring for sleep-related threat, and safety behaviours during the day, relative to positive feedback (based on 34 nights of data). These results indicate that the impaired daytime functioning reported by insomnia patients is maintained, at least in part, by subjective perception of sleep.

Self-report measures of insomnia in adults: rationales, choices, and needs

Self-report measures continue to provide key information in the evaluation and treatment of insomnia. While knowledge development about insomnia continues to require multi-trait, multi-method studies, self-report measures remain central in most study designs. The available stock of insomnia-related questionnaires has a substantial heterogeneity in their formats, foci, scopes, and other attributes. While there may be benefits from using specially tailored questionnaires in particular circumstances, in other cases the information quality of a study will be downgraded by poor choice of questionnaires. To assist clinicians and investigators in selecting questionnaires wisely, the present paper reviews questionnaire criteria and attribute priorities for clinical trials, theory tests, observational studies, and aging studies concerning insomnia. An extensive table of currently available questionnaires is provided, and some needs for future questionnaire development are also identified.

Cross-cultural validation of the Leeds sleep evaluation questionnaire (LSEQ) in insomnia patients

The Leeds sleep evaluation questionnaire (LSEQ) is a standardized self-reporting instrument comprising ten 100 mm visual analogue scales that pertain to the ease of getting to sleep (GTS), quality of sleep (QOS), ease of awakening from sleep (AFS) and alertness and behaviour following wakefulness (BFW). Although the LSEQ has been used in a variety of populations, published psychometric data on insomnia patients are limited. The LSEQ reliability and construct validity was evaluated in 396 French insomnia patients aged 55 years and over, who were treated with placebo (2 weeks) and melatonin (3 weeks). The results supported LSEQ internal consistency, reliability and construct validity with minor differences from those of the original English version. Then the internal consistency of the LSEQ was evaluated in 257 insomnia patients (age 20-80 years) in France and Israel who, following a 1 week placebo baseline, were randomized to placebo or melatonin treatment for 3 weeks. Cronbach's alpha and Pearson's r correlation coefficients for placebo and drug treatment conditions (p<0.001 for all) supported LSEQ internal consistency in different treatment and age groups and in different languages. It is concluded that the consistency, reliability and validity of the four LSEQ domains allows them to be singled out as independent outcome variables in cross cultural sleep research and clinical practice in adult and elderly patients with insomnia.

Determination of the minimal clinically significant difference on a patient visual analog sleep quality scale

The amount of change in quality of sleep (QOS), as measured by a 100-mm visual analog scale (VAS), that constitutes a minimum clinically significant difference was determined. A total of 428 patients with insomnia aged 55 years and older received placebo (2 weeks), prolonged release melatonin 2 mg (3 weeks) and then placebo (2 weeks). Sleep quality was assessed by the end of each period using the Leeds Sleep Evaluation Questionnaire (LSEQ) QOS variable and a five-point severity-rating scale. The mean difference between current and preceding VAS scores in patients improving or worsening by 1 point was 13 mm (95% CI 11-16). Correlation analysis indicated that a change of 1 point was associated with a mean change of 10.3 mm on the VAS. In conclusion, a change of 10 mm change in the 100-mm VAS QOS variable of the LSEQ, signifies an important change in patients' sleep quality.

Subjective assessment of the effects of CNS-active drugs on sleep by the Leeds sleep evaluation questionnaire: a review

The Leeds sleep evaluation questionnaire (LSEQ) comprises ten self-rating 100 mm line analogue questions concerned with sleep and early morning behaviour. A literature search identified 83 studies in peer-reviewed journals that reported the use of the LSEQ for psychopharmacological investigations of drug effects on self-reported aspects of sleep. High internal consistency and reliability of the questionnaire have been demonstrated. Findings from studies involving a variety of psychoactive agents indicated that the LSEQ was able to quantify subjective impressions of sleep and waking and the effects of drugs in healthy volunteers, depressed and insomnia patients. In accordance with their known activity profile nocturnal administration of sedative hypnotic agents and antihistamines induced dose-related improvements in self-reported ease of getting to sleep, and quality of sleep but a decrease in alertness and behavioural integrity the following morning. Psychostimulants, on the other hand, impaired subjective ratings of sleep and increased early morning alertness. Antidepressants and certain anxiolytic agents improved both self-reported sleep aspects and early morning alertness. Treatment effects measured by the LSEQ corresponded to those measured for the same drugs by other assessment methods. These data indicate that the LSEQ is a robust and reliable instrument for psychopharmacological evaluations. Self-evaluations of sleep, as obtained by the LSEQ, can therefore provide consistent and meaningful measures for estimating the effectiveness of sleep modulators and sedative-hypnotic drugs.

Sleep problems, health-related quality of life, work functioning and health care utilization among the chronically ill

OBJECTIVES

To provide a comprehensive assessment of whether sleep problems among the chronically ill are associated with decrements in functional health and well-being, decreases in work functioning and increases in the use of health care services.

DESIGN

Cross-sectional survey of patients from the Medical Outcomes Study (MOS), an observational study of functional health and well-being. Chronically ill patients (n = 3484) were sampled from health maintenance organizations, large multi-specialty groups, and solo or single-specialty group practices in Boston, Los Angeles, and Chicago. Chronic illness subgroups include: clinical depression (n = 527), congestive heart failure (229), diabetes (n = 577), recent myocardial infarction (n = 170), hypertension (n = 2206), asthma (n = 84), back problems (n = 771), and arthritis (n = 672). ANCOVA analyses of the relationship between sleep problems and SF-36 scales and summaries were performed. In addition, a 'relative impact' analysis determined what scales or summaries were most associated with sleep problems.

MAIN OUTCOME MEASURES

Eight scales and two summary measures from the SF-36 Health Survey, work productivity and work quality measures and self-reports of health care utilization.

RESULTS

Comparing chronically ill patients with no sleep problems to those with mild, moderate, or severe sleep problems revealed a direct association between sleep problems and decrements in health-related quality of life (HRQOL) as measured by SF-36 scales and summaries (MANOVA F 24.1; d.f. 24; p < or = 0.0001). In addition, significant differences in HRQOL were found when comparing patients with and without sleep problems within most of the disease groups studied. The relative impact analysis revealed that measures of mental health and the mental health summary were most associated with sleep problem severity in the total sample and chronic disease subsets, in comparison with measures of physical health. In addition, monotonic relationships were found between severity of sleep problems and decreases in work productivity and increases in health care utilization, as expected.

CONCLUSIONS

The analyses revealed that sleep problems go hand in hand with poorer mental health, diminished work productivity and work quality and greater use of health care services. Sleep problems, therefore, may be a significant confounding factor in the interpretation of health outcomes among patients with chronic diseases.

Neuropsychological outcomes of nocturnal asthma

In spite of frequent reports that nocturnal asthma results in fatigue and impaired cognitive performance, there exists little objective evidence as to the daytime consequences of this disorder. Treatment studies have established that the symptoms of nocturnal asthma improve with medication intervention, but performance does not. Studies of obstructive sleep apnea (OSA), a source of generally more severe sleep fragmentation, have demonstrated that measurement of sleep-deprivation effects is limited to tasks requiring heightened alertness and rapid information processing, and that the degree of score change is related to the degree of sleep disruption. Studies of normal, but sleep-deprived, subjects indicate that (1) utilization of repetitive measures sustained for long duration can potentiate motivation to overcome the effects of fatigue in the laboratory, and (2) even when average scores do not change significantly, performance becomes more irregular. These collective findings about the measurement of performance impairment secondary to sleep deprivation can be used to guide new studies of nocturnal asthma. Finally, children must be included in future investigations because they may be at even greater risk for daytime consequences of nocturnal asthma than adults.

Alpha sleep and information processing, perception of sleep, pain, and arousability in fibromyalgia

This study examined the relationship between alpha sleep and information processing during sleep, perception of sleep, musculoskeletal pain, and arousability in patients with fibromyalgia. Patients (n = 20) were allowed to sleep undisturbed for the first 60 minutes of the study to assess amount of alpha sleep and were classified as high or low alpha generators based on quantitative analyses of alpha activity during this period. The groups were compared for performance on two memory tasks, perceptions of polysomnographically-defined sleep and EEG arousals in response to auditory stimuli. Correlations between symptoms of fibromyalgia and alpha activity were also examined. Alpha activity during sleep in fibromyalgic patients was associated with the perception of shallow sleep and an increased tendency to arouse in relation to auditory stimuli. Alpha activity was not associated with increased memory for auditory stimuli presented during sleep, sleep state misperception, or with myalgia symptoms. Alpha sleep appears to be, electrophysiologically, a shallow form of sleep. Our results suggest that it is perceived as such phenomenologically and that it is also associated with increased arousability.