Showing papers in "Sleep in 2005"

Practice parameters for the indications for polysomnography and related procedures: an update for 2005.

Abstract: These practice parameters are an update of the previously-published recommendations regarding the indications for polysomnography and related procedures in the diagnosis of sleep disorders. Diagnostic categories include the following: sleep related breathing disorders, other respiratory disorders, narcolepsy, parasomnias, sleep related seizure disorders, restless legs syndrome, periodic limb movement sleep disorder, depression with insomnia, and circadian rhythm sleep disorders. Polysomnography is routinely indicated for the diagnosis of sleep related breathing disorders; for continuous positive airway pressure (CPAP) titration in patients with sleep related breathing disorders; for the assessment of treatment results in some cases; with a multiple sleep latency test in the evaluation of suspected narcolepsy; in evaluating sleep related behaviors that are violent or otherwise potentially injurious to the patient or others; and in certain atypical or unusual parasomnias. Polysomnography may be indicated in patients with neuromuscular disorders and sleep related symptoms; to assist in the diagnosis of paroxysmal arousals or other sleep disruptions thought to be seizure related; in a presumed parasomnia or sleep related seizure disorder that does not respond to conventional therapy; or when there is a strong clinical suspicion of periodic limb movement sleep disorder. Polysomnography is not routinely indicated to diagnose chronic lung disease; in cases of typical, uncomplicated, and noninjurious parasomnias when the diagnosis is clearly delineated; for patients with seizures who have no specific complaints consistent with a sleep disorder; to diagnose or treat restless legs syndrome; for the diagnosis of circadian rhythm sleep disorders; or to establish a diagnosis of depression.

Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test

Abstract: Characterization of excessive sleepiness is an important task for the sleep clinician, and assessment requires a thorough history and in many cases, objective assessment in the sleep laboratory. These practice parameters were developed to guide the sleep clinician on appropriate clinical use of the Multiple Sleep Latency Test (MSLT), and the Maintenance of Wakefulness Test (MWT). These recommendations replace those published in 1992 in a position paper produced by the American Sleep Disorders Association. A Task Force of content experts was appointed by the American Academy of Sleep Medicine to perform a comprehensive review of the scientific literature and grade the evidence regarding the clinical use of the MSLT and the MWT. Practice parameters were developed based on this review and in most cases evidence based methods were used to support recommendations. When data were insufficient or inconclusive, the collective opinion of experts was used to support recommendations. These recommendations were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. The MSLT is indicated as part of the evaluation of patients with suspected narcolepsy and may be useful in the evaluation of patients with suspected idiopathic hypersomnia. The MSLT is not routinely indicated in the initial evaluation and diagnosis of obstructive sleep apnea syndrome, or in assessment of change following treatment with nasal continuous positive airway pressure (CPAP). The MSLT is not routinely indicated for evaluation of sleepiness in medical and neurological disorders (other than narcolepsy), insomnia, or circadian rhythm disorders. The MWT may be indicated in assessment of individuals in whom the inability to remain awake constitutes a safety issue, or in patients with narcolepsy or idiopathic hypersomnia to assess response to treatment with medications. There is little evidence linking mean sleep latency on the MWT with risk of accidents in real world circumstances. For this reason, the sleep clinician should not rely solely on mean sleep latency as a single indicator of impairment or risk for accidents, but should also rely on clinical judgment. Assessment should involve integration of findings from the clinical history, compliance with treatment, and, in some cases, objective testing using the MWT. These practice parameters also include recommendations for the MSLT and MWT protocols, a discussion of the normative data available for both tests, and a description of issues that need further study.

Inadequate sleep as a risk factor for obesity : Analyses of the NHANES I

Abstract: Study objectives Sleep deprivation has been hypothesized to contribute toward obesity by decreasing leptin, increasing ghrelin, and compromising insulin sensitivity. This study examines cross-sectional and longitudinal data from a large United States sample to determine whether sleep duration is associated with obesity and weight gain. Design Longitudinal analyses of the 1982-1984, 1987, and 1992 NHANES I Followup Studies and cross-sectional analysis of the 1982-1984 study. Setting Probability sample of the civilian noninstitutionalized population of the United States. Participants Sample sizes of 9,588 for the cross-sectional analyses, 8,073 for the 1987, and 6,981 for the 1992 longitudinal analyses. Measurements and results Measured weight in 1982-1984 and self-reported weights in 1987 and 1992. Subjects between the ages of 32 and 49 years with self-reported sleep durations at baseline less than 7 hours had higher average body mass indexes and were more likely to be obese than subjects with sleep durations of 7 hours. Sleep durations over 7 hours were not consistently associated with either an increased or decreased likelihood of obesity in the cross-sectional and longitudinal results. Each additional hour of sleep at baseline was negatively associated with change in body mass index over the follow-up period, but this association was small and statistically insignificant. Conclusions These findings support the hypothesis that sleep duration is associated with obesity in a large longitudinally monitored United States sample. These observations support earlier experimental sleep studies and provide a basis for future studies on weight control interventions that increase the quantity and quality of sleep.

Epidemiology of insomnia, depression, and anxiety

Abstract: Study objectives This study used empirically validated insomnia diagnostic criteria to compare depression and anxiety in people with insomnia and people not having insomnia. We also explored which specific sleep variables were significantly related to depression and anxiety. Finally, we compared depression and anxiety in (1) different insomnia types, (2) Caucasians and African Americans, and (3) genders. All analyses controlled for health variables, demographics, organic sleep disorders, and symptoms of organic sleep disorders. Design Cross-sectional and retrospective. Participants Community-based sample (N=772) of at least 50 men and 50 women in each 10-year age bracket from 20 to more than 89 years old. Measurements Self-report measures of health, sleep, depression, and anxiety. Results People with insomnia had greater depression and anxiety levels than people not having insomnia and were 9.82 and 17.35 times as likely to have clinically significant depression and anxiety, respectively. Increased insomnia frequency was related to increased depression and anxiety, and increased number of awakenings was also related to increased depression. These were the only 2 sleep variables significantly related to depression and anxiety. People with combined insomnia (ie, both onset and maintenance insomnia) had greater depression than did people with onset, maintenance, or mixed insomnia. There were no differences between other insomnia types. African Americans were 3.43 and 4.8 times more likely to have clinically significant depression and anxiety than Caucasians, respectively. Women had higher levels of depression than men. Conclusion These results reaffirm the close relationship of insomnia, depression, and anxiety, after rigorously controlling for other potential explanations for the relationship.

The neural basis of the psychomotor vigilance task.

Abstract: STUDY OBJECTIVE To identify brain regions underlying the fastest and slowest reaction times on the Psychomotor Vigilance task (PVT) under well-rested conditions, as well as brain regions related to particularly poor performance after sleep deprivation. DESIGN Subjects took the PVT twice while undergoing functional magnetic resonance imaging: once 12 hours after waking from a normal night of sleep and once after 36 hours of total sleep deprivation (TSD). Session order was counterbalanced. SETTING UCSD J. Christian Gillin Laboratory for Sleep and Chronobiology (the sleep core of the General Clinical Research Center) and UCSD Magnetic Resonance Institute. PATIENTS OR PARTICIPANTS Twenty right-handed healthy adults (8 women; age = 27.4 +/- 6.7 years; education = 15.6 +/- 1.5 years). MEASUREMENTS AND RESULTS After a normal night of sleep, optimal performance was related to greater cerebral responses within a cortical sustained attention network and the cortical and subcortical motor systems. Slow reaction times, particularly after TSD, were associated with greater activity in the "default mode network" consisting of frontal and posterior midline regions. CONCLUSIONS Optimal performance on the PVT appears to rely on activation both within the sustained attention system and within the motor system. Poor performance following TSD may result from a disengagement from the task and related inattention, and brain regions responsible for this localize within midline structures shown to be involved in the brain's "default mode." Finally, particularly poor performance after TSD may elicit a subsequent attentional recovery that manifests as greater activation within the same regions normally responsible for fast reaction times.

Association of psychiatric disorders and sleep apnea in a large cohort.

Abstract: Study Objectives: We conducted the present study to determine whether psychiatric disorders are commonly associated with sleep apnea in Veterans Health Administration beneficiaries. Method: The Veterans Health Administration maintains several centralized databases containing healthcare data for more than 4 million veterans. We reviewed data from 1998 to 2001 and identified patient records having International Classification of Diseases-Ninth Edition-Clinical Modification codes indicating sleep apnea and various psychiatric conditions. Subsequently, we compared age, sex, ethnicity, and prevalence of comorbid psychiatric conditions for Veterans Health Administration beneficiaries with and without sleep apnea. Results: Out of 4,060,504 unique cases, 118,105 were identified as having sleep apnea (estimated prevalence of 2.91%). Mean age at the time of diagnosis was 57.6 years. Psychiatric comorbid diagnoses in the sleep apnea group included depression (21.8%), anxiety (16.7%), posttraumatic stress disorder (11.9%), psychosis (5.1), and bipolar disorders (3.3%). Compared with patients not diagnosed with sleep apnea, a significantly greater prevalence (P < .0001) was found for mood disorders, anxiety, posttraumatic stress disorder, psychosis, and dementia in patients with sleep apnea. Conclusions: Sleep apnea is associated with a higher prevalence of psychiatric comorbid conditions in Veterans Health Administration beneficiaries. This association suggests that patients with psychiatric disorders and coincident symptoms suggesting sleep-disordered breathing should be evaluated for sleep apnea.

Sleep/wake patterns derived from activity monitoring and maternal report for healthy 1- to 5-year-old children.

Abstract: Study objectives To describe behavioral sleep/wake patterns of young children from actigraphy and mothers' reports, assess age-group and sex differences, describe daytime napping, and investigate the impact of family demographic variables on sleep-wake measures. Design Cross-sectional sample of children wore actigraphs for 1 week; mothers kept concurrent diaries. Setting Children studied in their homes. Participants 169 normal healthy children in 7 age groups (12, 18, 24, 30, 36, 48, and 60 months old); 84 boys and 85 girls. Interventions N/A. Measurements and results Nocturnal sleep/wake measures estimated from activity recordings using a validated algorithm; mothers' reports of nocturnal sleep/wake patterns and daytime naps obtained from concurrent diaries. Bedtimes and sleep start times were earliest and time in bed and sleep period times were longest for 12-month-old children. Rise time, sleep end time, and nocturnal sleep minutes did not differ across age groups. Actigraphic estimates indicated that children aged 1 to 5 years slept an average of 8.7 hours at night. Actigraph-based nocturnal wake minutes and wake bouts were higher than maternal diary reports for all age groups. Daytime naps decreased monotonically across age groups and accounted for most of the difference in 24-hour total sleep over age groups. Children in families with lower socioeconomic status had later rise times, longer time in bed, more nocturnal wake minutes and bouts, and more night-to-night variability in bedtime and sleep period time. Children with longer naps slept less at night. Conclusions Individual differences in sleep/wake measures reflect characteristics of children, parents, or parent-child interactions.

The effects of sleep loss on medical residents' emotional reactions to work events : a cognitive-energy model

Abstract: Study objectives This study investigated the relationship between sleep loss and emotional reactivity in medical residents. We hypothesized that this relationship is shaped by the effect of sleep loss on cog-nitive-energy resources required for coping with goal-disruptive events or for capitalizing on new opportunities offered by goal-enhancing events. Settings 15 medical wards in 4 large hospitals in Israel. Participants 78 medical residents, 67% men, aged 26 to 39 years. Design Actigraphic sleep-wake cycles were measured for 5- to 7-day periods, surrounding nightshifts, every 6 months, covering the first 2 years of residency. During each study period, emotional reactivity was investigated using the experience-sampling methodology by which residents received 3 phone calls at random times during their working day for 3 consecutive days. These calls reminded them to fill out brief questionnaires concerning change of circumstances over the previous 15 minutes and to rate their emotional response to these circumstances using the Positive Affect and Negative Affect Scales. Fatigue at those times was measured by a subscale of the Profile of Mood States. Measurements and results Multilevel regression analysis was used to determine the influence of sleep duration and sleep fragmentation on the emotional reactions to goal-disruptive and goal-enhancing daytime events. We found that sleep loss intensified negative emotions and fatigue following daytime disruptive events, while positive emotion was mitigated following goal-enhancing events. Sleep loss also resulted in an overall elevated baseline for positive emotion. Conclusions Sleep loss amplifies the negative emotive effects of disruptive events while reducing the positive effect of goal-enhancing events. Methodologically, the study highlights the utility and advantages of event-level analysis as opposed to the current practice of random sampling of emotion states during waking hours, disregarding contextual factors associated with purposeful, goal-oriented behavior episodes.

Homeostatic sleep regulation in adolescents.

Abstract: STUDY OBJECTIVES: To examine the effects of total sleep deprivation on adolescent sleep and the sleep electroencephalogram (EEG) and to study aspects of sleep homeostasis. DESIGN: Subjects were studied during baseline and recovery sleep after 36 hours of wakefulness. SETTING: Four-bed sleep research laboratory. PARTICIPANTS: Seven prepubertal or early pubertal children (pubertal stage Tanner 1 or 2 = Tanner 1/2; mean age 11.9 years, SD +/- 0.8, 2 boys) and 6 mature adolescents (Tanner 5; 14.2 years, +/- 1.4, 2 boys). INTERVENTIONS: Thirty-six hours of sleep deprivation. MEASUREMENTS: All-night polysomnography was performed. EEG power spectra (C3/A2) were calculated using a Fast Fourier transform routine. RESULTS: In both groups, sleep latency was shorter, sleep efficiency was higher, non-rapid eye movement (NREM) sleep stage 4 was increased, and waking after sleep onset was reduced in recovery relative to baseline sleep. Spectral power of the NREM sleep EEG was enhanced after sleep deprivation in the low-frequency range (1.6-3.6 Hz in Tanner 1/2; 0.8-6.0 Hz in Tanner 5) and reduced in the sigma range (11-15 Hz). Sleep deprivation resulted in a stronger increase of slow-wave activity (EEG power 0.6-4.6 Hz, marker for sleep homeostatic pressure) in Tanner 5 (39% above baseline) than in Tanner 1/2 adolescents (18% above baseline). Sleep homeostasis was modeled according to the two-process model of sleep regulation. The build-up of homeostatic sleep pressure during wakefulness was slower in Tanner 5 adolescents (time constant of exponential saturating function 15.4 +/- 2.5 hours) compared with Tanner 1/2 children (8.9 +/- 1.2 hours). In contrast, the decline of the homeostatic process was similar in both groups. CONCLUSION: Maturational changes of homeostatic sleep regulation are permissive of the sleep phase delay in the course of adolescence.

The clinical use of the MSLT and MWT.

Abstract: The studies examined in this review indicate that the MSL is sensitive to conditions expected to increase sleepiness. MSL are generally lower following sleep loss, following use of sedating medications, during wakefulness in the late night or early morning hours, and among patients with sleep disorders associated with excessive sleepiness such as narcolepsy or obstructive sleep apnea. However, the wide range in MSL makes it difficult to establish a specific threshold value for excessive sleepiness or to discriminate patients with sleep disorders from non-patients. Some of this variation may be attributable to methodological differences and some may be attributable to individual differences in sleep tendency (e.g., related to age). The studies analyzed in this review indicate that the MSL on both the MSLT and MWT does not discriminate well between patients with sleep disorders and normal populations. This is due to large SD as well as floor or ceiling effects in the tests. However, the MSL shows appropriate change from initial testing to subsequent testing following treatment or manipulations intended to alter sleepiness or alertness. Additionally the presence of two or more SOREMPs on the MSLT is a common finding in narcolepsy patients. However, SOREMPs are not exclusive to narcolepsy patients but are frequent in untreated sleep apnea

Sleep loss and performance in residents and nonphysicians: a meta-analytic examination.

Abstract: Study Objectives: To explore the effect of sleep loss on cognitive function, memory, and vigilance in resident physicians and nonphysicians and on residents' clinical performance. Design: Meta-analysis of 60 studies on the effect of sleep deprivation, with a total sample of 959 physicians and 1,028 nonphysicians and 5,295 individual effect indexes. Outcome Measures: Cognitive performance and performance on clinical tasks under acute and partial chronic sleep deprivation. Additional analyses stratified the data by physician/nonphysician, type of performance, and length and type of sleep loss and assessed the combined effect of several of these factors. Results: Sleep loss of less than 30 hours reduced physicians' overall performance by nearly 1 standard deviation and clinical performance by more than 1.5 standard deviations. The effect of sleep deprivation was larger in nonphysicians than in physicians (corrected d value -.995 vs -.880), with these smaller effects likely resulting from study factors, primarily variation in the hours without sleep prior and chronically reduced sleep in the rested controls in physician studies. Conclusions: The weekly hours and continuous wakefulness permitted under the current national minimum standards for residents may not completely guard against the negative effect of sleep loss on cognitive and clinical performance. Research is needed to explore the effect of continuous duty periods and chronic partial sleep loss in residents and to assess the clinical and educational consequences of sleep loss. The goal should be to combine scientifically based duty-hour limits with broader efforts to enhance patient safety and resident learning.

Individual differences in adult human sleep and wakefulness: Leitmotif for a research agenda.

Abstract: This paper reviews the literature on interindividual variability in human sleep parameters, sleepiness, responses to sleep deprivation, and manifestations of sleep disorders. Variability among individuals in sleep/wake biology and behavior is pervasive. The magnitude of such individual differences is often considerable and comparable to the effect sizes of many experimental and clinical interventions. Evidence is accu- mulating that certain aspects of sleep/wake-related variability—such as sleep duration, daytime sleepiness, and vulnerability to the effects of sleep loss—involve trait characteristics in healthy populations and among sleep-disordered patients. Establishing the trait-specific nature of variabil- ity in sleep/wake parameters is a prerequisite for elucidating the corre- sponding neurophysiologic and/or genetic mechanisms. At present, it remains largely unknown what underlies or predicts sleep/wake-related traits, what relationships these traits may have to each other, and what functional significance may be associated with specific traits. Scientific studies addressing these issues are warranted, as understanding the basis of trait variability may yield new insights into sleep/wake regulation and sleep pathology. Understanding individual differences in sleep and wakefulness may also have provocative but important implications for health economics and clinical care, as well as for safety, productivity, and general well-being. This paper gives suggestions for a research agenda focusing on individual differences in sleep research and sleep medicine.

Severe obstructive sleep apnea/hypopnea mimicking REM sleep behavior disorder.

Abstract: Objective To describe the clinical and video-polysomnographic (VPSG) features of a group of subjects with severe obstructive sleep apnea/hypopnea (OSAH) mimicking the symptoms of REM sleep behavior disorder (RBD). Design Evaluation of clinical and VPSG data. Setting University hospital sleep laboratory unit. Participants Sixteen patients that were identified during routine first evaluation visits. Patients' PSG measures were compared with those of 20 healthy controls and 16 subjects with idiopathic RBD of similar age and sex distribution and apnea/hypopnea index lower than 10. Interventions NA. Results Sixteen subjects were identified presenting with dream-enacting behaviors and unpleasant dreams suggesting the diagnosis of RBD, in addition to snoring and excessive daytime sleepiness. VPSG excluded RBD showing REM sleep with atonia and without increased phasic EMG activity, and was diagnostic of severe OSAH with a mean apnea-hypopnea index of 67.5 +/- 18.7 (range, 41-105) demonstrating that the reported abnormal sleep behaviors occurred only during apnea-induced arousals. Continuous positive airway pressure therapy eliminated the abnormal behaviors, unpleasant dreams, snoring and daytime hypersomnolence. Conclusions Our study shows that severe OSAH may mimick the symptoms of RBD and that VPSG is mandatory to establish the diagnosis of RBD, and identify or exclude other causes of dream-enacting behaviors.

Differences between men and women in the clinical presentation of patients diagnosed with obstructive sleep apnea syndrome

Abstract: Study objectives Obstructive sleep apnea syndrome (OSAS) results from recurrent episodes of breathing cessation during sleep. Epidemiologic studies have shown that OSAS is more prevalent in men than women (4% vs 2%). Previous studies have explored gender-related differences in upper airway anatomy and function, hormone physiology, and polysomnographic findings. The aim of this study is to assess differences in clinical presentation between women and men with OSAS. Design Retrospective chart review analysis. Setting Tertiary university-based medical center Participants 130 randomly selected women with OSAS matched individually with 130 men with OSAS for age, body mass index, apnea-hypopnea index, and Epworth Sleepiness Scale score. Interventions N/A. Measurements and results Data were obtained from questionnaires and in-laboratory polysomnographic studies. There were no differences between the genders for age (48.0 +/- 1.1 years [mean +/- SEM] for women vs 47.6 +/- 1.0 years for men), body mass index (40.4 +/- 0.7 kg/m2 for women vs 40.0 +/- 0.6 kg/m2 for men), apnea-hypopnea index (36.8 +/- 3.3/hour for women vs 36.0 +/- 3.0/hour for men), or Epworth Sleepiness Scale score (12.45 +/- 0.53 for women vs 12.84 +/- 0.47 for men). Although snoring and sleepiness were similarly common in women and men, women more often described their main presenting symptoms as insomnia (odds ratio: 4.20; 95% confidence interval: 1.54-14.26) and were much more likely to have a history of depression (odds ratio: 4.60; 95% confidence interval: 1.71-15.49) and hypothyroid disease (odds ratio: 5.60; 95% confidence interval: 2.14-18.57). Women presented less often with a primary complaint of witnessed apnea (odds ratio: 0.66; 95% confidence interval: 0.38-1.12), consumed less caffeine per day (3.3 cups in women vs 5.2 cups in men; P = .0001), and admitted to less alcohol consumption (odds ratio: 0.36; 95% confidence interval: 0.18-0.70). Conclusions At the time of OSAS diagnosis, women with OSAS are more likely to be treated for depression, to have insomnia, and to have hypothyroidism than are men with the same degree of OSAS.

Experimental restriction of sleep opportunity in children: effects on teacher ratings.

Abstract: STUDY OBJECTIVE To determine the effects of experimental restriction of sleep opportunity on teacher ratings of academic performance and behavior in healthy normal children. DESIGN Home-based, within-subjects design in which participants followed 3 week-long sleep schedules-Baseline (self-selected), Optimized, and Restricted-while attending school, with order of conditions counter-balanced (Optimized and Restricted). PARTICIPANTS Seventy-four children (39 boys; aged 6 to 12 years, mean = 10) screened for medical and psychological health. MEASUREMENTS AND RESULTS Teachers masked to assigned hours of sleep completed paper-and-pencil questionnaires at the end of each study condition. Questionnaire items were selected from several published measures. Summary scores included Academic Problems, Hyperactive-Impulsive Behaviors, Internalizing, Oppositional-Aggressive, Sleepiness, Total Attention Problems, and Mean Severity of Attention Problems. Main effects of sleep condition were found forAcademic Problems, Sleepiness, Total Attention Problems, and Mean Severity of Attention Problems. Restricting sleep increased ratings of Academic Problems (medium effect) relative to both Baseline (P < .01, eta(p)2 = .11) and Optimized (P < .05, eta(p)2 = .10) conditions and increased the Mean Severity of Attention Problems (medium effect) relative to Baseline (P < .01, eta(p)2 = .12). CONCLUSIONS These findings provide experimental support for widely held beliefs about the importance of sufficient time-in-bed for academic functioning in children. Reducing sleep opportunity had a direct effect on academic performance, as rated by teachers, even among healthy students with no history of behavioral problems or academic difficulty. Findings also support insufficient sleep as a direct source of variability in the manifestation of attention problems but not hyperactivity.

Sleepiness in patients with moderate to severe sleep-disordered breathing

Abstract: Population-based studies suggest that complaints of sleepi-ness are absent in many individuals with sleep-disordered breathing. Weinvestigated the prevalence of sleepiness as well as factors associatedwith sleepiness in individuals with moderate to severe sleep-disorderedbreathing (apnea-hypopnea index >15).

Normative sleep data, cognitive function and daily living activities in older adults in the community.

Abstract: Study Objectives: To present normative data of sleep-wake characteristics and to examine risk factors associated with extreme values (ie, in the 5 lower and upper percentiles of the distribution) in older adults. Design: Cross-sectional telephone survey Setting: The metropolitan area of Paris, France. Participants: A total of 7010 randomly selected households were contacted. Among them, 1264 households included at least 1 resident 60 years of age or older; 1,026 subjects agreed to participate (participation rate: 80.9%). Interventions: None. Measurements and Results: Subjects were interviewed with the Sleep-EVAL System about their sleeping habits and sleep and psychiatric disorders. In addition, the system administered to all the participants the Psychological General Well-Being Schedule, the Cognitive Difficulties Scale (Mac Nair-R), and an independent living scale. The median nighttime sleep duration was 7 hours without significant difference between the age groups. Factors positively associated with the 5 percentile (4 hours 30 minutes or less) of nighttime sleep duration were obesity, poor health, insomnia, and insomnia accompanied by daytime sleepiness and cognitive impairment. At the other extremity (95 th percentile), long sleep (9 hours 30 minutes or more) was associated with organic disease, lack of physical exercise, and lower education. A daytime sleep duration of 1 hour or more (95 th percentile) was associated with being a man, cognitive impairment, high blood pressure, obesity, and insomnia. Long sleep latency (95 th percentile at 80 minutes) was associated with anxiety, lower education, poor health, insomnia without excessive daytime sleepiness, and obstructive sleep apnea syndrome. Obesity and loss of autonomy in activities of daily living was associated with both early (9 PM or earlier) and late bedtime (1 AM or later) and early (≤ 5 AM) and late (≥ 9 AM) wake-up time. Conclusions: This study illustrates the usefulness of normal distributions of sleep parameters in the general population to calculate different risk factors associated with extreme values of the normal distribution.

Deletion of the mammalian circadian clock gene BMAL1/Mop3 alters baseline sleep architecture and the response to sleep deprivation.

Abstract: Study objectives: The finding that deletion or mutation of core circadian clock genes in both mice and flies induce unexpected alterations in sleep amount, sleep architecture and the recovery response to sleep deprivation, has led to new insights into functions of the circadian system that extend beyond its role as a regulator of the timing of the sleep-wake cycle. A key transcription factor in the transcriptional/translational feedback loop of mammalian circadian genes is BMAL1/Mop3, a heterodimeric partner to CLOCK. It was previously shown that mice deficient in the BMAL1/Mop3 gene become immediately arrhythmic in constant darkness and have reduced locomotor activity levels under entrained and constant conditions. In this study, we tested the hypothesis that the mammalian BMAL1/Mop3 gene would have regulatory effects on sleep-wake patterns. Design: In mice with targeted deletion of the BMAL1/Mop3 gene, EEG/EMG sleep-wake patterns were recorded under entrained and freerunning conditions as well as following acute (6-hrs) sleep deprivation. Measurements and results: Mice homozygous for the BMAL1/Mop3 deletion showed an attenuated rhythm of sleep and wakefulness distribution across the 24-hr period. In addition, these mice showed increases in total sleep time, sleep fragmentation and EEG delta power under baseline conditions, and an attenuated compensatory response to acute sleep deprivation. Conclusions: These new data strengthen the hypothesis that molecular components of the circadian system play a central role in the generation of sleep and wakefulness beyond just the timing of these behavioral vigilance states.

Restless legs syndrome and attention-deficit/hyperactivity disorder: a review of the literature

Abstract: Although still limited, evidence from clinical studies demonstrates an association between RLS and ADHD or ADHD symptoms. Further clinical studies using standard criteria and procedures are needed to better estimate the degree of association. Epidemiologic studies are required to assess the relationship between ADHD and RLS symptoms in nonclinical samples. Further investigations should address the mechanisms underlying the relationship between RLS and ADHD. Several dopaminergic agents seem to be promising treatment for RLS associated with ADHD symptoms. To date, however, the absence of randomized and blinded controlled studies does not allow evidence-based recommendations.

Fatigue, sleepiness, and performance in simulated versus real driving conditions.

Abstract: STUDY OBJECTIVES: To determine whether real-life driving would produce different effects from those obtained in a driving simulator on fatigue, performances and sleepiness. DESIGN: Cross-over study involving real driving (1200 km) or simulated driving after controlled habitual sleep (8 hours) or restricted sleep (2 hours). SETTING: Sleep laboratory and open French Highway. PARTICIPANTS: Twelve healthy men (mean age +/- SD = 21.1 +/- 1.6 years, range 19-24 years, mean yearly driving distance +/- SD = 6563 +/- 1950 miles) free of sleep disorders. MEASUREMENTS: Self-rated fatigue and sleepiness, simple reaction time before and after each session, number of inappropriate line crossings from the driving simulator and from video-recordings of real driving. RESULTS: Line crossings were more frequent in the driving simulator than in real driving (P

An electrocardiogram-based technique to assess cardiopulmonary coupling during sleep

Abstract: Study objectives To evaluate a new automated measure of cardiopulmonary coupling during sleep using a single-lead electrocardiographic signal. Design Using training and test datasets of 35 polysomnograms each, we assessed the correlations of an electrocardiogram-based measure of cardiopulmonary interactions with respect to standard sleep staging, as well as to the cyclic alternating pattern classification. The pattern of coupling in 15 healthy individuals was also assessed. Setting American Academy of Sleep Medicine Accredited Sleep Disorders Center. Interventions None. Measurements and results From a continuous, single-lead electrocardiogram, we extracted both the normal-to-normal sinus interbeat interval series and a corresponding electrocardiogram-derived respiration signal. Employing Fourier-based techniques, the product of the coherence and cross-power of these 2 simultaneous signals was used to generate a spectrographic representation of cardiopulmonary coupling dynamics during sleep. This technique shows that non-rapid eye movement sleep in adults demonstrates spontaneous abrupt transitions between high- and low-frequency cardiopulmonary coupling regimes, which have characteristic electroencephalogram, respiratory, and heart-rate variability signatures in both health and disease. Using the kappa statistic, agreement with standard sleep staging was poor (training set 62.7%, test set 43.9%) but higher with cyclic alternating pattern scoring (training set 74%, test set 77.3%). Conclusions A sleep spectrogram derived from information in a single-lead electrocardiogram can be used to dynamically track cardiopulmonary interactions. The 2 distinct (bimodal) regimes demonstrate a closer relationship with visual cyclic alternating pattern and non-cyclic alternating pattern states than with standard sleep stages. This technique may provide a complementary approach to the conventional characterization of graded non-rapid eye movement sleep stages.

Restless Legs Syndrome, Periodic Limb Movements in Sleep, and Depression

Abstract: Study objectives To review the literature on restless legs syndrome (RLS), periodic limb movements in sleep, and depression. Design Literature review. SETTING, PARTICIPANTS, AND INTERVENTIONS: N/A. Measurements and results We conducted a comprehensive review of the literature searching for publications that included data on depression or antidepressants and RLS or periodic limb movements in sleep. Sixty-two relevant literature references were found and reviewed. Four population-based studies and 9 clinical studies reported significantly higher rates of depression symptoms in individuals with RLS than in controls. Conversely, the prevalence of RLS in patients presenting with depression was reported as elevated in 2 studies. Conflicting data were found regarding the effect of antidepressants on the sensory symptoms of RLS. In contrast, several studies have found that selective serotonin reuptake inhibitor antidepressant use is associated with increased periodic limb movements in sleep. Conclusions Depression symptoms are common in adults with RLS. However, the relationship appears complex, with overlap between RLS- and depression-related symptoms confounding the issue. Given what is known at this time, we propose a specific treatment approach to patients with RLS and depression symptoms.

Suicidality and sleep disturbances.

Abstract: STUDY OBJECTIVES: A growing body of research indicates that sleep disturbances may be specifically linked to suicidal behaviors. It remains unclear, however, whether this link is largely explained by depressive symptoms. The present study investigated the relationship between suicidality, depression, and sleep complaints in a clinical outpatient setting. DESIGN AND SETTING: Upon admission, 176 outpatients completed measures on sleep disturbances, suicidal symptoms, and depression. Several sleep disturbances were evaluated with regard to suicidal ideation, including insomnia, nightmares, and sleep-related breathing symptoms. MEASUREMENTS AND RESULTS: Regression analyses revealed that insomnia and nightmare symptoms were associated with both depressive symptoms and suicidality. Sleep-related breathing symptoms were associated with depressive symptoms, but did not show an association with suicidal ideation. After controlling for depressive symptoms, only nightmares demonstrated an association with suicidal ideation. This relationship emerged as a nonsignificant trend (P = .06). Nightmares were particularly associated with suicidality among women compared with men. Posthoc analyses revealed that, after controlling for sex and depressive symptoms, nightmare symptoms were significantly associated with suicidality (P = .04). CONCLUSIONS: Although insomnia and nightmares were significantly associated with depressive and suicidal symptoms, after controlling for additional variables, such as depression and sex, only nightmares remained associated with suicidality. This association was slightly stronger among women compared with men. Language: en

The K-Complex: A 7-Decade History

Abstract: The K-complex was first described by Loomis et al 67 years ago in a paper that was one of a series of seminal studies of sleep conducted in Loomis' private laboratory. The study of the K-complex was almost immediately taken up by many notable figures in early electroencephalography research, such as Robert Schwab, Mary Brazier, and W. Gray Walter. More than 200 papers have been published in the years since these early studies, including major reviews in 1956 by Roth et al and in 1985 by Peter Halasz. More recently, K-complex study has been taken up by event-related potentials researchers such as Ken Campbell and animal neurophysiologists such as Florin Amzica and Mircea Steriade. The present paper provides a historical and thematically based review of the K-complex literature and attempts to integrate the various theoretical positions and neurophysiologic data. Specifically, K-complexes are discussed in terms of their relationship to other electroencephalographic phenomena, their relationship to autonomic activation, their role in the study of information processing during sleep, and what is understood of their underlying neurophysiology.

Association of the length polymorphism in the human Per3 gene with the delayed sleep-phase syndrome: does latitude have an influence upon it?

Abstract: Study objectives The objective of this study is to analyze the influence of a previously reported hPer3 gene-length polymorphism in the delayed sleep-phase syndrome and in morningness-eveningness tendencies at low latitudes in the southern hemisphere. Design We have genotyped a length polymorphism in the hPer3 gene characterized by a short repeat allele (4-repeat) and a long repeat allele (5-repeat). Participants Seventeen patients with delayed sleep-phase syndrome; 156 volunteers chosen according to Horne-Ostberg questionnaire to have morning, intermediate, or evening preference; and 110 volunteers with no Horne-Ostberg score as a sample of the general population. Results We have found a higher frequency of 5-repeat allele in the delayed sleep-phase syndrome group and an association of this polymorphism with diurnal preference. Conclusion Our results suggest that latitude has a role in the influence of hPer3 gene polymorphism on delayed sleep-phase syndrome and confirm previous data showing its association with morningness-eveningness tendencies.

A double-blind study in healthy volunteers to assess the effects on sleep of pregabalin compared with alprazolam and placebo.

Abstract: Study objectives To assess the effects of pregabalin compared with alprazolam and placebo on aspects of sleep in healthy volunteers. Design Randomized, double-blind, placebo- and active-controlled, 3-way crossover. Setting Single research center. Participants and interventions Healthy adult (12 men) volunteers (N=24) received oral pregabalin 150 mg t.i.d., alprazolam 1 mg t.i.d., and placebo t.i.d. for 3 days. Measurements and results Objective sleep was measured by an 8-channel polysomnograph; subjective sleep was measured using the Leeds Sleep Evaluation Questionnaire. Compared with placebo, pregabalin significantly increased slow-wave sleep both as a proportion of the total sleep period and the duration of stage 4 sleep. Alprazolam significantly reduced slow-wave sleep. Pregabalin and alprazolam produced modest, but significant, reductions in sleep-onset latency compared with placebo. Rapid eye movement sleep latency after pregabalin was no different than placebo but was significantly shorter than that found with alprazolam. Although there were no differences between the active treatments, both pregabalin and alprazolam reduced rapid eye movement sleep as a proportion of the total sleep period compared with placebo. Pregabalin also significantly reduced the number of awakenings of more than 1 minute in duration. Leeds Sleep Evaluation Questionnaire ratings of the ease of getting to sleep and the perceived quality of sleep were significantly improved following both active treatments, and ratings of behavior following awakening were significantly impaired by both drug treatments. Conclusions Pregabalin appears to have an effect on sleep and sleep architecture that distinguishes it from benzodiazepines. Enhancement of slow-wave sleep is intriguing, since reductions in slow-wave sleep have frequently been reported in fibromyalgia and general anxiety disorder.

Phase-dependent treatment of delayed sleep phase syndrome with melatonin.

Abstract: Study Objective: Delayed sleep phase syndrome (DSPS) is a circadianrhythm sleep disorder characterized by abnormally late sleep and wake times. Melatonin, taken in the evening, advances sleep and circadian phase in patients with DSPS. However, little is known about the most effective dose or time of administration. In the present study, we tested the effectiveness of melatonin to advance the timing of sleep and circadian phase in individuals with DSPS. Design: Following baseline assessment of sleep and circadian phase, subjects were randomly assigned to 1 of 3 treatment groups. The administration of melatonin (0.3 or 3.0 mg) or placebo was double-blinded. Setting: All procedures were conducted on an outpatient basis. Participants: Thirteen subjects with DSPS, recruited via flyers, advertisements, and referrals from the Sleep Clinic, completed this study. Interventions: Melatonin (0.3 or 3.0 mg) or placebo was administered between 1.5 and 6.5 hours prior to dim light melatonin onset for a 4-week period. Measurements and Results: Both doses of melatonin advanced the circadian phase of endogenous melatonin. The magnitude of phase advance in dim-light melatonin onset correlated strongly with the time of melatonin administration, with earlier times being more effective (r 2 = 0.94, P <.0001). Similar, though weaker, relationships were obtained between the timing of melatonin administration and changes in sleep time. Conclusions: These results indicate that melatonin advances the circadian clock and sleep in patients with DSPS in a phase-dependent manner. This is the first study that reports a relationship between timing of melatonin administration and phase changes in patients with DSPS.

REM sleep behavior disorder and REM sleep without atonia in patients with progressive supranuclear palsy.

Abstract: STUDY OBJECTIVE To compare sleep characteristics, rapid eye movement (REM) sleep without atonia, and REM sleep behavior disorder (RBD) in patients with progressive supranuclear palsy (tauopathy), patients with Parkinson's disease (a synucleinopathy), and control subjects. DESIGN Sleep interview, overnight polysomnography, and Multiple Sleep Latency Tests. PATIENTS Forty-five age- and sex-matched patients with probable progressive supranuclear palsy, (n=15, aged 68 +/- 8 years, 7 men), patients with Parkinson disease (n=15), and control subjects (n=15). SETTINGS Tertiary-care academic hospital. INTERVENTION N/A. RESULTS Compared to the 2 other groups, patients with progressive supranuclear palsy had a longer duration of wakefulness after sleep onset and twice as much sleep fragmentation and percentage of stage 1 sleep but had similar apnea-hypopnea indexes, periodic leg movements indexes, and mean daytime sleep latencies. REM sleep percentage was as low in patients with progressive supranuclear palsy (8% +/- 6% of total sleep time) as in patients with Parkinson disease (10% +/- 4%), versus 20% +/- 6% in controls (analysis of variance, P < .0001). Interestingly, patients with progressive supranuclear palsy had percentages of REM sleep without atonia (chin muscle activity: 33% +/- 36% of REM sleep) similar to those of patients with Parkinson disease (28% +/- 35%) and dramatically higher than those of controls (0.5% +/- 1%, analysis of variance, P = .008). Four (27%) patients with progressive supranuclear palsy had more than 50% REM sleep without atonia (as did a similar number of patients with Parkinson disease), and 2 of them (13%, vs 20% of patients with Parkinson disease) had clinical RBD. The four patients with progressive supranuclear palsy with excessive daytime sleepiness slept longer at night than the 11 patients with progressive supranuclear palsy who were alert (442 +/- 14 minutes vs 312 +/- 74 minutes, student t tests, P = .004), suggesting a primary nonnarcoleptic hypersomnia. CONCLUSION REM sleep without atonia and RBD were as frequent in patients with progressive supranuclear palsy as in patients with Parkinson disease. It suggests that the downstream cause of parkinsonism, rather than its primary neuropathology (synucleinopathy vs tauopathy), is a key factor for REM sleep behavior disorder.

Changes in symptoms of sleep-disordered breathing during pregnancy.

Abstract: Background Although incident snoring is common in pregnant women and has been proposed as a potential risk factor for adverse maternal-fetal outcomes, the development of sleep-disordered breathing during pregnancy has not been prospectively described. Methods Using the Apnea Symptom Score from the Multivariable Apnea Prediction Index and the Epworth Sleepiness Scale, we prospectively assessed symptoms of sleep-disordered breathing and daytime somnolence in 155 women to determine whether symptoms increased during pregnancy and the characteristics associated with increasing symptoms. Results We found that sleep-disordered breathing symptoms (Apnea Symptom Score, 0.44 (SEM 0.58) vs 0.95 (0.09, P 10) was prevalent throughout pregnancy (31.0%-45.5%). Conclusions Our data demonstrate that symptoms of sleep-disordered breathing increase during pregnancy and that more than 10% of our subjects may be at risk for developing sleep apnea during pregnancy. Excessive daytime somnolence was highly prevalent even early in pregnancy and became increasingly common as pregnancy progressed.