Showing papers in "Sleep in 1997"
TL;DR: It is suggested that cumulative nocturnal sleep debt had a dynamic and escalating analog in cumulative daytime sleepiness and that asymptotic or steady-state sleepiness was not achieved in response to sleep restriction.
Abstract: To determine whether a cumulative sleep debt (in a range commonly experienced) would result in cumulative changes in measures of waking neurobehavioral alertness, 16 healthy young adults had their sleep restricted 33% below habitual sleep duration, to an average 4.98 hours per night [standard deviation (SD) = 0.57] for seven consecutive nights. Subjects slept in the laboratory, and sleep and waking were monitored by staff and actigraphy. Three times each day (1000, 1600, and 2200 hours) subjects were assessed for subjective sleepiness (SSS) and mood (POMS) and were evaluated on a brief performance battery that included psychomotor vigilance (PVT), probed memory (PRM), and serial-addition testing, Once each day they completed a series of visual analog scales (VAS) and reported sleepiness and somatic and cognitive/emotional problems. Sleep restriction resulted in statistically robust cumulative effects on waking functions. SSS ratings, subscale scores for fatigue, confusion, tension, and total mood disturbance from the POMS and VAS ratings of mental exhaustion and stress were evaluated across days of restricted sleep (p = 0.009 to p = 0.0001). PVT performance parameters, including the frequency and duration of lapses, were also significantly increased by restriction (p = 0.018 to p = 0.0001). Significant time-of-day effects were evident in SSS and PVT data, but time-of-day did not interact with the effects of sleep restriction across days. The temporal profiles of cumulative changes in neurobehavioral measures of alertness as a function of sleep restriction were generally consistent. Subjective changes tended to precede performance changes by 1 day, but overall changes in both classes of measure were greatest during the first 2 days (P1, P2) and last 2 days (P6, P7) of sleep restriction. Data from subsets of subjects also showed: 1) that significant decreases in the MSLT occurred during sleep restriction, 2) that the elevated sleepiness and performance deficits continued beyond day 7 of restriction, and 3) that recovery from these deficits appeared to require two full nights of sleep. The cumulative increase in performance lapses across days of sleep restriction correlated closely with MSLT results (r = -0.95) from an earlier comparable experiment by Carskadon and Dement (1). These findings suggest that cumulative nocturnal sleep debt had a dynamic and escalating analog in cumulative daytime sleepiness and that asymptotic or steady-state sleepiness was not achieved in response to sleep restriction.
2,040 citations
TL;DR: It is estimated that 93% of women and 82% of men with moderate to severe SAS have not been clinically diagnosed and these findings provide a baseline for assessing health care resource needs for sleep apnea.
Abstract: The proportion of sleep apnea syndrome (SAS) in the general adult population that goes undiagnosed was estimated from a sample of 4,925 employed adults. Questionnaire data on doctor-diagnosed sleep apnea were followed up to ascertain the prevalence of diagnosed sleep apnea. In-laboratory polysomnography on a subset of 1,090 participants was used to estimate screen-detected sleep apnea. In this population, without obvious barriers to health care for sleep disorders, we estimate that 93% of women and 82% of men with moderate to severe SAS have not been clinically diagnosed. These findings provide a baseline for assessing health care resource needs for sleep apnea.
1,616 citations
TL;DR: The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.
Abstract: The Sleep Heart Health Study (SHHS) is a prospective cohort study designed to investigate obstructive sleep apnea (OSA) and other sleep-disordered breathing (SDB) as risk factors for the development of cardiovascular disease. The study is designed to enroll 6,600 adult participants aged 40 years and older who will undergo a home polysomnogram to assess the presence of OSA and other SDB. Participants in SHHS have been recruited from cohort studies in progress. Therefore, SHHS adds the assessment of OSA to the protocols of these studies and will use already collected data on the principal risk factors for cardiovascular disease as well as follow-up and outcome information pertaining to cardiovascular disease. Parent cohort studies and recruitment targets for these cohorts are the following: Atherosclerosis Risk in Communities Study (1,750 participants), Cardiovascular Health Study (1,350 participants), Framingham Heart Study (1,000 participants), Strong Heart Study (600 participants), New York Hypertension Cohorts (1,000 participants), and Tucson Epidemiologic Study of Airways Obstructive Diseases and the Health and Environment Study (900 participants). As part of the parent study follow-up procedures, participants will be surveyed at periodic intervals for the incidence and recurrence of cardiovascular disease events. The study provides sufficient statistical power for assessing OSA and other SDB as risk factors for major cardiovascular events, including myocardial infarction and stroke.
990 citations
TL;DR: The FOSQ can be used to determine how disorders of excessive sleepiness affect patients' abilities to conduct normal activities and the extent to which these abilities are improved by effective treatment of DOES.
Abstract: This article reports the development of the functional outcomes of sleep questionnaire (FOSQ). This is the first self-report measure designed to assess the impact of disorders of excessive sleepiness (DOES) on multiple activities of everyday living. Three samples were used in the development and psychometric analyses of the FOSQ: Sample 1 (n = 153) consisted of individuals seeking medical attention for a sleep problem and persons of similar age and gender having no sleep disorder; samples 2 (n = 24) and 3 (n = 51) were composed of patients from two medical centers diagnosed with obstructive sleep apnea (OSA). Factor analysis of the FOSQ yielded five factors: activity level, vigilance, intimacy and sexual relationships, general productivity, and social outcome. Internal reliability was excellent for both the subscales (alpha = 0.86 to alpha = 0.91) and the total scale (alpha = 0.95). Test-retest reliability of the FOSQ yielded coefficients ranging from r = 0.81 to r = 0.90 for the five subscales and r = 0.90 for the total measure. The FOSQ successfully discriminated between normal subjects and those seeking medical attention for a sleep problem (T157 = -5.88, p = 0.0001). This psychometric evaluation of the FOSQ demonstrated parameters acceptable for its application in research and in clinical practice to measure functional status outcomes for persons with DOES. Thus, the FOSQ can be used to determine how disorders of excessive sleepiness affect patients' abilities to conduct normal activities and the extent to which these abilities are improved by effective treatment of DOES.
780 citations
TL;DR: It is concluded that even partial acute sleep loss delays the recovery of the HPA from early morning circadian stimulation and is thus likely to involve an alteration in negative glucocorticoid feedback regulation.
Abstract: Sleep curtailment constitutes an increasingly common condition in industrialized societies and is thought to affect mood and performance rather than physiological functions. There is no evidence for prolonged or delayed effects of sleep loss on the hypothalamo-pituitary-adrenal (HPA) axis. We evaluated the effects of acute partial or total sleep deprivation on the nighttime and daytime profile of cortisol levels. Plasma cortisol profiles were determined during a 32-hour period (from 1800 hours on day 1 until 0200 hours on day 3) in normal young men submitted to three different protocols: normal sleep schedule (2300-0700 hours), partial sleep deprivation (0400-0800 hours), and total sleep deprivation. Alterations in cortisol levels could only be demonstrated in the evening following the night of sleep deprivation. After normal sleep, plasma cortisol levels over the 1800-2300-hour period were similar on days 1 and 2. After partial and total sleep deprivation, plasma cortisol levels over the 1800-2300-hour period were higher on day 2 than on day 1 (37 and 45% increases, p = 0.03 and 0.003, respectively), and the onset of the quiescent period of cortisol secretion was delayed by at least 1 hour. We conclude that even partial acute sleep loss delays the recovery of the HPA from early morning circadian stimulation and is thus likely to involve an alteration in negative glucocorticoid feedback regulation. Sleep loss could thus affect the resiliency of the stress response and may accelerate the development of metabolic and cognitive consequences of glucocorticoid excess.
724 citations
TL;DR: Results indicate that unrecognized sleep-disordered breathing in the general population is linked to motor vehicle accident occurrence, and if the association is causal, unrecognized Sleep apnea may account for a significant proportion of motor vehicle accidents.
Abstract: Studies have consistently shown that sleep apnea patients have high accident rates, but the generalizability of the association beyond clinic populations has been questioned. The goal of this investigation was to determine if unrecognized sleep-disordered breathing in the general population, ranging from mild to severe, is associated with motor vehicle accidents. The sample comprised 913 employed adults enrolled in an ongoing study of the natural history of sleep-disordered breathing. Sleep-disordered breathing status was determined by overnight in-laboratory polysomnography and motor vehicle accident (MVA) history was obtained from a statewide data base of all traffic violations and accidents from 1988 to 1993. Men with five or more apneas and hypopneas per hour of sleep [apnea-plus-hypopnea index (AHI) > 5], compared to those without sleep-disordered breathing, were significantly more likely to have at least one accident in 5 years (adjusted odds ratio = 3.4 for habitual snorers, 4.2 for AHI 5-15, and 3.4 for AHI > 15). Men and women combined with AHI > 15 (vs. no sleep-disordered breathing) were significantly more likely to have multiple accidents in 5 years (odds ratio = 7.3). These results, free of clinic selection bias, indicate that unrecognized sleep-disordered breathing in the general population is linked to motor vehicle accident occurrence. If the association is causal, unrecognized sleep-disordered breathing may account for a significant proportion of motor vehicle accidents.
635 citations
TL;DR: The data suggest that 81% of habitually snoring children who have ADHD--25% of all children with ADHD--could have their ADHD eliminated if their habitual snoring and any associated SRBD were effectively treated.
Abstract: Children with sleep disorders are often inattentive or hyperactive, and some carry a diagnosis of attention deficit/hyperactivity disorder (ADHD) until their sleep disorder is detected. However, the potential behavioral impact of undiagnosed sleep disorders is not known. We sought to determine whether children with higher levels of inattention and hyperactivity more frequently have symptoms of sleep-related breathing disorders (SRBDs) or periodic limb movement disorder (PLMD). We surveyed parents of 2-18-year-old patients at a child psychiatry clinic (n = 70) and a general pediatrics clinic (n = 73) to assess the children's behavior, snoring, complaints of restless legs at night, and daytime sleepiness. A validated pediatric sleep questionnaire provided the explanatory variables, and a scale for inattention and hyperactivity, derived from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), provided the dependent variable. Habitual snoring was more frequent (33%) among children who carried a diagnosis of ADHD than among the other children at the psychiatry or general pediatric clinics (11 and 9%, respectively, chi-square test, p = 0.01). Snoring scores, derived from six snoring- and SRBD-related question items, were associated with higher levels of inattention and hyperactivity. The complaint of restless legs and a composite score for daytime sleepiness showed some evidence, though less consistent, of an association with inattention and hyperactivity. The association of snoring with inattention and hyperactivity suggests that SRBDs and perhaps other sleep disorders could be a cause of inattention and hyperactivity in some children. If a causal effect is present, our data suggest that 81% of habitually snoring children who have ADHD--25% of all children with ADHD--could have their ADHD eliminated if their habitual snoring and any associated SRBD were effectively treated.
530 citations
TL;DR: Analysis of night-to-night variability and nightly duration of continuous positive airway pressure (CPAP) therapy over the first 9 weeks of treatment and to determine when patients begin to establish a nonadherent pattern of use revealed that intermittent users continued to report significantly greater OSA symptoms posttreatment, suggesting that they continued to experience sleep disordered breathing.
Abstract: The purpose of this study was to examine the relationship between night-to-night variability and nightly duration of continuous positive airway pressure (CPAP) therapy over the first 9 weeks of treatment and to determine when patients begin to establish a nonadherent pattern of use. Data were analyzed from a study of daily CPAP use covertly monitored in 32 diagnosed patients with obstructive sleep apnea (OSA) using a microprocessor monitor encased in a CPAP machine. Patterns of CPAP use were bimodal, based on the frequency of nightly use. Approximately half the subjects were consistent users of CPAP, applying it > 90% of the nights for an average of 6.22 +/- 1.21 hours per night, while the other half comprised intermittent users who had a wide range of daily use averaging 3.45 +/- 1.94 hours per night on the nights CPAP was used. The percent of days skipped was significantly correlated with decreased nightly duration (rho = -0.73, p < 0.0001). Analysis of the night-to-night pattern of use revealed that the two groups differed significantly in the nightly duration of CPAP use by the fourth day of treatment (p = 0.001). Exploration of factors that potentially differentiate the two groups revealed no reliable predictors. However, intermittent users continued to report significantly greater OSA symptoms (snoring, snorting, and apnea) posttreatment, suggesting that they continued to experience sleep disordered breathing.
483 citations
TL;DR: Excessive daytime sleepiness in the general community is a newly recognized problem about which there is little standardized information and was related significantly but weakly to sleep-disordered breathing, the presence of insomnia, and reduced time spent in bed (insufficient sleep).
Abstract: Excessive daytime sleepiness in the general community is a newly recognized problem about which there is little standardized information. Our aim was to measure the levels of daytime sleepiness and the prevalence of excessive daytime sleepiness in a sample of Australian workers and to relate that to their self-reported sleep habits at night and to their age, sex, and obesity. Sixty-five percent of all 507 employees working during the day for a branch of an Australian corporation answered a sleep questionnaire and the Epworth sleepiness scale (ESS) anonymously. Normal sleepers, without any evidence of a sleep disorder, had ESS scores between 0 and 10, with a mean of 4.6 +/- 2.8 (standard deviation). They were clearly separated from the "sleepy" patients suffering from narcolepsy or idiopathic hypersomnia whose ESS scores were in the range 12-24, as described previously. ESS scores > 10 were taken to represent excessive daytime sleepiness, the prevalence of which was 10.9%. This was not related significantly to age (22-59 years), sex, obesity, or the use of hypnotic drugs but was related significantly but weakly to sleep-disordered breathing (frequency of snoring and apneas), the presence of insomnia, and reduced time spent in bed (insufficient sleep).
461 citations
TL;DR: The results show that the HLA association is as tight as previously reported (85-95%) when cataplexy is clinically typical or severe, and patients with mild, atypical, or no catAPlexy have a significantly increased DQB1*0602 frequency in comparison with ethnically matched controls.
Abstract: Narcolepsy is a sleep disorder associated with HLA DR15 (DR2) and DQB1*0602. We HLA typed 509 patients enrolled in a clinical trial for the drug modafinil and analyzed the results in relation to cataplexy, a symptom of narcolepsy characterized by muscle weakness triggered by emotions. The patients were either subjects with cataplexy who had a mean sleep latency (SL) of less than 8 minutes and two or more sleep onset rapid eye movement (REM) periods (SOREMPs) during a multiple sleep latency test, or narcoleptic patients without cataplexy but with a mean SL shorter than 5 minutes and two or more SOREMPs. The respective values of DRB1*15 (DR2) and DQB1*0602 as markers for narcolepsy were first compared in different ethnic groups and in patients with and without cataplexy. DQB1*0602 was found to be a more sensitive marker for narcolepsy than DRB1*15 across all ethnic groups. DQB1*0602 frequency was strikingly higher in patients with cataplexy versus patients without cataplexy (76.1% in 421 patients versus 40.9% in 88 patients). Positivity was highest in patients with severe cataplexy (94.8%) and progressively decreased to 54.2% in patients with the mildest cataplexy. A voluntary 50-item questionnaire focusing on cataplexy was also analyzed in 212 of the 509 HLA-typed patients. Subjects with definite cataplexy as observed by an experienced clinician were more frequently HLA DQB1*0602-positive than those with doubtful cataplexy, and the manifestations of cataplexy were clinically more typical in DQB1*0602-positive patients. These results show that the HLA association is as tight as previously reported (85-95%) when cataplexy is clinically typical or severe. We also found that patients with mild, atypical, or no cataplexy have a significantly increased DQB1*0602 frequency (40-60%) in comparison with ethnically matched controls (24%). These results could be explained by increased disease heterogeneity in the noncataplexy group or by a direct effect of the HLA DQB1*0602 genotype on the clinical expression of narcolepsy.
385 citations
TL;DR: The effects reported here may be underestimates of the efficacy of exercise for enhancing sleep among people with sleep disturbances, as previous narrative reviews suggested that exercise elicits larger changes in sleep than those quantified in this meta-analysis.
Abstract: We used meta-analytic methods to examine the influence of acute exercise on sleep. Thirty-eight studies were reviewed yielding 211 effects on 401 subjects. Mean effect sizes were calculated for sleep onset latency (SOL), stage 2, slow-wave sleep (SWS), rapid eye movement (REM) sleep, REM latency (REM-L), total sleep time (TST), and wakefulness after sleep onset (WASO). Moderating influences of subject fitness, heat load, exercise duration, time of day, associated light environment (i.e. indoor or outdoor), sleep schedule, and the scientific quality of the studies were examined. Effect sizes for SWS, REM, REM-L, and TST were moderate [0.18-0.52 standard deviation (SD)] and their associated 95% confidence intervals did not include zero. Exercise duration and time of day were the most consistent moderator variables. In contrast with previous hypotheses, heat load had little influence on sleep. The results of our quantitative synthesis of the literature are inconsistent with previous narrative reviews (1,2) which suggested that exercise elicits larger changes in sleep than those quantified in this meta-analysis. A major delimitation of published studies on the effects of acute exercise has been an exclusive focus on good sleepers. Hence, the effects we report herein may be underestimates of the efficacy of exercise for enhancing sleep among people with sleep disturbances.
TL;DR: It is indicated that sleep-disordered breathing is more common, especially among minorities, than had been previously believed, but less co-morbidity may be associated.
Abstract: Previous research has offered widely varying prevalence estimates for sleep apnea in the population, leaving uncertain which breathing patterns are abnormal. To explore the distribution of sleep apnea in the population and its co-morbidities, random telephone dialing was used between 1990 and 1994 to recruit subjects for a prevalence survey of sleep-disordered breathing in San Diego adults. Events from which blood oxygen desaturations ≥4% resulted were monitored with home recording instruments, usually for three consecutive nights. Among 190 women ages 40–64 years, a median of 4.3 desaturation events per hour of sleep were observed. A higher median of 6.7 events per hour was observed among 165 men. Frequencies were much higher among members of minority groups, leading to a standard estimate that 16.3% of U.S. Hispanics and racial minorities have ≥20 events/hour as compared to 4.9% of non-Hispanic Whites ages 40–64. Obesity indicated by body-mass index was the most important demographic predictor of sleep-disordered breathing, followed by age, male gender, and ethnicity. Quality of well-being was not significantly impaired in subjects with more respiratory events; however, there was some increase in blood pressure and wake-within-sleep associated with sleep-disordered breathing. This survey indicates that sleep-disordered breathing is more common, especially among minorities, than had been previously believed, but less co-morbidity may be associated.
TL;DR: It is concluded that theactigraphy is the most feasible technique for studying sleep and wake activity in demented nursing-home patients by testing the reliability of a wrist-activity monitor, the Actillume, against traditional sleep measurements and against observations of nursing- home patients.
Abstract: Actigraphy is applicable for studying sleep in populations who are unable to tolerate traditional sleep-recording techniques, such as nursing-home patients who are infirm and demented This study examined whether actigraphy can accurately reflect sleep/wake activity in this population by testing the reliability of a wrist-activity monitor, the Actillume, against traditional sleep measurements and against observations of nursing-home patients Data from the Actillume are presented as two variables, the sum (total of all activity movements within the prescribed epoch) and the maximum activity (the largest or maximum movement recorded during the prescribed epoch), and by electroencephalogram (EEG) One difficulty in making comparisons was that the EEG records showed diffuse slowing, making it extremely difficult to score sleep/wake activity and making it difficult to use the EEG as a "gold standard" Nevertheless, the correlation for total sleep time from EEG and Actillume was r = 091 (p < 0001) for sum activity and r = 081 for maximum activity (p < 0005) Correlations for percent sleep were r = 078 (p < 001) for maximum activity and r = 061 for sum activity The comparison of sleep/wake determined by the Actillume vs observations resulted in a sensitivity of 87% and specificity of 90% We conclude that the Actillume is the most feasible technique for studying sleep and wake activity in demented nursing-home patients
TL;DR: This paper is a review of the literature on the use of polysomnography in the diagnosis of sleep disorders in the adult based on a search of MEDLINE from January 1966 through April 1996 and provides the background for the accompanying ASDA Standards of Practice Committee's Parameters for the Practice of Sleep Medicine in North America.
Abstract: This paper is a review of the literature on the use of polysomnography in the diagnosis of sleep disorders in the adult. It is based on a search of MEDLINE from January 1966 through April 1996. It has been reviewed and approved by the Board of Directors of the American Sleep Disorders Association and provides the background for the accompanying ASDA Standards of Practice Committee's Parameters for the Practice of Sleep Medicine in North America. The diagnostic categories reviewed are: sleep-related breathing disorders; other respiratory disorders; narcolepsy; parasomnias and sleep-related epilepsy; restless legs syndrome and periodic limb movement disorders: insomnia; and circadian rhythm sleep disorders. Where appropriate, previously published practice parameters papers are cited and discussed. The relevant published peer-reviewed literature used as the basis for critical decisions was compiled into accompanying evidence tables and is analyzed in the text. In the section on the assessment of sleep apnea syndrome, options for estimating pretest probability to select high risk patients are also reviewed. Sleep-testing procedures other than standard polysomnography are also addressed (daytime polysomnography, split-night studies, oximetry, limited full respiratory recordings, and less-than-full respiratory recording) and treatment-related follow-up studies are discussed.
TL;DR: It is concluded that despite a longer TST, females report insufficient sleep, EDS, DMS, and the absence of feeling refreshed in the morning more frequently than males, which cannot explain the gender differences in sleep disturbances seen in this population.
Abstract: To study the prevalence of reported sleep disturbances and the association between these complaints and psychological status, 529 randomly selected subjects aged 20-45 years were questioned about their sleep symptoms and psychological status by means of questionnaires. In this young population, feeling refreshed in the morning almost every day was reported by only 15.3%. Females reported a significantly longer mean total sleep time (TST) than males (F: 425 +/- 58 minutes, M: 403 +/- 50 minutes; p or = 3/week) (F: 20.1%, M: 10.4%; p < 0.01), the absence of feeling refreshed in the morning (F: 36.2%, M: 26.8%; p < 0.05), and excessive daytime sleepiness (EDS) (F: 23.3%, M: 15.9%; p < 0.05) were significantly more common among females. According to the Hospital Anxiety and Depression scale, females suffered from anxiety more frequently than males (F: 32.8%, M: 18.9%; p < 0.001). An association was found between anxiety and many sleep disturbances. After making adjustments for age, smoking, snoring, gender and psychological status by means of multiple regression, the gender differences mentioned above remained significant. We conclude that despite a longer TST, females report insufficient sleep, EDS, DMS, and the absence of feeling refreshed in the morning more frequently than males. The higher prevalence of anxiety among females alone cannot explain the gender differences in sleep disturbances seen in this population.
TL;DR: Evidence is reviewed that changes in the quality, timing, and quantity of REM sleep that characterize narcolepsy, REM sleep behavior disorder, and neurodegenerative and affective disorders (depression and schizophrenia) reflect 1) changes in responsiveness of cells in the PPN region governed by these afferents; or 2) increase or decrease in PPN cell number.
Abstract: The pedunculopontine (PPN) region of the upper brainstem is recognized as a critical modulator of activated behavioral states such as wakefulness and rapid eye movement (REM) sleep. The expression of REM sleep-related physiology (e.g. thalamocortical arousal, ponto-geniculate-occipital (PGO) waves, and atonia) depends upon a subpopulation of PPN neurons that release acetylcholine (ACh) to act upon muscarinic receptors (mAChRs). Serotonin's potent hyperpolarization of cholinergic PPN neurons is central to present working models of REM sleep control. A growing body of experimental evidence and clinical experience suggests that the responsiveness of the PPN region, and thereby modulation of REM sleep, involves closely adjacent glutamatergic neurons and alternate afferent neurotransmitters. Although many of these afferents are yet to be defined, dopamine-sensitive GABAergic pathways exiting the main output nuclei of the basal ganglia and adjacent forebrain nuclei appear to be the most conspicuous and the most likely to be clinically relevant. These GABAergic pathways are ideally sited to modulate the physiologic hallmarks of REM sleep differentially (e.g. atonia versus cortical activation), because each originates from a functionally unique forebrain circuit and terminates in a unique pattern upon brain stem neurons with unique membrane characteristics. Evidence is reviewed that changes in the quality, timing, and quantity of REM sleep that characterize narcolepsy, REM sleep behavior disorder, and neurodegenerative and affective disorders (depression and schizophrenia) reflect 1) changes in responsiveness of cells in the PPN region governed by these afferents; 2) increase or decrease in PPN cell number; or 3) mAChRs mediating increased responsiveness to ACh derived from the PPN. Auditory evoked potentials and acoustic startle responses provide means independent from recording sleep to assess pathophysiologies affecting the PPN and its connections and thereby complement investigations of their role in affecting daytime functions (e.g. arousal and attention).
TL;DR: It is confirmed that circadian rhythms in nursing-home patients are disturbed with more disturbance in the severely demented, and much of the disturbance may be related not just to age but to mental status.
Abstract: We measured 24-hour circadian-rhythm patterns of activity and sleep/wake activity in a group of nursing-home patients (58 women and 19 men with a mean age of 85.7 years). Severely demented patients were contrasted with a composite group of moderate y, mild, or not-demented patients. Sleep/wake activity and light exposure were recorded with the Actillume recorder. Cosinor analyses were computed to determine the mesor, amplitude, acrophase, and circadian quotient of the activity rhythms. The diagnosis of dementia was based on the Mini Mental Examination and on examination of medical records. Sleep was extremely fragmented in both groups of nursing-home patients. Severely demented patients slept more both at night and during the day, but there were no significant differences in the number of awakenings during the night or in the number of naps during the day when compared to the composite group of moderate, mild, or no-dementia patients. The severely demented group had lower activity mesor, more blunted amplitude, and were more phase delayed (i.e. had later acrophases) than the other group. In addition, the severely demented patients spent less time exposed to bright light. These results confirm that circadian rhythms in nursing-home patients are disturbed with more disturbance in the severely demented. Much of the disturbance may be related not just to age but to mental status.
TL;DR: Improvements in methods to detect and quantitate changes in the cortical electroencephalogram (EEG) may better define the relationship between arousal and apnea termination, and result in improved criteria for identifying EEG changes of clinical significance.
Abstract: The mechanisms by which respiratory stimuli induce arousal from sleep and the clinical significance of these arousals have been explored by numerous studies in the last two decades. Evidence to date suggests that the arousal stimulus in nonrapid eye movement sleep (NREM) is related to the level of inspiratory effort rather than the individual stimuli that contribute to ventilatory drive. A component of the arousal stimulus proportional to the level of inspiratory effort may originate in mechanoreceptors either in the upper airway or respiratory pump. Medullary centers responsible for ventilatory drive may also send a signal proportionate to the level of drive to higher centers in the brain which are responsible for arousal. Thus, the arousal stimulus may consist of multiple components, each increasing as inspiratory effort increases. The level of effort triggering arousal is an index of the arousability of the brain (arousal threshold). A deeper stage of sleep, central nervous system depressants, prior sleep fragmentation, and the presence of obstructive sleep apnea (OSA) have been observed to increase the arousal threshold to airway occlusion. Less information is available concerning the mechanisms of arousal from rapid eye movement (REM) sleep. While REM sleep is associated with the longest obstructive apneas in patients with OSA, normal human subjects appear to have a similar or lower arousal threshold to respiratory stimuli in REM compared to NREM sleep. Recent studies have challenged the assumption that the termination of all obstructive apnea is dependent on arousal from sleep. Improvements in methods to detect and quantitate changes in the cortical electroencephalogram (EEG) may better define the relationship between arousal and apnea termination. This may result in improved criteria for identifying EEG changes of clinical significance. While little is known concerning the mechanisms of arousal in central sleep apnea, arousal may play an important role in inducing this type of apnea in some patients.
TL;DR: In conclusion, weight lifting exercise was effective in improving subjective sleep quality, depression, strength, and quality of life without significantly changing habitual activity.
Abstract: We tested the hypothesis that exercise would improve subjective sleep quality and activity in depressed elders. A 10-week randomized controlled trial was utilized. Participants consisted of a volunteer sample, aged > 60 with a diagnosis of major or minor depression or dysthymia. A total of 32 subjects aged 60-84 years with a mean age of 71.3 +/- 1.2 years was used. Intervention consisted of a supervised weight-training program three times a week or an attention-control group. Main outcome measures were Pittsburgh Subjective Sleep Quality Index (PSQI), Likert Scale of Subjective Sleep Quality and Quantity. Paffenbarger Activity Index. Geriatric Depression Scale (GDS). Beck Depression Inventory (BDI), Hamilton Rating Scale of Depression (HRSD), and the Medical Outcomes Survey Short Form 36 (SF-36). Results showed that exercise significantly improved all subjective sleep-quality and depression measures. Depression measures were reduced by approximately twice that of controls. Habitual activity was not significantly increased by exercise. Quality of life subscales significantly improved. In a forward stepwise multiple regression, percent improvement in GDS and percent increase in strength remained significant predictors of the improvement in total PSQI score (r = 0.71, p = 0.0002). In conclusion, weight lifting exercise was effective in improving subjective sleep quality, depression, strength, and quality of life without significantly changing habitual activity.
TL;DR: The results suggest that the MSLT cannot be used in isolation to confirm or exclude narcolepsy, is indicated only in selected patients with excessive daytime sleepiness, and is most valuable when interpreted in conjunction with clinical findings.
Abstract: Since its introduction, the multiple sleep latency test (MSLT) has played a major role in the diagnosis of narcolepsy. We assessed its diagnostic value in a series of 2,083 subjects of whom 170 (8.2%) were diagnosed with narcolepsy. The sensitivity of the combination of two or more sleep onset rapid eye movement (REM) periods (SOREMPs) with a mean sleep latency of < 5 minutes on an initial MSLT was 70% with a specificity of 97%, but 30% of all subjects with this combination of findings did not have narcolepsy. In some narcoleptics who had more than one MSLT, the proportion of naps with SOREMPs varied substantially from the initial MSLT to the follow-up test. The highest specificity (99.2%) and positive predictive value (PPV) (87%) for MSLT findings was obtained with the criteria of three or more SOREMPs combined with a mean sleep latency of < 5 minutes, but the sensitivity of this combination was only 46%. The combination of a SOREMP with a sleep latency < 10 minutes on polysomnography yielded a specificity (98.9%) and PPV (73%) almost equal to those obtained from combinations of MSLT findings, but the sensitivity was much lower. Our results suggest that the MSLT cannot be used in isolation to confirm or exclude narcolepsy, is indicated only in selected patients with excessive daytime sleepiness, and is most valuable when interpreted in conjunction with clinical findings.
TL;DR: It is concluded that the nasal cannula reliably detects respiratory events seen by thermistor, and it is proposed that respiratory monitoring during NPSG with nasal cannulas significantly improves event detection and classification over that with thermistor.
Abstract: Recording of respiratory airflow is an integral part of polysomnography (NPSG). It is conventionally monitored with a thermistor that measures temperature as a surrogate of flow. The subjectivity of interpreting hypopnea from this signal has prompted us to measure nasal airflow directly with a simple pneumotachograph consisting of a standard nasal cannula connected to a 2-cm H2O pressure transducer. We manually analyzed respiratory events using simultaneous thermistor and nasal cannula in 11 patients with obstructive sleep apnea syndrome (OSAS) and 9 with upper airway resistance syndrome (UARS). Definite events were scored separately for each signal when amplitude was 10 seconds. Events were also scored on the nasal cannula signal when the flattened shape of the signal suggested flow limitation, and these were tabulated separately. Definite events in one signal were tabulated by whether the other signal showed a definite event or not. In addition, nasal cannula events were compared to a more liberal thermistor criterion (any change in the signal for > or = 2 breaths). Visually, events were more easily recognized on the nasal cannula signal than on the thermistor signal. In OSAS, 1,873 definite thermistor events were detected. Of these, 99.1% were detected by nasal cannula, and 0.9% were missed. Of 3,541 definite nasal cannula events, 51.9% were detected by definite thermistor criteria; 75.0% were detected by liberal thermistor criteria; 25.0% were missed. In UARS, 123 definite thermistor events were detected. Of these, 89.4% were detected by nasal cannula and 10.6% were missed. Nine hundred and three nasal cannula events were detected. However, only 17.2% of these were detected by definite thermistor criteria; 38.6% were detected by liberal thermistor criteria; 61.4% were completely undetected by thermistor. When events identified on the nasal cannula by flow limitation alone were excluded, the thermistor detected 30.1% of events by definite criteria and 78.6% by liberal criteria, still leaving 21.4% completely undetected by the thermistor. We conclude that the nasal cannula reliably detects respiratory events seen by thermistor. Additional events (including some characterized only by flow limitation) that help define the UARS, were recognized by nasal cannula but often completely missed by thermistor. We propose that respiratory monitoring during NPSG with nasal cannula significantly improves event detection and classification over that with thermistor.
TL;DR: It is concluded that simple, inexpensive efforts to improve compliance with CPAP can be effective, especially when applied at the start of CPAP treatment, but optimal intervention may vary with certain patient characteristics.
Abstract: Effectiveness of continuous positive airway pressure (CPAP) as a treatment for obstructive sleep apnea can be limited by poor compliance, but little is known about how to improve compliance. We performed a randomized, controlled clinical trial among 33 subjects of two interventions to improve compliance. One group of subjects received weekly phone calls to uncover any problems and encourage use, another received written information about sleep apnea and the importance of regular CPAP use, and a third served as control subjects. We found that intervention improved CPAP compliance (p = 0.059) and that the effect was particularly strong when intervention occurred during the first month of CPAP treatment (p = 0.004). Although the sample size did not allow definitive investigation of other explanatory variables, subjects with lower levels of education or those with relatives who used CPAP may have benefited from intervention more than other subjects. We conclude that simple, inexpensive efforts to improve compliance with CPAP can be effective, especially when applied at the start of CPAP treatment, but optimal intervention may vary with certain patient characteristics.
TL;DR: "parasomnia overlap disorder" is a treatable condition that emerges in various clinical settings and can be understood within the context of current knowledge on parasomnias and motor control/dyscontrol during sleep.
Abstract: A series of 33 patients with combined (injurious) sleepwalking, sleep terrors, and rapid eye movement (REM) sleep behavior disorder (viz. "parasomnia overlap disorder") was gathered over an 8-year period. Patients underwent clinical and polysomnographic evaluations. Mean age was 34 +/- 14 (SD) years; mean age of parasomnia onset was 15 +/- 16 years (range 1-66); 70% (n = 23) were males. An idiopathic subgroup (n = 22) had a significantly earlier mean age of parasomnia onset (9 +/- 7 years) than a symptomatic subgroup (n = 11) (27 +/- 23 years, p = 0.002), whose parasomnia began with either of the following: neurologic disorders, n = 6 [congenital Mobius syndrome, narcolepsy, multiple sclerosis, brain tumor (and treatment), brain trauma, indeterminate disorder (exaggerated startle response/atypical cataplexy)]; nocturnal paroxysmal atrial fibrillation, n = 1; posttraumatic stress disorder/major depression, n = 1; chronic ethanol/amphetamine abuse and withdrawal, n = 1; or mixed disorders (schizophrenia, brain trauma, substance abuse), n = 2. The rate of DSM-III-R (Diagnostic and Statistical Manual, 3rd edition, revised) Axis 1 psychiatric disorders was not elevated; group scores on various psychometric tests were not elevated. Forty-five percent (n = 15) had previously received psychologic or psychiatric therapy for their parasomnia, without benefit. Treatment outcome was available for n = 20 patients; 90% (n = 18) had substantial parasomnia control with bedtime clonazepam (n = 13), alprazolam and/or carbamazepine (n = 4), or self-hypnosis (n = 1). Thus, "parasomnia overlap disorder" is a treatable condition that emerges in various clinical settings and can be understood within the context of current knowledge on parasomnias and motor control/dyscontrol during sleep.
TL;DR: Subjects with mild SDB may manifest a vigilance deficit in the absence of substantial sleepiness, and subjects with a mildly elevated RDI do not appear to suffer appreciable deficits in more complex neuropsychological processes.
Abstract: Although a broad range of neuropsychological deficits has been reported in patients with severe sleep disordered breathing (SDB), little is known about the impact of mild SDB on neuropsychological performance. In this study, we compared neuropsychological test performance in two groups of carefully screened volunteers who differed clearly according to the respiratory disturbance index (RDI). Controls (n = 20) were identified on the basis of an RDI < 5; cases (n = 32) had an RDI in the range of 10-30. Cases and controls were well matched with regard to IQ, age, and sex. Cases had significantly more self-reported snorting and apneas and a higher body mass index than controls but did not differ according to sleepiness as measured by either the multiple sleep latency test or the Epworth sleepiness scale. An extensive battery of neuropsychological and performance tests was administered after an overnight sleep study. Cases performed significantly more poorly on a visual vigilance task (perceptual sensitivity, d': 2.24 +/- 0.64 vs. 2.70 +/- 0.53, p = 0.01, for cases and controls, respectively) and a test of working memory, the Wechsler adult intelligence scale-revised digits backwards test (6.12 +/- 2.20 vs. 7.55 +/- 2.22, p = 0.02), than controls. The groups did not differ in their performance on other tests of memory, information processing, and executive functioning. In summary, subjects with mild SDB may manifest a vigilance deficit in the absence of substantial sleepiness. Subjects with a mildly elevated RDI (10-30) without sleepiness do not appear to suffer appreciable deficits in more complex neuropsychological processes (e.g. executive functions).
TL;DR: It is concluded that melatonin may benefit sleep by correcting circadian phase abnormalities and/or by a modest direct soporific effect that is most evident following daytime administration to younger subjects.
Abstract: Differing conclusions regarding the sleep-promoting effects of melatonin may be the result of the broad range of doses employed (0.1-2000 mg), the differing categories of subjects tested (normal subjects, insomniac patients, elderly, etc.), and the varying times of administration (for daytime vs. nighttime sleep). We conclude that melatonin may benefit sleep by correcting circadian phase abnormalities and/or by a modest direct soporific effect that is most evident following daytime administration to younger subjects. We speculate that these effects are mediated by interactions with specific receptors concentrated in the suprachiasmatic nucleus (SCN) that result in resetting of the circadian pacemaker and/or attenuation of an SCN-dependent circadian alerting process.
TL;DR: It is suggested that melatonin may be an effective method of promoting sleep for individuals attempting to sleep during their subjective day, such as shiftworkers and individuals rapidly traveling across multiple time zones.
Abstract: Sleep-promoting and hypothermic effects of orally administered melatonin during the daytime were assessed using a placebo-controlled, double-blind, cross-over design. Following a 7-hour nighttime sleep opportunity, healthy young male subjects (n = 8) were given either a placebo or one of three doses of melatonin (1 mg, 10 mg, and 40 mg) at 1000 hours. Sleep was polygraphically assessed in a 4-hour sleep opportunity from 1200 to 1600 hours. All doses of melatonin significantly shortened the latency to sleep onset. Melatonin also significantly increased total sleep time and decreased wake after sleep onset (WASO). Sleep following melatonin administration contained significantly more stage 2 and less stage 3-4, while stage 1 and rapid eye movement (REM) sleep were unaffected. In addition to the sleep-promoting effects, melatonin completely suppressed the normal diurnal rise of core body temperature. These data suggest that melatonin may be an effective method of promoting sleep for individuals attempting to sleep during their subjective day, such as shiftworkers and individuals rapidly traveling across multiple time zones.
TL;DR: Considering the frequency of nightmares in an adult insomniac population and the significant relationship between nightmares and certain subgroups, nightmares should receive more attention in patients, especially women complaining of disrupted sleep, as high rates of psychiatric disorders were found in this specific group.
Abstract: A representative sample of 5,622 subjects between 15 and 96 years of age from the noninstitutionalized general population of France were interviewed by telephone concerning their sleeping habits and sleep disorders. The interviews were conducted using the Sleep-Eval knowledge-based system, a nonmonotonic, level 2 expert system with a causal reasoning mode. Questions investigated nightmares, based on the Diagnostic and Statistical Manual, fourth edition (DSM-IV), definition, psychopathological traits, and included 12 other groups of information, including sociodemographics, sleep-wake schedule, daytime functioning, psychiatric and medical history, and drug intake. The data from 1,049 subjects suffering from insomnia were considered for this analysis. Bivariate analyses, logistic regression analysis using the method of indicator contrasts for the investigation of independent variables, and calculation of significant odds ratios were performed. Nightmares were reported in 18.3% of the surveyed insomniac population and were two times higher in women than in men. The following factors were found to be significantly associated with nightmares 1) sleep with many awakenings, 2) abnormally long sleep onset, 3) daytime memory impairment following poor nocturnal sleep, 4) daytime anxiety following poor nocturnal sleep, and 5) being a woman. There was a strong association between the report of nightmares in women and the presence of either a depressive disorder, anxiety disorder, or both disorders together. When the effects of major psychiatric disorders were controlled for, nightmares were significantly associated with being a woman, feeling depressed after a poor night's sleep, and complaining of a long sleep latency. Nightmares can lead to a negative conditioning toward sleep and to chronic sleep complaints. Considering the frequency of nightmares in an adult insomniac population and the significant relationship between nightmares and certain subgroups, nightmares should receive more attention in patients, especially women complaining of disrupted sleep, as high rates of psychiatric disorders were found in this specific group.
TL;DR: Before attributing sleepiness in epilepsy patients to antiepileptic medications or uncontrolled seizures, clinicians should consider the possibility of a coexisting sleep disorder.
Abstract: Sleepiness, a common complaint of epilepsy patients, is frequently attributed to antiepileptic medications. To determine predictors of subjective sleepiness in epilepsy patients, we gave self-administered, validated surveys of sleepiness [Epworth sleepiness scale (our major outcome measure)] and sleep apnea [sleep apnea scale of the sleep disorders questionnaire (SA/SDQ)] to 158 epilepsy patients and 68 neurology patients without epilepsy (controls). An elevated Epworth score (>10) was more likely in epilepsy patients compared to controls after controlling for age and gender (p 0.10) of elevated Epworth score. Before attributing sleepiness in epilepsy patients to antiepileptic medications or uncontrolled seizures, clinicians should consider the possibility of a coexisting sleep disorder.
TL;DR: It is concluded that BRM has some important advantages as a simple, minimally invasive method for monitoring sleep and was more accurate in determining SOL and subsequent wakefulness than polysomnography.
Abstract: Two alternative methods for detecting sleep, wrist actigraphy (ACT) and behavioral response monitoring (BRM), were compared to polysomnography (PSG). In the BRM paradigm, a threshold intensity visual or auditory stimulus generated by a palm-top computer was presented about once per minute, and subjects pressed a microswitch if the stimulus was detected. A response within 5 seconds of the stimulus was scored as "wake" and a failure to respond as "sleep." Four males and four females underwent two nights of simultaneous in-home PSG, BRM, and ACT. Each night, subjects underwent a protocol designed to generate five sleep latency trials. Subjects were awakened by alarm clocks at approximately 1-hour intervals and remained awake for 10 minutes before returning to bed for another sleep onset latency (SOL) trial. Minute-by-minute comparisons were made for PSG versus ACT and BRM. All measures were fairly sensitive in detecting sleep, but BRM was more accurate in determining SOL and subsequent wakefulness. Behavioral response monitoring using a tone resulted in more responses and arousals prior to and during light stages of sleep than BRM using a light. It is concluded that BRM has some important advantages as a simple, minimally invasive method for monitoring sleep.
TL;DR: It is suggested that a rapid decline in core body temperature increases the likelihood of sleep initiation and may facilitate an entry into the deeper stages of sleep.
Abstract: Relationships between changes in the slope of the body temperature (BT) and the initiation of sleep were examined in 44 subjects ranging from 19 to 82 years of age. Following an adaptation night, subjects remained in the laboratory for a baseline night and 72 hours in temporal and social isolation, with strictly limited behavioral options ("disentrainment") during which continuous electroencephalograph (EEG) and BT were recorded. Polysomnographic sleep variables (e.g. sleep onset, percentage of each sleep stage) were determined for nighttime sleep periods at baseline and during the disentrainment period. Periods of the BT curve surrounding these sleep bouts were examined for minute to minute changes, and the time at which the maximum rate of decline (MROD) in temperature occurred was compared with the time of sleep onset (SO) and sleep quality parameters. On the baseline night, the MROD occurred, on average, 60 minutes prior to SO. During disentrainment, the MROD occurred, on average, 44 minutes prior to SO. The proximity of MROD to SO did not affect subsequent sleep quality on the baseline night, but during disentrainment, there were significant correlations between the interval from MROD to sleep onset and the amount of slow-wave sleep (SWS) obtained during the sleep bout. There were no significant age differences on variables related to MROD on baseline night, but the timing of both MROD and SO were significantly advanced in older, relative to younger, subjects during the disentrainment period. It is suggested that a rapid decline in core body temperature increases the likelihood of sleep initiation and may facilitate an entry into the deeper stages of sleep.