Percentage Of Slow-wave Sleep Research Articles

Defining the Occurrence and Influence of Alpha-Delta Sleep in Chronic Fatigue Syndrome

Patients with chronic fatigue syndrome (CFS) present a disordered sleep pattern and frequently undergo polysomnography to exclude a primary sleep disorder. Such studies have shown reduced sleep efficiency, a reduction of deep sleep, prolonged sleep initiation, and alpha-wave intrusion during deep sleep. Deregulation of the 2-5A synthetase/RNase L antiviral pathway and a potential acquired channelopathy are also found in a subset of CFS patients and could lead to sleep disturbances. This article compiles a large sleep study database on CFS patients and correlates these data with a limited number of immune parameters as it has been thought that RNase L could be associated with these sleep disturbances. Forty-eight patients who fulfilled 1994 Centers for Disease Control and Prevention criteria for CFS underwent extensive medical evaluation, routine laboratory testing, and a structured psychiatric interview. Subjects then completed a complaint checklist and a two-night polysomnographic investigation. RNase L analysis was performed by gel electrophoresis using a radiolabeled 2',5'-oligoadenylate trimer. Basic descriptive statistical parameters were calculated. Patients experienced a prolonged sleep latency, showed a low sleep efficiency index, and had a low percentage of slow wave sleep. The present alpha-delta intrusion correlated with anxiety; no correlations appeared, however, between alpha-delta sleep and immunologic parameters, including RNase L. The main findings are 1) validation of sleep latency problems and other sleep disturbances as already suggested by several authors; 2) alpha-delta intrusion seems associated with anxiety; and 3) elevated RNase L did not correlate with alpha-delta sleep.

Lack of efficacy of music to improve sleep: A polysomnographic and quantitative EEG analysis

An increasing number of studies have been examining non-pharmacological methods to improve the quality of sleep, including the use of music and other types of auditory stimulation. While many of these studies have found significant results, they suffer from a combination of subjective self-report measures as the primary outcome, a lack of proper controls, often combine music with some type of relaxation therapy, or do not randomise subjects to control and treatment conditions. It is therefore difficult to assess the efficacy of music to induce or improve sleep. The present study therefore examined the effects of music using standard polysomnographic measures and quantitative analysis of the electroencephalogram, along with subjective ratings of sleep quality. In addition, a tones condition was used to compare any effects of music with the effects of general auditory stimulation. Using a counter-balanced within-subjects design, the music was not significantly better than the tones or control conditions in improving sleep onset latency, sleep efficiency, wake time after sleep onset, or percent slow wave sleep, as determined by objective physiological criteria.

Sleep Disturbance in Patients with Lichen Simplex Chronicus and Its Relationship to Nocturnal Scratching: A Case Control Study

Lichen simplex chronicus (LSC) is a common pruritic disorder resulting from repeated rubbing and scratching. Nighttime pruritus is a common feature in LSC and may disrupt the sleep pattern. The aim of this study is to determine whether there are sleep abnormalities in patients with LSC. Fifteen patients with LSC and 15 age-, sex- and body mass index-matched control subjects were enrolled in the study. No participant had any other medical or psychiatric illness. All subjects were evaluated by overnight polysomnography, scratch electrodes, Epworth sleepiness scale and a general questionnaire for demographic data and sleep problems. There were no significant differences in the groups for total sleep time, sleep efficiency, sleep latency, rapid eye movement (REM) latency, percentage of stage 1 non-REM sleep and REM sleep. The percentage of stage 2 non-REM sleep was higher (P < 0.05) and the percentage of slow wave sleep (stages 3 and 4) was lower in the study group (P < 0.05) than in the controls. The patient group had a mean of 15.9 +/- 7.5 arousal index and 22.8 +/- 14.1 awakenings compared with 9.5 +/- 3.1 and 10.4 +/- 3.9, respectively, in the controls (P < 0.05, P < 0.01, respectively). Arousals of patients were mainly observed in non-REM sleep. The number of scratching bouts ranged from 6 to 20 per night. Scratching episodes were observed frequently during stage 2 non-REM sleep. Polysomnographic findings of patients with LSC demonstrated that sleep structure is disturbed by arousals and awakenings related to scratching bouts during sleep.

Sleep-Facilitating Effect of Exogenous Melatonin in Healthy Young Men and Women Is Circadian-Phase Dependent

To investigate the effects of a physiologic and a pharmacologic dose of exogenous melatonin on sleep latency and sleep efficiency in sleep episodes initiated across a full range of circadian phases. Double-blind placebo-controlled parallel-group design in a 27-day forced desynchrony paradigm with a 20-hour scheduled sleep-wake cycle. Private suite of a general clinical research center, in the absence of time-of-day information. Thirty-six healthy, 18- to 30-year-old, men (n = 21) and women (n = 15). Oral melatonin (0.3 mg or 5.0 mg) or identical-appearing placebo was administered 30 minutes prior to each 6.67-hour sleep episode during forced desynchrony. Both doses of melatonin improved polysomnographically determined sleep efficiency from 77% in the placebo group to 83% for sleep episodes occurring during circadian phases when endogenous melatonin was absent. However, this remained below the average sleep efficiency of 88% observed during sleep episodes scheduled during the circadian night, when endogenous melatonin was present. Melatonin did not significantly affect sleep initiation or core body temperature. Melatonin appeared to maintain efficacy across the study and did not significantly affect percentages of slow-wave sleep or rapid eye movement sleep. Exogenous melatonin administration possesses circadian-phase-dependent hypnotic properties, allowing for improved consolidation of sleep that occurs out of phase with endogenous melatonin secretion during the circadian night. The results support the hypothesis that both exogenous and endogenous melatonin attenuate the wake-promoting drive from the circadian system.

Sex and Age Differences in Sleep Macroarchitecture in Childhood and Adolescent Depression

To evaluate age and sex differences in sleep macroarchitecture in children and adolescents with major depressive disorder. Ninety-seven (50 F, 47 M) symptomatic unmedicated depressed outpatients were compared with 76 healthy controls (42 F, 34 M) matched for age and sex. Participants spent 2 consecutive nights in the sleep laboratory. One hundred seventy-three children and adolescents, aged 8 to 18 years. Significant group-by-age-by-sex interactions were evident for total sleep period, percentage of Stage 1 sleep, percentage of Stage 2, percentage of slow-wave sleep, and rapid eye movement (REM) sleep latency. The depressed adolescent boys had the greatest sleep disturbance with the highest amount of percentage of Stage 1 sleep, the shortest REM latency, and the least percentage of slow-wave sleep and number of minutes of slow-wave sleep in the first non-REM period. There were minimal age differences in sleep parameters between depressed children and adolescent girls. Within age groups, the sex differences were minimal in the healthy controls. The sex differences within the depressed group were substantially larger than controls. These findings suggest a differential developmental influence on sleep in early-onset depression that is heavily dependent on sex. Sex differences are substantially smaller in healthy individuals compared with those with depression, in agreement with previous studies in depressed adults.

First Experience of Using New Adaptive Servo-Ventilation Device for Cheyne-Stokes Respiration With Central Sleep Apnea Among Japanese Patients With Congestive Heart Failure Report of 4 Clinical Cases

Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) in congestive heart failure (CHF) is generally considered a poor prognostic indicator, but treatment of CSR-CSA using an adaptive servo-ventilation (ASV) device has been developed. This is the first evaluation of its use in the management of CSR-CSA in Japanese CHF patients. Four CHF patients with CSR-CSA that was unresponsive to conventional positive airway pressure (CPAP) underwent 3 nights of polysomnography: baseline, CPAP or bi-level PAP, and on the ASV. The apnea - hypopnea index (AHI) and central-AHI (CAHI) were markedly improved on ASV (AHI 62.7+/-10.1 to 5.9+/-2.2 /h, p=0.0006, CAHI 54.5+/-6.7 to 5.6+/-2.3 /h, p=0.007). In addition, the sleep quality improved significantly on ASV, including arousal index (62.0+/-10.5 to 18.7 +/-6.2 /h, p=0.012), percentage of slow-wave sleep (2.6+/-2.6 to 19.4+/-4.8 %, p=0.042). ASV markedly improved CSR-CSA in patients with CHF. It is a promising treatment for Japanese patients with CHF.

Tiagabine enhances slow wave sleep and sleep maintenance in primary insomnia

Background and purpose To evaluate the effect of tiagabine on sleep and next-morning alertness and performance in adult patients with primary insomnia. Patients and methods Patients with primary insomnia, as defined by Diagnostic and Statistical Manual of Mental Disorders—Fourth Edition (DSM-IV), received tiagabine 4, 8, 12, 16 mg, and placebo in a randomized, double-blind, five-period, Latin square, crossover study. Efficacy was assessed using polysomnographic and self-report techniques; residual effects were evaluated using the Digit Symbol Substitution Test (DSST) and the Rey Auditory Verbal Learning Test (RAVLT). Results Fifty-eight patients (40f, 18m; mean age 46.6±8.0 years) were randomized. Results showed a significant dose-dependent increase in slow wave sleep percentage with all tiagabine doses, a trend toward a dose-dependent increase in total sleep time, and no effect on latency to persistent sleep. Wake after sleep onset also decreased in a dose-dependent manner, with the 16-mg dose differing significantly from placebo. The tolerability profiles of tiagabine 4 and 8 mg were similar to placebo. The most common adverse events reported following tiagabine 12 and 16 mg were dizziness and nausea. Residual effects were only apparent at 12- and 16-mg doses. Conclusions Tiagabine increased slow wave sleep and reduced wake after sleep onset in a dose-dependent manner. Tiagabine dosages up to 8 mg did not compromise next-morning alertness and psychomotor performance in adult patients with primary insomnia. Further investigation of tiagabine doses up to 8 mg is warranted.

Blockade of endogenous growth hormone-releasing hormone receptors dissociates nocturnal growth hormone secretion and slow-wave sleep

A temporal association between non-rapid eye movement (NREM) sleep stages 3 and 4 and nocturnal augmentation of GH release was found long ago, yet the precise mechanism for this association has not been identified. It has been shown, however that pulsatile GHRH administration increases both slow-wave sleep (SWS) and GH. Based on these data, a role for GHRH as an inducer of SWS was proposed. To test this hypothesis, we have performed the corollary experiment whereby the action of endogenous GHRH has been antagonized. Healthy men (20-33 years old) had an infusion of GHRH antagonist ((N-Ac-Tyr(1), D-Arg(2)) GHRH-29 (NH(2))) or saline for a 12-h period, between 2100 and 0900 h. An i.v. bolus of GHRH was given at 0700 h and GH samples were drawn from 0700 to 0900 h to document the efficacy of GH suppression by the GHRH antagonist. A limited montage sleep study was recorded from 2300 to 0700 h during each admission. Plasma GH concentrations were analyzed by the use of a sensitive chemiluminometric assay. Effectiveness of the GHRH antagonist was validated in all subjects by demonstrating 93+/-1.8% (P=0.012) suppression of GH response to a GHRH bolus. Polysomnography demonstrated that the percentage of SWS was not different when saline and GHRH antagonist nights were compared (P=0.607); other quantifiable sleep parameters were also unchanged. We conclude that endogenous GHRH is indispensable for the nocturnal augmentation of GH secretion, but that it is unlikely to participate in the genesis of SWS.

Meta-Analysis of Quantitative Sleep Parameters From Childhood to Old Age in Healthy Individuals: Developing Normative Sleep Values Across the Human Lifespan

The purposes of this study were to identify age-related changes in objectively recorded sleep patterns across the human life span in healthy individuals and to clarify whether sleep latency and percentages of stage 1, stage 2, and rapid eye movement (REM) sleep significantly change with age. Review of literature of articles published between 1960 and 2003 in peer-reviewed journals and meta-analysis. 65 studies representing 3,577 subjects aged 5 years to 102 years. The research reports included in this meta-analysis met the following criteria: (1) included nonclinical participants aged 5 years or older; (2) included measures of sleep characteristics by "all night" polysomnography or actigraphy on sleep latency, sleep efficiency, total sleep time, stage 1 sleep, stage 2 sleep, slow-wave sleep, REM sleep, REM latency, or minutes awake after sleep onset; (3) included numeric presentation of the data; and (4) were published between 1960 and 2003 in peer-reviewed journals. In children and adolescents, total sleep time decreased with age only in studies performed on school days. Percentage of slow-wave sleep was significantly negatively correlated with age. Percentages of stage 2 and REM sleep significantly changed with age. In adults, total sleep time, sleep efficiency, percentage of slow-wave sleep, percentage of REM sleep, and REM latency all significantly decreased with age, while sleep latency, percentage of stage 1 sleep, percentage of stage 2 sleep, and wake after sleep onset significantly increased with age. However, only sleep efficiency continued to significantly decrease after 60 years of age. The magnitudes of the effect sizes noted changed depending on whether or not studied participants were screened for mental disorders, organic diseases, use of drug or alcohol, obstructive sleep apnea syndrome, or other sleep disorders. In adults, it appeared that sleep latency, percentages of stage 1 and stage 2 significantly increased with age while percentage of REM sleep decreased. However, effect sizes for the different sleep parameters were greatly modified by the quality of subject screening, diminishing or even masking age associations with different sleep parameters. The number of studies that examined the evolution of sleep parameters with age are scant among school-aged children, adolescents, and middle-aged adults. There are also very few studies that examined the effect of race on polysomnographic sleep parameters.

Sleep polygraphy in Angelman syndrome.

Sleep disturbances are frequent in Angelman syndrome (AS); however, beside the few studies which have investigated sleep disorders in AS by means of questionnaires, to our knowledge, no systematic polysomnographic recordings have been carried out in AS patients. The present study represents the first attempt to study sleep patterns of AS by polysomnography, to evaluate the influences of sleep on the paroxysmal electroencephalogram (EEG) patterns of AS and to assess the eventual age-related changes of sleep architecture and of sleep EEG abnormalities in children and adolescents with AS. Fifteen children with AS (7 males and 8 females, mean age 7.2 years, range 3-16 years), attending the Sleep Center of the Department of Child Neurology and Psychiatry of the University of Rome 'La Sapienza' and the Sleep Research Centre of the Oasi Institute (IRCCS) of Troina were included and subdivided into two subgroups by age: subgroup 1, aged 3-5 years, and subgroup 2, aged 9-17 years. Two control groups of age-matched normal subjects were also included: one aged less than 8 years and another aged more than 8 years; additionally, two other groups of age-matched children with epilepsy and mental retardation of different origin, one aged less and one aged more than 9 years were taken into consideration. The statistical comparison between the sleep parameters obtained from the patients and those from the other groups was carried out by means of the non-parametric Kruskal-Wallis ANOVA and the Mann-Whitney U test. The most frequent EEG abnormality found in AS patients appeared to be the 2-3 c/s poorly defined spike/waves complexes. This pattern was influenced by sleep stages; the duration of the runs showed an increasing length with sleep deepening from sleep stage 1 to slow-wave sleep (SWS). Moreover, the 2-3 c/s bursts activity present in sleep stage 2 showed a slowing to 1-2 c/s during SWS. Regarding sleep architecture, in subjects with AS aged <8 year there was a significant reduction in sleep efficiency as compared to normal controls, while the percentage and duration of REM sleep was significantly lower and the percentage of SWS was significantly higher. REM sleep time was reduced in AS subjects aged >8 years than in normal controls. The comparison between AS groups and mental retardation with epilepsy groups did not show significant differences. Similarly to other types of genetically determined mental retardation syndromes, also subjects with AS seems to show important abnormalities of their sleep polysomnographic patterns. This is the first study which reports, in detail, these abnormalities and opens a new path for further insight into the knowledge of additional sleep-related disturbances which are reported in sleep questionnaires by the caregivers of AS subjects.

Evaluation of sleep disturbance in post-traumatic stress disorder

The present polysomnographic study compared sleep structures in patients with post-traumatic stress disorder (PTSD) with those of age-matched normal controls. Seven patients with relatively acute PTSD and seven normal controls were studied in a sleep laboratory. The post-traumatic patients demonstrated significantly poorer sleep, reduced sleep efficiency, increased numbers of arousals, and a remarkably decreased percentage of slow-wave sleep (SWS), and a decreased percentage of rapid eye movement (REM) sleep. In two patients who reported having frequent nightmares, REM interruptions of more than 10 min were recognized. Although several previous polysomnographic studies in PTSD subjects have demonstrated disagreements regarding REM sleep and slow-wave sleep, the subjects in those studies were mainly chronic PTSD subjects. Regarding this point, because we investigated relatively acute PTSD subjects, characteristic sleep data might be obtained.

Sleep and circadian rhythm disturbances in patients with delayed sleep phase syndrome.

The objective of this study was to clarify sleep characteristics and pathophysiology in patients with delayed sleep phase syndrome (DSPS), which is a major circadian rhythm sleep disorder subtype. Polysomnography was performed for 2 consecutive nights and core body temperature was sampled for 7 consecutive days, including the polysomnography study period, in all subjects. Findings were compared and statistically analyzed between patients with DSPS and matched controls. Sleep disorders unit in National Center Hospital. 11 DSPS patients and 11 age-matched healthy volunteers. N/A. Sleep latency, total sleep time, wakefulness after sleep-onset, and the amount and percentage of Stage 1 sleep were greater in DSPS patients than in volunteers. Sleep efficiency and the amount and percentage of slow wave sleep were lower in DSPS patients than in volunteers. Compared with the healthy volunteers, DSPS patients showed a decreased number and different temporal distribution of high-voltage and low-frequency delta waves. The time of minimum body temperature appeared earlier in the sleep phase for the patients than for the volunteers. Significant correlation was found between the amount of slow wave sleep and the time from sleep onset to minimum body temperature and between the amount and percentage of slow wave sleep and time from minimum body temperature to sleep offset. Disturbances were found in the sleep structure of patients with DSPS, and these disturbances were related to the discrepancy between patients and controls in the phase relationship difference between sleep and core body temperature rhythms.

The effect of combined therapy (ultrasound and interferential current) on pain and sleep in fibromyalgia

Multidisciplinary treatment has proven to be the best therapeutic option to fibromyalgia (FM) and physiotherapy has an important role in this approach. Considering the controversial results of electrotherapy in this condition, the aim of this study was to assess the effects of combined therapy with pulsed ultrasound and interferential current (CTPI) on pain and sleep in FM. Seventeen patients fulfilling FM criteria were divided into two groups, CTPI and SHAM, and submitted to pain and sleep evaluations. Pain was evaluated by body map (BM) of the painful areas; quantification of pain intensity by visual analog scale (VAS); tender point (TP) count and tenderness threshold (TT). Sleep was assessed by inventory and polysomnography (PSG). After 12 sessions of CTPI or SHAM procedure, patients were evaluated by the same initial protocol. After treatment, CTPI group showed, before and after sleep, subjective improvement of pain in terms of number (BM) and intensity (VAS) of painful areas ( P<0.001, both); as well as objective improvement, with decrease in TP count and increase in TT ( P<0.001, both). Subjective sleep improvements observed after CTPI treatment included decrease in morning fatigue and in non-refreshing sleep complaint ( P<0.001, both). Objectively, PSG in this group showed decrease in sleep latency ( P<0.001) and in the percentage of stage 1 ( P<0.001), increase in the percentage of slow wave sleep ( P<0.001) and in sleep cycle count ( P<0.001). Decrease in arousal index ( P<0.001), number of sleep stage changes ( P<0.05) and wake time after sleep onset ( P<0.05), were also observed and no difference regarding pain or sleep parameters were verified after SHAM procedure. This study shows that CTPI can be an effective therapeutic approach for pain and sleep manifestations in FM.

Long-lasting enhancement of rapid eye movement sleep and pontogeniculooccipital waves by vasoactive intestinal peptide microinjection into the amygdala temporal lobe.

The effect of a vasoactive intestinal peptide (VIP) microinjection into the amygdaloid central (CN) and basal nuclei (BN) on sleep organization and on the number and pattern of occurrence of pontogeniculooccipital (PGO) waves was analyzed. One group of 8 cats was studied in baseline conditions and after the microinjection of two doses of VIP applied into the CN and BN. Sleep research laboratory. PARTCIPANTS AND INTERVENTIONS: Eight cats were prepared with sleep-recording electrodes and with guide tubes in both amygdalae for saline and VIP microinjections. Neuropeptide doses of 0.10 microg/1 microl (30 microM) and 0.33 microg/1 microl (99.24 microM) were employed. Once the microinjection was applied, 23-hour polygraphic sleep recordings were performed for 5 consecutive days. Concomitantly the PGO waves were tape-recorded on each day and computationally analyzed. Results show that the 0.10 microg/1 microl microinjection produced no change. Unilateral VIP 0.33 microg/1 microl injection into the CN provoked a significant and lasting increase in the percentage of slow-wave sleep with PGO waves. Bilateral application of VIP increased the percentage of slow-wave sleep with PGO waves and rapid eye movement sleep for 5 days. Bilateral microinjection of the neuropeptide into the BN only enhanced the percentage of slow wave sleep with PGO waves. For both amygdaloid nuclei, we observed that VIP increased the number and modified the PGO wave pattern of occurrence during slow-wave sleep with PGO waves and during rapid eye movement sleep. The VIP microinjection into both the CN and BN induces increased amounts of rapid eye movement sleep, PGO waves, and slow-wave sleep with PGO waves, having a more robust effect on all of these three variables when applied into the CN.

Preliminary observations on the effects of sleep time in a sleep restriction paradigm

Objective: To evaluate of the effect of 7 days of sleep restriction – with sleep placed at the beginning of night or early morning hours – on sleep variables, maintenance of wakefulness test, and serum leptin. Methods: After screening young adults with questionnaires and actigraphy for 1 week, eight young adult males were recruited to participate in a sleep restriction study. The subjects were studied for baseline data for 2.5 days, with 8.5 h per night in bed, and then over 7 days of sleep restriction to 4 h per night with a 22:30 h bedtime for half the group and a 02:15 h bedtime for the other half. At the end of study, after one night of ad libitum sleep, subjects again had 2 days of 8.5 h in bed. Wakefulness was continuously verified and tests, including Maintenance of Wakefulness (MWT), were performed during the scheduled wake time. Blood was drawn six times throughout the 24 h of the 7th day of sleep restriction and after 2 days of the post-restriction schedule. Results: There was individual variability in response to sleep restriction, but independent of group distribution, MWT was significantly affected by sleep restriction, with the early morning sleep group having less decrease in MWT score. Sleep efficiency was also better in this group, which also had shorter sleep latency. Independent of group distribution there was a greater increase in the percentage of slow wave sleep than rapid eye movement sleep, despite a clear internal variability and variability between subjects. Peak serum leptin was significantly decreased with 7 days of sleep restriction for all subjects. Conclusion: Sleep restriction to 4 h affected all subjects, but there were individual and group differences in MWT and sleep data. In this group of young adult males (mean age 19 years), there was a better overall adaptation to the early morning sleep, perhaps related to the general tendency in most adolescents to present some phase-delay during late teen-aged years.

Study of Nocturnal Sleep and the Carryover Effects of Triazolam and Brotizolam Using Neurophysiological and Subjective Methods

In the present study, the effects of short-acting benzodiazepines on nocturnal sleep and the carryover effects of these drugs were studied. The study involved 10 young, healthy male subjects who had given their written informed consent to participate. Either a placebo (PLA), 0.125 mg triazolam (TRZ), 0.25 mg TRZ or 0.25 mg brotizolam (BRZ) was administered to the subjects in a double-blind crossover design by randomized allocation with a single oral administration at 23.00 h. A polysomnography (PSG) was recorded for each subject from 23.00 to 07.00 h the following day. Then, the Stanford Sleepiness Scale (SSS) and Kwansei Gakuin Sleepiness Scale (KSS) were checked between 07.55 and 08.00 h, and the sleep latency test (SLT) was performed between 08.00 and 08.20 h. Event-related potentials (ERPs) were then recorded with an oddball paradigm; the reaction time (RT) was measured simultaneously. According to the PSG, treatment with 0.25 mg TRZ resulted in a statistically significant increase in the percentage of stage 2 sleep (p < 0.05) and a reduction in the percentage of rapid eye movement sleep (p < 0.05) compared with PLA. None of the drugs had any effect on the percentage of slow-wave sleep compared with PLA. With regard to carryover effects, although none of the drugs had any effect on SSS, KSS, RT or ERPs, BRZ did cause a statistically significant decrease in sleep latency (p < 0.05) compared with PLA. TRZ (0.125 and 0.25 mg) and 0.25 mg BRZ exerted different effects on SLT. We suggest that these different effects are attributable to differences in the half-life of these hypnotics.

Healthy older adults' sleep predicts all-cause mortality at 4 to 19 years of follow-up.

Evidence concerning whether sleep disturbances in older adults predict mortality is mixed. However, data are limited to self-reported sleep problems and may be confounded with other comorbidities. We examined whether electroencephalographic (EEG) sleep parameters predicted survival time independently of known predictors of all-cause mortality. A total of 185 healthy older adults, primarily in their 60s through 80s, with no history of mental illness, sleep complaints, or current cognitive impairment, were enrolled in one of eight research protocols between October 1981 and February 1997 that included EEG sleep assessments. At follow-up (mean [SD] = 12.8 [3.7] years after baseline, range = 4.1-19.5), 66 individuals were positively ascertained as deceased and 118 remained alive (total N = 184). Controlling for age, gender, and baseline medical burden, individuals with baseline sleep latencies greater than 30 minutes were at 2.14 times greater risk of death (p =.005, 95% CI = 1.25-3.66). Those with sleep efficiency less than 80% were at 1.93 times greater risk (p =.014, CI = 1.14-3.25). Individuals with rapid eye movement (REM) sleep percentages in the lowest 15% or highest 15% of the total sample's distribution (percentage of REM <16.1 or >25.7) were at 1.71 times greater risk (p =.045, CI = 1.01-2.91). Percentage of slow-wave sleep was associated with time to death at the bivariate level, but not after controlling for potential confounders. Older adults with specific EEG sleep characteristics have an excess risk of dying beyond that associated with age, gender, or medical burden. The findings suggest that interventions to optimize and protect older adults' sleep initiation, continuity, and quality may be warranted.

Effects of Mirtazapine on Sleep Polygraphic Variables in Major Depression

Mirtazapine, a noradrenergic and specific serotonergic antidepressant(NaSSA), was administered on a flexible schedule in a sample of 17 drug-free patients meeting DSM-IV criteria for a major depressive episode. Sleep polygraphic recordings were performed before and during acute and chronic treatment. Severity of depression and subjective assessment of changes within different aspects of sleep were also evaluated. During the acute administration (first 2 days), mirtazapine significantly increased total sleep time, sleep efficiency, stage II, stage rapid eye movement and slow-wave sleep percentages, and decreased sleep latency and stage awake percentage. These effects persisted after 5 weeks of treatment. Subjectively, mirtazapine induced an improvement of sleep. This open, noncontrolled study suggests that mirtazapine ameliorates the sleep disturbances encountered in depressed patients both objectively and subjectively.

The study of sleep effect in the night and the next morning of triazolam and brotizolam on the polysomnography and subjective sleep rating scale

We studied the sleep effect, the carry over effect (sleepiness) on polysomnography (PSG), the sleep propensity test (SPT), the subjective sleep rating scale for the ultra short acting hypnotics triazolam and short acting hypnotics brotizolam. Ten healthy male volunteers were used for double blind crossover design by randomized allocation with a single oral administration. Informed consent was obtained from all subjects. Placebo (PL), triazolam (TL, 0.125 mg), triazolam (TH, 0.25 mg) and brotizolam (BR, 0.25 mg) were administered at 11 p.m. PSG was recorded from 11 p.m. to 7 a.m. in the next morning. Then, Stanford Sleepiness Scale (SSS) and Kwansei Gakuin Sleepiness Scale (KSS) were checked before 8 a.m., and SPT was recorded at 8:00–8:20 a.m. In PSG of total sleep, TH decreased the frequency of stage shifts significantly ( p<0.05) compared to PL. TH and BR increased the percentage of stage 1 combined with stage 2 sleep significantly ( p<0.01) and decreased the percentage of REM sleep significantly ( p<0.01) compared to PL. However, all the drugs had no effect on the percentage of slow wave sleep compared to PL. Although all drugs had no effect on the subjective feeling of sleepiness in SSS and KSS, BR decreased sleep latency significantly ( p<0.05) compared to PL in SPT.

Airway assessment by volumetric computed tomography in snorers and subjects with obstructive sleep apnea in a Far-East Asian population (Chinese).

To evaluate the airway dimension of simple snorers and subjects with obstructive sleep apnea (OSA) in a Far-East Asian population (Chinese). Prospective study of 117 near-consecutive patients evaluated for snoring and possible OSA from January 1998 to December 1998 in a sleep laboratory. Overnight polysomnography (PSG) was performed on all patients and the sleep parameters, including respiratory disturbance index (RDI), snoring index, minimal oxygen saturation (min O2), percentage of slow wave sleep (SWS), and rapid eye movement (REM) were recorded. Three-dimensional computerized tomography (CT) during awake periods was performed. The anteroposterior (AP) and the lateral distance of the retropalatal (RP) region in the oropharynx, the smallest area of RP, and retroglossal (RG) regions, and the total volume of the oropharynx were measured. Ninety-eight patients were diagnosed with OSA (mean RDI, 41.48 +/- 26.45 events per hour; min O2, 72.82 +/- 12.86%), whereas 19 were simple snorers. The AP and the lateral distance of the RP region, as well as the smallest area of the RP region, are significantly smaller in subjects with OSA. However, no differences in the RG region and the total volume of the oropharynx were found between the two groups. Linear regression analysis demonstrated that the lateral dimension and the smallest RP area in overweight subjects inversely correlated with the RDI, but only the AP dimension of the RP area was found to have an inverse correlation with the RDI in the underweight subjects. In Far-East Asians (Chinese), the RP airway was found to be the primary site of narrowing in subjects with OSA, and the narrowest RP area was inversely correlated with RDI. Furthermore, weight may influence the pattern of RP narrowing by contributing to lateral collapse.