Measures Of Sleep Latency Research Articles

Association of ambient air pollution exposure and its variability with subjective sleep quality in China: A multilevel modeling analysis

Growing epidemiological evidence has shown that exposure to ambient air pollution contributes to poor sleep quality. However, whether variability in air pollution exposure affects sleep quality remains unclear. Based on a large sample in China, this study linked individual air pollutant exposure levels and temporal variability with subjective sleep quality. Town-level data on daily air pollution concentration for 30 days prior to the survey date were collected, and the monthly mean value, standard deviations, number of heavily polluted days, and trajectory for six common pollutants were calculated to measure air pollution exposure and its variations. Sleep quality was subjectively assessed using the Pittsburgh Sleep Quality Index (PSQI), and a PSQI score above 5 indicated overall poor sleep quality. Multilevel and negative control models were used. Both air pollution exposure and variability contributed to poor sleep quality. A one-point increase in the one-month mean concentration of particulate matter with aerodynamic diameters of ≤2.5 μm (PM2.5) and ≤10 μm (PM10) led to 0.4% (95% confidence interval (CI): 1.002–1.006) and 0.3% (95% CI: 1.001–1.004) increases in the likelihoods of overall poor sleep quality (PSQI score >5), respectively; the odds ratios of a heavy pollution day with PM2.5 and PM10 were 2.2% (95% CI: 1.012–1.032) and 2.2% (95% CI: 1.012–1.032), respectively. Although the mean concentrations of nitrogen dioxide, sulfur dioxide, and carbon monoxide met the national standard, they contributed to the likelihood of overall poor sleep quality (PSQI score >5). A trajectory of air pollution exposure with maximum variability was associated with a higher likelihood of overall poor sleep quality (PSQI score >5). Subjective measures of sleep latency, duration, and efficiency (derived from PSQI) were affected in most cases. Thus, sleep health improvements should account for air pollution exposure and its variations in China under relatively high air pollution levels.

The relationship between the HDRS insomnia items and polysomnographic (PSG) measures in individuals with treatment-resistant depression

The Hamilton Depression Rating Scale (HDRS), which includes several insomnia-related items, is potentially valuable in evaluating both depressive and sleep symptoms. However, the HDRS insomnia items have not been fully assessed by objective measures. This study compared the three HDRS insomnia items (Early, Middle, and Late) with the corresponding objective polysomnography (PSG) measures of Sleep Latency (SL), middle wakefulness, and late wakefulness. The study used HDRS and PSG data from 130 baseline nights, drawn from 80 participants enrolled in clinical trials for treatment-resistant depression (TRD). Mixed models evaluated the relationship between the HDRS and PSG, and primary analyses examined the Early, Middle, and Late Insomnia HDRS items and the PSG variables SL and Waking After Sleep Onset (WASO). To approximate the Middle and Late HDRS Insomnia items more closely, WASO was divided into WASO before 4:00 a.m. (waking between Sleep Onset and 0400 h) and WASO after 4:00 a.m. (waking between 0400 h and 0700 h). Secondary analyses included summed HDRS Global Insomnia score. HDRS Early and Late Insomnia items predicted objective PSG measures of early and late wakefulness. For Early Insomnia, each additional point in severity was associated with 61% [95%CI: 35%, 93%] longer SL. For Late Insomnia, each additional point was associated with a 35% [95% CI: 13%, 63%] increase in WASO after 4:00 a.m. Middle Insomnia was marginally related to WASO before 4:00 a.m. HDRS Early and Late Insomnia items may thus provide an index of wakefulness in TRD and help monitor treatment response when objective measures such as PSG are not feasible. Clinical trials identifierwww.clinicaltrials.gov (NCT01204918, NCT00054704, NCT00088699).

Effects of resistance exercise training and stretching on chronic insomnia.

Objective:The aim of this study was to assess the effects of resistance exercise and stretching on sleep, mood, and quality of life in chronic insomnia patients.Methods:Three 4-month treatments included: resistance exercise (n=10), stretching (n=10), and control (n=8). Sleep was evaluated with polysomnography, actigraphy, and questionnaires. Mood and quality of life were assessed with the Profile of Mood States (POMS) and the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36), respectively.Results:There were no significant treatment differences between resistance exercise and stretching. However, compared with the control treatment, resistance exercise and stretching led to significantly greater improvements in Insomnia Severity Index scores (-10.5±2.3, -8.1±2.0 vs. 2.3±1.8, respectively), and actigraphic measures of sleep latency (-7.1±4.6, -5.2±1.9 vs. 2.2±2.1 min), wake after sleep onset (-9.3±2.8, -7.1±3.0 vs. 3.6±4.2 min), and sleep efficiency (4.4±1.8, 5.0±0.8 vs. -2.3±2%). Pittsburgh Sleep Quality Index (PSQI) global scores (-5.3±0.8, -3.9±1.5 vs. -0.1±0.8) and sleep duration (1.2±0.3, 1.6±0.6 vs. -0.1±0.2 h) also improved following both experimental treatments compared with control. PSQI-Sleep efficiency increased after resistance exercise compared with control (19.5±3.9 vs. 2.1±4.3%). No significant differences were observed in polysomnography or quality of life measures. Tension-anxiety was lower in the stretching group than the control group.Conclusion:Moderate-intensity resistance exercise and stretching led to similar improvements in objective and subjective sleep in patients with chronic insomnia.Clinical trial registration:NCT01571115

A novel forehead temperature-regulating device for insomnia: a randomized clinical trial.

Insomnia is one of the most common disorders in the general population. Hypnotic medications are efficacious, but their use is limited by adverse events (AEs). This study evaluated the safety and efficacy of a novel forehead temperature-regulating device that delivers frontal cerebral thermal therapy (maintained at 14-16°C, equivalent to 57-61°F) for the treatment of insomnia. This was a prospective, randomized controlled trial involving two nights of therapy in 106 adults diagnosed with insomnia. The main outcome measures included latency to persistent sleep and sleep efficiency derived from polysomnographic (PSG) recordings and frequency and severity of AEs. The safety profile was comparable to sham treatment. Statistically significant differences were not found in the two a priori co-primary endpoint measures absolute latency to persistent sleep (p = 0.092) or absolute sleep efficiency. Frontal cerebral thermal therapy produced improvements over sham in other convergent measures of sleep latency including relative changes from baseline in latency to persistent sleep (p = 0.013), the latency to stage 1 NREM sleep (p = 0.006), the latency to stage 2 NREM sleep (p = 0.002), a trend for the latency to stage 3 NREM sleep (p = 0.055), and an increase in the minutes of sleep during the first hour of the night (p = 0.024). Two-night frontal cerebral thermal therapy produced improvements in PSG measures of insomnia patients' ability to fall asleep and had a benign safety profile. Further studies are warranted to determine the role of this therapy in the longer-term management of insomnia. clinicaltrials.gov Identifier: NCT01966211.

Laboratory and home comparison of wrist-activity monitors and polysomnography in middle-aged adults

Accurate measurement of time at lights out is essential for calculation of several measures of sleep in wrist-activity monitors. While some devices use subjective reporting of time of lights out from a sleep diary, others utilise an automated proprietary scoring algorithm to calculate time at lights out, thereby negating the need for a sleep diary. This study aimed to compare sleep measures from two such devices to polysomnography (PSG) measures (In laboratory) and against each other when worn at home (At home). Fifty middle-aged adults from the Raine Study underwent overnight PSG during which they wore an ActiGraph™ and a Readiband™. They also wore both devices at home for 7 nights. The Readiband uses an automated proprietary algorithm to determine time at lights out whereas the ActiGraph requires completion of a sleep diary noting this time. In laboratory, compared to PSG: Readiband underestimated time at lights out, sleep onset, and wake after sleep onset, overestimated sleep latency and duration (p < 0.001 for all); while ActiGraph underestimated sleep latency and wake after sleep onset and overestimated sleep efficiency and duration (p < 0.001 for all). Similar differences between devices were observed on the laboratory night and when at home. In conclusion, an automated algorithm such as the Readiband may be used in the same capacity as the ActiGraph for the collection of sleep measures including time at sleep onset, sleep duration and time at wake. However, Readiband and ActiGraph measures of sleep latency, efficiency and wake after sleep onset should be interpreted with caution.

Validation of Nighttime Sleepability Scale Against Objective and Subjective Measures of Sleep Quality

Quick self-assessment of night sleep quality with reliable and valid instruments is often required in various fundamental and applied studies in the field of sleep medicine and chronomedicine. Individual differences in sleep quality are usually assessed with a special scale, whereas such a scale is absent in most of questionnaires for evaluation of individual differences in the domain of chronobiology. One of two exceptions is the 6-scale Sleep-Wake Pattern Assessment Questionnaire. It contains the 12-item scale S designed to self-assess nighttime sleepability. The purpose of the present report was to examine external validity of this scale by searching for correlates and predictors of S score. One hundred and sixty participants of sleep deprivation experiments self-reported their sleep latency, total sleep duration, nap frequency, and times for going to bed and awakening for one week prior to the experiment. Their objective and subjective sleepiness after sleepless night was measures in the course of experiment. Moreover, sleep latency and total sleep duration were measured by means of polysomnography in studies with 35 female participants. Other objective measurements included percentages of sleep stages, awakenings after sleep onset, and sleep efficiency. Additionally, sleep latencies were detected during 9 day- and nighttime 20-min napping attempts of 15 from 35 participants. It was found that significant correlates and predictors of S score include subjective and objective measures of sleep latency, percentage of slow wave sleep, subjectively and objectively assessed sleepiness, and self-reported total sleep time. These results provided solid evidence for external validity of scale S.

Subjective sleepiness is a sensitive indicator of insufficient sleep and impaired waking function.

The main consequence of insufficient sleep is sleepiness. While measures of sleep latency, continuous encephalographical/electro-oculographical (EEG/EOG) recording and performance tests are useful indicators of sleepiness in the laboratory and clinic, they are not easily implemented in large, real-life field studies. Subjective ratings of sleepiness, which are easily applied and unobtrusive, are an alternative, but whether they measure sleepiness sensitively, reliably and validly remains uncertain. This review brings together research relevant to these issues. It is focused on the Karolinska Sleepiness Scale (KSS), which is a nine-point Likert-type scale. The diurnal pattern of sleepiness is U-shaped, with high KSS values in the morning and late evening, and with great stability across years. KSS values increase sensitively during acute total and repeated partial sleep deprivation and night work, including night driving. The effect sizes range between 1.5 and 3. The relation to driving performance or EEG/EOG indicators of sleepiness is highly significant, strongly curvilinear and consistent across individuals. High (>6) KSS values are associated particularly with impaired driving performance and sleep intrusions in the EEG. KSS values are also increased in many clinical conditions such as sleep apnea, depression and burnout. The context has a strong influence on KSS ratings. Thus, physical activity, social interaction and light exposure will reduce KSS values by 1-2 units. In contrast, time-on-task in a monotonous context will increase KSS values by 1-2 units. In summary, subjective ratings of sleepiness as described here is as sensitive and valid an indicator of sleepiness as objective measures, and particularly suitable for field studies.

Effect of MonaVie Rest œ on sleep duration and sleep quality in moderately stressed subjects (647.23)

BACKGROUND: A variety of herbal teas, including Fennel (Foeniculum vulgare), Lemon balm (Melissa officinalis), and Chamomile (Chamaemelium nobile) are used to induce relaxation, improve sleep, and treat insomnia. OBJECTIVE: We conducted a pilot study in 9 moderately stressed subjects to assess changes in sleep duration, latency, and quality following consumption of a combination product (MonaVie RestTM) intended to induce relaxation and promote restful sleep. The product contains a blend of fennel, lemon balm, and chamomile in a ready‐to‐drink tea. METHODS: We used a portable sleep‐tracking device (Zeo Sleep Manager, Zeo Inc) to measure differences between sleep patterns following control (no tea) and supplemented (post‐tea) conditions. Subjects wore the sleep‐tracking EEG electrode headband nightly for two weeks, alternating between one night with no tea and one night consuming the tea. Results were averaged for “tea” versus “non‐tea” nights. RESULTS: Following 2 weeks of alternate‐night tea consumption, improvements were found on nights when tea was consumed for measures of sleep latency (‐24%; 10 v. 13min), sleep duration (+8%; 416 v. 384min), minutes in REM sleep (+7%; 140 v. 130min), and overall sleep quality (+8%; 79% v. 72%). CONCLUSION: These preliminary results suggest that supplementation with MonaVie Rest promotes restful sleep (latency and duration) and improves overall sleep quality.

Relationships between menopausal and mood symptoms and EEG sleep measures in a multi-ethnic sample of middle-aged women: the SWAN sleep study.

Examine associations of vasomotor and mood symptoms with visually scored and computer-generated measures of EEG sleep. Cross-sectional analysis. Community-based in-home polysomnography (PSG). 343 African American, Caucasian, and Chinese women; ages 48-58 years; pre-, peri- or post-menopausal; participating in the Study of Women's Health Across the Nation Sleep Study (SWAN Sleep Study). None. Measures included PSG-assessed sleep duration, continuity, and architecture, delta sleep ratio (DSR) computed from automated counts of delta wave activity, daily diary-assessed vasomotor symptoms (VMS), questionnaires to collect mood (depression, anxiety) symptoms, medication, and lifestyle information, and menopausal status using bleeding criteria. Sleep outcomes were modeled using linear regression. Nocturnal VMS were associated with longer sleep time. Higher anxiety symptom scores were associated with longer sleep latency and lower sleep efficiency, but only in women reporting nocturnal VMS. Contrary to expectations, VMS and mood symptoms were unrelated to either DSR or REM latency. Vasomotor symptoms moderated associations of anxiety with EEG sleep measures of sleep latency and sleep efficiency and was associated with longer sleep duration in this multi-ethnic sample of midlife women.

Measuring sleep habits using the Sleep Timing Questionnaire: A validation study for school-age children

In 2003 Monk and colleagues published a single-administration replacement for a standard sleep diary, the Sleep Timing Questionnaire (STQ). Reliable and valid for adult participants, it offers advantages over existing methodologies in cost and convenience. It takes approximately 10 min to complete but can yield information equivalent to a week of actigraphy, or a 2-week sleep diary. This study sought to validate the STQ for school-age children. Sixty-five children (20 boys, 45 girls), aged 11–16 years participated in this study. The participants wore wrist actigraphs, completed a 1-week sleep diary and the STQ. Analyses tested convergent validity between the STQ and actigraphy, and the STQ and sleep diaries. Correlations between STQ and actigraphy (r = 0.45–0.76, P < 0.001), and STQ and sleep diaries (r = 0.42–0.86, P < 0.001), were positive and significant for sleep onset and wake times. Correlations between STQ and actigraphy for sleep latency and wake after sleep onset (WASO) were very low (r < 0.10). In contrast, sleep latency was moderately and significantly correlated between STQ and sleep diary (r = 0.42, P < 0.001), and the correlation for WASO was high and significant (r = 0.74, P < 0.001). Differences between the STQ and sleep diary were within acceptable limits for all sleep parameters, and the differences between STQ and actigraphy were acceptable for sleep onset and school day wake time. The STQ may be a valid indicator of sleep onset and wake time in school-age children. It can also produce measures of sleep latency and WASO with comparable accuracy to a standard sleep diary.

Multiple sleep latency measures in narcolepsy and behaviourally induced insufficient sleep syndrome

Background Short mean latencies to the first epoch of non-rapid eye movement sleep stage 1 (NREM1) and the presence of ⩾2 sleep onset REM (SOREM) periods on multiple sleep latency test (MSLT) occur in both narcolepsy–cataplexy (NC) and behaviourally induced insufficient sleep syndrome (BIISS). It is not known whether specific MSLT findings help differentiate the two disorders. Methods We analyzed MSLT data including sleep latencies to and between different sleep stages of 60 age-, gender- and body mass index (BMI)-matched subjects (hypocretin-deficient NC, actigraphy-confirmed BIISS, healthy controls: each 20). Results Mean latency (in minutes) to NREM1 sleep was significantly shorter in NC (1.8 ± 1.5) than in BIISS (4.7 ± 2.1, p < 0.001) and controls (11.4 ± 3.3, p < 0.001). Mean latency to NREM2 sleep was similar in NC (8.6 ± 4.7) and BIISS (8.1 ± 2.7, p = 0.64); latency to either NREM2 or rapid eye movement (REM) sleep (i.e., the sum of the sleep latency to NREM1 and the duration of the first NREM1 sleep sequence), however, was shorter in NC (4.4 ± 2.9) than in BIISS (7.9 ± 3.5, p < 0.001). Referring to all naps with SOREM periods, the sequence NREM1–REM–NREM2 was more common (71%) in NC than in BIISS (15%, p < 0.001), reflecting the shorter latency from NREM1 to NREM2 in BIISS (3.7 ± 2.5) than in NC (6.1 ± 5.9, p < 0.001). Conclusions Our findings show that both sleepiness (as measured by NREM1 sleep latency) and REM sleep propensity are higher in NC than in BIISS. Furthermore, our finding of frequent REM sleep prior to NREM2 sleep in NC is in line with the recent assumption of an insufficient NREM sleep intensity in NC. Together with detailed clinical interviews, sleep logs, actigraphy, and nocturnal polysomnography, mean sleep latencies to NREM1 ⩽2.5 min, the presence of multiple SOREM periods, and the sequence NREM1–REM–NREM2 may be the best MSLT measures to discriminate NC from BIISS.

A randomized clinical trial of valerian fails to improve self-reported, polysomnographic, and actigraphic sleep in older women with insomnia

Objective To test the effects of nightly valerian ( Valeriana officinalis) extract to improve sleep of older women with insomnia. Methods Participants in this phase 2 randomized, double-blind, crossover controlled trial were 16 older women (mean age = 69.4 ± 8.1 years) with insomnia. Participants took 300 mg of concentrated valerian extract or placebo 30 min before bedtime for 2 weeks. Sleep was assessed in the laboratory by self-report and polysomnography (PSG) at baseline and again at the beginning and end of each treatment phase (total of nine nights in the laboratory) and at home by daily sleep logs and actigraphy. Results There were no statistically significant differences between valerian and placebo after a single dose or after 2 weeks of nightly dosing on any measure of sleep latency, wake after sleep onset (WASO), sleep efficiency, and self-rated sleep quality. In comparing each treatment to baseline in separate comparisons, WASO significantly increased (+17.7 ± 25.6 min, p = .02) after 2 weeks of nightly valerian, but not after placebo (+6.8 ± 26.4 min, NS). Side effects were minor and did not differ significantly between valerian and placebo. Conclusion Valerian did not improve sleep in this sample of older women with insomnia. Findings from this study add to the scientific evidence that does not support use of valerian in the clinical management of insomnia.

Paroxetine Treatment of Primary Insomnia in Older Adults

The goal of this study was to test the efficacy of paroxetine for primary insomnia in older adults. Adults over age 55 with primary insomnia were randomly assigned to six weeks of double-blind treatment with paroxetine (N = 14) or placebo (N = 13). Outcome measures included persistence or resolution of insomnia; weekly diary measures of sleep quality, daytime alertness, and mood; and pre-/postpolysomnographic measures of sleep latency, wake time after sleep onset, and sleep efficiency. Although weekly diary-based measures showed improved subjective sleep quality, daytime alertness, and mood with paroxetine, the authors observed no effect on sleep efficiency or categorical response rates. Paroxetine appears to be ineffective for treating primary insomnia in old age.

The Efficacy and Safety of the Melatonin Agonist beta-Methyl-6-Chloromelatonin in Primary Insomnia

While melatonin agonists are known to regulate circadian sleep rhythms, it is not clear whether melatonin agonists have a direct soporific effect. It has been suggested that melatonin's soporific effect is secondary to its ability to induce hypothermia. beta-Methyl-6-chloromelatonin is a high-affinity melatonin receptor agonist that is not associated with hypothermia. The purpose of the present study was to determine if the melatonin agonist beta-methyl-6-chloromelatonin has a direct soporific effect in subjects with primary insomnia. A double-blind, placebo-controlled, crossover safety and efficacy study of 20 mg, 50 mg, and 100 mg of beta-methyl-6-chloromelatonin and placebo was conducted in subjects with DSM-IV-TR primary insomnia. Of 84 subjects screened, 40 progressed to randomly receive each of 3 beta-methyl-6-chloromelatonin doses or placebo on each of 2 consecutive nights with 5-day washout periods between treatments. The effect of treatment on both polysomnographic and subjectively measured sleep parameters, next-morning psychomotor performance, and safety measures was determined. The primary outcome measure was latency to persistent sleep measured by polysomnography. A significant effect of beta-methyl-6-chloromelatonin on the primary efficacy variable, latency to persistent sleep, was observed (p = .0003). The 20-mg dose resulted in a significant 31% improvement in sleep latency compared with placebo, while significant 32% and 41% improvements were observed at the 50-mg and 100-mg doses, respectively (20 mg, p = .0082; 50 mg, p = .0062; 100 mg, p < .0001). Similarly, a significant effect of beta-methyl-6-chloromelatonin on subjective measures of time to fall asleep occurred (p = .0050), with significant improvement observed at both the 50-mg and 100-mg doses (p = .0350 and .0198, respectively) and a trend toward improvement observed at the 20-mg dose (p = .0582). Adverse events were mild to moderate in severity and did not differ in frequency between beta-methyl-6-chloromelatonin and placebo treatments. beta-Methyl-6-chloromelatonin significantly decreases both objective and subjective measures of sleep latency in subjects with primary insomnia. Thus, these data suggest that mel-atonin agonists may exert a direct soporific effect, as previous research indicates that beta-methyl-6-chloromelatonin is not associated with changes in body temperature, heart rate, or blood pressure.

Alexithymia and polysomnographic measures of sleep in healthy adults.

This study examined associations between alexithymia and objective characteristics of sleep (latencies, stages, and amount and patterning of REM sleep) that may contribute to subjective reports of poor sleep quality and impaired dream recall among alexithymic people. Fifty healthy, normally sleeping adults from the community completed the 20-item Toronto Alexithymia Scale and slept uninterrupted for one night in the laboratory while polysomnography was conducted. Various measures of sleep latency, sleep stages, and REM sleep-related variables were obtained, and analyses correlated these sleep measures with alexithymia, controlling for age, sex, and level of depressed affect. Higher alexithymia scores were significantly related to increased stage 1 (light) sleep and decreased stage 3/4 (deep) sleep. Alexithymia was unrelated to overall sleep efficiency or percentage of stage 2 sleep. Alexithymia was related to more frequent REM episodes and more stage 1 sleep during and immediately after REM episodes but was unrelated to the absolute amount of REM sleep. Alexithymia was also related to an earlier onset of the first REM episode. Alexithymia is associated with more light sleep and less deep sleep, which may contribute to subjective reports of poor sleep and increased sleepiness, fatigue, and somatic symptoms. Although alexithymia is not associated with an overall reduction of REM sleep, the increased frequency of episodes of REM that are interrupted and followed by light sleep rather than complete awakenings may contribute to limited dream recall.

Beyond the three-process model of alertness: estimating phase, time on shift, and successive night effects.

This paper starts by summarizing the development and refinement of the additive three-process model of alertness first published by Folkard and Akerstedt in 1987. It reviews some of the successes that have been achieved by the model in not only predicting variations in subjective alertness on abnormal sleep-wake schedules but also in accounting for objective measures of sleep latency and duration. Nevertheless, predictions derived from the model concerning alertness on different shifts, and over successive night shifts, are difficult to reconcile with published data on accident risk. In light of this, we have examined two large sets of alertness ratings with a view to further refining the model and identifying additional factors that may influence alertness at any given point in time. Our results indicate that, at least for the range of sleep durations and wake-up times commonly found on rotating shift systems, we may assume the phase of the endogenous circadian component of alertness (process C) to be "set" by the time of waking. Such an assumption considerably enhanced the predictive power of the model and yielded remarkably similar phase estimates to those obtained by maximizing the post-hoc fit of the model. We then examined the manner in which obtained ratings differed from predicted values over a complete 8-day cycle of two, 12-h shift systems. This revealed a pronounced "first night compensation effect" that resulted in shift workers rating themselves as progressively more alert than would be predicted over the course of the first night shift. However, this appeared to be achieved only at the cost of lowered ratings on the second night shift. Finally, we were able to identify a "time on shift" effect whereby, with the exception of the first night shift, alertness ratings decreased over the course of each shift before showing a modest "end effect." We conclude that the identification of these additional components offers the possibility that in the future we may be able to predict trends in accident risk on abnormal sleep-wake schedules.

Sleep latency measures of caffeine effects during sleep deprivation

Studies of stimulants during sleep deprivation have used performance assessment batteries (PABs) and occasionally the multiple sleep latency test (MSLT) as measures. Another type of sleep latency test, the maintenance of wakefulness test (MWT), assesses ability to remain awake without assistance, rather than ability to go to sleep. The MWT previously has not been used in studies of stimulants during sleep deprivation. This study of caffeine during 64 h without sleep included a PAB, the MSLT, and a single MWT trial per day. The PAB and the MSLT were sensitive to caffeine effects during the first 24 h without sleep. The MWT demonstrated that caffeine improved ability to remain awake even after 2 nights of sleep deprivation. Ability to go to sleep and ability to stay awake during sleep deprivation appear to be affected differently by caffeine. PAB testing may fail to detect this stimulant effect because technicians prevent subjects from nodding off during PAB testing, an external support not available to subjects during the MWT and also not available in many real-world work environments. The MWT was more sensitive to stimulant amelioration of sleep-deprivation effects. The findings need to be validated with MWTs at other times of day and with other stimulants.

Longitudinal changes in diary- and laboratory-based sleep measures in healthy "old old" and "young old" subjects: a three-year follow-up.

We report a longitudinal study of diary- and laboratory-based sleep measures in 50 healthy elderly subjects followed prospectively over a 3-year interval. Our hypothesis was that "old old" subjects (aged 75 to 87; n = 27) would show decline over time in measures of sleep quality, continuity, and depth, whereas "young old" subjects (aged 61 to 74; n = 23) were expected to show stability of outcome measures. Using analysis of variance-based planned contrast procedures, we found that this hypothesis was strongly supported for subjective sleep quality and laboratory measures of sleep latency, sleep efficiency, wakefulness after sleep onset, and slow-wave sleep percent. These changes were accompanied by increased napping in the old old. However, there was no change of habitual time in bed (total time or temporal placement of nighttime sleep), daily social rhythms, or sleep apnea. Change in medical burden scores did not correlate significantly with change in sleep efficiency or other outcome variables in the old old. Intervention designed to slow age-dependent decreases in sleep quality, continuity, and depth is discussed. The current results are representative of healthy elderly; sleep would probably deteriorate earlier and more quickly in elderly with more serious health problems and heavier medication use.

Subjective and psychophysiologic insomnia: An examination of sleep tendency and personality

The goal of this study was to compare insomniacs with and without objective verification, on the basis of sleep parameters, personality, and performance. An insomniac complaint group was subclassified as objective insomniac (OI) or subjective insomniac (SI) and compared to a non-complaint group. Groups did not differ on night sleep variables or daytime sleep latency measures; rather, a consistent sleep tendency was revealed for all three groups. The poorer the previous night sleep, the longer the daytime sleep latencies. Groups differed on subjective measures of conscious state during the day. SIs inaccurately estimated sleep/wake state in comparison to objective measures on the MSLT, whereas OIs were accurate in their estimations. Personality scores showed trends that suggested greater neuroticism for SIs and introversion for OIs. Results demonstrated subjective tendencies and related personality types that may help in the understanding of the complaint of insomnia with and without objective findings.

Plasma Concentrations of Flurazepam and Midazolam in Chronic Insomniacs during 14-Day Use and Their Relationship to Therapeutic Effects and Next-Day Performance and Mood

Blood samples were drawn from each of 99 chronic insomniacs twice during washout (days -20 and -6) and six times during the study (mornings after study nights -1, 1, 2, 7, 13, and 14) to examine the relationship between morning-after drug plasma levels, sleep efficiency, next-day mood, and performance. Patients in the four treatment groups received either flurazepam 30 mg, flurazepam 15 mg, midazolam 15 mg, or placebo. Plasma drug concentrations of N-desalkylflurazepam and midazolam were measured by electron-capture gas chromatography. Values of midazolam during the 14-day study were at or near the sensitivity limit of the assay and were not used in the calculations. Levels of N-desalkylflurazepam increased as expected during the 14 days. Mean level for the high-dose flurazepam group was approximately twice that of the low-dose group. The main consistency in the correlations, which were found on days 13 and 14, was that the high-dose desalkylflurazepam concentrations had a negative correlation with two independent measures of sleep latency. However, otherwise there was little or no relationship between N-desalkylflurazepam levels and sleep efficiency or next-day behavior. Issues of tolerance, individual variability in baseline and response, and their contribution to the findings are discussed.