Meta-analysis of age and actigraphy-assessed sleep characteristics across the lifespan.

STUDY OBJECTIVES: Sleep quantity and continuity vary across the lifespan. Actigraphy is a reliable and widely used behavioral measure of sleep in research and personal health monitoring. This meta-analysis provides a novel examination of whether age (in years) is associated with actigraphy-assessed sleep across the lifespan. METHODS: A systematic search of PubMed, Embase.com, Cochrane CENTRAL, and PsycINFO using "actigraphy" and "sleep" terms provided 7079 titles/abstracts; studies of individuals with known psychiatric or medical comorbidities were excluded. Ninety-one articles (N = 23 365) provided data for six meta-analyses examining sleep duration (k = 89), sleep efficiency (k = 58), bedtime (k = 19) and waketime (k = 9) for individuals ages 6-21, and bedtime (k = 7) and waketime (k = 7) for individuals ages 22 and older. RESULTS: At older ages, sleep duration was shorter (r = -0.12) and sleep efficiency was lower (r = -0.05). Older age was associated with later bedtime (r = 0.37) and wake-up time (r = 0.24) from ages 6-21, whereas older age was associated with earlier bedtime (r = -0.66) and wake-up time (r = -0.59) for ages 22 and above. The strength of these associations was modified by study continent, but not by any other moderator. CONCLUSIONS: Age was negatively associated with actigraphy-assessed sleep duration and efficiency, but the effects were small in magnitude. On the other hand, large associations were observed between age and sleep timing, despite a smaller literature and the absence of analyzable data for ages 30-60. Changes in sleep timing, rather than changes in sleep duration or continuity, may better characterize the effects of age on human sleep.

Multidimensional sleep health domains in older men and women: an actigraphy factor analysis.

The multidimensional sleep health framework emphasizes that sleep can be characterized across several domains, with implications for developing novel sleep treatments and improved prediction and health screening. However, empirical evidence regarding the domains and representative measures that exist in actigraphy-assessed sleep is lacking. We aimed to establish these domains and representative measures in older adults by examining the factor structure of 28 actigraphy-derived sleep measures from 2,841 older men from the Osteoporotic Fractures in Men Sleep Study and, separately, from 2,719 older women from the Study of Osteoporotic Fractures. Measures included means and standard deviations of actigraphy summary measures and estimates from extended cosine models of the raw actigraphy data. Exploratory factor analyses revealed the same five factors in both sexes: Timing (e.g. mean midpoint from sleep onset to wake-up), Efficiency (e.g. mean sleep efficiency), Duration (e.g. mean minutes from sleep onset to wake-up), Sleepiness/Wakefulness (e.g. mean minutes napping and amplitude of rhythm), and Regularity (e.g. standard deviation of the midpoint). Within each sex, confirmatory factor analyses confirmed the one-factor structure of each factor and the entire five-factor structure (Comparative Fit Index and Tucker-Lewis Index ≥ 0.95; Root Mean Square Error of Approximation 0.08-0.38). Correlation magnitudes among factors ranged from 0.01 to 0.34. These findings demonstrate the validity of conceptualizing actigraphy sleep as multidimensional, provide a framework for selecting sleep health domains and representative measures, and suggest targets for behavioral interventions. Similar analyses should be performed with additional measures of rhythmicity, other age ranges, and more racially/ethnically diverse samples.

Does midlife aging impact women's sleep duration, continuity, and timing?: A longitudinal analysis from the Study of Women's Health Across the Nation.

Our study objectives were to evaluate the age-related changes in actigraphy measures of sleep duration, continuity, and timing across 12 years in midlife women as they traversed the menopause, and to take into account factors affecting women's sleep that also change with age. Black, white, and Chinese women were recruited from the Study of Women's Health Across the Nation (SWAN) to participate in an ancillary sleep study on two occasions over 3 years apart and a third assessment 12 years after the first (N = 300, mean ages, 52, 55, and 64 at the three assessments). Women had at least four consecutive nights of actigraphy (95% with 7 nights) and sleep diaries, and self-reported sleep complaints measured at each time point. Partial correlations adjusted for time between assessments across the 12 years were significant and moderate in size (r's = .33-.58). PROC MIXED/GLIMMIX multivariate models showed that sleep duration increased over time; wake after sleep onset (WASO) declined, midpoint of sleep interval increased, and sleep latency and number of sleep complaints did not change between the first and third assessments. Blacks and whites had a greater increase in sleep duration than Chinese. Taken together, the results of this longitudinal study suggest that sleep may not worsen, in general, in midlife women. Perhaps, the expected negative effect of aging in midlife into early old age on sleep is overstated.

Hot flashes and awakenings among midlife women.

STUDY OBJECTIVES: For most women, the menopause is accompanied by hot flashes and sleep problems. Although hot flashes reportedly wake women from sleep, in the few studies that have used objective measures of both sleep and hot flashes, links between hot flashes and nocturnal awakening have been inconsistent. In a well-characterized cohort of midlife women, we examined the association between objectively assessed hot flashes and actigraphically defined wake from sleep. We hypothesized that wake episodes would be more likely during an objective hot flash relative to minutes without a hot flash. METHODS: Peri- and postmenopausal midlife women underwent simultaneous objective measurement of hot flashes (sternal skin conductance) and sleep (actigraphy) over 24 hours in the home. The likelihood of waking in the minutes during the hot flash relative to the minutes preceding the hot flash was compared using generalized estimating equations. RESULTS: We studied 168 women with at least one objective nocturnal hot flash and actigraphy data. Actigraphy-assessed wake episodes were concurrent with 78% of the objective hot flashes. We found an increased likelihood of wake in the minutes during the objective hot flash (0 to +5 min: OR [95% CI] = 5.31 (4.46 to 6.33); p < .0001) relative to the minutes preceding it (-10 to -1 min). The increased likelihood of wake occurred irrespective of whether the women reported the objective hot flash. CONCLUSION: Among these women who underwent objective measurement of sleep and hot flashes, nocturnal wakefulness was observed with the majority of hot flashes.

Empirical derivation of cutoff values for the sleep health metric and its relationship to cardiometabolic morbidity: results from the Midlife in the United States (MIDUS) study.

STUDY OBJECTIVES: Emerging evidence supports a multidimensional perspective of sleep in the context of health. The sleep health model, and composite sleep health score, are increasingly used in research. However, specific cutoff values that differentiate "good" from "poor" sleep, have not been empirically derived and its relationship to cardiometabolic health is less-well understood. We empirically derived cutoff values for sleep health dimensions and examined the relationship between sleep health and cardiometabolic morbidity. METHODS: Participants from two independent Biomarker Studies in the MIDUS II (N = 432, 39.8% male, age = 56.92 ± 11.45) and MIDUS Refresher (N = 268, 43.7% male, age = 51.68 ± 12.70) cohorts completed a 1-week study where sleep was assessed with daily diaries and wrist actigraphy. Self-reported physician diagnoses, medication use, and blood values were used to calculate total cardiometabolic morbidity. Receiver operating characteristic (ROC) curves were generated in the MIDUS II cohort for each sleep health dimension to determine cutoff values. Using derived cutoff values, logistic regression was used to examine the relationship between sleep health scores and cardiometabolic morbidity in the MIDUS Refresher cohort, controlling for traditional risk factors. RESULTS: Empirically derived sleep health cutoff values aligned reasonably well to cutoff values previously published in the sleep health literature and remained robust across physical and mental health outcomes. Better sleep health was significantly associated with a lower odds of cardiometabolic morbidity (OR [95% CI] = 0.901 [0.814-0.997], p = .044). CONCLUSIONS: These results contribute to the ongoing development of the sleep health model and add to the emerging research supporting a multidimensional perspective of sleep and health.

Racial/ethnic disparities in women's sleep duration, continuity, and quality, and their statistical mediators: Study of Women's Health Across the Nation.

STUDY OBJECTIVES: To describe racial/ethnic differences in sleep duration, continuity, and perceived sleep quality in postmenopausal women and to identify statistical mediators of differences in sleep characteristics. METHODS: Recruited from the observational Study of Women's Health Across the Nation (SWAN), 1,203 (548 white, 303 black, 147 Chinese, 132 Japanese, and 73 Hispanic; mean age 65 years, 97% postmenopausal) women participated in a week-long actigraphy and daily diary study in 2013-2015. Actigraphic measures of sleep duration and wake after sleep onset (WASO), and diary-rated sleep quality were averaged across the week. Candidate mediators included health-related variables; stress; and emotional well-being assessed up to 13 times across 18 years from baseline to sleep study. RESULTS: Whites slept longer than other groups; the significant mediators were concurrent financial hardship and increasing number of stressors for Hispanics or Japanese versus whites. Whites had less WASO than blacks and Hispanics; significant mediators were concurrent number of health problems, physical inactivity, waist circumference, vasomotor symptoms, number of life stressors, and financial hardship, and increasing number of health problems from baseline to sleep study. Whites reported better sleep quality than blacks, Chinese, and Japanese; significant mediators were concurrent physical inactivity, vasomotor symptoms, positive affect, and depressive symptoms. CONCLUSIONS: Sleep differences between blacks or Hispanics versus whites were mediated by health problems, number of stressors, and financial hardship, whereas sleep differences between Chinese or Japanese versus whites were mediated by emotional well-being. This is the first study using formal mediational approaches.

Which Sleep Health Characteristics Predict All-Cause Mortality in Older Men? An Application of Flexible Multivariable Approaches.

Study Objectives: Sleep is multidimensional, with domains including duration, timing, continuity, regularity, rhythmicity, quality, and sleepiness/alertness. Individual sleep characteristics representing these domains are known to predict health outcomes. However, most studies consider sleep characteristics in isolation, resulting in an incomplete understanding of which sleep characteristics are the strongest predictors of health outcomes. We applied three multivariable approaches to robustly determine which sleep characteristics increase mortality risk in the osteoporotic fractures in men sleep study. Methods: In total, 2,887 men (mean 76.3 years) completed relevant assessments and were followed for up to 11 years. One actigraphy or self-reported sleep characteristic was selected to represent each of seven sleep domains. Multivariable Cox models, survival trees, and random survival forests were applied to determine which sleep characteristics increase mortality risk. Results: Rhythmicity (actigraphy pseudo-F statistic) and continuity (actigraphy minutes awake after sleep onset) were the most robust sleep predictors across models. In a multivariable Cox model, lower rhythmicity (hazard ratio, HR [95%CI] =1.12 [1.04, 1.22]) and lower continuity (1.16 [1.08, 1.24]) were the strongest sleep predictors. In the random survival forest, rhythmicity and continuity were the most important individual sleep characteristics (ranked as the sixth and eighth most important among 43 possible sleep and non-sleep predictors); moreover, the predictive importance of all sleep information considered simultaneously followed only age, cognition, and cardiovascular disease. Conclusions: Research within a multidimensional sleep health framework can jumpstart future research on causal pathways linking sleep and health, new interventions that target specific sleep health profiles, and improved sleep screening for adverse health outcomes.

Objective Sleep Duration Is Prospectively Associated With Endothelial Health.

Study Objectives: The mechanisms linking short sleep duration to cardiovascular disease (CVD) are poorly understood. Emerging evidence suggests that endothelial dysregulation may lie along the causal pathway linking sleep duration to cardiovascular risk, although current evidence in humans is based on cross-sectional studies. Our objective was to evaluate the prospective association between objectively assessed sleep duration and clinical indices of endothelial health. Methods: A total of 141 medically healthy adults underwent an overnight laboratory sleep study when they were between the ages of 21 and 60 years. Total sleep time was objectively assessed by polysomnography at study entry. Endothelial health, including brachial artery diameter (BAD) and flow-mediated dilation (FMD), was measured 18.9 ± 4.6 years later. Medical health and psychiatric status were assessed at both time points. Approximately half of the sample had a lifetime history of major depressive disorder. Results: In univariate analyses, shorter sleep duration was associated with increased BAD (ß = -0.24, p = .004) and decreased FMD (ß = 0.17, p = .042). BAD, but not FMD, remained significantly associated with sleep duration after adjusting for sex, age, body mass index (BMI), smoking, diabetes, hypertension, and lifetime history of major depressive disorder (MDD) at T2. The association between sleep duration and BAD was stronger than the association between BAD and an aggregate measure of CVD risk including three or more of the following risk factors: male sex, age ≥ 65 years, smoker, BMI ≥ 30, diabetes, hypertension, and MDD. Conclusions: Objectively assessed short sleep duration was prospectively associated with increased BAD over a 12- to 30-year period.

Sleep-Wake Differences in Relative Regional Cerebral Metabolic Rate for Glucose among Patients with Insomnia Compared with Good Sleepers.

STUDY OBJECTIVES: The neurobiological mechanisms of insomnia may involve altered patterns of activation across sleep-wake states in brain regions associated with cognition, self-referential processes, affect, and sleep-wake promotion. The objective of this study was to compare relative regional cerebral metabolic rate for glucose (rCMRglc) in these brain regions across wake and nonrapid eye movement (NREM) sleep states in patients with primary insomnia (PI) and good sleeper controls (GS). METHODS: Participants included 44 PI and 40 GS matched for age (mean = 37 y old, range 21-60), sex, and race. We conducted [18F]fluoro-2-deoxy-D-glucose positron emission tomography scans in PI and GS during both morning wakefulness and NREM sleep at night. Repeated measures analysis of variance was used to test for group (PI vs. GS) by state (wake vs. NREM sleep) interactions in relative rCMRglc. RESULTS: Significant group-by-state interactions in relative rCMRglc were found in the precuneus/posterior cingulate cortex, left middle frontal gyrus, left inferior/superior parietal lobules, left lingual/fusiform/occipital gyri, and right lingual gyrus. All clusters were significant at Pcorrected < 0.05. CONCLUSIONS: Insomnia was characterized by regional alterations in relative glucose metabolism across NREM sleep and wakefulness. Significant group-by-state interactions in relative rCMRglc suggest that insomnia is associated with impaired disengagement of brain regions involved in cognition (left frontoparietal), self-referential processes (precuneus/posterior cingulate), and affect (left middle frontal, fusiform/lingual gyri) during NREM sleep, or alternatively, to impaired engagement of these regions during wakefulness.

Bedtime Variability and Metabolic Health in Midlife Women: The SWAN Sleep Study.

STUDY OBJECTIVES: Circadian misalignment, as seen in shift workers, can disrupt metabolic processes. Associations between sleep timing in nonshift workers and metabolic health are unknown. We examined sleep timing and indices of metabolic health in a community sample of midlife women. METHODS: Caucasian (n = 161), African American (n = 121) and Chinese (n = 56) non-shift-working women aged 48-58 y who were not taking insulin-related medications, participated in the Study of Women's Health Across the Nation (SWAN) Sleep Study and were subsequently examined approximately 5.39 (standard deviation = 0.71) y later. Daily diary-reported bedtimes were used to calculate four measures of sleep timing: mean bedtime, bedtime variability, bedtime delay and bedtime advance. Body mass index (BMI) and insulin resistance (homeostatic model assessment-insulin resistance, HOMA-IR) were measured at two time points. Linear regressions evaluated whether sleep timing was associated with BMI and HOMA-IR cross-sectionally and prospectively. RESULTS: In cross-sectional models, greater variability in bedtime and greater bedtime delay were associated with higher HOMA-IR (ß = 0.128; P = 0.007, and ß = 0.110; P = 0.013, respectively) and greater bedtime advance was associated with higher BMI (ß = 0.095; P = 0.047). Prospectively, greater bedtime delay predicted increased HOMA-IR at Time 2 (ß = 0.152; P = 0.003). Results were partially explained by shifted sleep timing on weekends. CONCLUSION: Frequent shifts in sleep timing may be related to metabolic health among non-shift working midlife women. COMMENTARY: A commentary on this article appears in this issue on page 269.

Chronic Stress is Prospectively Associated with Sleep in Midlife Women: The SWAN Sleep Study.

STUDY OBJECTIVES: Evaluate whether levels of upsetting life events measured over a 9-y period prospectively predict subjective and objective sleep outcomes in midlife women. DESIGN: Prospective cohort study. SETTING: Four sites across the United States. PARTICIPANTS: 330 women (46-57 y of age) enrolled in the Study of Women's Health Across the Nation (SWAN) Sleep Study. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Upsetting life events were assessed annually for up to 9 y. Trajectory analysis applied to life events data quantitatively identified three distinct chronic stress groups: low stress, moderate stress, and high stress. Sleep was assessed by self-report and in-home polysomnography (PSG) during the ninth year of the study. Multivariate analyses tested the prospective association between chronic stress group and sleep, adjusting for race, baseline sleep complaints, marital status, body mass index, symptoms of depression, and acute life events at the time of the Sleep Study. Women characterized by high chronic stress had lower subjective sleep quality, were more likely to report insomnia, and exhibited increased PSG-assessed wake after sleep onset (WASO) relative to women with low to moderate chronic stress profiles. The effect of chronic stress group on WASO persisted in the subsample of participants without baseline sleep complaints. CONCLUSIONS: Chronic stress is prospectively associated with sleep disturbance in midlife women, even after adjusting for acute stressors at the time of the sleep study and other factors known to disrupt sleep. These results are consistent with current models of stress that emphasize the cumulative effect of stressors on health over time.

African Genetic Ancestry is Associated with Sleep Depth in Older African Americans.

STUDY OBJECTIVES: The mechanisms that underlie differences in sleep characteristics between European Americans (EA) and African Americans (AA) are not fully known. Although social and psychological processes that differ by race are possible mediators, the substantial heritability of sleep characteristics also suggests genetic underpinnings of race differences. We hypothesized that racial differences in sleep phenotypes would show an association with objectively measured individual genetic ancestry in AAs. DESIGN: Cross sectional. SETTING: Community-based study. PARTICIPANTS: Seventy AA adults (mean age 59.5 ± 6.7 y; 62% female) and 101 EAs (mean age 60.5 ± 7 y, 39% female). MEASUREMENTS AND RESULTS: Multivariate tests were used to compare the Pittsburgh Sleep Quality Index (PSQI) and in-home polysomnographic measures of sleep duration, sleep efficiency, apnea-hypopnea index (AHI), and indices of sleep depth including percent visually scored slow wave sleep (SWS) and delta EEG power of EAs and AAs. Sleep duration, efficiency, and sleep depth differed significantly by race. Individual % African ancestry (%AF) was measured in AA subjects using a panel of 1698 ancestry informative genetic markers and ranged from 10% to 88% (mean 67%). Hierarchical linear regression showed that higher %AF was associated with lower percent SWS in AAs (ß (standard error) = -4.6 (1.5); P = 0.002), and explained 11% of the variation in SWS after covariate adjustment. A similar association was observed for delta power. No association was observed for sleep duration and efficiency. CONCLUSION: African genetic ancestry is associated with indices of sleep depth in African Americans. Such an association suggests that part of the racial differences in slow-wave sleep may have genetic underpinnings.

Identifying Insomnia in Early Pregnancy: Validation of the Insomnia Symptoms Questionnaire (ISQ) in Pregnant Women.

STUDY OBJECTIVES: Although a substantial number of pregnant women report symptoms of insomnia, few studies have used a validated instrument to determine the prevalence in early gestation. Identification of insomnia in pregnancy is vital given the strong connection between insomnia and the incidence of depression, cardiovascular disease, or immune dysregulation. The goal of this paper is to provide additional psychometric evaluation and validation of the Insomnia Symptom Questionnaire (ISQ) and to establish prevalence rates of insomnia among a cohort of pregnant women during early gestation. METHODS: The ISQ was evaluated in 143 pregnant women at 12 weeks gestation. The internal consistency and criterion validity of the dichotomized ISQ were compared to traditional measures of sleep from sleep diaries, actigraphy, and the Pittsburgh Sleep Quality Index using indices of sensitivity, specificity, positive and negative predictive value (PPV, NPV), and likelihood ratio (LR) tests. RESULTS: The ISQ identified 12.6% of the sample as meeting a case definition of insomnia, consistent with established diagnostic criteria. Good reliability was established with Cronbach α = 0.86. The ISQ had high specificity (most > 85%), but sensitivity, PPV, NPV, and LRs varied according to which sleep measure was used as the validating criterion. CONCLUSIONS: Insomnia is a health problem for many pregnant women at all stages in pregnancy. These data support the validity and reliability of the ISQ to identify insomnia in pregnant women. The ISQ is a short and cost-effective tool that can be quickly employed in large observational studies or in clinical practice where perinatal women are seen. COMMENTARY: A commentary on this article appears in this issue on page 593.

An actigraphy study of sleep and pain in midlife women: the Study of Women's Health Across the Nation Sleep Study.

OBJECTIVE: We examined whether women reporting nighttime pain would have more actigraphy-measured evidence for disturbed sleep and would report feeling less rested compared with women without nighttime pain. METHODS: Up to 27 consecutive nights of actigraphy and sleep diary data from each participant were analyzed in this community-based study of 314 African-American (n = 118), white (n = 141), and Chinese (n = 55) women, aged 48 to 58 years, who were premenopausal, perimenopausal, or postmenopausal and were participating in the Study of Women's Health Across the Nation Sleep Study. Dependent variables were actigraphy-measured movement and fragmentation index, total sleep time, sleep efficiency, and diary self-report of "feeling rested" after waking up. All outcomes were fitted using linear mixed-effects models to examine covariate-adjusted associations between the independent variable (nighttime pain severity) and sleep outcomes. RESULTS: Higher pain severity scores were associated with longer sleep duration but reduced sleep efficiency and less restful sleep. Women reporting nocturnal vasomotor symptoms had more sleep-related movement and sleep fragmentation, had reduced sleep efficiency, and were less likely to feel rested after wakening whether or not they reported pain. CONCLUSIONS: Midlife women who report higher nighttime pain levels have more objective evidence for less efficient sleep, consistent with self-reported less restful sleep. Nocturnal vasomotor symptoms also can contribute to restlessness and wakefulness in midlife women.

Association between sleep duration and mortality is mediated by markers of inflammation and health in older adults: the Health, Aging and Body Composition Study.

STUDY OBJECTIVES: Inflammation may represent a common physiological pathway linking both short and long sleep duration to mortality. We evaluated inflammatory markers as mediators of the relationship between sleep duration and mortality in community-dwelling older adults. DESIGN: Prospective cohort with longitudinal follow-up for mortality outcomes. SETTING: Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Participants in the Health, Aging and Body Composition (Health ABC) Study (mean age 73.6 ± 2.9 years at baseline) were sampled and recruited from Medicare listings. MEASUREMENTS AND RESULTS: Baseline measures of subjective sleep duration, markers of inflammation (serum interleukin-6, tumor necrosis factor-α, and C-reactive protein) and health status were evaluated as predictors of all-cause mortality (average follow-up = 8.2 ± 2.3 years). Sleep duration was related to mortality, and age-, sex-, and race-adjusted hazard ratios (HR) were highest for those with the shortest (< 6 h HR: 1.30, CI: 1.05-1.61) and longest (> 8 h HR: 1.49, CI: 1.15-1.93) sleep durations. Adjustment for inflammatory markers and health status attenuated the HR for short (< 6 h) sleepers (HR = 1.06, 95% CI = 0.83-1.34). Age-, sex-, and race-adjusted HRs for the > 8-h sleeper group were less strongly attenuated by adjustment for inflammatory markers than by other health factors associated with poor sleep with adjusted HR = 1.23, 95% CI = 0.93-1.63. Inflammatory markers remained significantly associated with mortality. CONCLUSION: Inflammatory markers, lifestyle, and health status explained mortality risk associated with short sleep, while the mortality risk associated with long sleep was explained predominantly by lifestyle and health status.

Behavioral treatment of chronic insomnia in older adults: does nocturia matter?

OBJECTIVE: To evaluate the impact of nocturia on the therapeutic response of chronic insomnia to behavioral treatment in older adults. METHODS: Secondary analysis of a randomized clinical trial designed to assess the efficacy of brief behavioral treatment of insomnia (BBTI) vs. an information-only control (IC) in 79 community-dwelling older adults with chronic insomnia. For the current analysis, participants were stratified into 2 groups: those with self-reported nocturia at baseline i.e., ≥ 1 void/night (N = 30; 16 IC, 14 BBTI) and those without nocturia (N = 49; 24 IC, 25 BBTI). We then determined the impact of BBTI on sleep, sleep quality, and nocturia as assessed by self-report, actigraphy, and polysomnography. RESULTS: Individuals without baseline nocturia responded well to BBTI with significant decrease in sleep latency, wake after sleep onset, and total sleep time assessed by sleep diary and actigraphy; these changes were significantly greater than those in the IC group. In comparison, changes in the same sleep parameters among participants with nocturia were not significantly different from the IC control. Although BBTI showed significant improvement in sleep quality in groups with and without nocturia (as assessed by PSQI and sleep diary), the effect size of these improvements was larger in those without nocturia than in those with nocturia (PSQI d = 0.82 vs. 0.53, diary sleep quality d = 0.83 vs. 0.51). CONCLUSIONS: These secondary analyses suggest that brief behavioral treatment of insomnia may be more efficacious in improving insomnia in participants without nocturia. Addressing nocturia may improve the efficacy of behavioral insomnia treatment.

A Neurobiological Model of Insomnia.

Insomnia is a common clinical condition resulting in significant costs and morbidity. Previous models of insomnia focusing on psychological and behavioral processes are useful clinically, but lack neurobiological specificity. We propose an insomnia model based on basic and clinical neuroscience findings, and hypothesize that insomnia results from persistent activity in wake-promoting neural structures during NREM sleep. The simultaneous occurrence of sleeping and waking neural activity helps to explain clinical phenomenology and treatment effects in insomnia.