Evaluation of the association of menopausal status with delta and beta EEG activity during sleep

Morning tiredness and insomnia symptoms are associated with increased blood pressure in midlife women

OBJECTIVES

The objective of this study was to investigate how blood pressure, sleep architecture, sleep-disordered breathing, body habitus, and levels of serum follicle-stimulating hormone are associated with symptoms of insomnia and sleep quality during menopausal transition.

METHODS

64 healthy premenopausal women (aged 45-47 years) were recruited to the study. Data were collected at baseline and at 10-year follow-up during sleep laboratory and laboratory visits. A sleep questionnaire was used to evaluate sleep quality and insomnia symptoms. Data were analysed using multiple linear and logistic regression with a backward method.

RESULTS

During the menopausal transition, a change in insomnia symptoms was associated with a change in morning systolic blood pressure (β = 0.114 (CI95% 0.023-0.205), p = 0.016). At follow-up, at the age of 56, a higher percentage of REM sleep was associated with a lower odds of restless sleep (OR = 0.842 (95 % CI 0.742-0.954), p = 0.007), while both higher systolic and diastolic evening blood pressure was associated with an increased odds of morning tiredness. OR = 1.047 (95 % CI 1.003-1.092), p = 0.034 and OR = 1.126 (95 % CI 1.018-1.245), p = 0.007, respectively.

CONCLUSIONS

In healthy midlife women, a change blood pressure is related to the development of insomnia symptoms during menopausal transition. In postmenopausal women, a high evening blood pressure may be associated with morning tiredness and a reduced amount of REM sleep may be perceived as restless sleep.

Effects of early midlife ovarian removal on sleep: Polysomnography-measured cortical arousal, homeostatic drive, and spindle characteristics

Bilateral salpingo-oophorectomy (BSO; removal of ovaries and fallopian tubes) prior to age 48 is associated with elevated risk for both Alzheimer's disease (AD) and sleep disorders such as insomnia and sleep apnea. In early midlife, individuals with BSO show reduced hippocampal volume, function, and hippocampal-dependent verbal episodic memory performance associated with changes in sleep. It is unknown whether BSO affects fine-grained sleep measurements (sleep microarchitecture) and how these changes might relate to hippocampal-dependent memory. We recruited thirty-six early midlife participants with BSO. Seventeen of these participants were taking 17β-estradiol therapy (BSO+ET) and 19 had never taken ET (BSO). Twenty age-matched control participants with intact ovaries (AMC) were also included. Overnight at-home polysomnography recordings were collected, along with subjective sleep quality and hot flash frequency. Multivariate Partial Least Squares (PLS) analysis was used to assess how sleep varied between groups. Compared to AMC, BSO without ET was associated with significantly decreased time spent in non-rapid eye movement (NREM) stage 2 sleep as well as increased NREM stage 2 and 3 beta power, NREM stage 2 delta power, and spindle power and maximum amplitude. Increased spindle maximum amplitude was negatively correlated with verbal episodic memory performance. Decreased sleep latency, increased sleep efficiency, and increased time spent in rapid eye movement sleep were observed for BSO+ET. Findings suggest there is an association between ovarian hormone loss and sleep microarchitecture, which may contribute to poorer cognitive outcomes and be ameliorated by ET.

Dorsal brain activity reflects the severity of menopausal symptoms

OBJECTIVE

The severity of menopausal symptoms, despite being triggered by hormonal imbalance, does not directly correspond to hormone levels in the blood; thus, the level of unpleasantness is assessed using subjective questionnaires in clinical practice. To provide better treatments, alternative objective assessments have been anticipated to support medical interviews and subjective assessments. This study aimed to develop a new objective measurement for assessing unpleasantness.

METHODS

Fourteen participants with menopausal symptoms and two age-matched participants who visited our outpatient section were enrolled. Resting-state brain activity was measured using magnetoencephalography. The level of unpleasantness of menopausal symptoms was measured using the Kupperman Kohnenki Shogai Index. The blood level of follicle-stimulating hormone and luteinizing hormone were also measured. Correlation analyses were performed between the oscillatory power of brain activity, index score, and hormone levels.

RESULTS

The level of unpleasantness of menopausal symptoms was positively correlated with high-frequency oscillatory powers in the parietal and bordering cortices (alpha; P = 0.016, beta; P = 0.015, low gamma; P = 0.010). The follicle-stimulating hormone blood level was correlated with high-frequency oscillatory powers in the dorsal part of the cortex (beta; P = 0.008, beta; P = 0.005, low gamma; P = 0.017), whereas luteinizing hormone blood level was not correlated.

CONCLUSION

Resting-state brain activity can serve as an objective measurement of unpleasantness associated with menopausal symptoms, which aids the selection of appropriate treatment and monitors its outcome.

The Relationship Between Mood and Sleep in Different Female Reproductive States

Mood and sleep are tightly interrelated. Mood and sleep symptoms and disorders are more common in women than in men and often associated with reproductive events. This article reviews the current literature on the reciprocal relationships between mood and sleep across reproductive phases in women, such as menstrual cycle and related disorders, pregnancy, climacteric, and use of hormonal contraception and hormone replacement therapy. Mood and sleep symptoms seem to covary in relation to physiologic and pathologic reproductive conditions, although the relationship seems more clear for subjective than objective sleep.

Disturbed sleep is associated with reduced verbal episodic memory and entorhinal cortex volume in younger middle-aged women with risk-reducing early ovarian removal

Introduction

Women with early ovarian removal (<48 years) have an elevated risk for both late-life Alzheimer's disease (AD) and insomnia, a modifiable risk factor. In early midlife, they also show reduced verbal episodic memory and hippocampal volume. Whether these reductions correlate with a sleep phenotype consistent with insomnia risk remains unexplored.

Methods

We recruited thirty-one younger middleaged women with risk-reducing early bilateral salpingo-oophorectomy (BSO), fifteen of whom were taking estradiol-based hormone replacement therapy (BSO+ERT) and sixteen who were not (BSO). Fourteen age-matched premenopausal (AMC) and seventeen spontaneously peri-postmenopausal (SM) women who were ~10y older and not taking ERT were also enrolled. Overnight polysomnography recordings were collected at participants' home across multiple nights (M=2.38 SEM=0.19), along with subjective sleep quality and hot flash ratings. In addition to group comparisons on sleep measures, associations with verbal episodic memory and medial temporal lobe volume were assessed.

Results

Increased sleep latency and decreased sleep efficiency were observed on polysomnography recordings of those not taking ERT, consistent with insomnia symptoms. This phenotype was also observed in the older women in SM, implicating ovarian hormone loss. Further, sleep latency was associated with more forgetting on the paragraph recall task, previously shown to be altered in women with early BSO. Both increased sleep latency and reduced sleep efficiency were associated with smaller anterolateral entorhinal cortex volume.

Discussion

Together, these findings confirm an association between ovarian hormone loss and insomnia symptoms, and importantly, identify an younger onset age in women with early ovarian removal, which may contribute to poorer cognitive and brain outcomes in these women.

Optimizing sleep across the menopausal transition

Women frequently experience sleep disturbances, particularly night-time awakenings, as they transition menopause and enter postmenopause. Sleep is essential for optimal functioning and health. Persistent and distressing sleep disturbances across menopause can negatively impact daytime functioning and productivity, and increase risk for mental and physical health conditions. While multiple factors can disturb sleep, two unique factors in the context of menopause are vasomotor symptoms and the changing reproductive hormone environment. Vasomotor symptoms are associated with sleep disturbances and contribute significantly to awakenings and amount of time spent awake during the night. Even after accounting for vasomotor and depressive symptoms, lower estradiol and higher follicle stimulating hormone levels, indicative of menopause, are associated with sleep disturbance, particularly awakenings, suggesting that the hormone environment may directly affect sleep. Management strategies for clinically significant menopausal sleep disturbances include cognitive behavioral therapy for insomnia, which is effective and durable in treating menopausal insomnia. Hormone therapy alleviates sleep disturbances, particularly in the presence of disruptive vasomotor symptoms. Sleep disturbances have a significant impact on women's functioning and health, and there is a need for further research of the underlying mechanisms to advance effective preventative and treatment strategies that ensure optimal health and well-being of midlife women.

Longitudinal trajectories of spectral power during sleep in middle-aged and older adults

Age-related changes in sleep appear to contribute to cognitive aging and dementia. However, most of the current understanding of sleep across the lifespan is based on cross-sectional evidence. Using data from the Sleep Heart Health Study, we investigated longitudinal changes in sleep micro-architecture, focusing on whether such age-related changes are experienced uniformly across individuals. Participants were 2,202 adults (age_Baseline = 62.40 ± 10.38, 55.36 % female, 87.92 % White) who completed home polysomnography assessment at two study visits, which were 5.23 years apart (range: 4-7 years). We analyzed NREM and REM spectral power density for each 0.5 Hz frequency bin, including slow oscillation (0.5-1 Hz), delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), sigma (12-15 Hz), and beta-1 (15-20 Hz) bands. Longitudinal comparisons showed a 5-year decline in NREM delta (p <.001) and NREM sigma power density (p <.001) as well as a 5-year increase in theta power density during NREM (p =.001) and power density for all frequency bands during REM sleep (ps < 0.05). In contrast to the notion that sleep declines linearly with advancing age, longitudinal trajectories varied considerably across individuals. Within individuals, the 5-year changes in NREM and REM power density were strongly correlated (slow oscillation: r = 0.46; delta: r = 0.67; theta r = 0.78; alpha r = 0.66; sigma: r = 0.71; beta-1: r = 0.73; ps < 0.001). The convergence in the longitudinal trajectories of NREM and REM activity may reflect age-related neural de-differentiation and/or compensation processes. Future research should investigate the neurocognitive implications of longitudinal changes in sleep micro-architecture and test whether interventions for improving key sleep micro-architecture features (such as NREM delta and sigma activity) also benefit cognition over time.

Estradiol and Estrogen-like Alternative Therapies in Use: The Importance of the Selective and Non-Classical Actions

Estrogen is one of the most important female sex hormones, and is indispensable for reproduction. However, its role is much wider. Among others, due to its neuroprotective effects, estrogen protects the brain against dementia and complications of traumatic injury. Previously, it was used mainly as a therapeutic option for influencing the menstrual cycle and treating menopausal symptoms. Unfortunately, hormone replacement therapy might be associated with detrimental side effects, such as increased risk of stroke and breast cancer, raising concerns about its safety. Thus, tissue-selective and non-classical estrogen analogues have become the focus of interest. Here, we review the current knowledge about estrogen effects in a broader sense, and the possibility of using selective estrogen-receptor modulators (SERMs), selective estrogen-receptor downregulators (SERDs), phytoestrogens, and activators of non-genomic estrogen-like signaling (ANGELS) molecules as treatment.

Comparing polysomnography, actigraphy, and sleep diary in the home environment: The Study of Women's Health Across the Nation (SWAN) Sleep Study

Study Objectives

Polysomnography (PSG) is considered the "gold standard" for assessing sleep, but cost and burden limit its use. Although wrist actigraphy and self-report diaries are feasible alternatives to PSG, few studies have compared all three modalities concurrently across multiple nights in the home to assess their relative validity across multiple sleep outcomes. This study compared sleep duration and continuity measured by PSG, actigraphy, and sleep diaries and examined moderation by race/ethnicity.

Methods

Participants from the Study of Women's Health Across the Nation (SWAN) Sleep Study included 323 White (n = 147), African American (n = 120), and Chinese (n = 56) middle-aged community-dwelling women (mean age: 51 years, range: 48-57). PSG, wrist actigraphy (AW-64; Philips Respironics, McMurray, PA), and sleep diaries were collected concurrently in participants' homes over three consecutive nights. Multivariable repeated-measures linear models compared time in bed (TIB), total sleep time (TST), sleep efficiency (SE), sleep latency (SL), and wake after sleep onset (WASO) across modalities.

Results

Actigraphy and PSG produced similar estimates of sleep duration and efficiency. Diaries yielded higher estimates of TIB, TST, and SE versus PSG and actigraphy, and lower estimates of SL and WASO versus PSG. Diary SL was shorter than PSG SL only among White women, and diary WASO was lower than PSG and actigraphy WASO among African American versus White women.

Conclusions

Given concordance with PSG, actigraphy may be preferred as an alternative to PSG for measuring sleep in the home. Future research should consider racial/ethnic differences in diary-reported sleep continuity.

A systematic review and meta-analysis of the cyclic alternating pattern across the lifespan

BACKGROUND

Cyclic alternating pattern (CAP) is the electroencephalogram (EEG) pattern described as a marker of sleep instability and assessed by NREM transient episodes in sleep EEG. It has been associated with brain maturation. The aim of this review was to evaluate the normative data of CAP parameters according to the aging process in healthy subjects through a systematic review and meta-analysis.

METHODS

Two authors independently searched databases using PRISMA guidelines. Discrepancies were reconciled by a third reviewer. Subgroup analysis and tests for heterogeneity were conducted.

RESULTS

Of 286 studies, 10 submitted a total of 168 healthy individuals to CAP analysis. Scoring of CAP can begin at 3 months of life, when K-complexes, delta bursts, or spindles can be recognized. Rate of CAP increased with age, mainly during the first 2 years of life, then decreased in adolescence, and increased in the elderly. The A1 CAP subtype and CAP rate were high in school-aged children during slow-wave sleep (SWS). A1 CAP subtypes were significantly more numerous in adolescents compared with other groups, while the elderly showed the highest amounts of A2 and A3 CAP subtypes. Our meta-analysis registered the lowest CAP rate in infants younger than 2 years old and the highest in the elderly.

CONCLUSIONS

This review summarized the normative data of CAP in NREM sleep during the aging process. The CAP rate increased with age and sleep depth, especially during SWS. Parameters of CAP may reflect gender hormonal effects and neuroplasticity. More reports on CAP subtypes are needed for their reference values establishment.

Influence of the menopausal transition on polysomnographic sleep characteristics: a longitudinal analysis

STUDY OBJECTIVES

To evaluate how change in menopausal status related to spectral analysis and polysomnographic measures of sleep characteristics.

METHODS

The Study of Women's Health Across the Nation (SWAN) Ancillary Sleep Study evaluated sleep characteristics of 159 women who were initially pre- or early perimenopausal and repeated the assessment about 3½ years later when 38 were pre- or early perimenopausal, 31 late perimenopausal, and 90 postmenopausal. Participants underwent in-home ambulatory polysomnography for two to three nights. Average EEG power in the delta and beta frequency bands was calculated during NREM and REM sleep, and sleep duration, wake after sleep onset (WASO), and apnea hypopnea index (AHI) were based on visually-scored sleep.

RESULTS

The women who transitioned to postmenopause had increased beta NREM EEG power at the second assessment, compared to women who remained pre-or early premenopausal; no other sleep measures varied by change in menopausal status. In multivariate models the associations remained; statistical controls for self-reported hot flashes did not explain findings. In secondary analysis, NREM beta power at the second assessment was greater among women who transitioned into the postmenopause after adjustments for initial NREM beta power.

CONCLUSIONS

Sleep duration and WASO did not vary by menopause transition group across assessments. Consistent with prior cross-sectional analysis, elevated beta EEG power in NREM sleep was apparent among women who transitioned to postmenopause, suggesting that independent of self-reported hot flashes, the menopausal transition is associated with physiological hyperarousal during sleep.

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.

Lowered progesterone metabolite excretion and a variable LH excretion pattern are associated with vasomotor symptoms but not negative mood in the early perimenopausal transition: Study of Women's Health Across the Nation

OBJECTIVE

The menopausal transition is characterized by progressive changes in ovarian function and increasing circulating levels of gonadotropins, with some women having irregular menstrual cycles well before their final menstrual period. These observations indicate a progressive breakdown of the hypothalamic-pituitary-ovarian axis often associated with an increase in menopausal symptoms. Relationships between vasomotor symptoms (VMS) and depressed mood and sleep as well as a bidirectional association between VMS and depressed mood in mid-life women have been reported, but the endocrine foundations and hormone profiles associated with these symptoms have not been well described. Our objective was to determine the relationship between daily urinary hormone profiles and daily logs of affect and VMS during the early perimenopausal transition.

STUDY DESIGN

SWAN, the Study of Women's Health Across the Nation, is a large, mutli-ethnic, multisite cohort study of 3302 women aged 42-52 at baseline, designed to examine predictors of health and disease in women as they traversed the menopause. Inclusion criteria were: an intact uterus and at least one ovary present, at least one menstrual period in the previous three months, no use of sex steroid hormones in the previous three months, and not pregnant or lactating. A subset (n = 849) of women aged 43-53 years from all study sites in the first Daily Hormone Study collection were evaluated for this substudy.

OUTCOME MEASURES

We measured daily VMS, and urinary hormones: follicle stimulating hormone (FSH), luteinizing hormone (LH), pregnanediol glucuronide (PdG) and estradiol (estrone conjugate, E1C).

RESULTS

A variable pattern of LH and negative LH feedback were the hormone patterns most strongly associated with increased VMS. In contrast, no hormone pattern was significantly related to negative mood.

CONCLUSION

Fluctuations of LH associated with low progesterone production were associated with VMS but not negative mood, suggesting different endocrine patterns may be related to increased negative mood than to the occurrence of VMS.

Effectiveness of Menosan® Salvia officinalis in the treatment of a wide spectrum of menopausal complaints. A double-blind, randomized, placebo-controlled, clinical trial

Objective

To evaluate efficacy and safety of fresh Salvia officinalis extract tablets in relieving typical symptoms in menopausal women and to gain insight in the mode of action by measuring altered cerebral wave intensities.

Methods

Randomized 80 menopausal women from 48 - 65 years of age received Menosan® tablets [3'400 mg ethanolic extract of freshly harvested Salvia officinalis L.] or placebo under double-blind conditions for 4 weeks. An efficacy analysis evaluated the developments of the menopausal rating scale [MRS], hot flush severity score [HFS] and quantitative electroencephalography [qEEG] intensities in the per protocol population. Results were further corroborated by data from the intention to treat population including late postmenopausal women.

Results

Salvia off. distinctly reduced MRS by 39.2% from 15.3 ± 6.87 to 9.3 ± 5.75 and significantly in comparison to placebo (p = 0.002). The HFS score decreased by 55.3% from 15.9 ± 13.77 to 7.1 ± 7.41, reaching significance on week 3 onwards (p = 0.028). Clinical effects of Salvia off. correlated with relevant reduction of frontal lobe beta2 wave qEEG intensities at electrodes F3/4/7/8 and are underpinned by secondary parameters and ITT analysis. Salvia off. within 4 weeks significantly reduced the somato-vegetative (e.g. hot flushes) and psychological MRS subscale (e.g. physical and mental exhaustion) subscale (p < 0.05) without a significant effect on the genito-urinary subscale. A positive impact of Salvia off. compared to placebo was furthermore seen on sleep quality, discontent and fatigue (p < 0.05) as evidenced by sleep and profile of mood state questionnaires.Tolerability was uniformly rated as very good for Salvia off. extract and placebo, with an overall incidence of three adverse events in total, none of which treatment-related.

Conclusion

The results support the use of Salvia off. for the specific treatment of a wide range of somato-vegetative and psychological symptoms as experienced by menopausal women and correlate this effect to a restoration of associated dysbalanced brain waves.The study was registered as EudraCT-No 2016-005033-77.

Nighttime melatonin secretion and sleep architecture: different associations in perimenopausal and postmenopausal women

BACKGROUND

Sleep quality typically decreases after menopause, but the underlying mechanisms are poorly understood. Concentrations of melatonin are lower and its secretion profiles different before and after menopause. However, whether and how melatonin and sleep architecture are associated in women of different reproductive states have not been examined to date.

METHODS

Overnight serum melatonin samples were taken from 17 perimenopausal and 18 postmenopausal healthy women. Sleep quality was measured with all-night polysomnography recordings.

RESULTS

Melatonin concentrations tended to be the lowest during NREM sleep, and were associated with higher odds of transitions from wake to NREM sleep. The curves of predicted overnight melatonin values from linear mixed models varied according to sleep phases (NREM, REM, Wake) in perimenopausal, but not in postmenopausal women. In perimenopause higher melatonin area under curve (AUC) correlated with higher slow-wave activity (p = 0.043), and higher minimum concentrations with shorter slow-wave sleep (SWS) latency (p = 0.029). In postmenopause higher mean and maximum melatonin concentrations and AUC correlated with lower SWS percentage (p = 0.044, p = 0.029, p = 0.032), and higher mean (p = 0.032), maximum (p = 0.032) and minimum (p = 0.037) concentrations with more awakenings from REM sleep. In the age- and BMI- adjusted regression models, the association between higher maximum (p = 0.046) melatonin concentration and lower SWS percentage remained.

CONCLUSIONS

The relationship between melatonin and sleep architecture differed in perimenopausal and postmenopausal women. After menopause, high melatonin concentrations were associated with worse sleep. Whether these different patterns are related to aging of the reproductive system, and to decrease in menopausal sleep quality, remains to be elucidated.

Role of Ovarian Hormones in the Modulation of Sleep in Females Across the Adult Lifespan

Ovarian hormones, including 17β-estradiol, are implicated in numerous physiological processes, including sleep. Beginning at puberty, girls report more sleep complaints than boys, which is maintained throughout the reproductive life stage. Sleep problems are exacerbated during the menopausal transition, evidenced by greater risk for sleep disorders. There is emerging evidence that menopause-associated hormone loss contributes to this elevated risk, but age is also an important factor. The extent to which menopause-associated sleep disturbance persists into postmenopause above and beyond the effects of age remains unknown. Untreated sleep disturbances have important implications for cognitive health, as they are emerging as risk factors for dementia. Given that sleep loss impairs memory, an important knowledge gap concerns the role played by menopause-associated hormone loss in exacerbating sleep disturbance and, ultimately, cognitive function in aging women. In this review, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining the sleep-wake cycle in younger and middle-aged females, with evidence implicating 17β-estradiol in supporting the memory-promoting effects of sleep. Sleep physiology is briefly reviewed before turning to behavioral and neural evidence from young females linking 17β-estradiol to sleep-wake cycle maintenance. Implications of menopause-associated 17β-estradiol loss is also reviewed before discussing how ovarian hormones may support the memory-promoting effects of sleep, and why menopause may exacerbate pathological aging via effects on sleep. While still in its infancy, this research area offers a new sex-based perspective on aging research, with a focus on a modifiable risk factor for pathological aging.

The menopause transition and women's health at midlife: a progress report from the Study of Women's Health Across the Nation (SWAN)

OBJECTIVE

Our initial understanding of the menopause transition (MT) has been framed by clinical samples of women seeking treatment rather than by population-based studies. The Study of Women's Health Across the Nation (SWAN) initiated in 1996 with an overall goal to define the MT, to characterize its biological and psychosocial antecedents and sequelae in an ethnically and racially diverse sample of midlife women.

METHODS

This review summarizes the central findings of SWAN to date that can inform women and their healthcare providers about the impact of the MT and midlife aging on overall health and well-being.

RESULTS

SWAN characterized changes in reproductive axis and menstrual cycle patterns that informed the development of the reproductive aging staging system Staging of Reproductive Aging Workshop+10; MT-related symptoms and mental health (vasomotor symptoms, sleep complaints, psychological symptoms, cognitive performance, and urogenital and sexual health); and physiological systems and functions (cardiovascular and cardiometabolic health, bone health, physical function performance) that are influenced by the MT. SWAN demonstrated substantial interrelations among these changes and significant racial/ethnic differences in the rate and magnitude of change in multiple health indictors in midlife women. The findings point to midlife as a critical stage for adopting healthy behavior and preventive strategies.

CONCLUSIONS

Over the past 23 years, SWAN has advanced our understanding of the impact of the MT and midlife aging on health and well-being in women. SWAN will be instrumental to determine whether MT-related changes during midlife are related to unfavorable health and well-being in early old age.

Insomnia and hot flashes

The increased prevalence of sleep disorders associated with menopause has been emphasized by multiple international studies. Many factors are associated with insomnia during menopause, among them: hot flashes (HF), anxiety and depression, other medical conditions, behavioral and psychosocial factors and primitive sleep patterns. The domino hypothesis connects various factors and suggests that HF disturb sleep, thereby causing insomnia, which in turn increases vulnerability to depression. Nevertheless, sleep disorders predict mood disturbances more robustly than vasomotor symptoms (VMS), indicating that sleep also influences mood via other mechanisms. The medical conditions that may compromise sleep in this age group are common; they include obesity, gastroesophageal reflux, cancer, urinary incontinence and nocturia, thyroid dysfunction, chronic pain, fibromyalgia (often starting or worsening in menopause), and hypertension. Common causes of sleep disorders in middle-aged women include poor sleep hygiene, volitional factors, environmental disturbances, alcohol intake, marital dissatisfaction, requests for care from children, grandchildren and/or elderly parents, and financial worries. Evidence from other populations suggests that if insomnia is not treated, it may negatively affect the outcome of comorbid conditions. Taken together, these observations suggest that insomnia should be considered a disorder requiring specific attention and treatment. Moreover, recent cross-sectional data link sleep with subclinical markers of cardiovascular risk. It should also be noted that insomnia is common in patients with mild to moderate obstructive sleep apnea syndrome (OSAS).

Sleep and Sleep Disorders in the Menopausal Transition

The menopausal transition is associated with an increase in insomnia symptoms, especially difficulty staying asleep, which negatively impacts quality of life. Vasomotor symptoms are a key component of sleep disruption. Findings from polysomnographic studies are less consistent in showing disrupted sleep in menopausal transition independent of aging; further prospective studies are needed. Hormone therapy alleviates subjective sleep disturbances, particularly if vasomotor symptoms are present. However, because of contraindications, other options should be considered. Further work is needed to develop preventive and treatment strategies for alleviating sleep disturbances to ensure better health, quality of life, and productivity in midlife women.

Changes in Sleep Characteristics and Breathing Parameters During Sleep in Early and Late Pregnancy

STUDY OBJECTIVES

Few studies have objectively evaluated sleep characteristics during pregnancy or investigated the relationship between altered spectral electroencephalogram (EEG) bands and sleep-disordered breathing (SDB). The study aimed to describe changes in sleep as measured by polysomnography (PSG) and spectral EEG bands during pregnancy and to examine the relationship between delta power in non-rapid eye movement (NREM) sleep and SDB.

METHODS

This is a secondary analysis of a prospective study. One hundred twenty-three women underwent full PSG in early pregnancy, and 97 repeated PSG in late pregnancy. Spectral analysis of the EEG in NREM sleep was performed. We used linear and logistic mixed-model regression to analyze the sleep measures and linear regression to explore the association between delta power and apnea-hypopnea index (AHI) changes during pregnancy.

RESULTS

In late pregnancy, women had shorter sleep duration, poorer sleep efficiency, more awakenings, more stage N2 sleep, less slow wave sleep, less REM sleep, higher AHI, and higher periodic limb movement index compared to early pregnancy. The percentage of stage N1 sleep, sleep latency, REM sleep latency, and arousal index frequency did not change. Regarding EEG-spectra, delta and theta powers decreased, but beta-2 power increased during pregnancy. In multivariable analyses, greater reduction of delta power was associated with larger increases in AHI (β [95% confidence interval] = -0.038 [-0.073, -0.002], P = .040). Estimates suggest that each one-unit increase in AHI reduces delta power by 4% in late pregnancy.

CONCLUSIONS

PSG-measured sleep characteristics change during pregnancy. Delta power decreases when the severity of SDB increases during pregnancy.

COMMENTARY

A commentary on this article appears in this issue on page 1095.

Symptoms of menopause - global prevalence, physiology and implications

The symptoms of menopause can be distressing, particularly as they occur at a time when women have important roles in society, within the family and at the workplace. Hormonal changes that begin during the menopausal transition affect many biological systems. Accordingly, the signs and symptoms of menopause include central nervous system-related disorders; metabolic, weight, cardiovascular and musculoskeletal changes; urogenital and skin atrophy; and sexual dysfunction. The physiological basis of these manifestations is emerging as complex and related, but not limited to, oestrogen deprivation. Findings generated mainly from longitudinal population studies have shown that ethnic, geographical and individual factors affect symptom prevalence and severity. Moreover, and of great importance to clinical practice, the latest research has highlighted how certain menopausal symptoms can be associated with the onset of other disorders and might therefore serve as predictors of future health risks in postmenopausal women. The goal of this Review is to describe in a timely manner new research findings on the global prevalence and physiology of menopausal symptoms and their impact on future health.

Altered nocturnal blood pressure profiles in women with insomnia disorder in the menopausal transition

OBJECTIVE

Insomnia disorder is a risk factor for cardiovascular (CV) pathology. It is unknown whether insomnia that develops in the context of the menopausal transition (MT) impacts the CV system. We assessed nocturnal blood pressure (BP) and heart rate (HR) profiles in women with insomnia disorder in the MT.

METHODS

Twelve women meeting DSM-IV criteria for insomnia in the MT (age, mean ± SD: 50.5 ± 3.6 y) and 11 controls (age, mean ± SD: 49.0 ± 3.0 y) had polysomnographic recordings on one or two nights during which beat-to-beat BP and HR were assessed and analyzed hourly from lights-out across the first 6 hours of the night and according to sleep stage. Physiological hot flashes were identified from fluctuations in sternal skin conductance.

RESULTS

Women with insomnia and controls had similar distributions of sleep stages and awakenings/arousals across hours of the night, although insomnia participants tended to have more wakefulness overall. More women in the insomnia group (7 of 12) than in the control group (2 of 11) had at least one physiological hot flash at night (P < 0.05). Both groups showed a drop in BP in the first part of the night; however, systolic and diastolic BP patterns diverged later, remaining low in controls but increasing in insomnia participants 4 to 6 hours after lights-out (P < 0.05). Both groups showed a similar pattern of decline in HR across the night.

CONCLUSIONS

Our findings suggest altered regulatory control of BP during sleep in the MT insomnia. The causes and long-term consequences of this altered nocturnal BP profile remain to be determined.

Sleep problems during the menopausal transition: prevalence, impact, and management challenges

A substantial number of women experience sleep difficulties in the approach to menopause and beyond, with 26% experiencing severe symptoms that impact daytime functioning, qualifying them for a diagnosis of insomnia. Here, we review both self-report and polysomnographic evidence for sleep difficulties in the context of the menopausal transition, considering severity of sleep complaints and links between hot flashes (HFs) and depression with poor sleep. Longitudinal population-based studies show that sleep difficulties are uniquely linked with menopausal stage and changes in follicle-stimulating hormone and estradiol, over and above the effects of age. A major contributor to sleep complaints in the context of the menopausal transition is HFs, and many, although not all, HFs are linked with polysomnographic-defined awakenings, with HF-associated wake time contributing significantly to overall wakefulness after sleep onset. Some sleep complaints may be comorbid with depressive disorders or attributed to sleep-related breathing or movement disorders, which increase in prevalence especially after menopause, and for some women, menopause, age, and environmental/behavioral factors may interact to disrupt sleep. Considering the unique and multifactorial basis for sleep difficulties in women transitioning menopause, we describe clinical assessment approaches and management options, including combination treatments, ranging from cognitive behavioral therapy for insomnia to hormonal and nonhormonal pharmacological options. Emerging studies suggest that the impact of severe insomnia symptoms could extend beyond immediate health care usage and quality of life issues to long-term mental and physical health, if left untreated in midlife women. Appropriate treatment, therefore, has immediate benefit as well as advantages for maintaining optimal health in the postmenopausal years.

Sleep Characteristics and Carotid Atherosclerosis Among Midlife Women

Introduction

Midlife, which encompasses the menopause transition in women, can be a time of disrupted sleep and accelerated atherosclerosis accumulation. Short or poor sleep quality has been associated with cardiovascular disease (CVD) risk; few studies have investigated relations among midlife women. We tested whether shorter actigraphy sleep time or poorer subjective sleep quality was associated with carotid atherosclerosis among midlife women.

Aims and Methods

Two hundred fifty-six peri- and postmenopausal women aged 40-60 years completed 3 days of wrist actigraphy, hot flash monitoring, questionnaires (Pittsburgh Sleep Quality Index [PSQI], Berlin), a blood draw, and carotid ultrasound [intima media thickness (IMT), plaque]. Associations of objective (actigraphy) and subjective (PSQI) sleep with IMT/plaque were tested in regression models (covariates: age, race, education, body mass index, blood pressure, lipids, insulin resistance, medications, snoring, depressive symptoms, sleep hot flashes, and estradiol).

Results

Shorter objective sleep time was associated with higher odds of carotid plaque (for each hour shorter sleep, plaque score ≥ 2, odds ratio (OR) [95% confidence interval, CI] = 1.58 [1.11-2.27], p = .01; plaque score = 1, OR [95% CI] = 0.95 [0.68-1.32], p = .75, vs. no plaque, multivariable). Poorer subjective sleep quality was associated with higher mean IMT [β, b (standard error, SE) = 0.004 (0.002), p = .03], maximal IMT [b (SE) = 0.009 (0.003), p = .005], and plaque [plaque score ≥ 2, OR (95% CI) = 1.23 (1.09-1.40), p = .001; score = 1, OR (95% CI) = 1.06 (0.93-1.21), p = .37, vs. no plaque] in multivariable models. Findings persisted additionally adjusting for sleep hot flashes and estradiol.

Conclusions

Shorter actigraphy-assessed sleep time and poorer subjective sleep quality were associated with increased carotid atherosclerosis among midlife women. Associations persisted adjusting for CVD risk factors, hot flashes, and estradiol.

Impact of insomnia on pain in postmenopausal women

BACKGROUND

Sleep disturbances and pain are assumed to be reciprocally linked. Insomnia and pain are central symptoms of the postmenopausal period and are closely related. Insomnia affects quality of life, increases pain sensitivity, the risk of pain-related disability, and other health problems.

OBJECTIVE

To investigate whether insomnia influences aspects of pain (pain intensity and the effect of pain on daily function) in postmenopausal women, and to evaluate the objective sleep pattern of insomniacs with pain.

METHODS

Fifty-seven women completed questionnaires about insomnia, climacteric symptoms, and pain. Polysomnography data were collected as well as their medical history. Patients were allocated into three groups: control, subthreshold insomnia, and insomnia. Pain intensity, climacteric symptoms and objective sleep pattern were compared between groups.

RESULTS

Postmenopausal women with insomnia had statistically significant higher pain interference in their activities (e.g. relationships with other people, enjoyment of life and sleep) than controls, and had more severe climacteric symptoms. There were no statistically significant differences in pain intensity and objective sleep pattern between groups.

CONCLUSIONS

Insomnia status affected climacteric symptoms and pain interference, but not pain intensity in postmenopausal women. Women with insomnia had higher rates of climacteric symptoms than those without insomnia or those with subthreshold insomnia. No changes in objective sleep pattern were found.

Sleep and menopause: a narrative review

OBJECTIVE

Our overall aim-through a narrative review-is to critically profile key extant evidence of menopause-related sleep, mostly from studies published in the last decade.

METHODS

We searched the database PubMed using selected Medical Subject Headings for sleep and menopause (n = 588 articles). Using similar headings, we also searched the Cochrane Library (n = 1), Embase (n = 449), Cumulative Index to Nursing and Allied Health Literature (n = 163), Web of Science (n = 506), and PsycINFO (n = 58). Articles deemed most related to the purpose were reviewed.

RESULTS

Results were articulated with interpretive comments according to evidence of sleep quality (self-reported) and sleep patterns (polysomnography and actigraphy) impact as related to reproductive aging and in the context of vasomotor symptoms (VMS; self-reported), vasomotor activity (VMA) events (recorded skin conductance), depressed mood, and ovarian hormones.

CONCLUSIONS

Predominantly, the menopausal transition conveys poor sleep beyond anticipated age effects. Perceptions of sleep are not necessarily translatable from detectable physical sleep changes and are probably affected by an emotional overlay on symptoms reporting. Sleep quality and pattern changes are mostly manifest in wakefulness indicators, but sleep pattern changes are not striking. Likely contributing are VMS of sufficient frequency/severity and bothersomeness, probably with a sweating component. VMA events influence physical sleep fragmentation but not necessarily extensive sleep loss or sleep architecture changes. Lack of robust connections between perceived and recorded sleep (and VMA) could be influenced by inadequate detection. There is a need for studies of women in well-defined menopausal transition stages who have no sleep problems, accounting for sleep-related disorders, mood, and other symptoms, with attention to VMS dimensions, distribution of VMS during night and day, and advanced measurement of symptoms and physiologic manifestations.

Reduction in menopause-related symptoms associated with use of a noninvasive neurotechnology for autocalibration of neural oscillations

OBJECTIVE

Increased amplitudes in high-frequency brain electrical activity are reported with menopausal hot flashes. We report outcomes associated with the use of High-resolution, relational, resonance-based, electroencephalic mirroring--a noninvasive neurotechnology for autocalibration of neural oscillations--by women with perimenopausal and postmenopausal hot flashes.

METHODS

Twelve women with hot flashes (median age, 56 y; range, 46-69 y) underwent a median of 13 (range, 8-23) intervention sessions for a median of 9.5 days (range, 4-32). This intervention uses algorithmic analysis of brain electrical activity and near real-time translation of brain frequencies into variable tones for acoustic stimulation. Hot flash frequency and severity were recorded by daily diary. Primary outcomes included hot flash severity score, sleep, and depressive symptoms. High-frequency amplitudes (23-36 Hz) from bilateral temporal scalp recordings were measured at baseline and during serial sessions. Self-reported symptom inventories for sleep and depressive symptoms were collected.

RESULTS

The median change in hot flash severity score was -0.97 (range, -3.00 to 1.00; P = 0.015). Sleep and depression scores decreased by -8.5 points (range, -20 to -1; P = 0.022) and -5.5 points (range, -32 to 8; P = 0.015), respectively. The median sum of amplitudes for the right and left temporal high-frequency brain electrical activity was 8.44 μV (range, 6.27-16.66) at baseline and decreased by a median of -2.96 μV (range, -11.05 to -0.65; P = 0.0005) by the final session.

CONCLUSIONS

Hot flash frequency and severity, symptoms of insomnia and depression, and temporal high-frequency brain electrical activity decrease after High-resolution, relational, resonance-based, electroencephalic mirroring. Larger controlled trials with longer follow-up are warranted.

High Resolution Topography of Age-Related Changes in Non-Rapid Eye Movement Sleep Electroencephalography

Sleeping brain activity reflects brain anatomy and physiology. The aim of this study was to use high density (256 channel) electroencephalography (EEG) during sleep to characterize topographic changes in sleep EEG power across normal aging, with high spatial resolution. Sleep was evaluated in 92 healthy adults aged 18–65 years old using full polysomnography and high density EEG. After artifact removal, spectral power density was calculated for standard frequency bands for all channels, averaged across the NREM periods of the first 3 sleep cycles. To quantify topographic changes with age, maps were generated of the Pearson’s coefficient of the correlation between power and age at each electrode. Significant correlations were determined by statistical non-parametric mapping. Absolute slow wave power declined significantly with increasing age across the entire scalp, whereas declines in theta and sigma power were significant only in frontal regions. Power in fast spindle frequencies declined significantly with increasing age frontally, whereas absolute power of slow spindle frequencies showed no significant change with age. When EEG power was normalized across the scalp, a left centro-parietal region showed significantly less age-related decline in power than the rest of the scalp. This partial preservation was particularly significant in the slow wave and sigma bands. The effect of age on sleep EEG varies substantially by region and frequency band. This non-uniformity should inform the design of future investigations of aging and sleep. This study provides normative data on the effect of age on sleep EEG topography, and provides a basis from which to explore the mechanisms of normal aging as well as neurodegenerative disorders for which age is a risk factor.

Use of an allostatic neurotechnology by adolescents with postural orthostatic tachycardia syndrome (POTS) is associated with improvements in heart rate variability and changes in temporal lobe electrical activity

Autonomic dysregulation and heterogeneous symptoms characterize postural orthostatic tachycardia syndrome (POTS). This study evaluated the effect of high-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM^®), a noninvasive, allostatic neurotechnology for relaxation and auto-calibration of neural oscillations, on heart rate variability, brain asymmetry, and autonomic symptoms, in adolescents with POTS. Seven subjects with POTS (three males, ages 15–18) underwent a median of 14 (10–16) HIRREM sessions over 13 (8–17) days. Autonomic function was assessed from 10-min continuous heart rate and blood pressure recordings, pre- and post-HIRREM. One-minute epochs of temporal high-frequency (23–36 Hz) brain electrical activity data (T3 and T4, eyes closed) were analyzed from baseline HIRREM assessment and subsequent sessions. Subjects rated autonomic symptoms before and after HIRREM. Four of seven were on fludrocortisone, which was stopped before or during their sessions. Heart rate variability in the time domain (standard deviation of the beat-to-beat interval) increased post-HIRREM (mean increase 51 %, range 10–143, p = 0.03), as did baroreflex sensitivity (mean increase in high-frequency alpha 65 %, range −6 to 180, p = 0.05). Baseline temporal electrical asymmetry negatively correlated with change in asymmetry from assessment to the final HIRREM session (p = 0.01). Summed high-frequency amplitudes at left and right temporal lobes decreased a median of 3.8 μV (p = 0.02). There was a trend for improvements in self-reported symptoms related to the autonomic nervous system. Use of HIRREM was associated with reduced sympathetic bias in autonomic cardiovascular regulation, greater symmetry and reduced amplitudes in temporal lobe high-frequency electrical activity, and a trend for reduced autonomic symptoms. Data suggest the potential for allostatic neurotechnology to facilitate increased flexibility in autonomic cardiovascular regulation, possibly through more balanced activity at regions of the neocortex responsible for autonomic management.

Clinical trial registry “Tilt Table with Suspected postural orthostatic tachycardia syndrome (POTS) Subjects,” Protocol Record: WFUBAHA01.

Insomnia in women approaching menopause: Beyond perception

The menopausal transition is marked by increased prevalence in disturbed sleep and insomnia, present in 40-60% of women, but evidence for a physiological basis for their sleep complaints is lacking. We aimed to quantify sleep disturbance and the underlying contribution of objective hot flashes in 72 women (age range: 43-57 years) who had (38 women), compared to those who had not (34 women), developed clinical insomnia in association with the menopausal transition. Sleep quality was assessed with two weeks of sleep diaries and one laboratory polysomnographic (PSG) recording. In multiple regression models controlling for menopausal transition stage, menstrual cycle phase, depression symptoms, and presence of objective hot flashes, a diagnosis of insomnia predicted PSG-measured total sleep time (p < 0.01), sleep efficiency (p = 0.01) and wakefulness after sleep onset (WASO) (p = 0.01). Women with insomnia had, on average, 43.5 min less PSG-measured sleep time (p < 0.001). There was little evidence of cortical EEG hyperarousal in insomniacs apart from elevated beta EEG power during REM sleep. Estradiol and follicle stimulating hormone levels were unrelated to beta EEG power but were associated with the frequency of hot flashes. Insomniacs were more likely to have physiological hot flashes, and the presence of hot flashes predicted the number of PSG-awakenings per hour of sleep (p = 0.03). From diaries, women with insomnia reported more WASO (p = 0.002), more night-to-night variability in WASO (p < 0.002) and more hot flashes (p = 0.012) compared with controls. Women who develop insomnia in the approach to menopause have a measurable sleep deficit, with almost 50% of the sample having less than 6h of sleep. Compromised sleep that develops in the context of the menopausal transition should be addressed, taking into account unique aspects of menopause like hot flashes, to avoid the known negative health consequences associated with insufficient sleep and insomnia in midlife women.

Validation of Sleep-Tracking Technology Compared with Polysomnography in Adolescents

STUDY OBJECTIVES

To evaluate the accuracy in measuring nighttime sleep of a fitness tracker (Jawbone UP) compared to polysomnography (PSG).

DESIGN

Jawbone UP and PSG data were simultaneously collected from adolescents during an overnight laboratory recording. Agreements between Jawbone UP and PSG sleep outcomes were analyzed using paired t tests and Bland-Altman plots. Multiple regressions were used to investigate which PSG sleep measures predicted Jawbone UP "Sound sleep" and "Light sleep."

SETTING

SRI International Human Sleep Laboratory.

PARTICIPANTS

Sixty-five healthy adolescents (28 females, mean age ± standard deviation [SD]: 15.8 ± 2.5 y).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Outcomes showed good agreements between Jawbone UP and PSG for total sleep time (mean differences ± SD: -10.0 ± 20.5 min), sleep efficiency (mean differences ± SD: -1.9 ± 4.2 %), and wake after sleep onset (WASO) (mean differences ± SD: 10.6 ± 14.7 min). Overall, Jawbone UP overestimated PSG total sleep time and sleep efficiency and underestimated WASO but differences were small and, on average, did not exceed clinically meaningful cutoffs of > 30 min for total sleep time and > 5% for sleep efficiency. Multiple regression models showed that Jawbone UP "Sound sleep" measure was predicted by PSG time in N2 (β = 0.25), time in rapid eye movement (β = 0.29), and arousal index (β = -0.34). Jawbone UP "Light sleep" measure was predicted by PSG time in N2 (β = 0.48), time in N3 (β = 0.49), arousal index (β = 0.38) and awakening index (β = 0.28). Jawbone UP showed a progression from slight overestimation to underestimation of total sleep time and sleep efficiency with advancing age. All relationships were similar in boys and girls.

CONCLUSIONS

Jawbone UP shows good agreement with polysomnography in measures of total sleep time and wake after sleep onset in adolescent boys and girls. Further validation is needed in other age groups and clinical populations before advocating use of these inexpensive and easy-to-use devices in clinical sleep medicine and research.

Menstrual Cycle-Related Variation in Physiological Sleep in Women in the Early Menopausal Transition

CONTEXT

Most studies show sleep homeostasis and continuity remain stable across the menstrual cycle in young women. The influence of the menstrual cycle on physiological sleep in midlife women is unknown.

OBJECTIVE

The objective of the study was to assess the impact of menstrual cycle phase on the polysomnogram and electroencephalographic (EEG) features of sleep in midlife women, accounting for the presence of an insomnia disorder.

DESIGN AND PARTICIPANTS

This was a laboratory study of 20 women in the early menopausal transition (48.8 ± 2.9 y), 11 with a Diagnostic and Statistical Manual of Mental Disorders, fourth edition, diagnosis of insomnia, studied on one night each in the follicular and luteal menstrual cycle phases.

MAIN OUTCOME MEASURES

Polysomnographic and sleep EEG indices were measured.

RESULTS

Both groups of women had more awakenings (P = .003) and arousals (P = .025) per hour of sleep and less percentage slow wave sleep (P = .024) when progesterone was raised (≥3 ng/mL(-1)) during the luteal compared with the follicular phase. Both groups had greater spindle density (P = .007), longer spindles (P = .037), and increased 14-17 Hz EEG activity in the luteal phase (P < .05), although for the 15- to 16-Hz bin, this effect was significant only in women without insomnia (P < .001). Women with insomnia had a shorter sleep duration (P = .012), more wakefulness after sleep onset (P = .031), and a lower sleep efficiency (P = .034) than women without insomnia, regardless of menstrual cycle phase.

CONCLUSION

Sleep is more disrupted in the luteal phase compared with the follicular phase in midlife women, whether or not they have an insomnia disorder. There is a prominent increase in sleep spindles and spindle frequency activity in the luteal phase, likely an effect of progesterone and/or its neuroactive metabolites acting on sleep regulatory systems.

Examining the relationship between subjective sleep disturbance and menopause: a systematic review and meta-analysis

OBJECTIVE

The purpose of this study was to conduct a systematic review and meta-analysis of the relationship between menopausal stages and sleep disturbance reported using subjective methods. Secondary aims included examining the influence of culture/ethnicity on the relationship between menopausal stages and sleep disturbance.

METHODS

Multiple electronic databases were searched from the first available year to November 2013, and a manual search of the reference lists of review articles identified was also conducted. Twenty-four studies with a total of 63,542 midlife women were identified, coded, and analyzed.

RESULTS

The crude and adjusted odds of experiencing sleep disturbance were small but statistically significant for perimenopausal and postmenopausal women, using premenopause as the reference group. The ethnicity of the samples influenced effect sizes; Asian and white women both experienced an increased rate of sleep disturbance at the perimenopausal and postmenopausal stages compared with the premenopausal stage, whereas Hispanic women experienced no change in sleep disturbance across the menopausal transition.

CONCLUSIONS

The prevalence of sleep disturbance is higher in perimenopausal, postmenopausal, and surgical menopausal women than in premenopausal women. There is an independent relationship between menopausal stages and sleep disturbance beyond the effects of aging and other confounders, although the magnitude of the relationship is small. Culture, ethnicity, or both might affect the levels of sleep disturbance at various menopausal stages.

Perimenopause as a neurological transition state

Perimenopause is a midlife transition state experienced by women that occurs in the context of a fully functioning neurological system and results in reproductive senescence. Although primarily viewed as a reproductive transition, the symptoms of perimenopause are largely neurological in nature. Neurological symptoms that emerge during perimenopause are indicative of disruption in multiple estrogen-regulated systems (including thermoregulation, sleep, circadian rhythms and sensory processing) and affect multiple domains of cognitive function. Estrogen is a master regulator that functions through a network of estrogen receptors to ensure that the brain effectively responds at rapid, intermediate and long timescales to regulate energy metabolism in the brain via coordinated signalling and transcriptional pathways. The estrogen receptor network becomes uncoupled from the bioenergetic system during the perimenopausal transition and, as a corollary, a hypometabolic state associated with neurological dysfunction can develop. For some women, this hypometabolic state might increase the risk of developing neurodegenerative diseases later in life. The perimenopausal transition might also represent a window of opportunity to prevent age-related neurological diseases. This Review considers the importance of neurological symptoms in perimenopause in the context of their relationship to the network of estrogen receptors that control metabolism in the brain.

Polysomnographic characteristics in nonmalignant chronic pain populations: A review of controlled studies

Sleep and pain are critical homeostatic systems that interact in a bidirectional manner. Complaints of sleep disturbance are ubiquitous among patients with chronic pain disorders, and conversely, patients with persistent insomnia symptoms commonly report suffering from chronic pain. Sleep deprivation paradigms demonstrate that partial or complete sleep loss induce hyperalgesia, possibly due to shared mechanistic pathways including neuroanatomic and molecular substrates. Further, chronic pain conditions and sleep disturbances are intertwined through comorbidities, which together cause detrimental psychological and physical consequences. This critical review examines 29 polysomnography studies to evaluate whether nonmalignant chronic pain patients, as compared to controls, show differences in objective measures of sleep continuity and sleep architecture. Whereas these controlled studies did not reveal a consistent pattern of objective sleep disturbances, alterations of sleep continuity were commonly reported. Alterations of sleep architecture such as increases in light sleep or decreases in slow-wave sleep were less commonly reported and findings were mixed and also inconsistent. Methodological flaws were identified, which complicated interpretation and limited conclusions; hence, recommendations for future research are suggested. Knowledge of abnormalities in the sleep process has implications for understanding the pathophysiology of chronic pain conditions, which might also direct the development of novel intervention strategies.

Magnitude of the impact of hot flashes on sleep in perimenopausal women

OBJECTIVE

To quantify the impact of objectively recorded hot flashes on objective sleep in perimenopausal women.

DESIGN

Cross-sectional study. Participants underwent 1-5 laboratory-based polysomnographic recordings for a total of 63 nights, including sternal skin-conductance measures, from which 222 hot flashes were identified according to established criteria. Data were analyzed with hierarchical mixed-effect models and Spearman's rank correlations.

SETTING

Sleep laboratory.

PATIENT(S)

Thirty-four perimenopausal women (age ± SD: 50.4 ± 2.7 years).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Perceived and polysomnographic sleep measures (sleep quality, amount of time spent awake after sleep onset, and number of awakenings). Subjective (frequency and level of bother) and objective (frequency and amount of hot flash-associated awake time) hot-flash measures.

RESULT(S)

Women had an average of 3.5 (95% confidence interval: 2.8-4.2, range = 1-9) objective hot flashes per night. A total of 69.4% of hot flashes were associated with an awakening. Hot flash-associated time awake per night was, on average, 16.6 minutes (95% confidence interval: 10.8-22.4 minutes), which accounted for 27.2% (SD 27.1) of total awake time per night. Hot flash-associated time awake, but not hot flash frequency, was negatively associated with sleep efficiency and positively associated with waking after sleep onset. In addition, self-reported wakefulness correlated with hot flash-associated waking, suggesting that women's estimates of wakefulness are influenced by the amount of time spent awake in association with hot flashes during the night. Having more perceived and bothersome hot flashes was correlated with more perceived wakefulness and awakenings and more objective hot flash-associated time awake and hot-flash frequency.

CONCLUSION(S)

The presence of physiological hot flashes accounts for a significant proportion of total objective time awake during the night in perimenopausal women.

Relationship between objectively recorded hot flashes and sleep disturbances among breast cancer patients: investigating hot flash characteristics other than frequency

OBJECTIVE

The aim of this study was to evaluate the relationship between various characteristics of objectively recorded hot flashes and sleep disturbances in breast cancer patients.

METHODS

Fifty-six women who had completed a similar treatment protocol for a first diagnosis of breast cancer within the previous 3 months wore ambulatory sternal skin conductance and polysomnography devices for a home-based nighttime recording of hot flashes and sleep.

RESULTS

Hot flash frequency was not associated with polysomnographic variables (r = -0.18 to 0.21) or beta-I and beta-II electroencephalographic activities (r = -0.01 and 0.03) but was significantly correlated with increased slow (r = 0.28) and delta (r = 0.32) electroencephalographic activities. A slower hot flash onset and a longer hot flash duration were associated with greater polysomnographic impairments (r = -0.50 to 0.48). Greater sleep disturbances were found during hot flash onset or hot flash plateau as compared with the pre-hot flash period (greater percentage of wake time, lower percentage of stage II sleep, and lower percentage of rapid eye movement sleep, all P values < 0.05). The probability that a stage change to a lighter sleep occurred was significantly greater during hot flash onset (11%) than during hot flash plateau (6%; P = 0.02).

CONCLUSIONS

This study suggests that the speed and duration of hot flashes would contribute more importantly to sleep alterations than hot flash frequency. Sleep disturbances tend to occur simultaneously with hot flashes, suggesting that these two nocturnal symptoms are manifestations of a higher-order mechanism involving the central nervous system.

A 24-hour approach to the study of health behaviors: temporal relationships between waking health behaviors and sleep

BACKGROUND

Although sleep is often associated with waking health behaviors (WHB) such as alcohol consumption, caffeine use, smoking, and exercise, the causal direction of these relationships is unclear.

PURPOSE

The present study used time series data to examine the temporal dynamics of WHB and sleep characteristics in participants of the Study of Women's Health Across the Nation Sleep Study.

METHODS

Three hundred three women completed daily assessments of WHB and wore wrist actigraphs to measure sleep characteristics for the duration of the study (mean = 29.42 days, SD = 6.71).

RESULTS

Vector autoregressive modeling revealed that weekly patterns of sleep and WHB best predicted subsequent sleep and WHB suggesting that the associations between WHB and sleep persist beyond their immediate influence. Some WHB predicted some subsequent sleep characteristics, but sleep did not predict subsequent WHB.

CONCLUSIONS

These novel findings provide insight into the temporal dynamics of 24-h behaviors and encourage consideration of both sleep and WHB in health promotion and behavior change efforts.

Prolonged menstruation and increased menstrual blood with generalized δ electroencephalogram power: A case report

Estradiol changes associated with the menstrual cycle have a great impact on brain activation. δ frequency mainly appears during normal sleep status or brain injury diseases, including encephalitis and mental confusion. The current case report presents a 51-year-old female with prolonged menstruation and increased menstrual blood volume whose electroencephalogram (EEG) recording demonstrated a rare generalized 3 Hz δ frequency band in the waking status. The patient had been suffering from heart palpitations and dizziness for 6 months and was receiving treatment in the Department of Neurology (Second Xiangya Hospital). The individual had been experiencing prolonged menstruation and increased menstrual blood volume for 6 years. Gynecologial examination revealed secondary anemia and hysteromyoma. Hemoglobin levels were decreased to 69 g/l. Physical and neurological examinations, and computed tomography results appeared normal. The EEG recording indicated a generalized 3 Hz δ frequency band with 30–80 μV power and a long-range δ frequency band when the patient was hyperventilating. The prolonged menstruation and increased menstrual blood volume may have induced the generalized δ frequency without brain injury. To the best of our knowledge, this is the first formal case report of prolonged menstruation and increased menstrual blood volume with the abnormality of δ EEG power.

Predictors of perceived sleep quality among men and women with insomnia

The present study determined which self-reported sleep variables and daytime impairment measures are most closely associated with sleep quality ratings (SQR) in men and women with insomnia. The participants were 137 people with insomnia, 56 men and 81 women. Multiple regression found that for men, sleep efficiency best predicted SQR, explaining 26.9% of variance. A similar analysis was conducted for women. After race was entered as a covariate, number of awakenings and total sleep time were significant predictors of SQR. Collectively, race, number of awakenings, and total sleep time explained 35.7% of variance. This suggests that the middle-of-the-night experience predicts sleep quality rating in women with insomnia, whereas the full night experience predicts sleep quality ratings in men with insomnia.