Menopausal hot flashes and the default mode network

Transfer of preclinical study data on the influence of cimicifuga racemosaon functional changes in the hippocampus during menopause

Menopausal transition in women involves complex neurobiochemical changes linked to ovarian dysfunction, resulting in symptoms like vasomotor symptoms (VMS), sleep disturbances, anxiety, and cognitive impairments. Hormone replacement therapy is the first-line treatment. However, many women are reluctant to use HRT or have contraindications toward HRT and seek for alternatives. Non-hormonal therapies with extracts of Cimicifuga racemosa rhizomes like the isopropanolic extract (iCR, black cohosh) offer a promising alternative. A preclinical pilot study exploring iCR's effects on gene expression in the hippocampus and hypothalamus of ovarectomized (OVX) rats mimicking menopausal conditions identified important signaling pathways and CNS-based contributions to the multitargeted modes of action of iCR. Especially in the hippocampus, iCR compensated effects of OVX on gene expression profiles. These changes are reflected by the genes AVPR1A, GAL, CALCA, HCRT, PNOC, ESR1, ESR2 and TAC3 contributing to the formation of hot flushes or thermoregulation as well as to secondary effects such as blood pressure, metabolism, hormonal regulation, homeostasis, mood regulation, neuroendocrine modulation, regulation of sleep and arousal, and in learning, memory and cognition. To understand the mechanisms in the brain of estrogen-depressed animals (OVX) and subsequent iCR treatment we combined the results of the pilot study with those of up-to-date literature and tried to transfer the current knowledge to humans during menopausal transition and adaptation. Focus was laid on changes in the hippocampal function, that is disturbed by hormonal fluctuations, but can also be brought back into balance by iCR.

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.

Menopausal vasomotor symptoms and plasma Alzheimer disease biomarkers

BACKGROUND

Identifying risk factors for Alzheimer disease in women is important as women compose two-thirds of individuals with Alzheimer disease. Previous work links vasomotor symptoms, the cardinal menopausal symptom, with poor memory performance and alterations in brain structure, function, and connectivity. These associations are evident when vasomotor symptoms are monitored objectively with ambulatory skin conductance monitors.

OBJECTIVE

This study aimed to determine whether vasomotor symptoms are associated with Alzheimer disease biomarkers.

STUDY DESIGN

Between 2017 and 2020, the MsBrain study enrolled 274 community-dwelling women aged 45 to 67 years who had a uterus and at least 1 ovary and were late perimenopausal or postmenopausal status. The key exclusion criteria included neurologic disorder, surgical menopause, and recent use of hormonal or nonhormonal vasomotor symptom treatment. Women underwent 24 hours of ambulatory skin conductance monitoring to assess vasomotor symptoms. Plasma concentrations of Alzheimer disease biomarkers, including amyloid β 42-to-amyloid β 40 ratio, phosphorylated tau (181 and 231), glial fibrillary acidic protein, and neurofilament light, were measured using a single-molecule array (Simoa) technology. Associations between vasomotor symptoms and Alzheimer disease biomarkers were assessed via linear regression models adjusted for age, race and ethnicity, education, body mass index, and apolipoprotein E4 status. Additional models adjusted for estradiol and sleep.

RESULTS

A total of 248 (mean age, 59.06 years; 81% White; 99% postmenopausal status) of enrolled MsBrain participants contributed data. Objectively assessed vasomotor symptoms occurring during sleep were associated with significantly lower amyloid β 42/amyloid β 40, (beta, -.0010 [standard error, .0004]; P=.018; multivariable), suggestive of greater brain amyloid β pathology. The findings remained significant after additional adjustments for estradiol and sleep.

CONCLUSION

Nighttime vasomotor symptoms may be a marker of women at risk of Alzheimer disease. It is yet unknown if these associations are causal.

Impact of sex and reproductive status on the default mode network in early midlife: implications for aging of memory circuitry and function

Alterations to the resting-state default mode network (rsDMN) are early indicators of memory decline and Alzheimer's disease (AD). Brain regions shared by the rsDMN and memory circuitry are highly sexually dimorphic. However, data are limited regarding the impact of sex and reproductive status on rsDMN connectivity and memory circuitry and function. In the current investigation, rsDMN connectivity was assessed in 180 early midlife adults aged 45 to 55 by sex and reproductive status (87 women; 93 men). Associations between left and right hippocampal connectivity of rsDMN and verbal memory encoding circuitry were examined using linear mixed models, controlled for age and parental socioeconomic status, testing interactions by sex and reproductive status. Relative to men, women exhibited greater rsDMN connectivity between the left and right hippocampus. In relation to rsDMN-memory encoding connectivity, sex differences were revealed across the menopausal transition, such that only postmenopausal women exhibited loss of the ability to decrease rsDMN left-right hippocampal connectivity during memory encoding associated with poorer memory performance. Results demonstrate that sex and reproductive status play an important role in aging of the rsDMN and interactions with memory circuitry/function. This suggests the critical importance of sex and reproductive status when studying early midlife indicators of memory decline and AD risk.

Menopause Hot Flashes and Molecular Mechanisms Modulated by Food-Derived Nutrients

The causes of vasomotor symptoms, including hot flashes, are not fully understood, may be related to molecular factors, and have a polygenic architecture. Nutrients and bioactive molecules supplied to the body with food are metabolized using various enzymatic pathways. They can induce molecular cell signaling pathways and, consequently, activate effector proteins that modulate processes related to hot flashes in menopausal women. In this review, we analyzed the literature data from the last 5 years, especially regarding genome-wide association study (GWAS) analysis, and selected molecular factors and cell signaling pathways that may potentially be related to hot flashes in women. These are the kisspeptin-GnRH pathway, adipocyte-derived hormones, aryl hydrocarbon receptor signaling, catechol estrogens and estrogen sulfotransferase, inflammatory and oxidative stress biomarkers, and glucose availability. Then, single compounds or groups of food ingredients were selected that, according to experimental data, influence the course of the discussed molecular pathways and thus can be considered as potential natural therapeutic agents to effectively reduce the troublesome symptoms of menopause in women.

A review of multi-modal magnetic resonance imaging studies on perimenopausal brain: a hint towards neural heterogeneity

The population ageing process worldwide is leading to an increasing number of women in the perimenopausal phase. Many of the perimenopausal symptoms, such as headache, depression, insomnia, and cognitive decline, are neurological in nature. Therefore, the study of the perimenopausal brain is of great importance. In addition, relevant studies can also provide an imaging basis for multiple therapies to treat perimenopausal symptoms. Because of its non-invasive nature, magnetic resonance imaging (MRI) has now been widely applied to the study of perimenopausal brains, revealing alterations in the brain associated with symptoms during the menopause transition. In this review, we collected papers and works of literature on the perimenopausal brain using MRI techniques in the Web of Science database. We firstly described the general principles and analysis methods of different MRI modalities briefly and then reviewed the structural, functional, perfusion, and metabolic compounds changes in the brain of perimenopausal women respectively, and described the latest advances in probing the perimenopausal brain using MRI, resulting in summary diagrams and figures. Based on the summary of existing works of the literature, this review further provided a perspective on multi-modal MRI studies in the perimenopausal brain, suggesting that population-based, multi-center, and longitudinal studies will be beneficial to the comprehensive understanding of changes in the perimenopausal brain. In addition, we found a hint towards neural heterogeneity in the perimenopausal brain, which should be addressed by future MRI studies to provide more help for the precise diagnosis and personalized treatment of perimenopausal symptoms. KEY POINTS: • Perimenopause is not only a physiological transition but also a period of neurological transition. • Multi-modal MRI studies have revealed that perimenopause is accompanied by alterations in the brain, which is implicated in many perimenopausal symptoms. • The diversity in the multi-modal MRI findings may give a hint to neural heterogeneity in the perimenopausal brain.

Role of estrogen in women's Alzheimer's disease risk as modified by APOE

Alzheimer's disease (AD) is characterized by numerous sexual dimorphisms that impact the development, progression, and probably the strategies to prevent and treat the most common form of dementia. In this review, we consider this topic from a female perspective with a specific focus on how women's vulnerability to the disease is affected by the individual and interactive effects of estrogens and apolipoprotein E (APOE) genotype. Importantly, APOE appears to modulate systemic and neural outcomes of both menopause and estrogen-based hormone therapy. In the brain, dementia risk is greater in APOE4 carriers, and the impacts of hormone therapy on cognitive decline and dementia risk vary according to both outcome measure and APOE genotype. Beyond the CNS, estrogen and APOE genotype affect vulnerability to menopause-associated bone loss, dyslipidemia and cardiovascular disease risk. An emerging concept that may link these relationships is the possibility that the effects of APOE in women interact with estrogen status by mechanisms that may include modulation of estrogen responsiveness. This review highlights the need to consider the key AD risk factors of advancing age in a sex-specific manner to optimize development of therapeutic approaches for AD, a view aligned with the principle of personalized medicine.

Brain fog in menopause: a health-care professional's guide for decision-making and counseling on cognition

Midlife women commonly experience changes in their cognitive function as they transition through menopause and express concern about whether these changes represent the initial stages of a more serious cognitive disorder. Health-care practitioners play an important role in counseling women on cognitive changes at midlife and normalizing women's experience. The aim of this commissioned International Menopause Society White Paper on cognition is to provide practitioners with an overview of data informing the clinical care of menopausal women and a framework for clinical counseling and decision-making. Among the topics presented are the specific cognitive changes occurring in menopause, the duration of such changes and their severity. The role of estrogen and menopause symptoms is reviewed. We present talking points for clinical counseling on the effects of hormone therapy on cognition and dementia risk in women, including discussion of absolute risk. Lastly, a brief review of modifiable risk factors for age-related cognitive decline and dementia is presented, with guidance for counseling patients on optimizing their brain health at midlife and beyond.

Hormonal Agents for the Treatment of Depression Associated with the Menopause

Perimenopause marks the transition from a woman’s reproductive stage to menopause. Usually occurring between 42 and 52 years of age, it is determined clinically by the onset of irregular menstrual cycles or variable cycle lengths. Women are at an increased risk of depression and anxiety during perimenopause and the menopausal transition. Depressive symptoms experienced in perimenopause are often more severe compared to pre- and post-menopause. During menopausal transition, the impact of fluctuating estrogen in the central nervous system (CNS) can have negative psychological effects for some women. Traditional first-line management of menopausal depression involves antidepressants, with modest outcomes. The positive effects of estrogen treatment in the CNS are becoming increasingly recognised, and hormonal therapy (HT) with estrogen may have a role in the treatment of menopausal depression. In this review we will outline the prevalence, impact and neurochemical basis of menopausal-associated depression, as well as hormone-based approaches that have increasing promise as effective treatments.

Ovarian steroid hormones: A long overlooked but critical contributor to brain aging and Alzheimer's disease

Ovarian hormones, particularly 17β-estradiol, are involved in numerous neurophysiological and neurochemical processes, including those subserving cognitive function. Estradiol plays a key role in the neurobiology of aging, in part due to extensive interconnectivity of the neural and endocrine system. This aspect of aging is fundamental for women's brains as all women experience a drop in circulating estradiol levels in midlife, after menopause. Given the importance of estradiol for brain function, it is not surprising that up to 80% of peri-menopausal and post-menopausal women report neurological symptoms including changes in thermoregulation (vasomotor symptoms), mood, sleep, and cognitive performance. Preclinical evidence for neuroprotective effects of 17β-estradiol also indicate associations between menopause, cognitive aging, and Alzheimer's disease (AD), the most common cause of dementia affecting nearly twice more women than men. Brain imaging studies demonstrated that middle-aged women exhibit increased indicators of AD endophenotype as compared to men of the same age, with onset in perimenopause. Herein, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining cognition in women, with evidence implicating menopause-related declines in 17β-estradiol in cognitive aging and AD risk. We will review research focused on the role of endogenous and exogenous estrogen exposure as a key underlying mechanism to neuropathological aging in women, with a focus on whether brain structure, function and neurochemistry respond to hormone treatment. While still in development, this research area offers a new sex-based perspective on brain aging and risk of AD, while also highlighting an urgent need for better integration between neurology, psychiatry, and women's health practices.

The association of vasomotor symptoms during the menopausal transition and cognition in later life

OBJECTIVE

The majority of women experience vasomotor symptoms (VMS) during the menopausal transition. Whether self-reported VMS are associated with cognitive test performance later in life remains unclear. The goal of this study was to determine whether a greater burden of VMS is associated with poor later-life cognition.

METHODS

The Wisconsin Longitudinal Study is a prospective study of randomly selected Wisconsin high school graduates of the class of 1957. At ages 65 and 72, a random subset of participants completed six cognitive tests, including similarities, letter and category fluency, immediate and delayed word recall, and digit ordering. Nested regression models were used to examine the association between extent of VMS, assessed at age 54, and baseline cognition at 65, adjusting for early-life socioeconomic status, women's reproductive health variables, intelligence quotient, and midlife income. This series of models was also used to examine the association between VMS and change in cognition score from age 65 to 72. In sensitivity analyses, models were repeated in a sample using multiple imputation for missing covariates.

RESULTS

Of the 5,326 women enrolled, 874 had data onVMS, covariates, and all cognitive tests. In an unadjusted model, higher VMS were associated with a lower similarities score (b = -0.09 95% CI -0.16 to -0.02) at age 65 but no other cognitive tests. In adjusted models, VMS were not related to cognition at age 65 or change in cognition. Results remained similar with multiple imputation.

CONCLUSIONS

Our study does not support a relationship between self-reported VMS and cognition later in life.

Menopause is more than Hot Flashes: What is Missing in Homeopathic Research? A Narrative Review

BACKGROUND

 Menopausal complaints are frequently treated with homeopathy in daily practice worldwide. Recently, vasomotor symptoms have been understood to have implications as predictors of other important and long-term outcomes, causing increased risk of mortality and/or disability.

METHODS

 A comprehensive search of the literature was conducted to investigate whether homeopathic treatments for menopausal women with vasomotor symptoms have a positive effect on other important health outcomes associated with menopause, such as cardiovascular disease, neurocognitive impairment, metabolic and mood disorders, or osteoporosis.

RESULTS

 Though observational studies have shown encouraging results in reducing the severity and frequency of hot flashes in women treated with homeopathy, few randomized controlled trials have shown positive results. In most of the studies using homeopathy, the primary outcome is reduction in the frequency and severity of hot flashes, and other menopausal complaints are assessed secondarily as a part of the symptoms evaluated in the menopausal scales. Quality of life improves with homeopathic treatments for hot flashes, but there is scarce evidence of the effect of homeopathy on other health outcomes associated with menopause. Limited evidence exists in the case of menopausal women treated with individualized homeopathy for depression and metabolic disorders.

CONCLUSION

 A more comprehensive approach for treating menopause in routine homeopathic practice constitutes a valuable opportunity to increase knowledge and high-quality research in this field. Future homeopathic research for menopause should be focused on well-designed, double-blind, placebo-controlled, randomized trials as well as on pragmatic trials to show whether homeopathic treatments for vasomotor symptoms can also improve outcomes that are well-known to increase the risk of mortality and/or disability.

Decoding the role of the cerebellum in the early stages of reading acquisition

Numerous studies have consistently reported functional activation of the cerebellum during reading tasks, especially in the right cerebellar hemisphere. However, it remains unclear whether this region is also involved in reading during the earliest stages of reading acquisition. Here, we investigated whether and how the cerebellum contributes to reading acquisition. We tested 80 5-6-year-old kindergarteners, who performed a visual word matching task during which functional MRI (fMRI) data were collected. We found that bilateral cerebellar hemispheres were significantly activated during visual word processing. Moreover, activation of left cerebellar lobule VII extending to lobule VIII negatively and significantly correlated with current reading ability, whereas activation of right cerebellar lobule VII extending to lobule VIII significantly and positively correlated with future reading ability. Functional decoding via functional connectivity patterns further revealed that left and right cerebellar lobules connected with different cerebral cortex regions. Our results suggest a division of labor between the left and right cerebellar lobules in beginning readers.

Physiologic vasomotor symptoms are associated with verbal memory dysfunction in breast cancer survivors

OBJECTIVE

Vasomotor symptoms (VMS), sleep disturbance, and cognitive complaints are common among women with a history of breast cancer and contribute to decreased quality of life. Studies in healthy women showed an association between verbal memory performance and physiologic VMS measured with ambulatory skin conductance monitors but not with VMS by self-report. We hypothesized that we would find a similar association in women with breast cancer.

METHODS

Participants included 30 female breast cancer survivors (mean age 52.7 y; 26.7% African-American) with moderate-to-severe VMS enrolled in a larger clinical trial of a nonhormonal intervention for VMS. At baseline, participants completed assessments of physiologic VMS, actigraphy-based assessments of sleep, questionnaires about mood, and two tests of verbal memory - Logical Memory (LM) and the California Verbal Learning Test (CVLT). Using baseline data, we conducted multivariate regression analyses to examine the association between VMS and memory, controlling for sleep and other factors.

RESULTS

On average, women reported 46% of total physiologic VMS. A higher frequency of physiologic VMS - but not reported VMS - was significantly associated with lower scores on the California Verbal Learning Test short-delay free recall (r[28] = -0.41, P = 0.03), long-delay free recall (r[28] = -0.42, P = 0.03), and total clustering, (r[28] = -0.39, P = 0.04). These associations were independent of sleep, mood, and other factors.

CONCLUSIONS

Independent of their effect on sleep, VMS may be a modifiable contributor to memory difficulties in women with breast cancer. These findings underscore the importance of objective measurement of VMS in cognitive studies. : Video Summary:http://links.lww.com/MENO/A623.

Hot flashes are associated with altered brain function during a memory task

OBJECTIVE

Vasomotor symptoms (VMS) are associated with decreased memory performance and alterations in brain function. We conducted a preliminary examination of VMS and patterns of brain activity during a verbal memory task to provide insights into the VMS-related brain mechanisms that can contribute to memory problems in midlife women.

METHODS

Fourteen postmenopausal women (mean age 53.5, 64% African-American) with moderate-to-severe VMS (>35/wk) and not taking hormone therapy completed functional magnetic resonance imaging (fMRI) assessments during word encoding and recognition, 24-hour physiologic VMS monitoring, symptom questionnaires, and two verbal memory tests.

RESULTS

In regression analyses, a higher number of physiologic VMS, but not reported VMS, was associated with worse verbal memory on immediate and delayed logical memory (r = 0.53 and r = 0.72, P < 0.05). On fMRI assessments, a higher number of physiologic VMS, but not subjective VMS, was associated with greater activation in the left orbitofrontal cortex, left medial and superior frontal gyrus, right superior frontal gyrus, and right parahippocampal gyrus during the encoding task (P < 0.005). During the recognition task, physiologic VMS were associated with greater activation in the left medial and superior frontal gyrus, left parahippocampal gyrus and hippocampus, right medial and superior frontal gyrus, right parahippocampal gyrus and hippocampus (P < 0.005), and with decreased activation in the ventral medial prefrontal cortex (P < 0.005). Those associations were independent of symptoms and hormone levels.

CONCLUSIONS

Preliminary data suggest that VMS may contribute to memory performance through effects on the hippocampus and prefrontal cortex. Larger studies are warranted to determine the robustness of these initial observations. : Video Summary:http://links.lww.com/MENO/A508.

Menopause and Brain Health: Hormonal Changes Are Only Part of the Story

Most studies of menopause and brain aging have focused on the role of the sex steroid hormone, estradiol, as a key mechanisms contributing to cognitive and brain aging in women. An emerging literature demonstrates that beyond endogenous estradiol levels, menopausal symptoms, particularly vasomotor symptoms (VMS), are also key determinants of menopause-related changes in cognition and brain function. Critically, that literature shows the importance of using objective techniques to identify associations of VMS with memory performance, brain structure, and brain function. While self-report measures are important patient-centered outcomes in women's health research, objective measures of VMS typically relate more strongly to indices of cognitive and brain health. Currently, it is premature to make a causal claim about VMS and memory dysfunction, but initial findings raise the possibility that women with VMS might experience an improvement in cognition with VMS treatment. More generally, these findings underscore the utility of investigating female-specific risk factors for cognitive decline.

Low-dose brain estrogen prevents menopausal syndrome while maintaining the diversity of the gut microbiomes in estrogen-deficient rats

We evaluated the effects of intracerebroventricular administration (ICV) of brain estrogen and progesterone on menopausal symptoms and their effects on the secretion of follicle-stimulating hormone(FSH) and luteinizing hormone (LH) in estrogen-deficient rats. Three weeks after ovariectomy (OVX) or sham operation, OVX rats were given ICV infusions of either 17β-estradiol (4 μg/day; ICV-E), progesterone(0.8 μg/day; ICV-P), or vehicle (control) for 4 wk. OVX rats in the positive-control group were orally provided 150 μg 17β-estradiol·kg body wt^-1·day^-1. Sham rats had ICV vehicle infusion (normal-control). Serum 17β-estradiol levels of ICV-E and ICV-P groups were higher than the control group but much lower than the normal- and positive-control groups. Tail skin temperature was higher in the control group than the other groups. Serum FSH and LH levels were much higher in the control group than positive- and normal-control groups, but ICV-E and ICV-P lowered the levels similar to the normal-control treatment. ICV-E and ICV-P prevented the decreased energy expenditure in OVX rats. Homeostasis model assessment estimate of insulin resistance was lowered in the descending order of the control, positive-control, ICV-P, ICV-E, and normal-control treatments. The decreased bone mineral density was prevented by the positive-control, ICV-E, and ICV-P treatments. The control group exhibited decreased short-term memory and spatial memory compared with the other groups. Surprisingly, the control group exhibited a decreased richness of the gut microbiome compared with normal-control group, and ICV-E protected against the decrease the most. In conclusion, small amounts of brain estrogen and, to some extent, progesterone improved menopausal symptoms by decreasing serum FSH levels and maintaining the diversity of the gut microbiome in estrogen-deficient rats.

Vasomotor symptoms: natural history, physiology, and links with cardiovascular health

Vasomotor symptoms (VMS), or hot flushes and night sweats, are the classic symptom of menopause. Recent years have brought key advances in the knowledge about VMS. VMS last longer than previously thought, on average 7-10 years for frequent or moderate to severe VMS. Although VMS have long been understood to be important to women's quality of life, research has also linked VMS to indicators of cardiovascular disease (CVD) risk, such as an adverse CVD risk factor profile, greater subclinical CVD and, in emerging work, CVD events. Relations between VMS and CVD are not typically accounted for by CVD risk factors. In newer work, VMS-CVD risk relations are demonstrated with state-of-the-art subjective and objective measures of VMS. Some research indicates that VMS-CVD risk relations may be sensitive to the timing or duration of VMS. Thus, research collectively supports relations between VMS and CVD risk independent of known CVD risk factors. Next steps include identifying the mechanisms linking VMS and CVD risk indicators, understanding any timing effects, and clarifying the precise nature of relations between VMS and CVD risk. Clinical implications are discussed.

Impact of sex steroids and reproductive stage on sleep-dependent memory consolidation in women

Age and sex are two of the three major risk factors for Alzheimer's disease (ApoE-e4 allele is the third), with women having a twofold greater risk for Alzheimer's disease after the age of 75 years. Sex differences have been shown across a wide range of cognitive skills in young and older adults, and evidence supports a role for sex steroids, especially estradiol, in protecting against the development of cognitive decline in women. Sleep may also be a protective factor against age-related cognitive decline, since specific electrophysiological sleep events (e.g. sleep spindle/slow oscillation coupling) are critical for offline memory consolidation. Furthermore, studies in young women have shown fluctuations in sleep events and sleep-dependent memory consolidation during different phases of the menstrual cycle that are associated with the levels of sex steroids. An under-appreciated possibility is that there may be an important interaction between these two protective factors (sex steroids and sleep) that may play a role in daily fluctuations in cognitive processing, in particular memory, across a woman's lifespan. Here, we summarize the current knowledge of sex steroid-dependent influences on sleep and cognition across the lifespan in women, with special emphasis on sleep-dependent memory processing. We further indicate gaps in knowledge that require further experimental examination in order to fully appreciate the complex and changing landscape of sex steroids and cognition. Lastly, we propose a series of testable predictions for how sex steroids impact sleep events and sleep-dependent cognition across the three major reproductive stages in women (reproductive years, menopause transition, and post-menopause).

The middle-aged ovariectomized marmoset (Callithrix jacchus) as a model of menopausal symptoms: Preliminary evidence

Menopausal women often suffer from hot flashes and sleep disturbances that significantly impact their quality of life. Both human and animal studies suggest that loss of estrogens during menopause contribute to these symptoms. In the female rat, both core body temperature (CBT) and sleep are sensitive to 17β-estradiol (E2) levels, but important differences between the rat and the human patterns limit the interpretation of the results. The sleep and thermoregulation of the common marmoset (Callithrix jacchus) more closely resemble human patterns. However, no study to date has examined whether E2 influences sleep and thermoregulation in this species. The main goal of the present study was to investigate the suitability of the ovariectomized (OVX) marmoset for studying two major menopausal symptoms experienced by women, sleep disturbance and thermodysregulation. Two middle-aged OVX marmosets (6years old) were implanted with a telemeter that records electroencephalograms (EEG), electromyograms (EMG), and CBT. Sleep patterns and CBT were recorded under baseline, two E2 replacement (6 and 12μg/kg/day, p.o.) conditions and two E2 withdrawal conditions. Relative to both baseline and withdrawal, high E2 replacement was associated with lower nighttime CBT. In addition, fewer nighttime arousals were observed under low E2 replacement compared to baseline. Higher delta power was observed under both E2 replacement conditions suggesting enhanced sleep quality. These preliminary results suggest that E2 modulates sleep and thermoregulation in the OVX marmoset, making it a promising model for studying menopausal symptoms.

Stellate ganglion blockade and verbal memory in midlife women: Evidence from a randomized trial

OBJECTIVES

In a pilot randomized clinical trial of active stellate ganglion blockade (SGB) versus sham control, SGB significantly reduced the frequency of reported moderate to severe vasomotor symptoms (VMS) and the frequency of physiologic VMS measured using ambulatory skin conductance monitors. Here we examine secondary effects of SGB on verbal learning and memory.

STUDY DESIGN

In a randomized, sham-controlled study, 36 women met eligibility criteria for cognitive assessments, of whom 17 were randomized to receive fluoroscopy-guided SGB and 19 to sham control.

MAIN OUTCOME MEASURES

At baseline and three months post-treatment, women completed tests of verbal learning and memory (primary outcome) and other cognitive measures and also wore an ambulatory monitor for 24h to measure physiologic VMS and VMS reported in real time.

RESULTS

Verbal learning improved following active SGB (p<0.05) but not sham treatment; however, the interaction between group and time was not significant (p values 0.13-0.20). Two secondary cognitive measures improved only in the sham group. Improvements in physiologic VMS correlated significantly with improvements in verbal learning (r=0.51, p<0.05).

CONCLUSIONS

SGB might confer benefits to memory in relation to the magnitude of improvement in physiologic VMS. Broadly these findings suggest a possible link between physiologic VMS and memory problems in midlife women.

Verbal memory and menopause

Midlife women frequently report memory problems during the menopausal transition. Recent studies validate those complaints by showing significant correlations between memory complaints and performance on validated memory tasks. Longitudinal studies demonstrate modest declines in verbal memory during the menopausal transition and a likely rebound during the postmenopausal stage. Clinical studies that examine changes in memory following hormonal withdrawal and add-back hormone therapy (HT) demonstrate that estradiol plays a critical role in memory. Although memory changes are frequently attributed to menopausal symptoms, studies show that the memory problems occur during the transition even after controlling for menopausal symptoms. It is well established that self-reported vasomotor symptoms (VMS) are unrelated to objective memory performance. However, emerging evidence suggests that objectively measured VMS significantly correlate with memory performance, brain activity during rest, and white matter hyperintensities. This evidence raises important questions about whether VMS and VMS treatments might affect memory during the menopausal transition. Unfortunately, there are no clinical trials to inform our understanding of how HT affects both memory and objectively measured VMS in women in whom HT is indicated for treatment of moderate to severe VMS. In clinical practice, it is helpful to normalize memory complaints, to note that evidence suggests that memory problems are temporary, and to counsel women with significant VMS that memory might improve with treatment.