Measuring cognition in menopause research: a review of test use

The Association of Reproductive Aging with Cognitive Function in Sub-Saharan African Women

Life expectancy in sub-Saharan African women is increasing, and by the late 2020s an estimated 76% of postmenopausal women globally will be living in developing countries. Menopause transition has been associated with cognitive decline in a wide range of studies, but data on cognition and reproductive aging are lacking in sub-Saharan African women. Approximately 72 million people in the region are expected to suffer from dementias and neurocognitive decline by 2050. Studies show that compromised cognitive health in low-income countries has significant implications for adult quality of life and socioeconomic development. There is now an urgent need to further examine risk factors for cognitive decline in these aging women and to understand the ability of public health programs to diagnose and treat cognitive dysfunction. This review examines studies assessing cognition and aging in sub-Saharan African adults, while addressing the significant research gaps. It examines data on the association of the menopause transition with cognitive function and describes how validated tools should be available to assess both menopausal stage and symptoms. Culturally appropriate and validated neurocognitive measures are required to better understand the relationship of reproductive aging with cognition. Longitudinal population-based studies are needed to assess the effect of lifestyle interventions, such as diet and exercise, on cognitive health in sub-Saharan African populations, with an emphasis on women as they transition into menopause.

Sex hormones affect neurotransmitters and shape the adult female brain during hormonal transition periods

Sex hormones have been implicated in neurite outgrowth, synaptogenesis, dendritic branching, myelination and other important mechanisms of neural plasticity. Here we review the evidence from animal experiments and human studies reporting interactions between sex hormones and the dominant neurotransmitters, such as serotonin, dopamine, GABA and glutamate. We provide an overview of accumulating data during physiological and pathological conditions and discuss currently conceptualized theories on how sex hormones potentially trigger neuroplasticity changes through these four neurochemical systems. Many brain regions have been demonstrated to express high densities for estrogen- and progesterone receptors, such as the amygdala, the hypothalamus, and the hippocampus. As the hippocampus is of particular relevance in the context of mediating structural plasticity in the adult brain, we put particular emphasis on what evidence could be gathered thus far that links differences in behavior, neurochemical patterns and hippocampal structure to a changing hormonal environment. Finally, we discuss how physiologically occurring hormonal transition periods in humans can be used to model how changes in sex hormones influence functional connectivity, neurotransmission and brain structure in vivo.

Hormonal environment affects cognition independent of age during the menopause transition

CONTEXT

Cognitive decline is prevalent in aging populations, and cognitive complaints are common during menopause. However, the extent of hormonal influence is unclear, particularly when considered independent of the aging process.

OBJECTIVE

We sought to determine differences in cognitive function attributable to menopause, hypothesizing that differences would be associated with reproductive rather than chronological age.

DESIGN AND SETTING

In this cross-sectional study at a university hospital, we combined neuropsychological measures with functional magnetic resonance imaging to comprehensively assess cognitive function.

PARTICIPANTS

Sixty-seven menopausal women, aged 42-61 yr, recruited from a population-based menopause study, grouped into menopause stages based on hormonal and cycle criteria (premenopause, perimenopause, and postmenopause), participated in the study.

MAIN OUTCOME MEASURES

Neuropsychological and functional magnetic resonance imaging measures of verbal, visual, and executive cognitive function.

RESULTS

We found age-independent menopause effects on verbal function. Menopause groups differed in phonemic verbal fluency (F = 3.58, P < 0.019) and regional brain activation (inferior frontal cortex: corrected P < 0.000 right, P < 0.036 left; left prefrontal cortex: P < 0.012); left temporal pole: P < 0.001). Verbal measures correlated with estradiol and FSH (phonemic fluency: R = 0.249, P < 0.047 estradiol, R = -0.275, P < 0.029 FSH; semantic fluency: R = 0.318, P < 0.011 estradiol, R = -0.321, P < 0.010 FSH; right inferior frontal cortex: R = 0.364, P < 0.008 FSH; left inferior frontal cortex: R = -0.431, P < 0.001 estradiol, left prefrontal cortex: R = 0.279, P < 0.045 FSH; left temporal pole: R = -0.310, P < 0.024 estradiol, R = 0.451, P < 0.001 FSH; left parahippocampal gyrus: R = -0.278, P < 0.044 estradiol; left parietal cortex: R = -0.326, P < 0.017 estradiol).

CONCLUSIONS

Results suggest that verbal fluency mechanisms are vulnerable during the menopausal transition. Targeted intervention may preserve function of this critical cognitive domain.

Sertraline improves the somatic and psychological symptoms of the climacteric syndrome

OBJECTIVE

To evaluate the efficacy of sertraline versus placebo in the management of somatic and psychological complaints of the climacteric syndrome.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial. A total of 44 women with moderate to severe complaints, defined as 16 or more points according to the Menopause Rating Scale (MRS) considering only the psychological and somatic domains, were incorporated into the trial and randomized to receive either sertraline (50 mg/day) or placebo. Both groups were evaluated at baseline and after 45 and 90 days of treatment. A reduction of 50% or more in the score was considered as a successful response.

RESULTS

Thirty-three patients finished the trial (16 in the sertraline group and 17 in the placebo group), showing an odds ratio of 7.94 (95% confidence interval 1.3-57.3), p = 0.0038 for the sertraline group, in spite of the prominent effect of placebo.

CONCLUSIONS

Sertraline was more effective than placebo in the management of the somatic and psychological complaints of the climacteric syndrome.

[Cognitive function in menopausal women evaluated with the Mini-Mental State Examination and Word-List Memory Test]

There is little research in Brazil on cognition and menopause, despite the high frequency of neuropsychiatric complaints in this phase of women's life. The authors present a cross-sectional study aimed at describing the scores by 156 menopausal women on the Mini-Mental State Examination (MMSE) and the Word-List Memory Test (WLMT). The mean score on the MMSE was 25.86 points (SD = 2.67), similar to other studies, except for better performance by illiterate women; scores on the sub-items 'attention and calculation' and 'immediate recall' showed lower values. In the WLMT, the mean was also consistent with the literature (M = 18.83 words; SD = 3.82). The only significant associations with score were for schooling in both tests and arterial hypertension in the WLMT. The authors conclude that cognitive performance in these menopausal women is similar to that of other Brazilian samples, corroborating the wider range of scores among individuals with lower schooling. Complaints pertaining to memory in middle-aged women may be related to decreased attention.

Estradiol and tryptophan depletion interact to modulate cognition in menopausal women

Despite an abundance of data in animals, there is little research in humans regarding how estrogen and serotonin (5-HT) may interact to influence cognition. Through the use of estrogen treatment (ET) and tryptophan depletion (TRP-D) in a within-subject design involving healthy menopausal women, we have manipulated both estrogen and 5-HT in order to evaluate their individual and joint effects. Although neither manipulation influenced visuospatial learning, a significant interaction suggested that estrogen exerted a protective effect on verbal memory, such that TRP-D impaired performance to a greater extent before the administration of ET. In consonance with this finding, ET was associated with a small, but positive mood effect on the day following active TRP-D. In addition, ET significantly improved letter-cued verbal fluency with and without TRP-D. Finally, time since last menstrual period was significantly associated with verbal memory scores, such that longer length of hypogonadism resulted in decreased verbal memory performance. These data support the interaction of estrogen and 5-HT in nonreproductive behavior in humans as well as highlight the role of ovarian steroids in cognition.

Cognitive function across the life course and the menopausal transition in a British birth cohort

OBJECTIVE

Despite biological plausibility, relationships between menopause and cognitive function are inconsistent. We investigated whether menopause status and menopause age were associated with general cognitive ability, verbal memory, and visual search speed and concentration in a large cohort of women while considering vasomotor and psychological symptoms, previous childhood and adult measures of cognitive function, lifetime socioeconomic circumstances, educational attainment, lifestyle factors, and chronic diseases.

DESIGN

A nationally representative British cohort of 1261 women born in March 1946 and all aged 53 years at cognitive testing, with prospective information on previous cognitive function, menopausal characteristics, and potential confounders.

RESULTS

There was only weak evidence of the effect of natural menopause on cognitive function and no evidence of any effects of hormone therapy use or hysterectomy status. There was a trend across the phases of the natural menopausal transition (pre-, peri-, and postmenopause) for the National Adult Reading Test (P = 0.005) and search speed and concentration (P = 0.042), with postmenopausal women having the lowest cognitive function, but there was no trend in verbal memory. Variation in vasomotor and psychological symptoms did not explain these trends. In postmenopausal women, there was a positive trend across menopause age for verbal memory (P = 0.004) and a weak positive trend for the National Adult Reading Test (P = 0.052), with women who reached menopause later having higher cognitive function. Previous cognitive function generally explained the associations, which were further weakened by adjusting for socioeconomic and educational confounders. One exception was the association between the natural menopause transition and search speed and concentration, which remained after adjustment for these factors.

CONCLUSION

Menopause adversely affects cognitive function, but this effect may be largely explained by premenopausal cognitive function. These findings suggest that common environmental or genetic factors, operating through long-term or lifelong hormonal mechanisms, may influence the timing of natural menopause and lifetime cognitive function.

A longitudinal study of cognition change during early menopausal transition in a rural community

OBJECTIVE

To characterize changes in cognition that occur during the hormonal transitions of menopause.

METHOD

We conducted a longitudinal population-based study in Kinmen, Taiwan, recruiting all women age 40-54 years who were premenopausal and without a history of hormone replacement therapy (HRT) or hysterectomy. The cognitive measures used to assess function included the Auditory-Verbal Learning Test, visual memory, verbal fluency, Trail Making Test and digit span.

RESULTS

A total of 694 eligible women participated in the baseline study, and 573 women (83%) completed follow-up 18 months later. After excluding 78 women who received hysterectomy or HRT, the final sample was composed of 495 subjects, of whom 114 (23%) progressed to perimenopause during follow-up. Women who remained premenopausal were younger than those who became perimenopausal (44.7 +/- 2.3 years versus 47.1 +/- 3.0 years, p < 0.01). All follow-up cognitive scores in women who entered perimenopause were slightly better than baseline measures except for Rey Auditory-Verbal Learning Test, which decreased by 0.23 (S.D. = 2.9, p = 0.3). At follow-up, cognitive function except for verbal fluency did not differ significantly between women who stayed premenopausal and those became perimenopausal after controlling for age, education, and baseline cognitive scores. Women who entered perimenopause have an average of 1.3 items (S.D. = 0.4) less in verbal fluency measures as compared with their premenopausal peers at the follow-up period.

CONCLUSIONS

The menopausal transition might not accompany significant cognitive decline except for verbal fluency.

Effect of estrogen-serotonin interactions on mood and cognition

Both the neurotransmitter serotonin and the ovarian steroid estrogen have been implicated in the modulation of mood and cognition. Although significant functional interactions between estrogen and serotonin are acknowledged, the nature of their relationship has not been fully elucidated. Research using ovariectomized animals has identified estrogen-induced changes in serotonin transmission, binding, and metabolism in brain regions implicated in the regulation of affect and cognition. Studies in humans, particularly of menopausal women undergoing estrogen treatment, have provided some support for these findings and identified instances in which change in mood or cognition is accompanied by alterations in serotonin function and hormonal status. However, it is apparent that further research is required to understand the neural processes involved in the interplay between estrogen and serotonin. By reviewing animal and human data regarding estrogen and serotonin's effects on mood and cognition, the authors aim to better define their relationship and highlight areas for further research.

Memory after menopause: preliminary considerations of hormone influence on cognitive functioning

Oestrogen has been shown to have a wide variety of organisational and activating effects on brain structure and function. Despite the significant amount of research investigating the relation and effects of oestrogen to cognitive performance in menopausal women over the past two decades, studies have failed to produce consistent findings. This paper reports on evaluations of eighty-one community-based postmenopausal Australian women comparing current, past and never users of hormone therapy (HT) on a wide range of cognitive measures of general, verbal and visual memory, delayed recall, attention, concentration and verbal comprehension. Few significant differences were found among the three groups in the demographic profile, health status or psychological functioning. Although never users had significantly lower scores on verbal memory than past users, the differences were not statistically significant when adjustments were made controlling for age, education level, verbal comprehension, attention and concentration. These findings challenge long-held beliefs regarding the usefulness of oestrogen supplements as a protective factor against cognitive decline in older women's later years.

No changes in event-related potentials with estrogen or estrogen plus progesterone treatment in healthy older hysterectomized women: results from a double-blind, placebo-controlled study

RATIONALE

The potential to improve cognition in older women with estrogen or estrogen/progesterone therapy is currently a matter of intense debate. Only a few studies conducted so far have used electrophysiological indicators of cognitive information processing as outcome measures in randomised placebo controlled studies.

OBJECTIVES

This study was undertaken to measure changes in event-related potentials (ERPs) after short (4 weeks) or prolonged (24 weeks) hormone treatment in older women.

METHODS

A randomised, double-blind, placebo-controlled study in hysterectomized older women (aged 58-75 years) was performed (n = 51). The participants received orally estradiol (2 mg estradiol valerate), estradiol plus progesterone (100 mg micronized progesterone) or placebo for 24 weeks. Using four different paradigms, early and late ERPs were assessed at baseline and after 4 and 24 weeks of treatment.

RESULTS

Strong hormone increases were observed in the two active treatment groups. However, no significant effects on any of the assessed ERPs were observed in either of the two treatment groups. Similar non-significant findings were obtained for reaction time and error rate.

CONCLUSIONS

Estradiol or estradiol/progesterone treatment appears to have no strong effects on several ERP markers of information processing in older hysterectomized women. The current negative findings might suggest a reduced sensitivity of the aged brain to gonadal steroids.

Raloxifene exposure enhances brain activation during memory performance in healthy elderly males; its possible relevance to behavior

Raloxifene is a selective estrogen receptor modulator (SERM) that is prescribed in females only, but its use in male subjects is increasingly considered. With a growing number of patients having potential benefit from raloxifene, the need for an assessment of its effects on brain function is growing. Effects of estrogens on brain function are very subtle and difficult to detect by neuropsychological assessment. Functional imaging techniques, however, have been relatively successful in detecting such changes. This study used functional magnetic resonance imaging (fMRI) to examine effects of raloxifene treatment on memory function. Healthy elderly males (n = 28; mean age 63.6 years, SD 2.4) were scanned during performance on a face encoding paradigm. Scans were made at baseline and after 3 months of treatment with either raloxifene (n = 14) or placebo (n = 14). Treatment effects were analyzed using mixed-effects statistical analysis (FSL). Activation during task performance involved bilateral parietal and prefrontal areas, anterior cingulate gyrus, and inferior prefrontal, occipital, and mediotemporal areas bilaterally. When compared to placebo, raloxifene treatment significantly enhanced activation in these structures (Z > 3.1), except for mediotemporal areas. Task performance accuracy diminished in the placebo group (P = 0.02), but remained constant in the raloxifene group (P = 0.60). In conclusion, raloxifene treatment enhanced brain activation in areas spanning a number of different cognitive domains, suggesting an effect on cortical arousal. Such effects may translate into small effects on behavior, including effects on attention and working memory performance, executive functions, verbal skills, and episodic memory. Further neuropsychological assessment is necessary to test the validity of these predictions.

Sex, Age, and Training Modulate Spatial Memory in the Rhesus Monkey (Macaca mulatta)

The authors tested 90 rhesus monkeys (Macaca mulatta) on a task of spatial memory, the spatial Delayed Recognition Span Test. The results showed that performance declined significantly with age, males had greater scores than females, and the rate of apparent decline with age was greater in males than in females. Both working and reference memory declined with age, but only working memory showed sex differences. The authors compared these data with that of 22 monkeys who were trained on a simpler version of the task before formal testing. Training had no effect on males but dramatically improved working memory in young females. The results confirm a male advantage in spatial working memory at a young age and confirm a greater decline with age in males than in females. It is important to note that prior training completely reverses the deficits of young females.