Sex-based memory advantages and cognitive aging: a challenge to the cognitive reserve construct?

Sex differences in cognitive decline among middle-aged and older adults: a cohort study in Europe

OBJECTIVES

Previous studies on sex differences in cognitive decline provide inconsistent findings, with many European countries being underrepresented. We determined the association between sex and cognitive decline in a sample of Europeans and explored differences across birth cohorts and regions.

METHODS

Participants 50+ years old enrolled in the Survey of Health, Ageing and Retirement in Europe had their cognition measured by tests of immediate recall, delayed recall and verbal fluency biennially up to 17 years of follow-up (median 6, interquartile range 3-9 years). We used linear mixed-effects models to assess the relationship between sex and the rate of cognitive decline, adjusting for sociodemographic and health-related characteristics.

RESULTS

Of 66,670 participants (mean baseline age 63.5 ± standard deviation 9.4), 55% were female. Males and females had similar rates of decline in the whole sample in immediate recall (beta for interaction sex × time B = 0.002, 95% CI -0.001 to 0.006), delayed recall (B = 0.000, 95% CI -0.004 to 0.004), and verbal fluency (B = 0.008, 95% CI -0.005 to 0.020). Females born before World War II had a faster rate of decline in immediate recall and delayed recall compared to males, while females born during or after World War II had a slower rate of decline in immediate recall. Females in Central and Eastern Europe had a slower rate of cognitive decline in delayed recall compared to males.

DISCUSSION

Our study does not provide strong evidence of sex differences in cognitive decline among older Europeans. However, we identified heterogeneity across birth cohorts and regions.

Handicraft art leisure activities and cognitive reserve

ObjectiveOlder individuals face a higher likelihood of developing dementia. The rate of cognitive decline resulting from dementia is not equivalent for all, as some patients with dementia are able to function independently longer than others, despite having similar disease burden. The cognitive reserve (CR) theory provides one explanation for the differing rate of decline. CR suggests that there are factors-most notably, educational attainment and occupational attainment-that can protect against the cognitive decline. Although the beneficial effects of these notable CR factors are clear, not all are easily modifiable. Participation in leisure activities may represent a more easily modifiable factor. Some research hints at beneficial effects of leisure activities, although specific leisure activities have not been well examined. The present study examined the relations between handicraft art leisure activities (HALAs) and multiple cognitive domains. MethodArchival WAIS-IV and demographic data for 50 California retirement community residents were examined. ResultsHALA participation accounted for statistically significant variance in working memory performance (R2 = .40, β = .24%) over and above the established CR factors of age, depression, educational attainment, and occupational attainment. In addition, HALA participation was related to a better ability to perform abstract visual information tasks (Block Design subtest, r = .28, p = .05) and non-verbal reasoning tasks (Visual Puzzles subtest, r = .38, p = .008). ConclusionsHALA participation among older adults could contribute to the retention of cognitive function, supporting the role of HALA participation as a CR factor.

APOE ε4-Allele in Middle-Aged and Older Autistic Adults: Associations with Verbal Learning and Memory

Autism spectrum disorder (ASD) is a neurodevelopmental disability and recent evidence suggests that autistic adults are more likely to develop Alzheimer's disease (Alz) and other dementias compared to neurotypical (NT) adults. The ε4-allele of the Apolipoprotein E (APOE) gene is the strongest genetic risk factor for Alz and negatively impacts cognition in middle-aged and older (MA+) adults. This study aimed to determine the impact of the APOE ε4-allele on verbal learning and memory in MA+ autistic adults (ages 40-71 years) compared to matched NT adults. Using the Auditory Verbal Learning Test (AVLT), we found that ε4 carriers performed worse on short-term memory and verbal learning across diagnosis groups, but there was no interaction with diagnosis. In exploratory analyses within sex and diagnosis groups, only autistic men carrying APOE ε4 showed worse verbal learning (p = 0.02), compared to autistic men who were not carriers. Finally, the APOE ε4-allele did not significantly affect long-term memory in this sample. These findings replicate previous work indicating that the APOE ε4-allele negatively impacts short-term memory and verbal learning in MA+ adults and presents new preliminary findings that MA+ autistic men may be vulnerable to the effects of APOE ε4 on verbal learning. Future work with a larger sample is needed to determine if autistic women may also be vulnerable.

Hippocampal connectivity and memory decline in cognitively intact APOE ε4 carriers

INTRODUCTION

Resting-state functional magnetic resonance imaging (fMRI) graph theory may help detect subtle functional connectivity changes affecting memory prior to impairment.

METHODS

Cognitively normal apolipoprotein E (APOE) ε4 carriers/noncarriers underwent longitudinal cognitive assessment and one-time MRI. The relationship of left/right hippocampal connectivity and memory trajectory were compared between carriers/noncarriers.

RESULTS

Steepness of verbal memory decline correlated with decreased connectivity in the left hippocampus, only among APOE ε4 carriers. Right hippocampal metrics were not correlated with memory and there were no significant correlations in the noncarriers. Verbal memory decline correlated with left hippocampal volume loss for both carriers and noncarriers, with no other significant volumetric findings.

DISCUSSION

Findings support early hippocampal dysfunction in intact carriers, the AD disconnection hypothesis, and left hippocampal dysfunction earlier than the right. Combining lateralized graph theoretical metrics with a sensitive measure of memory trajectory allowed for detection of early-stage changes in APOE ε4 carriers before symptoms of mild cognitive impairment are present.

HIGHLIGHTS

Graph theory connectivity detects preclinical hippocampal changes in APOE ε4 carriers. The AD disconnection hypothesis was supported in unimpaired APOE ε4 carriers. Hippocampal dysfunction starts asymmetrically on the left.

Executive function performance in middle-aged adults

Executive functions have been widely studied in the extreme of ages, but studies in middle-aged adults remain largely neglected. Education and gender are known to influence cognitive performance; however, their effect on executive function in middle-aged adults remains unclear.

Objective

The study aimed to observe the effect of hierarchy of educational qualifications (graduate, postgraduate, and PhD) and gender on various executive function tests across middle-aged adults with or without comorbidity.

Methods

A total of 66 middle-aged individuals volunteered for the study (mean age=48.45±5.45 years; 20 graduates, 28 postgraduates, and 18 PhD; 36 males and 30 females; 38 healthy adults and 28 adults with comorbidities). Each subject performed a test assessing short-term memory, spatial working memory, and multitasking abilities on the Cambridge Neuropsychological Test Automated Battery with rest periods in no specific order of tests. Key parameters of cognitive tests were analyzed for differences in educational qualifications (ANOVA), gender (t-test), and the effect of comorbidity as a covariate (ANCOVA).

Results

PhDs performed significantly better (p<0.05) in multitasking than graduates and had superior visuospatial working memory (fewer errors). Differences in simultaneous matching abilities, lower incongruence cost and multitasking cost were statistically significant in healthy females than in males.

Conclusion

On considering adults with comorbidity, those with higher educational attainment retained the ability to multitask compared to their healthy counterparts, which was not seen in the group with lower educational attainment. Thus, higher educational attainment attenuated the influence of comorbidities and deterioration of executive functions in general in middle-aged adults.

Sex differences in cognitive aging and the role of socioeconomic status: Evidence from multi-cohort studies

BACKGROUND

Sex differences exist in cognitive function, and socioeconomic status (SES) may play a role in changing these discrepancies. This study investigated the role of SES in contributing to sex differences in cognitive function.

METHODS

We conducted a pooled multi-cohort study on the basis of four comparative cohort studies from the UK, the US, Europe and China to assess sex differences and the role of SES in cognitive decline by birth cohort (1930-1938, 1939-1945, 1946-1968). Cognitive function was measured in three domains based on the mean and SD of the corresponding tests: episodic memory, working memory, and time orientation. SES was the summed scores of education and household wealth.

FINDINGS

61,019 individuals were involved. Cognitive function of women declined faster than those of men as growing old (particularly after 80 years old). As SES increased, cognitive function increased more for women than for men in most cases among later-born cohorts (1930-1938, 1939-1945, 1946-1968) (e.g., episodic memory scores at 60 years old: women exhibited an increase from -0.09 [95%CI -0.12, -0.07] in low SES to 0.89 [0.86, 0.92] in high SES; men from -0.16 [-0.19, -0.14] to 0.59 [0.56, 0.62]). However, sex-specific cognitive benefits were absent in the oldest birth cohort (1895-1929).

INTERPRETATION

These findings highlight the importance of considering the role of SES in the discrepancy of sex difference in cognitive aging.

Differentiation of memory processing stages and effect of demographic variables with alternative scoring approaches to the Rey auditory verbal learning test

BACKGROUND

The Rey Auditory Verbal Learning Test (RAVLT) is the third most popular verbal memory test and the tenth most frequently used neuropsychological test. The original scoring system of RAVLT does not differentiate stages of memory processing, but a recently developed composite scoring system has this potential. The objectives were to compare the two systems in terms of their capacity to differentiate the stages of memory processing and to study the effect of demographic variables on the learning trials (T) of the Turkish form of RAVLT (T-RAVLT).

METHOD

The sample consisted of 600 Caucasian Turkic adults, who were categorized into three levels of age, three levels of education, and two levels of gender. Individual administration of T-RAVLT was performed using the standard procedures of RAVLT.

RESULTS

The components in the exploratory factor analysis (EFA) and latent variables in the confirmatory factor analysis (CFA) of the original scores were consistent with sequentially ordered T-RAVLT stages. Demographic variables (age, education, and gender) affected performances in all of the learning trials. The composite scores revealed retrieval and retention as separate components, but these scores could not be predicted from the relevant T-RAVLT scores.

CONCLUSIONS

Findings recommend a combined utilization of the two scoring systems: The original system to provide scores on the performance at each stage of T-RAVLT and the combined system to provide separate scores on learning, retention, and retrieval, the three stages of memory processing. A selective effect of demographic variables on T1 was not observed, indicating a need for cross-cultural studies that are meticulously controlled for age and education.

Sex Differences in Cognitive Functioning with Aging in the Netherlands

Introduction

Dementia prevalence in older women is higher than that in men. The purpose of the present study was to investigate whether there is a female disadvantage in cognitive functioning at adult age and/or whether a female disadvantage develops with age.

Methods

Data of 5,135 women and 4,756 men from the Longitudinal Aging Study Amsterdam (LASA) and the Doetinchem Cohort Study (DCS) were used. In the LASA, memory, processing speed, fluid intelligence, and global cognitive function were measured every 3–4 years since 1992 in persons aged 55+ years for up to 23 years. In the DCS, memory, processing speed, cognitive flexibility, and global cognitive function were measured every 5 years since 1995 in persons aged 45+ years for up to 20 years. Sex differences in cognitive aging were analyzed using linear mixed models and also examined by the 10-year birth cohort or level of education.

Results

Women had a better memory, processing speed, flexibility, and, in the DCS only, global cognitive function than men (p's < 0.01). However, women showed up to 10% faster decline in these cognitive domains, except for flexibility, where women showed 9% slower decline. In the LASA, women scored poorer on fluid intelligence (p < 0.01), but their decline was 10% slower than that in men. Female advantage was larger in later born cohorts; adjustment for the educational level increased the female advantage.

Conclusion

Women have better memory and processing speed than men at middle age. This female advantage becomes smaller with aging and has increased in more recent birth cohorts.

APOE moderates the effect of hippocampal blood flow on memory pattern separation in clinically normal older adults

Pattern separation, the ability to differentiate new information from previously experienced similar information, is highly sensitive to hippocampal structure and function and declines with age. Functional MRI studies have demonstrated hippocampal hyperactivation in older adults compared to young, with greater task-related activation associated with worse pattern separation performance. The current study was designed to determine whether pattern separation was sensitive to differences in task-free hippocampal cerebral blood flow (CBF) in 130 functionally intact older adults. Given prior evidence that apolipoprotein E e4 (APOE e4) status moderates the relationship between CBF and episodic memory, we predicted a stronger negative relationship between hippocampal CBF and pattern separation in APOE e4 carriers. An interaction between APOE group and right hippocampal CBF was present, such that greater right hippocampal CBF was related to better lure discrimination in noncarriers, whereas the effect reversed directionality in e4 carriers. These findings suggest that neurovascular changes in the medial temporal lobe may underlie memory deficits in cognitively normal older adults who are APOE e4 carriers.

The Neurocognitive Study for the Aging: Longitudinal Analysis on the Contribution of Sex, Age, Education and APOE ɛ4 on Cognitive Performance

Objective: The effects of normal cognitive aging on executive functions (EF), Verbal Episodic Memory (VEM) and the contribution of age, sex, education, and APOΕ ε4 in a group of old Greek Cypriots across a five-year period were investigated.

Design: NEUROAGE, the first project on cognitive aging in Cyprus, is a prospective longitudinal study with a rolling admission process. Participants are assessed at baseline and retested every 24–30 months.

Subjects: 170 participants completed all three testing cycles; 86 men and 84 women with ages ranging between 60 and 88 years (mean = 73.21, SD = 5.84); education, 2–20 years (mean = 9.07, SD = 4.27).

Results: Α Repeated Measures Multivariate Analysis of Covariance was conducted with one between-subject factor: sex; two covariates: age and education, while Time (time 1, time 2, time 3) served as a within – subject factor. Time did not have an effect on mini mental status examination in Greek (MMSE), EF or VEM. Also, sex had no effect on MMSE, EF and VEM. There was no time by sex interaction. Age and Education significantly predicted the EF performance, F(1, 168) = 11.23, p < 0.05; F(1, 158) = 90.03, p < 0.001 and VEM performance, F(1, 171) = 17.22, p < 0.001; F(1, 171) = 61.25, p < 0.001. Furthermore, there was a significant interaction effect between time and education, for EF, F(2, 167) = 7.02, p < 0.001. Performance of the APOE ε4 carriers did not differ on any of the above measures as compared to performance of non-carriers in this older adult group.

Conclusion: Cognitively healthy adults maintained overall cognitive performance across the five-year period. Male and female participants performed similarly and the pattern of change over time was similar across the two sexes. Education was predictive of VEM and EF performance across time. Furthermore, those with higher education maintained higher levels of EF performance. APOE results did not differentiate performance at baseline. Implications of findings are discussed.

Race, APOE genotypes, and cognitive decline among middle-aged urban adults

Background

Associations of Apolipoprotein (APOE) ε2 or ε4 (APOE2 or APOE4) dosages with cognitive change may differ across racial groups.

Methods

Longitudinal data on 1770 middle-aged White and African American adults was compiled from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS 2004-2013) study. APOE2 and APOE4 dosages were the two main exposures, while v₁ and annual rate of change in cognitive performance (between v₁ and v₂) on 11 test scores were the main outcomes of interest (v1: 2004–2009 and v2: 2009–2013). Mixed-effects linear regression models were conducted adjusting for socio-demographic, lifestyle, and health-related potential confounders. Race (African American vs. White) and sex within racial groups were main effect modifiers.

Results

Upon adjustment for multiple testing and potential confounders, APOE4 allelic dosage was associated with faster decline on a test of verbal memory among Whites only (CVLT-List A: γ₁₂ = − 0.363 ± 0.137, p = 0.008), but not among African Americans. In contrast, among African American women, APOE4 dosage was linked to slower decline on a test of attention (BTA: γ₁₂ = + 0.106 ± 0.035, p = 0.002), while no association was detected among African American men. APOE2 and APOE4 dosages showed inconsistent results in other domains of cognition overall and across racial groups that did not survive correction for multiple testing.

Conclusions

In conclusion, APOE4 dosage was associated with faster decline on a test of verbal memory among Whites only, while exhibiting a potential protective effect among African American women in the domain of attention. Further longitudinal studies are needed to replicate our race and sex-specific findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-021-00855-y.

TAR DNA-Binding Protein 43 Is Associated with Rate of Memory, Functional and Global Cognitive Decline in the Decade Prior to Death

Background:

Transactive response DNA-binding protein of 43 kDa (TDP-43) is associated with memory impairment and overall cognitive decline. It is unclear how TDP-43 contributes to the rate of clinical decline.

Objective:

To determine whether cross-sectional and longitudinal cognitive and functional decline are associated with anatomical distribution of TDP-43 in the brain.

Methods:

Longitudinal clinical-neuropathologic autopsy cohort study of 385 initially cognitively normal/mildly impaired older adults prospectively followed until death. We investigated how TDP-43, amyloid-β (Aβ), tau neurofibrillary tangles (NFT), Lewy body disease (LBD), age, sex, and genetics are associated with clinical scores and rates of their longitudinal decline.

Results:

Of 385 participants, 260 (68%) had no TDP-43, 32 (8%) had TDP-43 limited to amygdala, and 93 (24%) had TDP-43 in the hippocampus and beyond. Higher TDP-43 and Braak NFT stages independently were associated with faster decline in global cognition, functional performance measured by Clinical Dementia Rating scale, and naming and episodic memory, whereas older age was associated with slower rate of cognitive, psychiatric, and functional decline. Cross-sectionally the following associations were found: higher TDP-43 and Braak NFT - worse performance; higher Aβ burden - worse global cognition, more behavioral changes, the latter also with higher LBD; older age - worse naming, lower frequency of behavioral changes; female sex - more impaired naming and better preserved episodic memory. There were no genetic associations.

Conclusion:

The association of TDP-43 distribution with decline in cognitive and functional performance suggests that TDP-43 is playing a role in the clinical progression to dementia. Further characterization of clinical features associated with TDP-43 can facilitate establishment of antemortem diagnosis.

Mayo Normative Studies: Regression-Based Normative Data for the Auditory Verbal Learning Test for Ages 30-91 Years and the Importance of Adjusting for Sex

OBJECTIVE

Rey's Auditory Verbal Learning Test (AVLT) is a widely used word list memory test. We update normative data to include adjustment for verbal memory performance differences between men and women and illustrate the effect of this sex adjustment and the importance of excluding participants with mild cognitive impairment (MCI) from normative samples.

METHOD

This study advances the Mayo's Older Americans Normative Studies (MOANS) by using a new population-based sample through the Mayo Clinic Study of Aging, which randomly samples residents of Olmsted County, Minnesota, from age- and sex-stratified groups. Regression-based normative T-score formulas were derived from 4428 cognitively unimpaired adults aged 30-91 years. Fully adjusted T-scores correct for age, sex, and education. We also derived T-scores that correct for (1) age or (2) age and sex. Test-retest reliability data are provided.

RESULTS

From raw score analyses, sex explained a significant amount of variance in performance above and beyond age (8-10%). Applying original age-adjusted MOANS norms to the current sample resulted in significantly fewer-than-expected participants with low delayed recall performance, particularly in women. After application of new T-scores adjusted only for age, even in normative data derived from this sample, these age-adjusted T-scores showed scores <40 T occurred more frequently among men and less frequently among women relative to T-scores that also adjusted for sex.

CONCLUSIONS

Our findings highlight the importance of using normative data that adjust for sex with measures of verbal memory and provide new normative data that allow for this adjustment for the AVLT.

Cognitive phenotypes 1 month after ICU discharge in mechanically ventilated patients: a prospective observational cohort study

BACKGROUND

ICU patients undergoing invasive mechanical ventilation experience cognitive decline associated with their critical illness and its management. The early detection of different cognitive phenotypes might reveal the involvement of diverse pathophysiological mechanisms and help to clarify the role of the precipitating and predisposing factors. Our main objective is to identify cognitive phenotypes in critically ill survivors 1 month after ICU discharge using an unsupervised machine learning method, and to contrast them with the classical approach of cognitive impairment assessment. For descriptive purposes, precipitating and predisposing factors for cognitive impairment were explored.

METHODS

A total of 156 mechanically ventilated critically ill patients from two medical/surgical ICUs were prospectively studied. Patients with previous cognitive impairment, neurological or psychiatric diagnosis were excluded. Clinical variables were registered during ICU stay, and 100 patients were cognitively assessed 1 month after ICU discharge. The unsupervised machine learning K-means clustering algorithm was applied to detect cognitive phenotypes. Exploratory analyses were used to study precipitating and predisposing factors for cognitive impairment.

RESULTS

K-means testing identified three clusters (K) of patients with different cognitive phenotypes: K1 (n = 13), severe cognitive impairment in speed of processing (92%) and executive function (85%); K2 (n = 33), moderate-to-severe deficits in learning-memory (55%), memory retrieval (67%), speed of processing (36.4%) and executive function (33.3%); and K3 (n = 46), normal cognitive profile in 89% of patients. Using the classical approach, moderate-to-severe cognitive decline was recorded in 47% of patients, while the K-means method accurately classified 85.9%. The descriptive analysis showed significant differences in days (p = 0.016) and doses (p = 0.039) with opioid treatment in K1 vs. K2 and K3. In K2, there were more women, patients were older and had more comorbidities (p = 0.001) than in K1 or K3. Cognitive reserve was significantly (p = 0.001) higher in K3 than in K1 or K2.

CONCLUSION

One month after ICU discharge, three groups of patients with different cognitive phenotypes were identified through an unsupervised machine learning method. This novel approach improved the classical classification of cognitive impairment in ICU survivors. In the exploratory analysis, gender, age and the level of cognitive reserve emerged as relevant predisposing factors for cognitive impairment in ICU patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier:NCT02390024; March 17,2015.

Effect of ladostigil treatment of aging rats on gene expression in four brain areas associated with regulation of memory

Episodic and spatial memory decline in aging and are controlled by the hippocampus, perirhinal, frontal and parietal cortices and the connections between them. Ladostigil, a drug with antioxidant and anti-inflammatory activity, was shown to prevent the loss of episodic and spatial memory in aging rats. To better understand the molecular effects of aging and ladostigil on these brain regions we characterized the changes in gene expression using RNA-sequencing technology in rats aged 6 and 22 months. We found that the changes induced by aging and chronic ladostigil treatment were brain region specific. In the hippocampus, frontal and perirhinal cortex, ladostigil decreased the overexpression of genes regulating calcium homeostasis, ion channels and those adversely affecting synaptic function. In the parietal cortex, ladostigil increased the expression of several genes that provide neurotrophic support, while reducing that of pro-apoptotic genes and those encoding pro-inflammatory cytokines and their receptors. Ladostigil also decreased the expression of axonal growth inhibitors and those impairing mitochondrial function. Together, these actions could explain the protection by ladostigil against age-related memory decline.

Nuances in Alzheimer's Genetic Risk Reveal Differential Predictions of Non-demented Memory Aging Trajectories: Selective Patterns by APOE Genotype and Sex

BACKGROUND

Apolipoprotein E (APOE) is a prominent genetic risk factor for Alzheimer's disease (AD) and a frequent target for associations with non-demented and cognitively impaired aging. APOE offers a unique opportunity to evaluate two dichotomous comparisons and selected gradations of APOE risk. Some evidence suggests that APOE effects may differ by sex and emerge especially in interaction with other AD-related biomarkers (e.g., vascular health).

METHODS

Longitudinal trajectories of non-demented adults (n = 632, 67% female, Mage = 68.9) populated a 40-year band of aging. Focusing on memory performance and individualized memory trajectories, a sequence of latent growth models was tested for predictions of (moderation between) APOE and pulse pressure (PP) as stratified by sex. The analyses (1) established robust benchmark PP effects on memory trajectories, (2) compared predictions of alternative dichotomous groupings (ε4- vs ε4+, ε2- vs ε2+), and (3) examined precision-based predictions by disaggregated APOE genotypes.

RESULTS

Healthier (lower) PP was associated with better memory performance and less decline. Therefore, all subsequent analyses were conducted in the interactive context of PP effects and sex stratification. The ε4-based dichotomization produced no differential genetic predictions. The ε2-based analyses showed sex differences, including selective protection for ε2-positive females. Exploratory follow-up disaggregated APOE genotype analyses suggested selective ε2 protection effects for both homozygotic and heterozygotic females.

CONCLUSION

Precision analyses of AD genetic risk will advance the understanding of underlying mechanisms and improve personalized implementation of interventions.

Subjective Cognitive Decline Among Sexual and Gender Minorities: Results from a U.S. Population-Based Sample

The risk of dementia and mild cognitive impairment between older adults in same-sex relationships and those in opposite-sex relationships have been found to be statistically not different. However, studies examining subjective cognitive decline (SCD) among sexual and gender minority populations (SGM) are lacking. The primary objective was to determine if SGM report greater SCD compared to non-SGM populations in a U.S. population-based sample of non-institutionalized adults aged 45 and older. The secondary objective was to assess the association between gender and SCD. Cross-sectional data were obtained from the 2016 Behavioral Risk Factor Surveillance System (n = 36,734). There were 1,094 SGM adults in the sample. Descriptive statistics examined sociodemographic characteristics and their distribution by SCD and SGM status. Crude and multivariable logistic regression models were used to determine the association between SGM status, gender, and SCD. Adjusted models controlled for age, race/ethnicity, income, education, employment, marital status, depression, and diabetes. Statistically significant differences in SGM status and SCD existed by age, race/ethnicity, education, employment, marital status, and depression. Differences in SCD also existed by income and diabetes status. There was no statistically significant association between SGM status and SCD (OR: 0.88; 95% CI: 0.63-1.24). However, men had 64% higher odds (OR: 1.64; 95% CI: 1.44-1.88) of reporting SCD compared to women. Future studies examining the potential reasons for this null association, including resilience and/or premature aging are warranted. Future research assessing potential reasons for gender differences in SCD, whether physiological or environmental, is also needed.

Memory differences by sex, but not by previous diagnosis of major depressive disorder

Memory difficulties are consistently reported in Major Depressive Disorder (MDD). Nonetheless, it has not been thoroughly investigated as to whether these deficits persist during remission from MDD. A group of 32 healthy young adults with no history of a mood disorder (M_age = 20.8, SD = 2.1) and 62 remitted depressed young adults (M_age = 21.1, SD = 1.9) completed a neuropsychological battery. The test battery included two measures of nonverbal memory, two measures of verbal memory, and a measure of performance validity. The testing session was repeated three to six weeks later to determine performance stability. No differences were found between healthy controls and remitted depressed patients in either memory domain (all ps > .05) and improvement in performance was exhibited over time for both groups (p = 0.004). Potential practice effects are examined. We found a stronger performance for women than men (p = 0.003), particularly for the Semantic List Learning Task (SLLT) (p = .047). Verbal and nonverbal memory and effort may not be impacted in those who are in a remitted state of MDD, early in the course of the illness. Women demonstrated auditory memory superiority over men, similar to prior research.

Effects of APOE on cognitive aging in community-dwelling older adults

OBJECTIVE

The apolipoprotein E (APOE) gene is an established risk factor for sporadic Alzheimer's disease, with elevated risk for ε4-carriers and reduced risk for ε2-carriers. However, it is unclear whether APOE modifies risk for cognitive decline in normal aging. The objective of this study was to determine whether ε2 and ε4 are associated with rates of normal cognitive aging, and whether associations of ε4 with cognitive decline are modified by sex, education or health behaviors (exercise, alcohol consumption, smoking).

METHOD

A community-based sample of 1,393 older adults were genotyped for APOE and underwent cognitive assessment up to seven times over a maximum of period of 27 years.

RESULTS

ε2-carriers showed slower executive function decline with age relative to ε3 homozygotes or ε4-carriers, whereas ε4-carriers demonstrated more rapid executive function and verbal fluency decline. Accelerated executive function decline was particularly pronounced in ε4-carriers with lower education. After excluding individuals with cognitive impairment, faster executive function decline was still apparent in ε4-carriers, and the effect of ε4 on episodic memory interacted with alcohol consumption, such that only ε4-carriers who did not drink showed more rapid memory decline than ε4 noncarriers. The influence of ε4 on cognitive aging did not differ by sex, nor was it modified by smoking or exercise.

CONCLUSIONS

These findings indicate that the ε2 and ε4 alleles have differential effects on cognitive aging, and that negative effects of ε4 may be partly mitigated by behavioral choices. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Change in Cognitive Performance From Midlife Into Old Age: Findings from the Midlife in the United States (MIDUS) Study

OBJECTIVES

A substantial body of research has documented age-related declines in cognitive abilities among adults over 60, yet there is much less known about changes in cognitive abilities during midlife. The goal was to examine longitudinal changes in multiple cognitive domains from early midlife through old age in a large national sample, the Midlife in the United States (MIDUS) study.

METHODS

The Brief Test of Adult Cognition by Telephone (BTACT) was administered on two occasions (MIDUS 2, MIDUS 3), an average of 9 years apart. At MIDUS 3, those with the cognitive assessment (N=2518) ranged in age from 42 to 92 years (M=64.30; SD=11.20) and had a mean education of 14.68 years (SD=2.63). The BTACT includes assessment of key aging-sensitive cognitive domains: immediate and delayed free recall, number series, category fluency, backward digit span, processing speed, and reaction time for attention switching and inhibitory control, which comprise two factors: episodic memory and executive functioning.

RESULTS

As predicted, all cognitive subtests and factors showed very small but significant declines over 9 years, with differences in the timing and extent of change. Processing speed showed the earliest and steepest decrements. Those with higher educational attainment scored better on all tests except reaction time. Men had better executive functioning and women performed better on episodic memory.

CONCLUSIONS

Examining cognitive changes in midlife provides opportunities for early detection of cognitive impairments and possibilities for preventative interventions. (JINS, 2018, 24, 805-820).

Sex differences in progression to mild cognitive impairment and dementia in Parkinson's disease

INTRODUCTION

Identification of factors associated with progression of cognitive symptoms in Parkinson's disease (PD) is important for treatment planning, clinical care, and design of future clinical trials. The current study sought to identify whether prediction of cognitive progression is aided by examining baseline cognitive features, and whether this differs according to stage of cognitive disease.

METHODS

Participants with PD in the Pacific Udall Center Clinical Consortium who had longitudinal data available and were nondemented at baseline were included in the study (n = 418). Logistic and Cox regression models were utilized to examine the relationship between cognitive, demographic, and clinical variables with risk and time to progression from no cognitive impairment to mild cognitive impairment (PD-MCI) or dementia (PDD), and from PD-MCI to PDD.

RESULTS

Processing speed (OR = 1.05, p = 0.009) and working memory (OR = 1.01, p = 0.03) were associated with conversion to PDD among those with PD-MCI at baseline, over and above demographic variables. Conversely, the primary predictive factor in the transition from no cognitive impairment to PD-MCI or PDD was male sex (OR = 4.47, p = 0.004), and males progressed more rapidly than females (p = 0.01). Further, among females with shorter disease duration, progression was slower than for their male counterparts, and poor baseline performance on semantic verbal fluency was associated with shorter time to cognitive impairment in females but not in males.

CONCLUSIONS

This study provides evidence for sex differences in the progression to cognitive impairment in PD, while specific cognitive features become more important indicators of progression with impending conversion to PDD.

Gender Differences in Cognitive Test Performance in Adults With Heart Failure

BACKGROUND

Cognitive deficits are found in up to 73% of persons with heart failure (HF) and are associated with increased mortality and other poor clinical outcomes. It is known that women have better memory test performance than men do in healthy samples, but gender differences in cognitive performance in the context of HF are not well understood and may have important clinical implications.

OBJECTIVE

The objective of this study was to examine possible gender differences in cognitive function in a sample of individuals with HF (98.9% New York Heart Association class II and III).

METHODS

A total of 183 adults with HF (116 men and 67 women) completed a neuropsychological test battery as part of a larger project. Measures were chosen to assess functioning in attention/executive function and memory.

RESULTS

After controlling for demographic and medical factors, multivariate analysis of covariance revealed that men and women differed on memory test performance (λ = 0.90, F4, 169 = 4.76, P = .001). Post hoc comparisons revealed that women performed better on California Verbal Learning Test Learning, Short Recall, and Delayed Recall. No differences emerged on tests of attention/executive function (λ = 0.97, F5, 168 = 0.96, P = .44).

CONCLUSIONS

In this sample of persons with HF, men exhibited poorer performance on memory measures than women did. Future studies are needed to determine the underlying mechanisms for this pattern and its possible influence on daily function.

Alzheimer Disease: Scientific Breakthroughs and Translational Challenges

Alzheimer disease (AD) was originally conceived as a rare disease that caused presenile dementia but has come to be understood as the most prevalent cause of dementia at any age worldwide. It has an extended preclinical phase characterized by sequential changes in imaging and cerebrospinal fluid biomarkers with subtle memory decline beginning more than a decade before the emergence of symptomatic memory loss heralding the beginning of the mild cognitive impairment stage. The apolipoprotein E ε4 allele is a prevalent and potent risk factor for AD that has facilitated research into its preclinical phase. Cerebral Aβ levels build from preclinical through early dementia stages followed by hyperphosphorylated tau-related pathology, the latter driving cognitive deficits and dementia severity. Structural and molecular imaging can now recapitulate the neuropathology of AD antemortem. Autosomal dominant forms of early-onset familial AD gave rise to the amyloid hypothesis of AD, which, in turn, has led to therapeutic trials of immunotherapy designed to clear cerebral amyloid, but to date results have been disappointing. Genome-wide association studies have identified multiple additional risk factors, but to date none have yielded an effective alternate therapeutic target. Current and future trials aimed at presymptomatic individuals either harboring cerebral amyloid or at genetically high risk offer the hope that earlier intervention might yet succeed where trials in patients with established dementia have failed. A major looming challenge will be that of expensive, incompletely effective disease-modifying therapy: who and when to treat, and how to pay for it.

Gender Differences in Alzheimer Disease: Brain Atrophy, Histopathology Burden, and Cognition

Multiple studies suggest that females are affected by Alzheimer disease (AD) more severely and more frequently than males. Other studies have failed to confirm this and the issue remains controversial. Difficulties include differences in study methods and male versus female life expectancy. Another element of uncertainty is that the majority of studies have lacked neuropathological confirmation of the AD diagnosis. We compared clinical and pathological AD severity in 1028 deceased subjects with full neuropathological examinations. The age of dementia onset did not differ by gender but females were more likely to proceed to very severe clinical and pathological disease, with significantly higher proportions having a Mini-Mental State Examination score of 5 or less and Braak stage VI neurofibrillary degeneration. Median neuritic plaque densities were similar in females and males with AD but females had significantly greater tangle density scores. In addition, we found that AD-control brain weight differences were significantly greater for females, even after adjustment for age, disease duration, and comorbid conditions. These findings suggest that when they are affected by AD, females progress more often to severe cognitive dysfunction, due to more severe neurofibrillary degeneration, and greater loss of brain parenchyma.

Sex and post-menopause hormone therapy effects on hippocampal volume and verbal memory

Many studies suggest sex differences in memory and hippocampal size, and that hormone therapy (HT) may positively affect these measures in women; however, the parameters of HT use that most likely confer benefits are debated. We evaluated the impact of sex and postmenopausal HT use on verbal learning and memory and hippocampal size in 94 cognitively intact women and 49 men. Using analysis of covariance that controlled for age and education, women had better total word learning and delayed verbal memory performance than men. HT analyses showed that non-HT users performed similarly to men, while HT users performed better than men in Delayed Memory regardless of whether use was current or in the past. Women had larger hippocampal volumes than men regardless of whether they were HT users. Using univariate linear models, we assessed group differences in the predictive value of hippocampal volumes for verbal learning and memory. Hippocampal size significantly predicted memory performance for men and non-HT users, but not for HT users. This lack of relationship between hippocampal size and verbal learning and memory performance in HT users suggests HT use may impact memory through extra-hippocampal neural systems.

Sex differences in visuospatial abilities persist during induced hypogonadism

BACKGROUND

Despite well-established sex differences in the performance on tests of several cognitive domains (e.g., visuospatial ability), few studies in humans have evaluated if these sex differences are evident both in the presence of circulating sex hormones and during sex steroid hormonal suppression. Sex differences identified in the relative absence of circulating levels of estradiol and testosterone suggest that differences in brain structure or function exist independent of current hormonal environment and are more likely a reflection of differing developmental exposures and/or genetic substrates.

OBJECTIVE

To evaluate cognitive performance in healthy eugonadal men and women before and again during GnRH agonist-induced hypogonadism.

METHODS

Men (n=16) and women (n=15) without medical or psychiatric illness were matched for IQ. Cognitive tests were performed at baseline (when eugonadal) and after 6-8 weeks of GnRH agonist-induced gonadal suppression. The test batteries included measures of verbal and spatial memory, spatial ability, verbal fluency, motor speed/dexterity, and attention/concentration. Data were analyzed using repeated-measures models.

RESULTS

During both eugonadism and hypogonadism, men performed significantly better than women on several measures of visuospatial performance including mental rotation, line orientation, Money Road Map, Porteus maze, and complex figure drawing. Although some test performances showed an effect of hormone treatment, the majority of these differences reflected an improved performance during hypogonadism compared with baseline (and probably reflected practice effects).

CONCLUSION

The well-documented male advantage in visuospatial performance, which we observed during eugonadal conditions, was maintained in the context of short-term suppression of gonadal function in both men and women. These findings suggest that, in humans, sex differences in visuospatial performance are not merely dependent on differences in the current circulating sex steroid environment. Thus sex differences in visuospatial performance in adulthood could reflect early developmental effects of sex steroid exposure or other environmental exposures differing across the sexes as our data confirm that these differences are independent of circulating estradiol or testosterone levels in men and women.