Gender comparisons of cognitive performances among vascular dementia, Alzheimer disease, and older adults without dementia

Dissociations between musical semantic memory and verbal memory in a patient with behavioral variant frontotemporal dementia

OBJECTIVES

Patients with dementia show dissociations between musical semantic memory (i.e., spared musical lexicon) and other memory modalities, except in some severe cases. We aim to study, from a neuropsychological point of view, the dissociation between musical semantic memory compared to language and verbal memory in a patient with severe Behavioral Variant Frontotemporal Dementia (bvFTD). We hypothesize a single dissociation between these domains will be found, with sparing of musical semantic memory.

METHODS

LC, a patient with severe bvFTD, and three matched controls were assessed through language, semantic, and episodic memory, and musical semantic memory tasks. The control group had similar music taste as LC: to participate as controls, tango must be one of their favorite musical genres.

RESULTS

LC showed impairment in all Verbal Memory tasks, but not in musical tasks. There was a dissociation between musical semantic memory, and language and verbal semantic memory.

CONCLUSIONS

The musical lexicon can be preserved in advanced stages of dementia, which supports the idea that music can be a therapeutic tool in patients with severe dementia.

Bone Mineral Density Measurements and Association With Brain Structure and Cognitive Function: The Framingham Offspring Cohort

BACKGROUND

Bone mineral density (BMD) is a potential surrogate marker of lifetime estrogen exposure previously linked to increased risk of Alzheimer dementia among elderly women. We examine the association between BMD in the "young old" with imaging biomarkers of brain aging and cognitive performance.

METHODS

Offspring participants (N=1905, mean age 66) of a population-based cohort who had BMD, brain imaging and detailed cognitive assessment were included in the study. Sex-stratified, linear, and logistic regression models were used for analysis.

RESULTS

Higher femoral neck BMD was associated with lower white matter hyperintensity burden and better performance on Trails B-A in both sexes, even after adjustment for cerebrovascular risk factors. Among women, the positive association with Trails B-A performance was seen only in APOE4 allele carriers. Higher BMD measurements were linked to better visual reproductions test performance in men. Finally, among women, higher femoral trochanter BMD was associated with better logical memory and Hooper visual organization test performance.

CONCLUSION

Among the "young old," higher BMD is associated with less white matter hyperintensity burden and better, domain-specific, cognitive performance. This suggests that lifetime estrogen exposure may modulate the degree of cumulative vascular brain injury independent of cerebrovascular risk factors.

Gut Microbiota Alterations and Cognitive Impairment Are Sexually Dissociated in a Transgenic Mice Model of Alzheimer's Disease

BACKGROUND

Normal aging is accompanied by cognitive deficiencies, affecting women and men equally. Aging is the main risk factor for Alzheimer's disease (AD), with women having a higher risk. The higher prevalence of AD in women is associated with the abrupt hormonal decline seen after menopause. However, other factors may be involved in this sex-related cognitive decline. Alterations in gut microbiota (GM) and its bioproducts have been reported in AD subjects and transgenic (Tg) mice, having a direct impact on brain amyloid-β pathology in male (M), but not in female (F) mice.

OBJECTIVE

The aim of this work was to determine GM composition and cognitive dysfunction in M and F wildtype (WT) and Tg mice, in a sex/genotype segregation design.

METHODS

Anxiety, short term working-memory, spatial learning, and long-term spatial memory were evaluated in 6-month-old WT and Tg male mice. Fecal short chain fatty acids were determined by chromatography, and DNA sequencing and bioinformatic analyses were used to determine GM differences.

RESULTS

We observed sex-dependent differences in cognitive skills in WT mice, favoring F mice. However, the cognitive advantage of females was lost in Tg mice. GM composition showed few sex-related differences in WT mice. Contrary, Tg-M mice presented a more severe dysbiosis than Tg-F mice. A decreased abundance of Ruminococcaceae was associated with cognitive deficits in Tg-F mice, while butyrate levels were positively associated with better working- and object recognition-memory in WT-F mice.

CONCLUSION

This report describes a sex-dependent association between GM alterations and cognitive impairment in a mice model of AD.

Influence of sex differences in interpreting learning and memory within a clinical sample of older adults

Sex is an important factor to consider when evaluating memory with older adults. This present study aimed to examine sex differences in memory within a clinical sample of older adults (N = 1084). Raw learning and recall scores on the Hopkins Verbal Learning Test, Revised (HVLT-R) and Brief Visuospatial Memory Test, Revised (BVMT-R) were compared between sexes within the entire sample and cohorts stratified by age. Within the entire sample, women outperformed men in HVLT-R learning and recall, and there were no sex differences in BVMT-R performance. These sex differences, however, were absent or reversed for those with impaired HVLT-R performance and functional deficits, indicating that women retain an early advantage in verbal memory, which is lost with greater indication of disease severity. These findings indicate that women retain an advantage in verbal learning and memory, at least before significant levels of impairment, within a sample of older adults seen at an outpatient neurology clinic, which may have implications for diagnosing memory disorders.

Semantic Memory in the Clinical Progression of Alzheimer Disease

BACKGROUND AND OBJECTIVE

Semantic memory measures may be useful in tracking and predicting progression of Alzheimer disease. We investigated relationships among semantic memory tasks and their 1-year predictive value in women with Alzheimer disease.

METHODS

We conducted secondary analyses of a randomized clinical trial of raloxifene in 42 women with late-onset mild-to-moderate Alzheimer disease. We assessed semantic memory with tests of oral confrontation naming, category fluency, semantic recognition and semantic naming, and semantic density in written narrative discourse. We measured global cognition (Alzheimer Disease Assessment Scale, cognitive subscale), dementia severity (Clinical Dementia Rating sum of boxes), and daily function (Activities of Daily Living Inventory) at baseline and 1 year.

RESULTS

At baseline and 1 year, most semantic memory scores correlated highly or moderately with each other and with global cognition, dementia severity, and daily function. Semantic memory task performance at 1 year had worsened one-third to one-half standard deviation. Factor analysis of baseline test scores distinguished processes in semantic and lexical retrieval (semantic recognition, semantic naming, confrontation naming) from processes in lexical search (semantic density, category fluency). The semantic-lexical retrieval factor predicted global cognition at 1 year. Considered separately, baseline confrontation naming and category fluency predicted dementia severity, while semantic recognition and a composite of semantic recognition and semantic naming predicted global cognition. No individual semantic memory test predicted daily function.

CONCLUSIONS

Semantic-lexical retrieval and lexical search may represent distinct aspects of semantic memory. Semantic memory processes are sensitive to cognitive decline and dementia severity in Alzheimer disease.

Exosomes in the Diseased Brain: First Insights from In vivo Studies

Extracellular vesicles (EVs) are nanoscale size vesicles secreted by cells and are important mediators of intercellular communication and genetic exchange. Exosomes, EVs generated in endosomal multivesicular bodies, have been the focus of numerous publications as they have emerged as clinically valuable markers of disease states. Exosomes have been mostly studied from conditioned culture media and body fluids, with the difficulty of isolating exosomes from tissues having delayed their study in vivo. The implementation of a method designed to isolate exosomes from tissues, however, has yielded the first insights into characteristics of exosomes in the brain. It has been observed that brain exosomes from murine models of neurodegenerative diseases and human postmortem brains tend to mirror the protein content of the cells of origin, and interestingly, they are enriched with toxic proteins. Whether this enrichment with neurotoxic proteins is beneficial by relieving neurons of accumulated toxic material or detrimental to the brain by propagating pathogenicity throughout the brain remains to be answered. Here is summarized the first group of studies describing exosomes isolated from brain, results that demonstrate that exosomes in vivo reflect complex multicellular pathogenic processes in neurodegenerative disorders and the brain's response to injury and damage.

How Studies of the Serotonin System in Macaque Models of Menopause Relate to Alzheimer's Disease1

Serotonin plays a key role in mood or affect, and dysfunction of the serotonin system has been linked to depression in humans and animal models. Depression appears prior to or coincident with overt symptoms of Alzheimer's disease (AD) in about 50% of patients, and some experts consider it a risk factor for the development of AD. In addition, AD is more prevalent in women, who also show increased incidence of depression. Indeed, it has been proposed that mechanisms underlying depression overlap the mechanisms thought to hasten AD. Women undergo ovarian failure and cessation of ovarian steroid production in middle age and the postmenopausal period correlates with an increase in the onset of depression and AD. This laboratory has examined the many actions of ovarian steroids in the serotonin system of non-human primates using a rhesus macaque model of surgical menopause with short or long-term estradiol (E) or estradiol plus progesterone (E+P) replacement therapy. In this mini-review, we present a brief synopsis of the relevant literature concerning AD, depression, and serotonin. We also present some of our data on serotonin neuron viability, the involvement of the caspase-independent pathway, and apoptosis-inducing factor in serotonin-neuron viability, as well as gene expression related to neurodegeneration and neuron viability in serotonin neurons from adult and aged surgical menopausal macaques. We show that ovarian steroids, particularly E, are crucial for serotonin neuron function and health. In the absence of E, serotonin neurons are endangered and deteriorating toward apoptosis. The possibility that this scenario may proceed or accompany AD in postmenopausal women seems likely.

Sex differences in cognitive impairment in Alzheimer’s disease

Sex differences in neurocognitive abilities have been extensively explored both in the healthy population and in many disorders. Until recently, however, little work has examined such differences in people with Alzheimer’s disease (AD). This is despite clear evidence that AD is more prevalent in women, and converging lines of evidence from brain imaging, post-mortem analyses, hormone therapy and genetics suggesting that AD affects men and women differently. We provide an overview of evidence attesting to the poorer cognitive profiles in women than in men at the same stage of AD. Indeed, men significantly outperform women in several cognitive domains, including: Language and semantic abilities, visuospatial abilities and episodic memory. These differences do not appear to be attributable to any differences in age, education, or dementia severity. Reasons posited for this female disadvantage include a reduction of estrogen in postmenopausal women, greater cognitive reserve in men, and the influence of the apolipoprotein E ε4 allele. Assessment of cognitive abilities contributes to the diagnosis of the condition and thus, it is crucial to identify the role of sex differences if potentially more accurate diagnoses and treatments are to emerge.

Effects of age, gender, and stimulus presentation period on visual short-term memory

This study focused on age-related changes in visual short-term memory using visual stimuli that did not allow verbal encoding. Experiment 1 examined the effects of age and the length of the stimulus presentation period on visual short-term memory function. Experiment 2 examined the effects of age, gender, and the length of the stimulus presentation period on visual short-term memory function. The worst memory performance and the largest performance difference between the age groups were observed in the shortest stimulus presentation period conditions. The performance difference between the age groups became smaller as the stimulus presentation period became longer; however, it did not completely disappear. Although gender did not have a significant effect on d' regardless of the presentation period in the young group, a significant gender-based difference was observed for stimulus presentation periods of 500 ms and 1,000 ms in the older group. This study indicates that the decline in visual short-term memory observed in the older group is due to the interaction of several factors.

A normative study of total scores of the CERAD neuropsychological assessment battery in an educationally diverse elderly population

BACKGROUND

This study aimed to investigate the influences of age, education, and gender on the two total scores (TS-I and TS-II) of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological assessment battery (CERAD-NP) and to provide normative information based on an analysis for a large number of elderly persons with a wide range of educational levels.

METHODS

In the study, 1,987 community-dwelling healthy volunteers (620 males and 1,367 females; 50-90 years of age; and zero to 25 years of education) were included. People with serious neurological, medical, and psychiatric disorders (including dementia) were excluded. All participants underwent the CERAD-NP assessment. TS-I was generated by summing raw scores from the CERAD-NP subtests, excluding Mini-Mental State Examination and Constructional Praxis (CP) recall subtests. TS-II was calculated by adding CP recall score to TS-I.

RESULTS

Both TS-I and TS-II were significantly influenced by demographic variables. Education accounted for the greatest proportion of score variance. Interaction effect between age and gender was found. Based on the results obtained, normative data of the CERAD-NP total scores were stratified by age (six overlapping tables), education (four strata), and gender.

CONCLUSIONS

The normative information will be very useful for better interpretation of the CERAD-NP total scores in various clinical and research settings and for comparing individuals' performance of the battery across countries.

Blood pressure variability and risk of dementia in an elderly cohort, the Three-City Study

BACKGROUND

The relationship between blood pressure and dementia is incompletely understood in elderly individuals. Blood pressure variability may have a role in the risk of dementia.

METHODS

This investigation was a cohort study of 6506 elderly individuals followed-up for 8 years (1999-2001 through 2008) with assessments at years 2, 4, and 7-8. Blood pressure was measured by electronic devices at baseline and at 2- and 4-year follow-up examinations. Cox proportional hazard models adjusted for potential confounders were used to estimate the risk of incident dementia according to blood pressure (means and coefficients of variation of the three measures).

RESULTS

During the 40,151 person-years of follow-up 474 participants developed dementia. We observed no association between mean blood pressure and risk of dementia. In contrast, an increase of 1 standard deviation in the coefficient of variation of blood pressure was associated with a 10% increased risk of dementia. Analysis by deciles of the coefficient of variation showed that the higher the variability, the higher the risk of dementia (P<.02 for trend). In the fully adjusted Cox model, the risk of dementia for those in the highest decile of the coefficient of variation of systolic blood pressure was 1.77 (1.17-2.69) compared with the lowest decile.

CONCLUSIONS

In this cohort study, variability of blood pressure during follow-up was associated with an increased risk of incident dementia, whereas mean blood pressure was not. Limitation of blood pressure fluctuation may be an important target to preserve cognitive function in the elderly.

Stage-specific gender differences in cognitive and neuropsychiatric manifestations of vascular dementia

Studies on gender differences in the clinical manifestations of vascular dementia (VaD) are still lacking. In the present study, gender comparisons of cognitive and neuropsychiatric profiles were conducted separately for mild and moderate-to-severe VaD in a total of 467 patients with VaD. There were no significant gender differences in cognitive manifestations, except that females performed better on immediate verbal recall than males in mild stage. Women were more likely to exhibit delusions (15.5% vs 7.4%), hallucinations (9.5% vs 3.4%), and depression (43.1% vs 27.3%) in mild stage. The predominance of male patients was observed in apathy at moderate-to-severe stage (50.5% vs 34.8%). To conclude, gender differences existed in neuropsychiatric symptoms of VaD and were especially pronounced in mild stage. Delusions, hallucinations, and depression were more prevalent in females in mild VaD, with the male predominance only in apathy in the later stage.

Women have farther to fall: gender differences between normal elderly and Alzheimer's disease in verbal memory engender better detection of Alzheimer's disease in women

We analyzed verbal episodic memory learning and recall using the Logical Memory (LM) subtest of the Wechsler Memory Scale-III to determine how gender differences in AD compare to those seen in normal elderly and whether or not these differences impact assessment of AD. We administered the LM to both an AD and a Control group, each comprised of 21 men and 21 women, and found a large drop in performance from normal elders to AD. Of interest was a gender interaction whereby the women's scores dropped 1.6 times more than the men's did. Control women on average outperformed Control men on every aspect of the test, including immediate recall, delayed recall, and learning. Conversely, AD women tended to perform worse than AD men. Additionally, the LM achieved perfect diagnostic accuracy in discriminant analysis of AD versus Control women, a statistically significantly higher result than for men. The results indicate the LM is a more powerful and reliable tool in detecting AD in women than in men.

Gender differences in neurotrophin and glutamate receptor expression in cholinergic nucleus basalis neurons during the progression of Alzheimer's disease

The higher incidence rate of Alzheimer's disease (AD) in elderly women indicates that gender plays a role in AD pathogenesis. Evidence from clinical and pharmacologic studies, neuropathological examinations, and models of hormone replacement therapy suggest that cholinergic basal forebrain (CBF) cortical projection neurons within the nucleus basalis (NB), which mediate memory and attention and degenerate in AD, may be preferentially vulnerable in elderly women compared to men. CBF neurons depend on nerve growth factor (NGF) and their cognate receptors (trkA and p75(NTR)) for their survival and maintenance. We recently demonstrated a shift in the balance of NGF and its receptors toward cell death mechanisms during the progression of AD. To address whether gender affects NGF signaling system expression within the CBF, we used single cell RNA amplification and custom microarray technologies to compare gene expression profiles of single cholinergic NB neurons in tissue specimens from male and female members of the Religious Orders Study who died with a clinical diagnosis of no cognitive impairment (NCI), mild cognitive impairment (MCI), or mild/moderate AD. p75(NTR) expression within male cholinergic NB neurons was unchanged across clinical diagnosis, whereas p75(NTR) mRNA levels in female NB neurons exhibited a ∼40% reduction in AD compared to NCI. Male AD subjects displayed a ∼45% reduction in trkA mRNA levels within NB neurons compared to NCI and MCI. In contrast, NB neuronal trkA expression in females was reduced ∼50% in both MCI and AD compared to NCI. Reduced trkA mRNA levels were associated with poorer global cognitive performance and higher Braak scores in the female subjects. In addition, we found a female-selective reduction in GluR2 AMPA glutamate receptor subunit expression in NB neurons in AD. These data suggest that cholinergic NB neurons in females may be at greater risk for degeneration during the progression of AD and support the concept of gender-specific therapeutic interventions during the preclinical stages of the disease.

Gender differences in neuropsychological performance in individuals with atherosclerosis: impact of vascular function

This study was conducted to assess gender differences in cognition in elderly individuals (N = 88; 38 women, 50 men) with atherosclerotic vascular disease (AVD) and to determine whether these were attributable to differences in vascular health. Assessments included neuropsychological testing and measurement of forearm vascular function using venous occlusion plethysmography. There was a significant female advantage on multiple neuropsychological tests. This gender effect was reduced somewhat but remained significant when controlling for education and vascular function. Our study suggests that gender differences in cognition persist into older age and are not primarily due to gender differences in vascular health.

Which presidents are most memorable?

BACKGROUND/RATIONALE

Episodic memory loss is a hall-mark of Alzheimer's disease (AD), with recall of recent events becoming progressively difficult. A commonly used tool, the recollection of US presidents, was assessed in evaluating episodic versus semantic memory loss among AD patients compared with spouse controls.

METHODS

A total of 36 patients (12 men, 24 women) with possible or probable AD were asked to "give the names of 5 US presidents" and concurrently administered the Mini-Mental State Examination (MMSE). Twenty-three spouses (12 men, 11 women) were controls. The year 1980 demarcated "remote" versus "recent" presidents.

RESULTS

Patients were older, had lower MMSE scores (P < .001), and recalled fewer presidents than controls (P < .005), after controlling for age. Among patients, men were more educated than women (P < .05) and recalled more presidents (P < .001). No gender differences were observed in controls.

CONCLUSIONS

Patients with AD preferentially recalled remote presidents, supporting retention of semantic memory in this group. There were no gender differences between groups.

Gender-specificities in Alzheimer's disease and mild cognitive impairment

BACKGROUND

Amnestic Mild Cognitive Impairment (MCI) is a condition with an increased risk for developing Alzheimer's disease (AD). Presently, gender differences are neglected in the assessment of MCI and AD.

METHODS

We examined verbal and visuospatial episodic memory in 143 subjects diagnosed as healthy controls (HC; N = 48, Mini-Mental State Examination (MMSE) 29.2 +/- 1.0 (mean +/- standard deviation)), MCI (N = 43,MMSE 28.5 +/- 1.4), and AD (N = 49, MMSE 25.1 +/- 2.2).

FINDINGS

Female HC and MCI subjects performed better on verbal episodic memory tasks than males. In contrast, visuospatial episodic memory was better in male than female AD patients.

CONCLUSIONS

We interpret the results in light of a gender-specific cognitive reserve and conclude that the gender-specificity of neuropsychological performance needs to be accounted for in clinical diagnosis of Alzheimer's disease.

Gender differences in brain reserve : an (18)F-FDG PET study in Alzheimer's disease

BACKGROUND

Neuropathological studies suggest that the association between neurodegenerative brain damage and clinical symptoms may be stronger in women than in men.

OBJECTIVE

To test the hypothesis that cerebral metabolic deficits due to neurodegeneration are more pronounced in men than in women at the same level of clinical disease severity.

METHODS

93 patients with mild Alzheimer's disease (AD; 50 men, 43 women) underwent an extensive clinical and neuropsychological examination and (18)F-FDG PET imaging at a university-based outpatient unit for cognitive disorders. An analysis of covariance (with age, total score of the CERAD neuropsychological battery, and years of school education as covariates) was conducted in each study group to identify gender differences in glucose metabolism.

RESULTS

Controlling for age, education, and clinical severity, cortical regions were identified,where glucose metabolism was significantly reduced in men as compared with women. These regions were located in areas typically affected by AD pathology (right inferior frontal, superior temporal and insular cortex, and hippocampus).

CONCLUSIONS

These data suggest that the same clinical severity of dementia is associated with greater reductions in cerebral metabolism in men than in women suggesting a greater degree of brain reserve in men.

A meta-analytic review of category naming in Alzheimer's disease

Patients with Alzheimer's disease (AD) experience word-finding difficulties that become increasingly pronounced as pathological changes accrue in the brain. One question that has received increasing attention over the last two decades concerns whether the anomia in AD is category-specific, i.e. differentially affects the ability to name living things (LT) and non-living things (NLT). The current meta-analysis systematically reviewed the effect sizes for naming pictures of LT and NLT in comparisons of AD patients and healthy controls in 21 studies with over 1000 participants (557 patients and 509 healthy controls). A random effects model analysis revealed no significant difference in the large weighted effect sizes for naming pictures of LT and NLT (d=1.76 and 1.49, respectively). Moderator variable analyses revealed a significant impact of stimulus colour on the effect size for LT, indicating that using colour stimuli significantly increases the impairment of naming LT in AD patients. Additionally, we found that LT and the NLT effect sizes were larger for samples with proportionally more female patients; smaller samples produced larger LT effect sizes. In contrast, effect sizes were not significantly related to dementia severity, patient age, the number of stimuli, years of education, or the number of matching variables controlled.

Sex influences on cholinesterase inhibitor treatment in elderly individuals with alzheimer's disease

BACKGROUND

The second generation of cholinesterase inhibitors (ChEIs) is approved in the United Kingdom for the treatment of mild to moderate Alzheimer's disease (AD). The UK National Institute of Clinical Excellence has raised questions, however, about whether ChEIs are cost-effective for the treatment of dementia. To address these concerns, it is important to identify factors that predict which patients may have the best response to ChEl treatment.

OBJECTIVE

We reviewed animal studies and human clinical studies to address whether sex can predict and influence the response to ChEI treatment based on differences in neuroanatomy, pharmacokinetics, and prevalence of dementia.

METHODS

Relevant articles examining the use of ChEIs in humans with dementia (especially in AD) and in animals were identified through searches of several databases, including MEDLINE, PubMed, and EMBASE for general medical topics, the Cochrane Controlled Clinical Trials Register and CINAHL DIRECT for nursing and allied health issues, and PsycLIT for reviews of psychology and psychiatry topics (1980 June 2006). Articles reviewed were limited to those that discussed the use of ChEIs in relation to sex.

RESULTS

Animal studies have produced a substantial amount of evidence to support the hypothesis that sex may influence the response to ChEIs and, in particular, that testosterone may play a significant role in producing this difference by its influence on the entry of ChEIs into the brain. The results of clinical studies in humans, on the other hand, have been mixed. Two double-label and open-label clinical studies suggested that there may be a 3-way interaction between apolipoprotein E genotype, sex, and tacrine (range, P = 0.03 to P = 0.05). Seven double-blind, open-label clinical trials and 13 case studies of donepezil, rivastigmine, and galantamine produced little evidence of an association between treatment outcomes (as measured with clinical rating scales) and sex, although in an open-label 2-year study in women with AD treated with donepezil, women had lower mortality rates than men (10% and 20%, respectively; P = 0.003). One study produced weak evidence that women treated with ChEIs may experience more adverse effects than men, but this may have been attributable to low body weight rather than to sex differences.

CONCLUSIONS

A substantial relation has not been established between sex and the second-generation ChEIs currently used in clinical settings for the treatment of AD. If an interaction between sex and ChEI treatment does exist, as suggested in 10 of the studies we analyzed, it is likely to be small and subtle, with much individual variation, as is the case with most neurologic sex differences. Nevertheless, sexual dimorphism in response to ChEI therapy warrants further investigation, especially in regard to its role in the development of novel AD therapies.

Plasma total homocysteine and memory in the elderly: the Hordaland Homocysteine Study

We examined the relation between plasma total homocysteine (tHcy), folate, vitamin B12, and episodic memory in elderly community-dwelling subjects. A population-based study was conducted in 1992 and 1993, and subjects were re-investigated after 6 years. Plasma analytes were determined on both occasions. At follow-up, memory performance, using the Kendrick Object Learning Test, was investigated in 2,189 subjects (age, 65-67 years at baseline). Subjects with memory deficit (test score, < 25) had higher tHcy and lower folate at follow-up compared with those without memory deficit: 12.6 (95% confidence interval [CI], 12.1, 13.1) versus 11.5 (95% CI, 11.3, 11.6) micromol/L (p < 0.001) for tHcy, and 6.7 (95% CI, 6.2, 7.1) versus 7.6 (95% CI, 7.5, 7.8) nmol/L (p < 0.001) for folate. The risk of memory deficit increased according to quintiles of tHcy both at baseline and at follow-up. A decline in tHcy, or an increase in folate, over a 6-year period was associated with a higher memory test score; and vice versa. These findings indicate that increased plasma tHcy is an independent risk factor for memory deficit both cross-sectionally and prospectively, and that a "favorable" change in folate or tHcy concentrations over time is associated with better memory performance.

Comparing gray matter loss profiles between dementia with Lewy bodies and Alzheimer's disease using cortical pattern matching: diagnosis and gender effects

We used magnetic resonance imaging (MRI) and cortical pattern matching to map differences in cortical gray matter deficits between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), and explored the possible influence of gender on these patterns. Twenty-nine patients with AD (age 77.9 +/- 5.5), 16 patients with DLB (76.4 +/- 6.7), and 38 controls (75.3 +/- 6.8) were included. Dementia groups were matched for illness severity. Detailed spatial analyses of gray matter were conducted across the entire cerebral cortex by measuring local proportions of gray matter at thousands of homologous cortical surface locations in each subject and between diagnostic groups. To visualize regional changes, statistical differences were mapped at each cortical surface location in 3D. Main effects of diagnosis demonstrated prominent gray matter differences in orbitofrontal and temporal cortices, where AD exhibited the greatest deficits relative to DLB. Main effects of sex showed less gray matter in men within all group comparisons. Exploratory findings for sex by diagnosis interactions suggest greater gray matter loss in the anterior cingulate for men with AD, relative to controls, AD females, and individuals with DLB. Relative preservation of orbitofrontal cortices in addition to temporal structures may contribute to distinguishing DLB from AD. Further investigation of the influence of gender might provide a more comprehensive understanding of the pathophysiological differences underlying the two forms of dementia.

Analyses of gender differences in profiles of nursing home residents with Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD), a progressive, neurodegenerative disorder characterized by memory loss, language deterioration, impairment of visuospatial skills, poor judgment, and indifference, but preserved motor function, is the most common type of dementia, accounting for two thirds or more of all cases of dementia. The identification of differences between men and women with AD might present opportunities to improve the quality of AD-related care provided by nursing facilities, as well as lead to additional analyses of nursing home residents with AD.

OBJECTIVE

The objectives of this study were to gain additional insight into gender differences in nursing home residents with AD in the United States, and to provide a better understanding of their health status and the care they receive in nursing facilities.

METHODS

All admission assessments recorded in the Minimum Data Set (MDS) throughout the United States during 2000 were analyzed. P values for all significant differences were <0.001.

RESULTS

A total of 49,607 residents with a diagnosis of AD (67.9% women) were identified. Female residents with AD were more likely to be older and widowed, whereas male residents with AD were more likely to be married. We found minimal gender differences in cognitive impairment among these residents with AD, although women were more likely to understand and be understood by others. Male residents with AD were more likely to exhibit behavioral symptoms, whereas female residents with AD tended to be more physically impaired and dependent on others for activities of daily living. Significant differences in comorbidities were found between the sexes, with greater proportions of male residents with AD having cardiac-related conditions, stroke, cancer, and other life-threatening chronic conditions. Male residents with AD were more likely to receive care in AD special-care units; daily antipsychotic medications; and intervention programs for mood, behavior, and cognitive loss than female residents with AD.

CONCLUSIONS

In this study of nursing home residents identified using the MDS, key differences were found between male and female residents with AD, including age; cognitive and communicative abilities; and mental health, mood, and behavioral patterns.

Behavioral impairment of APP(V717F) mice in fear conditioning: is it only cognition?

Alzheimer's Disease (AD) is a devastating human neurodegenerative disorder associated with progressive deterioration of cognitive abilities. The APP(V717F) mouse, an animal model of AD showing robust overexpression of the human amyloid precursor protein (APP) carrying the mutation 717 V --> F, was also shown to exhibit learning and memory performance deficits. However, AD patients suffer from other abnormalities including altered emotionality. Emotionality has not been analyzed in AD mouse models. Here, motor and posture patterns exhibited by APP(V717F) mice are described in a detailed manner in fear conditioning, a paradigm that allows one to test both mnemonic and emotional characteristics of mice. Our results revealed a complex set of behavioral alterations in APP(V717F) mice in measures of exploratory behavior and fear suggesting that the effects of APP(V717F) overexpression in this mouse model are not limited to cognition and may need to be thoroughly examined in the future in a broad range of behavioral tests.

Structure of the cerebral cortex in men and women

Expanding previous studies of human cerebral cortical sexual dimorphism showing higher neuronal densities in males, we investigated whether gender differences also exist in the extent of neuropil, size of neuronal somata, and volumes of astrocytes. This histo-morphometric study includes select autopsy brains of 6 males and 5 females, 12 to 24 yr old. In each brain, 86 defined loci were analyzed for cortical thickness, neuronal and astrocytic (8 loci) density (stereological counts), and neuronal and astrocytic (8 loci) soma size, enabling calculations of neuropil and astrocytic volumes. The female group showed significantly larger neuropil volumes than males, whereas neuronal soma size and astrocytic volumes did not differ. The expanded data confirmed higher neuronal densities in males than in females without a gender difference in cortical thickness. These findings indicate that fundamental gender differences exist in the structure of the human cerebral cortex, with more numerous, smaller neuronal units in men and fewer, larger ones in women; they may underlie gender-specific abilities and susceptibilities to disease affecting the neocortex. Laterality differences between the sexes were restricted to neuronal soma size showing significantly larger values in the female group in the left hemisphere. This gender difference may support female's right-handedness, language advantage, and tendency for bilateral activation patterns.

Decline of language among women and men with Alzheimer's disease

Previous research raises the possibility that gender differences occur in language function in Alzheimer's disease, but this hypothesis has not been evaluated systematically in longitudinal studies. The authors examined the association of gender with rate of decline in language and other cognitive functions among 410 persons with Alzheimer's disease. Participants were recruited from a dementia clinic and followed for up to 5 annual evaluations. Follow-up participation among survivors exceeded 90%. Decline in a composite score based on 8 language tests was evaluated in random effects models with age, education, and race controlled. Annual decline was 0.71 standard units (95% confidence interval [CI] = 0.62-0.79) for women and 0.74 units (95% CI = 0.61-0.86) for men, not a significant difference. Decline on the individual language tests and on composite measures of memory, perception, and global cognition also indicated no significant association with gender. These results suggest that Alzheimer's disease affects language and other cognitive functions similarly in women and men.

Sex differences in prefrontal volume with aging and Alzheimer's disease

We used volumetric magnetic resonance imaging to examine sex differences in prefrontal tissue volumes of healthy aged and patients with Alzheimer's disease (AD). Healthy subjects had greater total prefrontal volume than AD, and men had greater total prefrontal volume than women (ps < or = 0.02). This was true for both gray and white matter volumes. There were no interactions between group and sex for total prefrontal volume. An exploratory analysis of each group suggested that sex differences in both gray and white matter in healthy aging are not sustained in AD.

Differentiation of vascular dementia from AD on neuropsychological tests

BACKGROUND

The concept of vascular dementia (VaD) is currently in a state of evolution. Memory impairment is emphasized as a primary criterion, reflecting the influence of AD on the concept of dementia. We have systematically reviewed whether the nature of neuropsychological dysfunction is distinct in AD and VaD, and whether similar defining criteria for the concept of dementia in both disorders can be supported.

METHODS

We searched five bibliographic databases (Medline, Biological Abstracts, EMBASE, PsychINFO, PsychLIT) for research articles in which VaD and AD had been compared using neuropsychological tests and that met criteria for scientific merit.

RESULTS

Of the 45 studies, 18 were excluded because of inadequacies, and the remaining 27 were analyzed. There were a number of similarities of dysfunction between VaD and AD. However, when matched for age, education, and severity of dementia, VaD patients had relatively superior function in verbal long-term memory and more impairment in frontal executive functioning compared with AD patients. Interpretation of the results is limited by uncertainty in diagnostic criteria for VaD, possible inclusion bias due to use of clinical diagnosis alone, possible overlap of AD and VaD, and the methodologic shortcomings of some studies.

CONCLUSIONS

The neuropsychological differentiation of VaD from AD was consistent with the different neuroimaging findings in the two disorders, and argues for differential criteria for the definition of the syndromes. The simple application of Alzheimer's dementia criteria to VaD, with the inclusion of cerebrovascular disease etiology, may not be sufficient to capture the uniqueness of VaD.