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

Sex Differences in Alzheimer's Disease

Reviewing the research presented in this article, it is evident that from an epidemiological perspective, it is important to evaluate the extent to which findings of sex and gender differences in Alzheimer's dementia (AD) are due to differences in longevity, survival bias, and comorbidities. Medical, genetic, psychosocial, and behavioral factors, in addition to hormonal factors, can differentially affect the risk and progression of AD in women versus men. Further, evaluation of sex differences in AD progression and the trajectory of change in cognitive function, neuroimaging, cerebrospinal fluid (CSF), and blood-based biomarkers of AD is needed. Finally, identifying sex differences in AD biomarkers and change across the lifespan is critical for the planning of prevention trials to reduce the risk of developing AD.

Modifiable, Non-Modifiable, and Clinical Factors Associated with Progression of Alzheimer's Disease

There is an extensive literature relating to factors associated with the development of Alzheimer's disease (AD), but less is known about factors which may contribute to its progression. This review examined the literature with regard to 15 factors which were suggested by PubMed search to be positively associated with the cognitive and/or neuropathological progression of AD. The factors were grouped as potentially modifiable (vascular risk factors, comorbidities, malnutrition, educational level, inflammation, and oxidative stress), non-modifiable (age at clinical onset, family history of dementia, gender, Apolipoprotein E ɛ4, genetic variants, and altered gene regulation), and clinical (baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs). Although conflicting results were found for the majority of factors, a positive association was found in nearly all studies which investigated the relationship of six factors to AD progression: malnutrition, genetic variants, altered gene regulation, baseline cognitive level, neuropsychiatric symptoms, and extrapyramidal signs. Whether these or other factors which have been suggested to be associated with AD progression actually influence the rate of decline of AD patients is unclear. Therapeutic approaches which include addressing of modifiable factors associated with AD progression should be considered.

Sex and gender differences in Alzheimer's disease: current challenges and implications for clinical practice: Position paper of the Dementia and Cognitive Disorders Panel of the European Academy of Neurology

Alzheimer's disease (AD) is characterized by high heterogeneity in disease manifestation, progression and risk factors. High phenotypic variability is currently regarded as one of the largest hurdles in early diagnosis and in the design of clinical trials; there is therefore great interest in identifying factors driving variability that can be used for patient stratification. In addition to genetic and lifestyle factors, the individual's sex and gender are emerging as crucial drivers of phenotypic variability. Evidence exists on sex and gender differences in the rate of cognitive deterioration and brain atrophy, and in the effect of risk factors as well as in the patterns of diagnostic biomarkers. Such evidence might be of high relevance and requires attention in clinical practice and clinical trials. However, sex and gender differences are currently seldom appreciated; importantly, consideration of sex and gender differences is not currently a focus in the design and analysis of clinical trials for AD. The objective of this position paper is (i) to provide an overview of known sex and gender differences that might have implications for clinical practice, (ii) to identify the most important knowledge gaps in the field (with a special regard to clinical trials) and (iii) to provide conclusions for future studies. This scientific statement is endorsed by the European Academy of Neurology.

Is there a relationship between accelerometer-assessed physical activity and sedentary behavior and cognitive function in US Hispanic/Latino adults? The Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

Normative changes in cognitive function are expected with increasing age. Research on the relationship between normative cognitive decline and moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SED) needs further investigation in Hispanic/Latinos adults. We assessed the cross-sectional association between accelerometer assessed MVPA and SED with cognitive function in 7,478 adults aged 45-74years from the Hispanic Community Health Study/Study of Latinos. At baseline, cognitive tests included two executive function tests (Digit Symbol Substitution Test (DSST), a test of language (Word Fluency), and a test of memory (Spanish English Verbal Learning Test). Multiple regression models were used to examine associations of time spent in MVPA and SED with cognitive function by age groups, adjusted for age, education, sex, acculturation, and field center. Mean time spent in sedentary behaviors was 12.3h/day in females and 11.9 h/day in males (75% and 77% of accelerometer wear time, respectively). Higher SED, but not MVPA, was associated with lower DSST raw scores (β -0.03 with each 10-min increment in SED; P<0.05), indicating lower performance in executive function in all age groups. No associations were observed for MVPA and SED with tests of language or memory tests. Our findings suggest a distinct association of SED but not MVPA on executive functioning in middle-aged and older Latino adults. Longitudinal studies are needed to more conclusively determine causal links.

Curcumin: a natural substance with potential efficacy in Alzheimer's disease

Curcumin is a component of turmeric, a spice used in many types of cooking. Epidemiological evidence suggesting that populations that eat food with a substantial amount of curcumin were at lower risk of Alzheimer’s disease (AD) led to the idea that this compound might have a neuroprotective effect. Curcumin has substantial antioxidant and anti-inflammatory effects, and is being used as a potential preventative agent or treatment for many types of cancer. There is evidence to suggest that the addition of curcumin to cultured neuronal cells decreases brain inflammation and protects against β-amyloid-induced neurotoxicity. Curcumin also protects against toxicity when β-amyloid is administered to produce animal models of AD. Curcumin decreases β-amyloid formation from amyloid precursor protein, and also inhibits aggregation of β-amyloid into pleated sheets. Studies in transgenic mice with overproduction of β-amyloid demonstrate a neuroprotective effect of curcumin as well. Cognitive function was also improved in these animal models. Clinical trials of curcumin in AD have not been very promising. It is possible that this is due to poor oral bioavailability of curcumin in humans, and thus several approaches are being developed to improve delivery systems or to create analogs that will mimic the neuroprotective effects and easily reach the brain. The lack of efficacy of curcumin in humans with AD may also result from treating for too short a time or starting treatment too late in the course of the disease, where substantial neuronal death has already occurred and cannot be reversed. Curcumin may be beneficial in protecting against development or progression of AD if taken over the long term and started before symptoms of AD become apparent.

Role of neuroinflammation in adult neurogenesis and Alzheimer disease: therapeutic approaches

Neuroinflammation, a specialized immune response that takes place in the central nervous system, has been linked to neurodegenerative diseases, and specially, it has been considered as a hallmark of Alzheimer disease, the most common cause of dementia in the elderly nowadays. Furthermore, neuroinflammation has been demonstrated to affect important processes in the brain, such as the formation of new neurons, commonly known as adult neurogenesis. For this, many therapeutic approaches have been developed in order to avoid or mitigate the deleterious effects caused by the chronic activation of the immune response. Considering this, in this paper we revise the relationships between neuroinflammation, Alzheimer disease, and adult neurogenesis, as well as the current therapeutic approaches that have been developed in the field.

Maternal hypertensive disorders in pregnancy and self-reported cognitive impairment of the offspring 70 years later: the Helsinki Birth Cohort Study

OBJECTIVE

We tested whether maternal hypertensive disorders during pregnancy predict self-reported cognitive impairment, which is one of the earliest behavioral markers of dementia, of the offspring 70 years later.

STUDY DESIGN

We included 876 participants of the Helsinki Birth Cohort Study 1934-44 who were born after normotensive, preeclamptic, or hypertensive pregnancies that were defined by the use of the mother's blood pressure and urinary protein measurements at maternity clinics and birth hospitals. The participants completed a psychological questionnaire that included questions on cognitive failures and dysexecutive functioning at an average age of 69.3 ± 3.1 (SD) years.

RESULTS

In comparison with the offspring who were born after normotensive pregnancies, the offspring who were born after preeclamptic pregnancies reported more frequent complaints of cognitive failures, distractibility, and false triggering. Further, among women we found maternal hypertension without proteinuria that was associated with more frequent complaints of cognitive failures, forgetfulness, and false triggering.

CONCLUSION

Hypertensive disorders during pregnancy are associated with more frequent subjective complaints of cognitive failures of the offspring in old age.

Greater cognitive deterioration in women than men with Alzheimer's disease: a meta analysis

Studies reporting on the cognitive abilities of men and women with Alzheimer's disease (AD) are surprisingly rare. We carried out a meta-analysis of neurocognitive data from 15 studies (n = 828 men; 1,238 women), which revealed a consistent male advantage on verbal and visuospatial tasks and tests of episodic and semantic memory. Moderator regression analyses showed that age, education level, and dementia severity did not significantly predict the male advantage. Reasons posited for this advantage include a reduction of estrogen in postmenopausal women, sex differences in AD pathology, and greater cognitive reserve in men.

A random change point model for cognitive decline in Alzheimer's disease and mild cognitive impairment

BACKGROUND

We present a random change point model to characterize decline in cognition among community-based elderly who developed Alzheimer's disease (AD) or amnestic mild cognitive impairment (MCI), and to examine how decline varies with age, sex, education, and APOE status.

METHODS

Using longitudinal cohort data on cognitive function, we fit a piecewise linear trajectory with a random change point that allows different rates of cognitive decline before and after the change point. We estimated the change point that signals the onset of cognitive impairment, and examined the association of risk factors with the location of the change point as well as the rates of decline before and after the change point.

RESULTS

Among participants who were dementia free at enrollment and developed incident AD, the change point occurred on average 5.7 years after enrollment and the rate of cognitive decline after the change point nearly quadrupled. Age, education, and APOE status play important but different roles in the timing of the onset of cognitive impairment and in the rates of decline before and after its onset. Results were similar among participants who were cognitively unimpaired at enrollment but later developed amnestic MCI or AD.

CONCLUSIONS

The random change point model provides a more comprehensive understanding of the relation of risk factors with the onset of cognitive impairment and rates of decline before and after its onset.

Sex differences in grey matter atrophy patterns among AD and aMCI patients: results from ADNI

We used longitudinal magnetic resonance imaging (MRI) data to determine whether there are any gender differences in grey matter atrophy patterns over time in 197 individuals with probable Alzheimer's disease (AD) and 266 with amnestic mild cognitive impairment (aMCI), compared with 224 healthy controls participating in the Alzheimer's Disease Neuroimaging Initiative (ADNI). While previous research has differentiated probable AD and aMCI groups from controls in brain atrophy, it is unclear whether and how sex plays a role in patterns of change over time. Using regional volumetric maps, we fit longitudinal models to the grey matter data collected at repeated occasions, seeking differences in patterns of volume change over time by sex and diagnostic group in a voxel-wise analysis. Additionally, using a region-of-interest approach, we fit longitudinal models to the global volumetric data of predetermined brain regions to determine whether this more conventional approach is sufficient for determining sex and group differences in atrophy. Our longitudinal analyses revealed that, of the various grey matter regions investigated, males and females in the AD group and the aMCI group showed different patterns of decline over time compared to controls in the bilateral precuneus, bilateral caudate nucleus, right entorhinal gyrus, bilateral thalamus, bilateral middle temporal gyrus, left insula, and right amygdala. As one of the first investigation to model more than two time points of structural MRI data over time, our findings add insight into how AD and aMCI males and females differ from controls and from each other over time.

Endogenous hormones, androgen receptor CAG repeat length and fluid cognition in middle-aged and older men: results from the European Male Ageing Study

OBJECTIVE

Data remain divergent regarding the activational effects of endogenous hormones on adult cognitive function. We examined the association between cognition, hormones and androgen receptor (AR) CAG repeat length in a large cohort of men.

DESIGN

Community-based, cross-sectional study of 3369 men aged 40-79 years.

METHODS

Cognition tests were the Rey-Osterrieth Complex Figure, Camden Topographical Recognition Memory and Digit-Symbol Substitution. A fluid cognition (FC) z-score was computed from the individual tests. Testosterone, oestradiol (OE(2)) and 5alpha-dihydrotestosterone were measured by gas chromatography-mass spectrometry; DHEAS, LH, FSH and sex hormone-binding globulin (SHBG) by electrochemiluminescence. Free testosterone and OE(2) were calculated from total hormone, SHBG and albumin. CAG repeat lengths were assayed by PCR genotyping.

RESULTS

Total testosterone and free testosterone were associated with higher FC z-scores, LH and FSH with lower FC z-scores in age-adjusted linear regressions. After adjusting for health, lifestyle and centre, a modest association was only observed between DHEAS and a lower FC z-score (beta=-0.011, P=0.02), although this was driven by subjects with DHEAS levels >10 micromol/l. Locally weighted plots revealed no threshold effects between hormones and FC. There was no association between CAG repeat length and FC z-score after adjustment for age and centre (beta=-0.007, P=0.06), nor any interaction effect between CAG repeat length and hormones.

CONCLUSION

Our results suggest that endogenous hormones are not associated with a vision-based measure of FC among healthy, community-dwelling men. Further studies are warranted to determine whether 'high' DHEAS levels are associated with poorer performance on a broader range of neuropsychological tests.

Cognitive decline in incident Alzheimer disease in a community population

OBJECTIVE

To measure the cognitive consequences of incident Alzheimer disease (AD) in older African American and white subjects.

METHODS

Data are from the Chicago Health and Aging Project, a longitudinal cohort study of older white and black persons residing in a geographically defined community. At 3-year intervals, the entire study population completed 4 brief cognitive tests, from which a previously established composite measure of global cognition was derived, and a subset underwent detailed clinical evaluation that supported clinical classification of mild cognitive impairment, dementia, and AD. We used mixed-effects models to examine change in cognitive function following the diagnostic evaluation.

RESULTS

On clinical evaluation, 614 persons were found to have no cognitive impairment, 395 had mild cognitive impairment, and 149 had AD (88.5% mild); 10 persons with other dementias were excluded from analyses. During up to 11 years of observation following the clinical evaluation (mean = 5.5, SD = 2.5), the composite measure of global cognition declined a mean of 0.042 unit per year (SE = 0.008, p < 0.001) in those with no cognitive impairment. In comparison to the no cognitive impairment group, the annual rate of decline was increased more than twofold in mild cognitive impairment (estimate = 0.086, SE = 0.011, p < 0.001) and more than fourfold in AD (estimate = 0.173, SE = 0.020, p < 0.001). Results did not reliably vary by race, sex, or age.

CONCLUSIONS

Alzheimer disease has a devastating impact on cognition, even in its prodromal stages, with comparable effects in African American and white persons.

Neuropsychological assessment in the diagnosis of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia in older adults. It represents a significant public health concern because of its associated personal, social, and economic burden. As such, AD is the focus of considerable research worldwide. This unit reviews the major cognitive and behavioral impairments associated with AD, and the practical application of current neuropsychological procedures used to assess these deficits.

Executive decline and dysfunction precedes declines in memory: the Women's Health and Aging Study II

BACKGROUND

Understanding preclinical transitions to impairment in cognitive abilities associated with risks for functional difficulty and dementia. This study characterized in the Women's Health and Aging Study (WHAS) II 9-year declines and transitions to impairment across domains of cognition.

METHODS

The WHAS II is an observational study of initially high-functioning, community-dwelling women aged 70-80 years at baseline. Random-effects models jointly compared rates of decline, and discrete-time Cox models estimated hierarchies of incident clinical impairment on measures of psychomotor speed and executive function (EF) using the Trail Making Test and in immediate and delayed verbal recall using the Hopkins Verbal Learning Test. Patterns of transition were related to incidence of global cognitive impairment on the Mini-Mental State Exam (MMSE).

RESULTS

Mean decline and impairment occurred first in EF and preceded declines in memory by about 3 years. Thereafter, memory decline was equivalent to that for EF. Over 9 years, 49% developed domain-specific impairments. Risk of incident EF impairment occurred in 37% of the sample and was often the first impairment observed (23.7%), at triple the rate for psychomotor speed (p < .01). Risk of immediate and delayed recall impairments was nearly double that for psychomotor speed (p values <.01). Incident impairment in EF and delayed recall was associated with greater risk for MMSE impairment.

CONCLUSIONS

Executive dysfunction developed first among nearly one quarter of older women and was associated with elevated risk for global cognitive impairment. Because EF declines preceded memory declines and are important to efficient storage and retrieval EF represents an important target for interventions to prevent declines in memory and MMSE both of which are associated with progression to dementia.

Dementia of the Alzheimer type

Dementia of the Alzheimer type is a progressive, fatal neurodegenerative condition characterized by deterioration in cognition and memory, progressive impairment in the ability to carry out activities of daily living, and a number of neuropsychiatric symptoms. This narrative review summarizes the literature regarding descriptive epidemiology, clinical course, and characteristic neuropathological changes of dementia of the Alzheimer type. Although there are no definitive imaging or laboratory tests, except for brain biopsy, for diagnosis, brief screening instruments and neuropsychiatric test batteries used to assess the disease are discussed. Insufficient evidence exists for the use of biomarkers in clinical practice for diagnosis or disease management, but promising discoveries are summarized. Optimal treatment requires both nonpharmacological and pharmacological interventions, yet none have been shown to modify the disease's clinical course. This review describes the current available options and summarizes promising new avenues for treatment. Issues related to the care of persons with dementia of the Alzheimer type, including caregiver burden, long-term care, and the proliferation of dementia special care units, are discussed. Although advances have been made, more research is needed to address the gaps in our understanding of the disease.

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.

Stigmatization in Alzheimer's disease research on African American elders

Stigmatization in research sustains the spread of the silent epidemic of Alzheimer's disease (AD) in African American populations. Researchers use stereotypes and inappropriate assumptions to select a paradigm to examine the symptoms of AD. This paradigm fails to encompass the symptoms as manifested by African American elders. Yet, stigmatization can be minimized by recognizing the genetic heterogeneity of the symptoms within the general population, especially those manifested by African American elders. Thus, researchers can utilize pioneering genetic analyses to identify other paradigms critical in the assessment and proactive treatment of the symptoms of AD needed for this vulnerable population.

Change in cognitive function in Alzheimer's disease in African-American and white persons

Few studies have examined the association of race with change in cognitive function in Alzheimer's disease (AD). We studied the rate of decline in global and specific measures of cognitive function in a cohort of 410 older African-Americans and whites with clinically diagnosed AD. Persons were examined annually for an average of 3.5 years, and follow-up participation among survivors exceeded 90%. In mixed-effects models that controlled for age, gender, education, and premorbid reading activity, African-Americans scored lower than whites at baseline on a composite measure of global cognition and on specific measures of visuoconstruction and naming. However, they experienced less rapid decline in episodic memory (p < 0.01), with similar but not quite significant effects for global cognition (p = 0.06), perceptual speed (p = 0.07) and naming (p = 0.08). The results suggest that the rate of cognitive decline in AD is slower in African-Americans compared with whites, particularly for episodic memory.

The Effect of a Memory Screening Program on the Early Diagnosis of Alzheimer Disease

CONTEXT

Alzheimer Disease (AD) is often diagnosed at a moderately advanced stage, even though its early detection has become increasingly important, because of the continuing development of treatments that may improve its outcome.

OBJECTIVE

To determine if a free memory screening program is associated with an earlier diagnosis of AD, compared with traditional referral methods, such as by physicians and family members.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective study of 1489 consecutive patients with AD who presented to an outpatient memory disorders clinic between 1993 and 2002. Subjects were classified according to referral source (memory screening, physician, family/friend, other), and self-reported ethnicity (white non-Hispanic, white Hispanic). The associations between referral source and the presenting cognitive and behavioral status of subjects were evaluated using analysis of variance and logistic regression analyses, after controlling for potentially confounding factors.

MAIN OUTCOME MEASURES

Score on the Folstein Mini-Mental State Examination (MMSE), duration of cognitive symptoms, and presence of psychosis, defined as delusions and/or hallucinations.

RESULTS

After controlling for ethnicity, gender, and the year of diagnosis, subjects with AD, who were referred by the memory screening program, scored significantly higher at presentation on the MMSE (20.8 +/- 5.7), than those referred by physicians (18.8 +/- 6.6), family/friends (16.8 +/- 6.6), or other referral sources (15.3 +/- 7.1). Subjects with AD, referred by the memory screening program, also had a lower reported duration of illness at presentation, and a decreased frequency of psychosis compared with those referred by family/friend and other methods. Other factors related to a diagnosis of AD at a later stage included female gender, Hispanic ethnicity, and a diagnosis early in the 1993 to 2002 time period.

CONCLUSIONS

The memory screening program referred patients with AD to a memory clinic at an earlier phase of illness compared with traditional methods such as physician referral.