Cognition, Gender, and Functional Abilities in Alzheimer's Disease: How are They Related?

Differences in brain aging between sexes in Parkinson's disease

Parkinson's disease (PD) is linked to faster brain aging. Male sex is associated with higher prevalence, severe symptoms, and a faster progression rate in PD. There remains a significant gap in understanding the function of sex in the process of brain aging in PD. The structural T1-weighted MRI-driven brain-predicted age difference (i.e., Brain-PAD: the actual age subtracted from the brain-predicted age) was computed in a group of 373 people with PD (mean age ± SD: 61.37 ± 9.81, age range: 33-85, 34% female) from the Parkinson's Progression Marker Initiative database using a robust brain-age estimation framework that was trained on 949 healthy subjects. Linear regression models were used to investigate the association between Brain-PAD and clinical variables in PD, stratified by sex. Males with Parkinson's disease (PD-M) exhibited a significantly higher mean Brain-PAD than their female counterparts (PD-F) (t(256) = 2.50, p = 0.012). In the propensity score-matched PD-M group (PD-M*), Brain-PAD was found to be associated with a decline in general cognition, a worse degree of sleep behavior disorder, reduced visuospatial acuity, and caudate atrophy. Conversely, no significant links were observed between these factors and Brain-PAD in the PD-F group. Having 'older' looking brains in PD-M than PD-F supports the idea that sex plays a vital function in PD, such that the PD mechanism may be different in males and females. This study has the potential to broaden our understanding of dissimilarities in brain aging between sexes in the context of PD.

Do physical fitness and cognitive function mediate the relationship between basic activities of daily living and quality of life in older adults with dementia?

PURPOSE

Independence in activities of daily living (ADLs) is associated with quality of life (QoL) in individuals with dementia. However, the contribution of physical and cognitive functions to this relationship needs further examination. This study aims to examine the mediating effect of physical fitness and cognitive function in the relationship between independence in basic ADLs and QoL among older adults with dementia.

METHODS

This cross-sectional study included 107 older adults with dementia (74.8% women; age 78.21 ± 7.70 years). Independence in basic ADL and QoL were evaluated using the Barthel Index (BI) and QoL- Alzheimer's Disease Scale, respectively. The Alzheimer's Disease Assessment Scale-Cognitive Subscale and the Mini-Mental State Examination were applied to assess cognitive function. Physical fitness was evaluated using the 30-s chair stand, 2-min step and the Timed-Up and Go tests. A structural equation modelling (SEM) with bootstrapping estimation was conducted to determine the relationship between all variables.

RESULTS

Independence in basic ADL positively affected QoL and this association was mediated by physical fitness (β = 0.242, p = 0.011). No statistically significant results were observed when testing cognitive function as a mediator between BI and QoL (β = 0.009, p = 0.345).

CONCLUSIONS

Physical fitness (i.e., lower body strength, aerobic capacity, and mobility) plays a role in the relationship between basic ADL independence and QoL of older adults with dementia, reinforcing the need to improve and monitor these parameters throughout the disease progression. Future longitudinal studies should explore the temporal relationship between physical and cognitive function and its contribution to basic ADL independence and QoL.

Minding the Gap: Exploring Neuroinflammatory and Microglial Sex Differences in Alzheimer's Disease

Research into Alzheimer's Disease (AD) describes a link between AD and the resident immune cells of the brain, the microglia. Further, this suspected link is thought to have underlying sex effects, although the mechanisms of these effects are only just beginning to be understood. Many of these insights are the result of policies put in place by funding agencies such as the National Institutes of Health (NIH) to consider sex as a biological variable (SABV) and the move towards precision medicine due to continued lackluster therapeutic options. The purpose of this review is to provide an updated assessment of the current research that summarizes sex differences and the research pertaining to microglia and their varied responses in AD.

Sex and gender differences in dementia

The dementia landscape has undergone a striking paradigm shift. The advances in understanding of neurodegeneration and proteinopathies has changed our approach to patients with cognitive impairment. Firstly, it has recently been shown that the various proteinopathies that are the cause of the dementia begin to build up long before the appearance of any obvious symptoms. This has cemented the idea that there is an urgency in diagnosis as it occurs very late in the pathophysiology of these diseases. Secondly, that accurate diagnosis is required to deliver targeted therapies, that is precision medicine. With this latter point, the realization that various factors of a person need to be considered as they may impact the presentation and progression of disease has risen to the forefront. Two of these factors aside from race and age are biological sex and gender (social construct), as both can have tremendous impact on manifestation of disease. This chapter will cover what is known and remains to be known on the interaction of sex and gender with some of the major causes of dementia.

Sex Differences in Brain and Cognition in de novo Parkinson's Disease

Background and Objective: Brain atrophy and cognitive impairment in neurodegenerative diseases are influenced by sex. We aimed to investigate sex differences in brain atrophy and cognition in de novo Parkinson's disease (PD) patients. Methods: Clinical, neuropsychological and T1-weighted MRI data from 205 PD patients (127 males: 78 females) and 69 healthy controls (40 males: 29 females) were obtained from the PPMI dataset. Results: PD males had a greater motor and rapid eye movement sleep behavior disorder symptomatology than PD females. They also showed cortical thinning in postcentral and precentral regions, greater global cortical and subcortical atrophy and smaller volumes in thalamus, caudate, putamen, pallidum, hippocampus, and brainstem, compared with PD females. Healthy controls only showed reduced hippocampal volume in males compared to females. PD males performed worse than PD females in global cognition, immediate verbal recall, and mental processing speed. In both groups males performed worse than females in semantic verbal fluency and delayed verbal recall; as well as females performed worse than males in visuospatial function. Conclusions: Sex effect in brain and cognition is already evident in de novo PD not explained by age per se, being a relevant factor to consider in clinical and translational research in PD.

Sex Differences in Neurodegeneration: The Role of the Immune System in Humans

Growing evidence supports significant involvement of immune dysfunction in the etiology of neurodegenerative diseases, several of which also display prominent sex differences across prevalence, pathology, and symptomology. In this review, we summarize evidence from human studies of established and recent findings of sex differences in multiple sclerosis, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis and discuss how sex-specific central nervous system innate immune activity could contribute to downstream sex differences in these diseases. We examine human genomic and transcriptomics studies in each neurodegenerative disease through the lens of sex differences in the neuroimmune system and highlight the importance of stratifying sex in clinical and translational research studies. Finally, we discuss the limitations of the existing studies and outline recommendations for further advancing sex-based analyses to uncover novel disease mechanisms that could ultimately help treat both sexes.

AD-linked R47H-TREM2 mutation induces disease-enhancing microglial states via AKT hyperactivation

The hemizygous R47H variant of triggering receptor expressed on myeloid cells 2 (TREM2), a microglia-specific gene in the brain, increases risk for late-onset Alzheimer’s disease (AD). Using transcriptomic analysis of single nuclei from brain tissues of patients with AD carrying the R47H mutation or the common variant (CV)–TREM2, we found that R47H-associated microglial subpopulations had enhanced inflammatory signatures reminiscent of previously identified disease-associated microglia (DAM) and hyperactivation of AKT, one of the signaling pathways downstream of TREM2. We established a tauopathy mouse model with heterozygous knock-in of the human TREM2 with the R47H mutation or CV and found that R47H induced and exacerbated TAU-mediated spatial memory deficits in female mice. Single-cell transcriptomic analysis of microglia from these mice also revealed transcriptomic changes induced by R47H that had substantial overlaps with R47H microglia in human AD brains, including robust increases in proinflammatory cytokines, activation of AKT signaling, and elevation of a subset of DAM signatures. Pharmacological AKT inhibition with MK-2206 largely reversed the enhanced inflammatory signatures in primary R47H microglia treated with TAU fibrils. In R47H heterozygous tauopathy mice, MK-2206 treatment abolished a tauopathy-dependent microglial subcluster and rescued tauopathy-induced synapse loss. By uncovering disease-enhancing mechanisms of the R47H mutation conserved in human and mouse, our study supports inhibitors of AKT signaling as a microglial modulating strategy to treat AD.

Functional (un-)Coupling: Impairment, Compensation, and Future Progression in Alzheimer's Disease

Background: Functional (un-)coupling (task-related change of functional connectivity) between different sites of the brain is a mechanism of general importance for cognitive processes. In Alzheimer's disease (AD), prior research identified diminished cortical connectivity as a hallmark of the disease. However, little is known about the relation between the amount of functional (un-)coupling and cognitive performance and decline in AD. Method: Cognitive performance (based on CERAD-Plus scores) and electroencephalogram (EEG)-based functional (un-)coupling measures (connectivity changes from rest to a Face-Name-Encoding task) were assessed in 135 AD patients (age: M = 73.8 years; SD = 9.0). Of these, 68 patients (M = 73.9 years; SD = 8.9) participated in a follow-up assessment of their cognitive performance 1.5 years later. Results: The amounts of functional (un-)coupling in left anterior-posterior and homotopic interhemispheric connections in beta1-band were related to cognitive performance at baseline (β = .340; p < .001; β = .274; P = .001, respectively). For both markers, a higher amount of functional coupling was associated with better cognitive performance. Both markers also were significant predictors for cognitive decline. However, while patients with greater functional coupling in left anterior-posterior connections declined less in cognitive performance (β = .329; P = .035) those with greater functional coupling in interhemispheric connections declined more (β = -.402; P = .010). Conclusion: These findings suggest an important role of functional coupling mechanisms in left anterior-posterior and interhemispheric connections in AD. Especially the complex relationship with cognitive decline in AD patients might be an interesting aspect for future studies.

The role of physical and cognitive function in performance of activities of daily living in patients with mild-to-moderate Alzheimer's disease - a cross-sectional study

BACKGROUND

Several factors may play a role in the ability of patients with Alzheimer's disease to perform activities of daily living (ADL). The aim of this study was to examine the impact of different aspects of physical performance and cognitive functions on ADL in patients suffering from mild-to-moderate Alzheimer's disease.

METHODS

We conducted secondary analyses on cross-sectional baseline data from the randomized controlled multicentre study "Preserving quality of life, physical health and functional ability in Alzheimer's Disease: The effect of physical exercise" (ADEX). In total, 185 AD patients (76 women and 109 men), with a mean age on 70,4 years, were included. Data from physical performance tests (Astrand cycle test, Timed up & Go (TUG), Sit to Stand test (STS)) and cognitive tests (Mini Mental Status Examination (MMSE), Symbol Digit Modalities Test (SDMT), Stroop Color and Word test (Stroop)) were used. Their associations with ADL, measured on the ADCS-ADL scale was assessed in multivariable regression analyses.

RESULTS

SDMT and MMSE had significant, moderate correlations with total ADL (SDMT: r = 0.33, MMSE: r = 0.42) and instrumental ADL (SDMT: r = 0.31, MMSE: r = 0.42), but not with basic ADL. Adjusting for age and sex, the associations between SDMT and MMSE to total ADL and instrumental ADL persisted. No significant associations were found between Astrand, TUG, STS or Stroop and total ADL, basic ADL or instrumental ADL.

CONCLUSION

Total ADL and instrumental ADL are associated with cognitive functions, including executive function. No significant association between examined physical performance parameters and ADL functions was observed, and consequently does not support an impact of physical function on ADL functions in patients with mild-to-moderate Alzheimer's disease and relatively well-preserved physical function. Strategies aimed to improve cognition may be better suited to improve ADL function in patients with mild-to-moderate Alzheimer's disease.

TRIAL REGISTRATION

NCT01681602 . Registered 10 September 2012, retrospectively registered.

Clinical factors associated with activities of daily living and their decline in patients with severe dementia

BACKGROUND

To identify the clinical factors affecting activities of daily living (ADL) at baseline and after 6 months.

METHODS

We conducted a single-centre observational study at two time points across 6 months (baseline and after 6 months) from April 2015 to March 2017. in a 270-bed rural recuperation hospital at Hyogo prefecture in Japan. The total number of participants was 131 (male 33, female 98; mean age: 87.0 ± 7.0; mild and moderate dementia, 38; severe dementia, 93). Measurement scales used were Personal Self-Maintenance Scale (PSMS) for assessing ADL, Mini-Mental State Examination and Cognitive Test in Severe Dementia (CTSD) for cognitive function, Neuropsychiatric Inventory-Nursing Home version and Cornell Scale for Depression in Dementia (CSDD) for behavioural/psychological symptoms of dementia, Mini Nutritional Assessment Short form (MNA-SF) for nutritional status, Pain Assessment in Advanced Dementia for pain, and Charlson comorbidity index (CCI) and the number of illness categories based on Cumulative Illness Rating Scale Geriatrics for comorbidities. Multiple regression analyses identified the association between PSMS score as the dependent variable and other variables as independent variables.

RESULTS

In participants with severe dementia, the PSMS scores at baseline were significantly associated with CTSD, CCI, MNA-SF, and CSDD scores. In the longitudinal analysis, only CTSD score was significantly associated with PSMS score after 6 months. It is noteworthy that for participants with severe dementia, the only factor associated with ADL after 6 months was cognitive function, as assessed by CTSD score.

CONCLUSIONS

The most important factor predicting functional decline is cognitive function, even at the severe and profound stage.

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.

Activities of daily living in Parkinson's disease: Time/gender perspective

OBJECTIVE

The objectives of this study were to explore the changes in the activities of daily living (ADL) in persons with Parkinson's disease (pwPD) over time and to investigate possible differences in ADL performance between men and women with PD.

MATERIALS & METHODS

One hundred twenty-nine persons (76 men) with a clinically established PD self-assessed their ADL performance from the time of diagnosis up to 8 years follow-up using the ADL taxonomy. Other demographic and clinical data (motor state, cognition, depression) were also collected and subjected to further analysis.

RESULTS

Nine of 12 domains in the ADL taxonomy showed a change over time (Eating and Drinking [P = .009], Mobility [P < .001], Toilet activities [P = .031], Dressing [P < .001], Personal hygiene [P < .001], Communication [P < .001], Cooking [P = .001], Shopping [P < .001] and Cleaning [P < .001]). In addition to time, two domains, (Shopping [P = .007] and Cleaning [P = .027]) also showed an effect of gender with worse scores in women. The nine ADL domains showing effect of time, showed temporary improvement at 12 months follow-up, most probably due to dopaminergic medication. All nine domains deteriorated at later follow-up.

CONCLUSIONS

As expected, there was deterioration in self-assessed performance in the majority od ADL domains over time. Women assessed their ADLs worse in two domains (Shopping and Cleaning) probably reflecting a general gender-related activity pattern rather than being a PD-specific finding.

Real-space navigation testing differentiates between amyloid-positive and -negative aMCI

OBJECTIVE

To distinguish between patients with amyloid-positive (A+) and -negative (A-) amnestic mild cognitive impairment (aMCI) by simultaneously investigating navigation performance, visual exploration behavior, and brain activations during a real-space navigation paradigm.

METHODS

Twenty-one patients with aMCI were grouped into A+ (n = 11) and A- cases by amyloid-PET imaging and amyloid CSF levels and compared to 15 healthy controls. Neuropsychological deficits were quantified by use of the Consortium to Establish a Registry for Alzheimer's Disease-plus cognitive battery. All participants performed a navigation task in which they had to find items in a realistic spatial environment and had to apply egocentric and allocentric route planning strategies. ¹⁸F-fluorodeoxyglucose was injected at the start to detect navigation-induced brain activations. Subjects wore a gaze-controlled, head-fixed camera that recorded their visual exploration behavior.

RESULTS

A+ patients performed worse during egocentric and allocentric navigation compared to A- patients and controls (p < 0.001). Both aMCI subgroups used fewer shortcuts, moved more slowly, and stayed longer at crossings. Word-list learning, figural learning, and Trail-Making tests did not differ in the A+ and A- subgroups. A+ patients showed a reduced activation of the right hippocampus, retrosplenial, and parietal cortex during navigation compared to A- patients (p < 0.005).

CONCLUSIONS

A+ patients with aMCI perform worse than A- patients with aMCI in egocentric and allocentric route planning because of a more widespread impairment of their cerebral navigation network. Navigation testing in real space is a promising approach to identify patients with aMCI with underlying Alzheimer pathology.

Is Barthel Index Suitable for Assessing Activities of Daily Living in Patients With Dementia?

OBJECTIVES

To evaluate application of the Barthel Index (BI) in assessing basic activities of daily living (ADL) of patients with dementia using Rasch analysis.

DESIGN

A multi-country cross-sectional study.

SETTING AND PARTICIPANTS

Nineteen long-term care facilities located in China, Japan, South Korea, and Thailand. A total of 644 patients with dementia were included.

METHODS

Unidimensionality, global and item fit, local dependence, person-item targeting, threshold disordering, and differential item functioning (DIF) were examined. Negative correlations between scores for DIF items and Neuropsychiatric Inventory Nursing Home version (NPI-NH) were evaluated.

RESULTS

Item reliability (1.0) and person reliability (.88) were acceptable. The Rasch dimension explained 72.9% of the variance (Eigenvalue = 27), while the first contrast explained 6.6% (Eigenvalue = 2.4). The "mobility" was misfitting to the Rasch model (infit mean square = 1.86). The overall difficulty of the BI exceeded patients' ability (person location = -2.27 logits). The "stairs climbing" and "mobility" showed narrow category thresholds (< 1.4 logits). The location of "controlling bladder" and "toilet use" overlapped. Removing "stairs climbing", collapsing categories with narrow threshold widths in "mobility", and combining "controlling bowel" and "controlling bladder" into one item, improved unidimensionality, and item fit of the scale. Only three items ("grooming", "dressing", and "toilet use") were free from DIF across countries. The scores for "feeding" were negatively related to scores for "disinhibition" (r = -0.46, P < 0.01), and scores for "controlling bowel" were negatively related to scores for "disinhibition" (r = -0.44, P < 0.01), "agitation" (r = -0.32, P < 0.05), and "aggression" (r = -0.27, P < 0.01) in Japanese samples.

CONCLUSIONS AND IMPLICATIONS

The performance of the BI for assessing patients with dementia might be compromised by misfit items, person-item mistargeting, measurement gaps, redundant items, narrow threshold width, and item bias. Mobility ability might not be helpful for determining capability of basic ADL in the patients. Comparisons of BI scores between countries should be undertaken with caution due to item bias. Neuropsychiatric symptoms might interact with basic ADL abilities of the patients. We will not suggest using the instrument in patients with dementia, without future refining to improve its performance.

Gender medicine: Towards a gender-specific treatment of neuropsychiatric disorders

Sex and gender are increasingly recognized as major influencing factors in disorders across all medical specialties. Even though there is ample evidence of sex and gender differences in neuropsychiatric disorders, a sex and gender-differentiated approach has not yet been sufficiently applied to diagnostics and management. Therefore, there is an urgent need to establish general recommendations and guidelines toward precision and sex/gender medicine, with regard to dosage, tolerability, interactions and side effects, sensitivity of diagnostic tests, and distinct treatment strategies. This chapter illustrates the current knowledge about sex and gender aspects in neuropsychiatric disorders, providing a base not only to assist the clinician in the handling of specific pathologic entities, but also to sensitize medical practitioners to consider sex and gender in clinical decision-making. As such, the chapter is a call to action to physicians and researchers to produce more sex- and gender-stratified evidence, leading to an acceleration of guideline development. Such novel guidelines will provide a base for medical education, of both medical students and specialists, as well as a reference point for practitioners, toward precision medicine.

Sex differences in Alzheimer disease - the gateway to precision medicine

Alzheimer disease (AD) is characterized by wide heterogeneity in cognitive and behavioural syndromes, risk factors and pathophysiological mechanisms. Addressing this phenotypic variation will be crucial for the development of precise and effective therapeutics in AD. Sex-related differences in neural anatomy and function are starting to emerge, and sex might constitute an important factor for AD patient stratification and personalized treatment. Although the effects of sex on AD epidemiology are currently the subject of intense investigation, the notion of sex-specific clinicopathological AD phenotypes is largely unexplored. In this Review, we critically discuss the evidence for sex-related differences in AD symptomatology, progression, biomarkers, risk factor profiles and treatment. The cumulative evidence reviewed indicates sex-specific patterns of disease manifestation as well as sex differences in the rates of cognitive decline and brain atrophy, suggesting that sex is a crucial variable in disease heterogeneity. We discuss critical challenges and knowledge gaps in our current understanding. Elucidating sex differences in disease phenotypes will be instrumental in the development of a 'precision medicine' approach in AD, encompassing individual, multimodal, biomarker-driven and sex-sensitive strategies for prevention, detection, drug development and treatment.

Neuropsychological predictors of health and safety abilities in dementia

The Independent Living Scales Health and Safety (ILS HS) scale is commonly used by neuropsychologists when evaluating older adults' instrumental activities of daily living (IADLs). However, there is a minimal amount of research on its use in dementia populations and, specifically, its relationship to other neuropsychological measures. The present study investigated relationships between the ILS HS scale and measures of cognition and depression. The study utilized archival data from a sample (N = 142) of older adults (mean age = 77.85) diagnosed with dementia, who were evaluated at Saint Louis University Medical Center and administered the ILS HS scale as part of a larger clinical neuropsychological evaluation. Multiple regression analyses demonstrated that up to 37% of the variance in ILS HS performance was accounted for by demographic variables, premorbid intelligence, and cognitive functioning (e.g., global cognition, delayed verbal recall, and executive functioning), and regression models demonstrated medium to large effect sizes. Depression and self- or informant-reported IADLs were unrelated to the ILS HS scale. Results suggest that older adults' ability to function in health and safety-related situations requires a range of cognitive abilities. Performance on these measures may help guide clinical decision making regarding independent living and treatment planning.

Predictors of care dependency in nursing home residents with moderate to severe dementia: A cross-sectional study

BACKGROUND

Nursing home residents with dementia show a rapid decline in their ability to perform activities of daily living. This decline is linked to a greater care dependency, which is associated with a reduced quality of life. Care dependency is influenced by multiple predictors, yet current research often focuses on the contribution of a single or a small number of predictors of care dependency.

OBJECTIVES

To examine the contribution of multiple predictors in predicting care dependency.

DESIGN

The present study analyzed baseline data from a 6-month double-parallel randomized controlled trial which examined the effect of three physical activity interventions on multiple outcomes.

SETTING

This study was conducted in eleven nursing homes in Bergen op Zoom, the Netherlands.

PARTICIPANTS

In total, 85 nursing home residents with moderate to severe dementia were included in the study, of which 75 were included for analysis.

METHODS

Predictors considered were cognitive, physical, neuropsychiatric, demographic, and disease related factors. The outcome measure care dependency was assessed with the Care Dependency Scale and the Erlangen Test of Activities of Daily Living. Linear multilevel regression analyses were used to identify the most important predictors of care dependency.

RESULTS

Apathy, physical endurance, number of comorbidities, and global cognition were significant predictors of care dependency. The model explained 66% of the variance in care dependency. Global cognition was a significant predictor of ability to perform activities of daily living and explained 60% percent of its variance.

CONCLUSION

The present study shows that multiple predictors (i.e., apathy, cognitive and physical abilities, and disease-related factors) contribute to predicting care dependency. Future research could focus on the effectiveness of multifactorial interventions to maintain the highest possible level of independence in nursing home residents with dementia.

Functional Reserve: Experience Participating in Instrumental Activities of Daily Living is Associated with Gender and Functional Independence in Mild Cognitive Impairment

BACKGROUND

Gender differences in instrumental activities of daily living (IADLs) in mild cognitive impairment (MCI) and Alzheimer's disease may be explained by gender differences in IADL involvement.

OBJECTIVE

We introduce a novel theoretical construct, termed functional reserve, and empirically examine gender differences in IADL experience as a proxy of this reserve.

METHODS

We cross-sectionally examined men (n = 502) and women (n = 340) with MCI from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Demographic factors, depressive symptoms, neuropsychological scores, and IADL experience were included as independent variables and total Functional Activities Questionnaire (FAQ) scores as the dependent variable. Regression analyses were performed on the full cohort and stratified by gender to identify differential predictive relationships for men and women.

RESULTS

Gender was associated with total FAQ (p < 0.05) until adjusting for IADL experience. Furthermore, the combination of cognitive measures accounted for the most variance in functional dependence (12% explained, p < 0.001), although IADL experience was the most important single variable (4.8% explained, p < 0.001). Stratification by gender revealed that IADL experience accounted for 6.6% of the variance in FAQ score in men (p < 0.001) but only 2.4% in women (p = 0.001); however, the interaction between gender and experience was not statistically significant.

DISCUSSION

A small effect of men showing greater functional dependence in MCI may be explained by lower IADL experience. Additionally, IADL experience was associated with superior functioning in all analyses, potentially through increased functional reserve. This concept of functional reserve may have implications for identifying individuals at risk for IADL dependence, preventing or delaying decline, and potentially treating functional impairment.

Modeling Alzheimer Disease Through Functional Independence and Participation

INTRODUCTION

The relationship between cognitive and functional impairment in Alzheimer Disease (AD) at the earliest stages of the disease is not well characterized. This study aimed at investigating such relationships along AD evolution by means of the Disability Assessment for Dementia (DAD).

METHODS

Consecutive pairs of AD outpatients and their primary informal caregivers were enrolled. Patients were evaluated by means of the Mini Mental State Examination and neuropsychological tests. A clinician completed the Clinical Dementia Rating Scale to stage dementia severity and interviewed the caregivers to complete the Neuropsychiatric Inventory to assess behavioral disturbances and the DAD to evaluate patients' functional competence.

RESULTS

A total of 158 dyads were enrolled; the Mini Mental State Examination score was used to stratify patients into 4 groups (>24; 20 to 23.9; 10 to 19.9; <10) that were compared. The statistical analysis revealed that all the cognitive domains were positively related to functional independence, but only logical and executive functions seemed to predict autonomy. An intergroup comparison did not show significant differences in the DAD subscales measuring initiation, planning and organization, and performance. The role of education emerged, confirming the relevance of cognitive reserve.

DISCUSSION

As the field moves toward earlier intervention in preclinical AD, the detection of early functional changes may drive the definition of trials on prevention or intervention for dementia.

Predictive factors for disease progression in patients with early-onset Alzheimer's disease

BACKGROUND

Only a few studies have investigated disease progression in patients with early-onset Alzheimer's disease (EOAD). Therefore, the aim of this study was to investigate disease progression in patients with EOAD and the influence of various factors, such as gender, education, and apolipoprotein E (APOE) genotype on disease progression.

METHODS

A total of 288 EOAD patients were enrolled in the study. Linear mixed models were used to investigate the rate of cognitive and functional decline in terms of age at onset, gender, education, follow-up period, and APOE genotype.

RESULTS

EOAD patients showed an annual decline of -1.54 points/years in the Korean version mini-mental examination score, an annual increase of 3.46 points/year in the Seoul instrumental activities of daily living (SIADL) score, and an annual increase of 1.15 points/year in the clinical dementia rating scale-sum of boxes score. After stratification, higher educated patients showed faster disease progression in all three parameters, and female patients demonstrated faster disease progression as assessed by the SIADL score. Age at onset and APOE genotype had no influence on disease progression.

CONCLUSION

We confirmed the rate of disease progression in Korean patients with EOAD in real-life hospital-based clinical practice. The results of this study suggest that education and female gender, not APOE genotype, may be important as independent strong predictive factors for disease progression in patients with EOAD.

Neuropsychiatric Symptoms Predict Functional Status in Alzheimer's Disease

BACKGROUND

Cognitive deficits are presumed to be the primary driver of functional impairment in Alzheimer's disease (AD); however, functional impairment is likely multifactorially determined.

OBJECTIVE

Our objective was to determine the relative contribution of neuropsychiatric symptoms in predicting ratings of functional status.

METHODS

A total of 223 patients received routine neurological and neuropsychological evaluations and met criteria of probable AD dementia based on the McKhann criteria. Demographic, cognitive, and neuropsychiatric variables were entered in a hierarchical linear regression analysis to predict functional status as measured by the Functional Activities Questionnaire (FAQ).

RESULTS

The total model explained 29.7% of the variance (p <  0.001) in FAQ. Importantly, neuropsychiatric variables explained 12.7% of the unique variance, with apathy and sleep as significant contributors.

CONCLUSION

Two neuropsychiatric variables, apathy and changes in sleep/nighttime behaviors, predicted ratings of functional status in AD patients independent of age, global cognition, memory and executive function measures, and depressive symptoms. These results highlight the importance of neuropsychiatric symptoms in understanding and potentially treating the functional limitations so prevalent in AD.

Predictors of functional disability in mild cognitive impairment and dementia

OBJECTIVE

Knowledge about factors predicting functional disability in mild cognitive impairment (MCI) and dementia would help health care providers to identify those patients who are at high risk of functional disability. Previous research is scarce and focused on only a small number of possible predictors. The aim of this study was to identify predictors of functional disability in patients with MCI and dementia.

STUDY DESIGN

Cross-sectional cohort study.

MAIN OUTCOME MEASURES

Data from patients who visited a memory clinic between 2011 and 2015 were evaluated. The Disability Assessment for Dementia (DAD) was used to assess functional disability. Patients diagnosed with MCI or dementia and with a DAD score available were included. This led to the inclusion of 474 patients. Univariate analyses with a broad range of variables were performed to detect factors that had a significant relationship to the DAD score. Age, gender and variables with a p-value of 0.1 or lower in the univariate analyses were taken into a multivariable analysis. This multiple linear regression analysis was performed to determine which variables were independently associated with the DAD score.

MAIN RESULTS

Our multivariable model explained 42% of the variance in the DAD score. Independent predictors of the DAD score were age (B=0.03, 95%CI=0.002-0.05), gender (B=-0.43, 95%CI=-0.78 to -0.07), score on the Clinical Dementia Rating scale (CDR) (B=1.53, 95%CI=1.07-1.99 for CDR 1, B=2.93, 95%CI=2.28-3.58 for CDR 2, B=3.96, 95%CI=2.65-5.27 for CDR 3) and level of physical activity (B=0.56, 95%CI=0.05-1.07).

CONCLUSION

Older age, male gender, higher CDR score and lower levels of physical activity are independent predictors of functional disability in MCI and dementia.

Serum levels of hydroperoxides and multimorbidity among older patients with mild cognitive impairment or late-onset Alzheimer's disease

BACKGROUND

Oxidative stress (OxS) might be involved in the pathogenesis of late-onset Alzheimer disease (LOAD); noteworthy, the presence of multimorbidity is regarded as a common denominator of OxS and dementia.

AIM

To evaluate the contribution of multimorbidity to OxS in LOAD and mild cognitive impairment (MCI).

METHODS

Serum hydroperoxides and multimorbidity (CIRS-CI scale) were evaluated in 46 Controls, 104 MCI and 75 LOAD.

RESULTS

A trend toward an increase of hydroperoxides from Controls to MCI to LOAD was observed (LOAD vs Controls p = 0.01). This OxS marker was positively and significantly correlated with CIRS-CI in Controls (p = 0.002) and patients with MCI (p = 0.005) but not in those with LOAD (p = 0.104).

CONCLUSIONS

Multimorbidity is associated with systemic OxS but only in elderly people with either no or mild cognitive impairment. Although OxS is elevated in LOAD patients, its association with multimorbidity seems to be negligible, confirming the existence of strong disease-specific pro-oxidant mechanisms.

A 36-month follow-up of decline in activities of daily living in individuals receiving domiciliary care

Background

There have been few studies of how personal and instrumental activities of daily living (P-ADL and I-ADL) develop over time in older people receiving domiciliary care. This study aimed at assessing variables associated with the development of P-ADL and I-ADL functioning over a 36-month follow-up period, with a particular focus on cognitive functioning.

Method

In all, 1001 older people (≥70 years) receiving domiciliary care were included in a longitudinal study with three assessments of P-ADL and I-ADL functioning during 36 months. P-ADL and I-ADL were assessed using the Lawton and Brody’s Physical Self-Maintenance Scale and Instrumental Activities of Daily Living Scale, respectively. Mini Mental State Examination (MMSE), diagnosis of dementia and MCI, neuropsychiatric symptoms and use of psychotropic medication were also evaluated during the three assessments. Baseline demographic and general medical health information and information of being a nursing home resident at follow-up were recorded. Linear mixed models were estimated.

Results

There was a significant decline in P-ADL and I-ADL functioning throughout the follow-up. A lower MMSE sum-score, diagnosed MCI and dementia, a higher level of neuropsychiatric symptoms and the use of antipsychotics and antidepressants recorded at each assessment were associated with a decline in both P-ADL and I-ADL functioning. Furthermore, a decline in P-ADL and I-ADL functioning at follow-ups was associated with being male, a higher baseline age and in poorer medical health as well as residing in a nursing home at follow-up.

Conclusion

P-ADL and I-ADL functioning in older people worsened over time. The worsening was associated with lower MMSE sum-score, diagnosed MCI and dementia, poorer medical health, neuropsychiatric symptoms, use of psychotropic medication and being transferred to nursing home care. Clinicians should pay close attention to the assessment and treatment of these factors to help older people maintain their level of functioning for as long as possible.

Everyday cognition in prodromal Huntington disease

OBJECTIVE

Assessment of daily functions affected by cognitive loss in prodromal Huntington's disease (HD) is necessary in practice and clinical trials. We evaluated baseline and longitudinal sensitivity of the Everyday Cognition (ECog) scales in prodromal HD and compared self- and companion-ratings.

METHOD

Everyday cognition was self-assessed by 850 participants with prodromal HD and 768 companions. We examined internal structure using confirmatory factor analysis (CFA) on baseline data. For longitudinal analysis, we stratified participants into Low, Medium, and High disease progression groups. We examined ECog scores for group differences and participant-and-companion differences using linear mixed effects regression (LMER). Comparison with the Total Functional Capacity (TFC) scale was made.

RESULTS

CFA revealed good fit of a 5-factor model having a global factor (total score), and subfactors (subscales) of memory, language, visuospatial perception, and executive function. At study entry, participants and companions in the Medium and High groups reported significantly worsened everyday cognition as well as significant functional decline over time. Losses became more pronounced and participant and companion ratings diverged as individuals progressed. TFC showed significant functional loss over time in the High group but not in the Medium group.

CONCLUSIONS

Disease progression is associated with reduced self- and companion-reported everyday cognition in prodromal HD participants who are less than 13 years to estimated motor onset. Our findings suggest companion ratings are more sensitive than participants' for detecting longitudinal change in daily cognitive function. ECog appears more sensitive to specific functional changes in the prodrome of HD than the TFC.

Quantitative EEG in Alzheimer's disease: cognitive state, resting state and association with disease severity

BACKGROUND

Quantitative electroencephalogram (qEEG) recorded during cognitive tasks has been shown to differentiate between patients with Alzheimer's disease (AD) and healthy individuals. However, the association between various qEEG markers recorded during mnestic paradigms and clinical measures of AD has not been studied in detail.

OBJECTIVE

To evaluate if 'cognitive' qEEG is a useful diagnostic option, particularly if memory paradigms are used as cognitive stimulators.

METHODS

This study is part of the Prospective Registry on Dementia in Austria (PRODEM), a multicenter dementia research project. A cohort of 79 probable AD patients was included in a cross-sectional analysis. qEEG recordings performed in resting states were compared with recordings during cognitively active states. Cognition was evoked with a face-name paradigm and a paired-associate word list task, respectively. Relative band powers, coherence and auto-mutual information were computed as functions of MMSE scores for the memory paradigms and during rest. Analyses were adjusted for the co-variables age, sex, duration of dementia and educational level.

RESULTS

MMSE scores explained 36-51% of the variances of qEEG-markers. Face-name encoding with eyes open was superior to resting state with eyes closed in relative theta and beta1 power as well as coherence, whereas relative alpha power and auto-mutual information yielded more significant results during resting state with eyes closed. The face-name task yielded stronger correlations with MMSE scores than the verbal memory task.

CONCLUSION

qEEG alterations recorded during mnestic activity, particularly face-name encoding showed the highest association with the MMSE and may serve as a clinically valuable marker for disease severity.

Association of early-onset dementia with activities of daily living (ADL) in middle-aged adults with intellectual disabilities: the caregiver's perspective

Few studies have investigated in detail which factors influence activities of daily living (ADL) in adults with intellectual disabilities (ID) comorbid with/without dementia conditions. The objective of the present study was to describe the relation between early onset dementia conditions and progressive loss of ADL capabilities and to examine the influence of dementia conditions and other possible factors toward ADL scores in adults with ID. This study was part of the "Healthy Aging Initiatives for Persons with an Intellectual Disability in Taiwan: A Social Ecological Approach" project. We analyzed data from 459 adults aged 45 years or older with an ID regarding their early onset symptoms of dementia and their ADL profile based on the perspective of the primary caregivers. Results show that a significant negative correlation was found between dementia score and ADL score in a Pearson's correlation test (r=-0.28, p<0.001). The multiple linear regression model reported that factors of male gender (β=4.187, p<0.05), marital status (β=4.79, p<0.05), education level (primary: β=5.544, p<0.05; junior high or more: β=8.147, p<0.01), Down's syndrome (β=-9.290, p<0.05), severe or profound disability level (β=-6.725, p<0.05; β=-15.773, p<0.001), comorbid condition (β=-4.853, p<0.05) and dementia conditions (β=-9.245, p<0.001) were variables that were able to significantly predict the ADL score (R(2)=0.241) after controlling for age. Disability level and comorbidity can explain 10% of the ADL score variation, whereas dementia conditions can only explain 3% of the ADL score variation in the study. The present study highlights that future studies should scrutinize in detail the reasons for the low explanatory power of dementia for ADL, particularly in examining the appropriateness of the measurement scales for dementia and ADL in aging adults with ID.

The Women's Healthy Ageing Project: fertile ground for investigation of healthy participants 'at risk' for dementia

Alzheimer's disease neuropathology (amyloid, tauopathies) and brain atrophy are present decades prior to manifestation of clinical symptoms. With the failure of treatment trials it is becoming clearer that the window for prevention and therapeutic intervention is before significant neuronal loss and clinical deterioration of cognition has occurred. Early identification of those at risk of disease and optimizing their management to prevent disease in later life are crucial to delaying disease onset and improving people's quality of life. The Women's Healthy Aging Project (WHAP) is a longitudinal study of over 400 Australian-born women, epidemiologically randomly sampled in 1990. The WHAP aims to identify modifiable mid-life risk factors for the development of late-life cognitive decline, improve the understanding of the pathogenesis of dementia, and target early disease identification utilizing clinical, biomarker and health risk profiles. These aims are fortified by the ability to leverage the considerable database on health, lifestyle and socio-demographics collected prospectively from 1990 to date. This is the first study with a comprehensive neuropsychological battery, over a decade of cognitive follow-up, with all participants being offered amyloid imaging from 2012, and prospective longitudinal data including clinical and physical measures and bio-bank samples from over 20 years prior.