Sex Differences in the Role of Sleep on Cognition in Older Adults.

Study Objectives: The study aimed to investigate sex differences in the relationship between sleep quality (self-report and objective) and cognitive function across three domains (executive function, verbal memory, and attention) in older adults. Methods: We analyzed cross-sectional data from 207 participants with normal cognition or mild cognitive impairment (89 males and 118 females) aged over 60. The relationship between sleep quality and cognitive performance was estimated using generalized additive models. Objective sleep was measured with the GT9X Link Actigraph, and self-reported sleep was measured with the Pittsburgh Sleep Quality Index. Results: We found that females exhibited stable performance of executive function with up to about 400 minutes of total sleep time, with significant declines in performance (p = 0.02) when total sleep time was longer. Additionally, a longer total sleep time contributed to lower verbal memory in a slightly non-linear manner (p = 0.03). Higher self-reported sleep complaints were associated with poorer executive function in females with normal cognition (p = 0.02). In males, a positive linear relationship emerged between sleep efficiency and executive function (p = 0.04), while self-reported sleep was not associated with cognitive performance in males with normal cognition. Conclusions: Our findings suggest that the relationships between sleep quality and cognition differ between older males and females, with executive function being the most influenced by objective and self-reported sleep. Interventions targeting sleep quality to mitigate cognitive decline in older adults may need to be tailored according to sex, with distinct approaches for males and females.

A text message intervention to support latino dementia family caregivers (CuidaTEXT): feasibility study.

OBJECTIVES: To test the feasibility, acceptability, and preliminary efficacy of CuidaTEXT: a bidirectional text message intervention to support Latino dementia family caregivers. METHODS: CuidaTEXT is a six-month, bilingual intervention tailored to caregiver needs (e.g., education, problem-solving, resources). We used convenience sampling and reached 31 potential participants via clinics, registries, community promotion, and online advertising. We enrolled 24 Latino caregivers in a one-arm trial and assessed feasibility, acceptability, and preliminary efficacy within six months. RESULTS: None of the participants unsubscribed from CuidaTEXT and 83.3% completed the follow up survey. Most participants (85.7%) reported reading most text messages thoroughly. All participants reported being very or extremely satisfied with the intervention. Participants reported that CuidaTEXT helped a lot (vs not at all, a little, or somehow) in caring for their care recipient (71.4%; n = 15), for themselves (66.7%; n = 14), and understanding more about dementia (85.7%; n = 18). Compared to baseline, at six months caregiver behavioral symptom distress (0-60) decreased from 19.8 to 12.0 and depression (0-30) from 8.8 to 5.4 (p < .05). CONCLUSIONS: CuidaTEXT demonstrated high levels of feasibility, acceptability, and preliminary efficacy among Latino caregivers. CLINICAL IMPLICATIONS: CuidaTEXT's feasibility and potential for widespread implementation holds promise in supporting Latino caregivers of people with dementia.

Alzheimer's disease cortical morphological phenotypes are associated with TOMM40'523-APOE haplotypes.

Both the APOE ε4 and TOMM40 rs10524523 ("523") genes have been associated with risk for Alzheimer's disease (AD) and neuroimaging biomarkers of AD. No studies have investigated the relationship of TOMM40'523-APOE ε4 on the structural complexity of the brain in AD individuals. We quantified brain morphology and multiple cortical attributes in individuals with mild cognitive impairment (MCI) and AD, then tested whether APOE ε4 or TOMM40 poly-T genotypes were related to AD morphological biomarkers in cognitively unimpaired (CU) and MCI/AD individuals. We identified several AD-specific phenotypes in brain morphology and found that TOMM40 poly-T short alleles are associated with early, AD-specific brain morphological differences in healthy aging. We observed decreased cortical thickness, sulcal depth, and fractal dimension in CU individuals with the poly-T short alleles. Moreover, in MCI/AD participants, the APOE ε4 (TOMM40 L) individuals had a higher rate of gene-related morphological markers indicative of AD. Our data suggest that TOMM40'523 is associated with early brain structure variations in the precuneus, temporal, and limbic cortices.

TOMM40 '523 Genotype Distinguishes Patterns of Cognitive Improvement for Executive Function in APOEɛ3 Homozygotes.

BACKGROUND: TOMM40 '523 has been associated with cognitive performance and risk for developing Alzheimer's disease independent of the effect of APOE genotype. Few studies have considered the longitudinal effect of this genotype on change in cognition over time. OBJECTIVE: Our objective was to evaluate the relationship between TOMM40 genotype status and change in cognitive performance in the TOMMORROW study, which was designed to prospectively evaluate an algorithm that includes TOMM40 '523 for genetic risk for conversion to mild cognitive impairment. METHODS: We used latent growth curve models to estimate the effect of TOMM40 allele carrier (short, very long) status on the intercept and slope of change in cognitive performance in four broad cognitive domains (attention, memory, executive function, and language) and a combined overall cognitive score over 30 months. RESULTS: TOMM40 very long allele carriers had significantly lower baseline performance for the combined overall cognitive function score (B = -0.088, p = 0.034) and for the executive function domain score (B = -0.143, p = 0.013). Slopes for TOMM40 very long carriers had significantly greater increases over time for the executive function domain score only. In sensitivity analyses, the results for executive function were observed in participants who remained clinically stable, but not in those who progressed clinically over the study duration. CONCLUSIONS: Our results add to the growing body of evidence that TOMM40, in the absence of APOEɛ4, may contribute to cognitive changes with aging and dementia and support the view that mitochondrial function is an important contributor to Alzheimer's disease risk.

Context-dependent sexual changes during women's midlife transitions.

For women, midlife represents an important stage of transition, including shifts in physiological, social, and sexual experiences. Prior research demonstrates that women's sexuality is more dynamic and context-dependent than men's. Most research focused on women's sexuality in mid- to later-life emphasizes physiological changes, while largely ignoring changes stemming from social, psychological, and relational contexts. The present study examined midlife women's diverse sexual experiences within the context of their lives. We conducted semi-structured interviews with 27 women, ages 39-57, and used interpretative phenomenological analysis to investigate perceptions and interpretations of midlife sexual experiences and changes. Themes included changes in sexual engagement, unwanted sexual experiences, body image, and sexual healthcare. Participants reported changes in the frequency of sex and sexual desire within the context of their diverse social roles and identities, prior intimate relationships, and sexual health. Women contrasted perceptions of their own bodies with societal perceptions of sexiness. Frequently reported negative experiences with sexual healthcare informed a distrust of healthcare systems. The diverse and changing nature of participants' experiences supports prior evidence of sexual fluidity and context-dependence. By questioning societal expectations around sexuality and body image, participants illustrated the potential of counternarratives to combat dominant beliefs and stereotypes about midlife women's sexuality. To improve sexual health and education, psychoeducational interventions for women in midlife are needed.

Distributional data analysis via quantile functions and its application to modeling digital biomarkers of gait in Alzheimer's Disease.

With the advent of continuous health monitoring with wearable devices, users now generate their unique streams of continuous data such as minute-level step counts or heartbeats. Summarizing these streams via scalar summaries often ignores the distributional nature of wearable data and almost unavoidably leads to the loss of critical information. We propose to capture the distributional nature of wearable data via user-specific quantile functions (QF) and use these QFs as predictors in scalar-on-quantile-function-regression (SOQFR). As an alternative approach, we also propose to represent QFs via user-specific L-moments, robust rank-based analogs of traditional moments, and use L-moments as predictors in SOQFR (SOQFR-L). These two approaches provide two mutually consistent interpretations: in terms of quantile levels by SOQFR and in terms of L-moments by SOQFR-L. We also demonstrate how to deal with multi-modal distributional data via Joint and Individual Variation Explained using L-moments. The proposed methods are illustrated in a study of association of digital gait biomarkers with cognitive function in Alzheimers disease. Our analysis shows that the proposed methods demonstrate higher predictive performance and attain much stronger associations with clinical cognitive scales compared to simple distributional summaries.

Differential effects of chronotype on physical activity and cognitive performance in older adults.

Introduction: Chronotypes reflect individuals' preferred activity and sleep patterns (e.g., "morning-types" vs. "evening-types") and are associated with health and physical activity. Less is known about the relationship between chronotype and cognitive health in older adults. It is unclear whether chronotype's influence is driven by sleep timing or disruption. This study explored the relationship between chronotype, physical activity, and cognitive performance in older adults with and without self-reported sleep disorders. Methods: Participants were 153 older adults (M = 70.35, SD = 5.89) who wore an Actigraph on the non-dominant wrist for seven days to measure total physical activity, peak physical activity, and chronotype (sleep interval midpoint). We categorized participants as morning-, evening-, and intermediate-chronotypes and assessed cognitive performance in domains of attention, executive function, and verbal memory. Results: MANCOVAs showed patterns of activity across the 24-hour day differed between chronotypes such that morning-types were active earlier and evening-types active later, ps > .001. Total physical activity and average peak activity did not differ between chronotypes, (ps ≥ .117). Timing of peak activity followed expectations (morning-types peaked earliest (p = .019). Evening-types exhibited significantly worse executive function and attention than intermediate-types, p = .008. When excluding participants with sleep disorders, evening-types engaged in significantly less total physical activity than other groups, but cognitive performance did not differ. Discussion: We found no differences in total or peak physical activity between groups, which is inconsistent with findings from studies in younger samples. This suggests the role of chronotype on physical activity may change with age and points to the potential impact of methodological discrepancies. While evening-types exhibited worse executive function and attention performance, this finding disappeared when participants with sleep disorders were excluded. Sleep dysregulation rather than sleep timing may be driving this difference. Recent trends in physical activity research explore activity patterns across the 24-hour day and acknowledge codependence between different activity types. Our findings suggest chronotype and activity timing may be important as researchers advance this line of research in older adults.

A Mitochondrial DNA Haplogroup Defines Patterns of Five-Year Cognitive Change.

BACKGROUND: Mitochondrial DNA (mtDNA) may play a role in Alzheimer's disease (AD) and cognitive decline. A particular haplogroup of mtDNA, haplogroup J, has been observed more commonly in patients with AD than in cognitively normal controls. OBJECTIVE: We used two mtDNA haplogroups, H and J, to predict change in cognitive performance over five years. We hypothesized that haplogroup J carriers would show less cognitive resilience. METHODS: We analyzed data from 140 cognitively normal older adults who participated in the University of Kansas Alzheimer's Disease Research Center clinical cohort between 2011 and 2020. We used factor analysis to create three composite scores (verbal memory, attention, and executive function) from 11 individual cognitive tests. We performed latent growth curve modeling to describe trajectories of cognitive performance and change adjusting for age, sex, years of education, and APOE ɛ4 allele carrier status. We compared haplogroup H, the most common group, to haplogroup J, the potential risk group. RESULTS: Haplogroup J carriers had significantly lower baseline performance and slower rates of improvement on tests of verbal memory compared to haplogroup H carriers. We did not observe differences in executive function or attention. CONCLUSION: Our results reinforce the role of mtDNA in changes to cognitive function in a domain associated with risk for dementia, verbal memory, but not with other cognitive domains. Future research should investigate the distinct mechanisms by which mtDNA might affect performance on verbal memory as compared to other cognitive domains across haplogroups.

Scalar on time-by-distribution regression and its application for modelling associations between daily-living physical activity and cognitive functions in Alzheimer's Disease.

Wearable data is a rich source of information that can provide a deeper understanding of links between human behaviors and human health. Existing modelling approaches use wearable data summarized at subject level via scalar summaries in regression, temporal (time-of-day) curves in functional data analysis (FDA), and distributions in distributional data analysis (DDA). We propose to capture temporally local distributional information in wearable data using subject-specific time-by-distribution (TD) data objects. Specifically, we develop scalar on time-by-distribution regression (SOTDR) to model associations between scalar response of interest such as health outcomes or disease status and TD predictors. Additionally, we show that TD data objects can be parsimoniously represented via a collection of time-varying L-moments that capture distributional changes over the time-of-day. The proposed method is applied to the accelerometry study of mild Alzheimer's disease (AD). We found that mild AD is significantly associated with reduced upper quantile levels of physical activity, particularly during morning hours. In-sample cross validation demonstrated that TD predictors attain much stronger associations with clinical cognitive scales of attention, verbal memory, and executive function when compared to predictors summarized via scalar total activity counts, temporal functional curves, and quantile functions. Taken together, the present results suggest that SOTDR analysis provides novel insights into cognitive function and AD.

A Text Messaging Intervention to Support Latinx Family Caregivers of Individuals With Dementia (CuidaTEXT): Development and Usability Study.

BACKGROUND: Latinx family caregivers of individuals with dementia face many barriers to caregiver support access. Interventions to alleviate these barriers are urgently needed. OBJECTIVE: This study aimed to describe the development of CuidaTEXT, a tailored SMS text messaging intervention to support Latinx family caregivers of individuals with dementia. METHODS: CuidaTEXT is informed by the stress process framework and social cognitive theory. We developed and refined CuidaTEXT using a mixed methods approach that included thematic analysis and descriptive statistics. We followed 6 user-centered design stages, namely, the selection of design principles, software vendor collaboration, evidence-based foundation, caregiver and research and clinical advisory board guidance, sketching and prototyping, and usability testing of the prototype of CuidaTEXT among 5 Latinx caregivers. RESULTS: CuidaTEXT is a bilingual 6-month-long SMS text messaging-based intervention tailored to caregiver needs that includes 1-3 daily automatic messages (n=244) about logistics, dementia education, self-care, social support, end of life, care of the person with dementia, behavioral symptoms, and problem-solving strategies; 783 keyword-driven text messages for further help with the aforementioned topics; live chat interaction with a coach for further help; and a 19-page reference booklet summarizing the purpose and functions of the intervention. The 5 Latinx caregivers who used the prototype of CuidaTEXT scored an average of 97 out of 100 on the System Usability Scale. CONCLUSIONS: CuidaTEXT's prototype demonstrated high usability among Latinx caregivers. CuidaTEXT's feasibility is ready to be tested.

Continuous gait monitoring discriminates community-dwelling mild Alzheimer's disease from cognitively normal controls.

INTRODUCTION: Few studies have explored whether gait measured continuously within a community setting can identify individuals with Alzheimer's disease (AD). This study tests the feasibility of this method to identify individuals at the earliest stage of AD. METHODS: Mild AD (n = 38) and cognitively normal control (CNC; n = 48) participants from the University of Kansas Alzheimer's Disease Center Registry wore a GT3x+ accelerometer continuously for 7 days to assess gait. Penalized logistic regression with repeated five-fold cross-validation followed by adjusted logistic regression was used to identify gait metrics with the highest predictive performance in discriminating mild AD from CNC. RESULTS: Variability in step velocity and cadence had the highest predictive utility in identifying individuals with mild AD. Metrics were also associated with cognitive domains impacted in early AD. DISCUSSION: Continuous gait monitoring may be a scalable method to identify individuals at-risk for developing dementia within large, population-based studies.

Aerobic exercise improves hippocampal blood flow for hypertensive Apolipoprotein E4 carriers.

Cerebrovascular dysfunction likely contributes causally to Alzheimer's disease (AD). The strongest genetic risk factor for late-onset AD, Apolipoprotein E4 (APOE4), may act synergistically with vascular risk to cause dementia. Therefore, interventions that improve vascular health, such as exercise, may be particularly beneficial for APOE4 carriers. We assigned cognitively normal adults (65-87 years) to an aerobic exercise intervention or education only. Arterial spin labeling MRI measured hippocampal blood flow (HBF) before and after the 52-week intervention. We selected participants with hypertension at enrollment (n = 44). For APOE4 carriers, change in HBF (ΔHBF) was significantly (p = 0.006) higher for participants in the exercise intervention (4.09 mL/100g/min) than the control group (-2.08 mL/100g/min). There was no difference in ΔHBF between the control (-0.32 mL/100g/min) and exercise (-0.54 mL/100g/min) groups for non-carriers (p = 0.918). Additionally, a multiple regression showed an interaction between change in systolic blood pressure (ΔSBP) and APOE4 carrier status on ΔHBF (p = 0.035), with reductions in SBP increasing HBF for APOE4 carriers only. Aerobic exercise improved HBF for hypertensive APOE4 carriers only. Additionally, only APOE4 carriers exhibited an inverse relationship between ΔSBP and ΔHBF. This suggests exercise interventions, particularly those that lower SBP, may be beneficial for individuals at highest genetic risk of AD.ClinicalTrials.gov Identifier: NCT02000583.

Effect of aerobic exercise on amyloid accumulation in preclinical Alzheimer's: A 1-year randomized controlled trial.

BACKGROUND: Our goal was to investigate the role of physical exercise to protect brain health as we age, including the potential to mitigate Alzheimer's-related pathology. We assessed the effect of 52 weeks of a supervised aerobic exercise program on amyloid accumulation, cognitive performance, and brain volume in cognitively normal older adults with elevated and sub-threshold levels of cerebral amyloid as measured by amyloid PET imaging. METHODS AND FINDINGS: This 52-week randomized controlled trial compared the effects of 150 minutes per week of aerobic exercise vs. education control intervention. A total of 117 underactive older adults (mean age 72.9 [7.7]) without evidence of cognitive impairment, with elevated (n = 79) or subthreshold (n = 38) levels of cerebral amyloid were randomized, and 110 participants completed the study. Exercise was conducted with supervision and monitoring by trained exercise specialists. We conducted 18F-AV45 PET imaging of cerebral amyloid and anatomical MRI for whole brain and hippocampal volume at baseline and Week 52 follow-up to index brain health. Neuropsychological tests were conducted at baseline, Week 26, and Week 52 to assess executive function, verbal memory, and visuospatial cognitive domains. Cardiorespiratory fitness testing was performed at baseline and Week 52 to assess response to exercise. The aerobic exercise group significantly improved cardiorespiratory fitness (11% vs. 1% in the control group) but there were no differences in change measures of amyloid, brain volume, or cognitive performance compared to control. CONCLUSIONS: Aerobic exercise was not associated with reduced amyloid accumulation in cognitively normal older adults with cerebral amyloid. In spite of strong systemic cardiorespiratory effects of the intervention, the observed lack of cognitive or brain structure benefits suggests brain benefits of exercise reported in other studies are likely to be related to non-amyloid effects. TRIAL REGISTRATION: NCT02000583; ClinicalTrials.gov.

Predicting Exertion from Metabolic, Physiological and Cognitive Variables in Older Adults / Predicción del esfuerzo con variables metabólicas, fisiológicas y cognitivas en adultos mayores / Predição do esforço com variáveis metabólicas, fisiológicas e congênitas em idosos

Abstract Objective. To determine the association between perceived exertion (RPE) and physiological variables and to determine the predictive factors of RPE during submaximal and maximal exertion in older adults. Method. Older adults from Kansas (n = 100) and Costa Rica (n = 79) performed a submaximal and maximal stress test. RPE, education level and a total score of cognitive function (CFTS) were collected. Correlation and multiple regression analyses were computed using RPE as the criterion variable and oxygen consumption (VO2), respiratory exchange ratio (RER), CFTS and education level as predictors. Results. There was a significant correlation between VEP and RER (r = 0.22, p = 0.029) at maximal exertion. The RPE predictors for women were VO2, RER, and CFTS at different stages of the test. For men, VEP was predicted by RER, education level, and VO2 at different stages. Conclusion. Metabolic and physiological variables predicted RPE in older adults. Age, cognition, and heart rate were unrelated to RPE at maximal exertion, and RER predicted RPE scores during submaximal and maximal exertion.

Resumen Objetivo. Determinar la asociación entre el esfuerzo percibido (VEP) y variables fisiológicas y determinar los factores predictivos de VEP durante el esfuerzo submáximo y máximo en adultos mayores. Método. Adultos mayores de Kansas (n = 100) y Costa Rica (n = 79) realizaron una prueba de esfuerzo submáxima y máxima. Se recopiló la VEP, nivel de educación y una puntuación total de la función cognitiva (PTFC). Se usaron análisis de correlación y regresión múltiple utilizando VEP como variable criterio y el consumo de oxígeno (VO2), tasa de intercambio respiratorio (RER), PTFC y nivel de educación como predictores. Resultados. Se encontró una correlación significativa entre la VEP y la RER (r = 0.22, p = 0.029) en el esfuerzo máximo. Los predictores de VEP para las mujeres fueron VO2, RER y PTFC en diferentes etapas de la prueba. Para los hombres, la VEP fue predicha por RER, nivel de educación y VO2 en diferentes etapas. Conclusión. Las variables metabólicas y fisiológicas predijeron los valores de VEP en adultos mayores. La edad, la cognición y la FC no se relacionaron con la VEP en el esfuerzo máximo y la RER predijo las puntuaciones de la VEP durante el esfuerzo submáximo y máximo.

Resumo Escopo. Determinar a associação entre o esforço percebido (VEP) e as variáveis fisiológicas e determinar os fatores preditivos de VEP durante o esforço submáximo e máximo em idosos. Metodologia. Idosos de Kansas (n= 100) e Costa Rica (n= 79) realizaram uma prova de esforço submáxima e máxima. Foi recopilada o VEP, nível de educação e pontuação total da função cognitiva (PTFCO. Foram usadas análises de correlação e regressão múltipla utilizando VEP como variável critério e o consumo de oxigeno (VO2), taxa de intercambio respiratório (RER), PTFC e nível de educação como preditores. Resultados. Foi encontrada uma correlação significativa entre a VEP e a RER (r = 0.22, p = 0.029)) no esforço máximo. Os preditores de VEP para as mulheres foram VO2, RER e PTFC em diferentes etapas da prova. Para os homens, a VEP foi predita por RER, nível de educação e VO2 em diferentes etapas. Conclusão. As variáveis metabólicas e fisiológicas predisseram os valores de VEP em idosos. A idade, a cognição e a FC não estiveram relacionadas com a VEP no esforço máximo e a RER predizia as pontuações da VEP durante o esforço submáximo e máximo.

Rate of Perceived Exertion and Cardiorespiratory Fitness in Older Adults with and without Alzheimer's Disease.

Exercise has many benefits for physical and cognitive health in older adults, yet there are many barriers to exercise adherence in this population. Subjective perception of exercise difficulty, or rate of perceived exertion (RPE), may especially be a barrier to exercise in individuals with Alzheimer's disease (AD), due to changes in initiation and motivation that accompany changes in cognition and brain function. RPE is the most commonly used measure of subjective effort in exercise research, yet the relationship between RPE and objective fitness is not fully understood in older adults. A better understanding is needed to support initiation, engagement, and maintenance of exercise and determine the appropriateness for use of RPE as a measure in this population. Our study aimed to 1) evaluate the degree to which objective measures of cardiorespiratory fitness correlates with the most commonly used subjective measure of effort, RPE and 2) examine any difference in the relationship between objective cardiorespiratory fitness and RPE between individuals with and without AD. We explored these relationships during a graded exercise test. Objective fitness and subjective effort were negatively associated. Independent of cardiorespiratory fitness, older age, female gender, cognitive impairment, and use of heart medications predicted greater self-reported effort during exercise. Results are discussed in terms of social psychological phenomena and potential neuropsychological deficits leading to increased subjective feelings of effort. These findings establish that the RPE measure may not be appropriate and may even detract from effort during graded exercise testing among older adults with AD.

TOMM40 '523 Associations with Baseline and Longitudinal Cognition in APOE ɛ3 Homozygotes.

TOMM40 '523 is associated with Alzheimer's disease (AD), but APOE linkage disequilibrium confounds this association. In 170 APOE ɛ3 homozygotes, we evaluated relationships between short and very long TOMM40 alleles and longitudinal declines in three cognitive domains (attention, verbal memory, and executive function). We used factor analysis to create composite scores from 10 individual cognitive tests, and latent growth curve modeling adjusting for clinical status (normal, amnestic mild cognitive impairment, or AD) to summarize initial performance and change over three years. Relative to individuals with two very long TOMM40 alleles, APOEɛ3 homozygotes with one or two short alleles showed lower baseline cognitive performance regardless of clinical status. The number of short or very long TOMM40 alleles was not associated with longitudinal cognitive changes. In APOEɛ3 homozygotes from the University of Kansas Alzheimer's Disease Center cohort, an association between TOMM40 '523 and cognition is consistent with the possibility that TOMM40 influences cognition independent of APOE.

Use of Physical Activity Questionnaires in People With Dementia: A Scoping Review.

Physical activity questionnaires are an important means to assess habitual physical activity. It remains unclear what questionnaires are used and whether they are appropriate for people with dementia who have impaired information recall but are also often largely sedentary. This scoping review aimed to identify and quantify the use of physical activity questionnaires within a dementia population. Eighteen studies met the inclusion criteria for this review. The majority of studies used questionnaires that were validated for use within an older adult population (e.g., Modified Baecke Questionnaire for the Elderly), though none had specifically been validated for use in people with dementia. Interestingly, just over half of the studies (N = 10, 55.6%) adapted the questionnaires from the original validated version by allowing a proxy to provide input to the responses. Future research needs to robustly validate the use of proxy-report measures of physical activity in people with dementia.

The cause-effect relationship between bone loss and Alzheimer's disease using statistical modeling.

BACKGROUND: Animal studies provide strong evidence that the CNS directly regulates bone remodeling through the actions of the hypothalamus via two distinct pathways, the neural (mediated by leptin) arm and neurohumoral (mediated by neurohormones and growth factors) arm. The impact of AD on central regulatory mechanisms of bone mass is not known. OBJECTIVES: To test a model that assesses the relationship between hypothalamic atrophy and bone loss in Alzheimer's disease (AD) and potential mediation through neural (leptin) and neurohumoral (insulin-like growth factor -1, IGF-1) mechanisms. HYPOTHESES: AD-related hypothalamic structural change alters neural and neurohumoral regulatory systems of bone remodeling and contributes to bone loss in early AD. DESIGN: A secondary data analysis of data obtained in a two-year longitudinal study with path analysis and longitudinal mediation modeling. PARTICIPANTS: The data were collected as a part of the University of Kansas Brain Aging Project, a two-year observational study of 71 older adults with early stage AD and 69 non-demented controls. MEASUREMENTS: Demographic characteristics and measures of bone density, body composition, and hypothalamic volume, serum levels of leptin, growth hormone, and IGF-1 were collected. RESULTS: Hypothalamic atrophy and bone loss were observed in AD group and were associated. Data modeling suggests that bone loss may precede measurable changes in the brain. Leptin increased over two years in AD and the increase in leptin was associated with hypothalamic atrophy. However, changes in leptin or IGF-1 levels did not mediate the relationship between hypothalamic atrophy and bone loss. CONCLUSIONS: This study extends previous findings by suggesting that bone loss in AD may be related to neurodegenerative changes (atrophy) in the hypothalamus. Further studies are needed to explore the role of brain atrophy and mediating mechanisms in bone loss. Further exploring temporal relationship between bone loss and AD may have an important diagnostic value.

Depressive symptoms as a barrier to engagement in physical activity in older adults with and without Alzheimer's disease.

OBJECTIVES: Physical activity shows promise for reduced risk of Alzheimer's disease (AD) and protection against cognitive decline among individuals with and without AD. Older adults face many barriers to adoption of physically active lifestyles and people with AD face even further challenges. Physical activity is a promising non-pharmacological approach to improve depressive symptoms, but little is known about the impact of depressive symptoms as a potential barrier to engagement in physical activity. The present study aimed to investigate depressive symptoms as a potential barrier for participation in physical activity across a range of dementia severity. METHOD: We used longitudinal structural equation modelling to investigate the bi-directional relationship between depressive symptoms and physical activity in 594 older adults with and without AD over a 2 year longitudinal follow up. Participants ranged from no cognitive impairment to moderately severe AD. RESULTS: We found that depressive symptoms predicted reduced engagement in subsequent physical activity, but physical activity did not predict subsequent reductions in depressive symptoms. CONCLUSION: We conclude that depressive symptoms may be an important barrier to engagement in physical activity that may be addressed in clinical practice and intervention research.

The Impact of Creative Arts in Alzheimer's Disease and Dementia Public Health Education.

Previous research involving dramatic performances about Alzheimer's disease and dementia perception have targeted health care workers or caretakers. We examined the influence of a theater performance on the emotional affect of a general audience to determine the utility of this type of theater in large-scale public health education efforts. Our study included 147 participants that attended a self-revelatory theater performance based on the social/relationship experiences of those with dementia and those who care for them. This type of theater engages the audience and actors in a dual transformative process, supporting the emotional growth of all involved. Participants completed pre- and post-performance questionnaires regarding their beliefs and feelings surrounding the topic of dementia and the importance of the Arts for educating on issues surrounding dementia care. We tested for change in emotional affect pre- and post-performance using sensitivity and center of gravity statistical analyses. We found a significant change in emotional affect from an initial strong negative affect to slightly more positive/relaxed view after viewing the performance. Findings support self-revelatory theater as a resource to destigmatize preconceived notions of dementia. Large-scale community health education efforts could benefit from using this style of theater to elicit a change in audience perception of disease realities.