In this manuscript, we summarize published results showing that obesity and aging are inflammatory conditions associated with serious health problems, increased risk for disease and death. We show that fat mass increases with age and represents a major contributor to insulin resistance and the metabolic syndrome. We summarize the effects of age on the adipose tissue (AT), related to the abundance, distribution, cellular composition, endocrine signaling and function of the tissue. The AT is an immunological tissue, with several hallmarks of innate and adaptive immune responses. We show that in both mice and humans, the AT is heavily infiltrated by immune cells that have receptors for pro-inflammatory cytokines and chemokines secreted by the adipocytes and also by the immune cells that have infiltrated the AT. We also show that the AT provides an environment for the secretion of IgG antibodies with anti-self (autoimmune) reactivity. As we have previously shown, this is due to the release of self antigens following cell death due to hypoxia, as well as to the expression of activation-induced cytidine deaminase, the enzyme of class switch recombination, and the transcription factor T-bet by the resident B cells, which also express the membrane marker CD11c, both involved in the production of autoimmune IgG antibodies. We show data in support of the AT as a tertiary lymphoid organ (TLO), showing the examples of TLOs that develop within the AT, such as fat-associated lymphoid clusters and milky spots, as well as artery TLOs that develop in the adventitia areas of the aorta.
Posted: August 14, 2019, 2:05 pm
Background: Age-related declines in many cognitive abilities are common in healthy aging. However, the ability to effectively regulate emotions is preserved, and possibly even enhanced, in late adulthood. This capacity has been examined most commonly in relation to low-intensity emotional stimuli that typically involve static pictures. Evidence is suggesting that older adults may become overwhelmed when exposed to emotional cues of heightened intensity. Objective: In the current study, we assessed whether older adults retain the ability to regulate emotions successfully when exposed to more emotionally evocative (e.g., dynamic) stimuli. Methods: Young and older adults were instructed to regulate, using expressive suppression, their outward behavioral expression of emotions while viewing dynamic stimuli involving amusing and sad films. Facial reactivity, as indexed using electromyography, self-rated emotional experience, and memory for the stimuli were assessed. Results: The results showed that, relative to young adults, older adults were unable to suppress zygomaticus (cheek) activity to amusing films or corrugator (brow) reactivity to sad films, which is likely due to their relatively reduced facial muscle reactivity. Expressive suppression did not affect young or older adults’ subjective feelings or memory for the stimuli. Conclusion: Our findings suggest that there are age differences in facial muscle reactivity to amusing and sad cues of heightened intensity. These findings suggest that older adults’ ability to effectively regulate emotions may be limited, at least with expressive suppression, in the context of high-intensity emotional cues. Further research is needed to investigate possible exceptions the preservation of emotion regulation in older adults.
Posted: August 7, 2019, 12:03 pm
Period life expectancy is one of the most used summary indicators for the overall health of a population. Its levels and trends direct health policies, and researchers try to identify the determining risk factors to assess and forecast future developments. The use of period life expectancy is often based on the assumption that it directly reflects the mortality conditions of a certain year. Accordingly, the explanation for changes in life expectancy are typically sought in factors that have an immediate impact on current mortality conditions. It is frequently overlooked, however, that this indicator can also be affected by at least three kinds of effects, in particular in the situation of short-term fluctuations: cohort effects, heterogeneity effects, and tempo effects. We demonstrate their possible impact with the example of the almost Europe-wide decrease in life expectancy in 2015, which caused a series of reports about an upsurge of a health crisis, and we show that the consideration of these effects can lead to different conclusions. Therefore, we want to raise an awareness concerning the sensitivity of life expectancy to sudden changes and the menaces a misled interpretation of this indicator can cause.
Posted: August 7, 2019, 10:53 am
Background: Detecting manifestations of spatial disorientation in real time is a key requirement for adaptive assistive navigation systems for people with dementia. Objective: To identify predictive patterns of spatial disorientation in cognitively impaired people during unconstrained locomotion behavior in an urban environment. Methods: Accelerometric data and GPS records were gathered during a wayfinding task along a route of about 1 km in 15 people with amnestic mild cognitive impairment or clinically probable Alzheimer’s disease dementia (13 completers). We calculated a set of 48 statistical features for each 10-s segment of the acceleration sensor signal to characterize the physical motion. We used different classifiers with the wrapper method and leave-one-out cross-validation for feature selection and for determining accuracy of disorientation detection. Results: Linear discriminant analysis using three features showed the best classification results, with a cross-validated ROC AUC of 0.75, detecting 65% of all scenes of spatial disorientation in real time. Consideration of an additional feature that informed about a person’s distance to the next traffic junction did not provide an additional information gain. Conclusions: Accelerometric data are able to capture the uniformity and activity of a person’s walking, which are identified as the most informative locomotion features of spatially disoriented behavior. This serves as an important basis for real-time navigation assistance. To improve the required accuracy of real-time disorientation prediction, as a next step we will analyze whether location-based behavior is able to inform about person-centered habitual factors of orientation.
Posted: July 30, 2019, 1:23 pm
Background: Cognitively stimulating activities contribute to the accumulation of cognitive reserve that is proposed to be instrumental for maintaining cognitive functioning in aging. Adopting a novel, more general conceptual perspective including models of vulnerability, we argue that cognitive reserve may modify the longitudinal association between perceived stress and the rate of subsequent decline in executive functioning. Objective: The present study set out to investigate the longitudinal relationship between perceived stress and subsequent decline in executive functioning over 6 years as measured through performance changes in the Trail Making Test (TMT) and whether this longitudinal relationship differed by key markers of cognitive reserve (education, occupation, and leisure activities), taking into account age, sex, and chronic diseases as covariates. Methods: We used latent change score modeling based on longitudinal data from 897 older adults tested on TMT parts A and B in two waves 6 years apart. Mean age in the first wave was 74.33 years. Participants reported information on perceived stress, education, occupation, leisure activities, and chronic diseases. Results: The longitudinal relationship between greater perceived stress in the first wave of data collection and steeper subsequent decline in executive functioning over 6 years was significantly reduced in individuals who had pursued a higher frequency of leisure activities in the first wave. Conclusion: The longitudinal relationship between perceived stress and subsequent decline in executive functioning may be attenuated in individuals who have accumulated greater cognitive reserve through an engaged lifestyle. Implications for current cognitive reserve and gerontological research are discussed.
Posted: July 26, 2019, 7:55 am
Background: Older adults improve their cognitive performance on a target task after succeeding in a prior task. We tested whether effects of prior-task success occur via changing older adults’ ability to select the better strategy and/or to execute strategies efficiently. Methods: Young and older participants (n = 162) accomplished a computational estimation task (i.e., providing the best estimates to arithmetic problems) after accomplishing a dot comparison task. Results: Both groups increased their performance on computational estimation following success on dot comparison. Older adults improved most and outperformed young adults following prior-task success. Prior-task success led older adults to select the better strategy more often and to repeat (or not) the same strategy more often when it was appropriate. Better strategy use mediated effects of prior-task success. Individual differences in baseline performance moderated individuals’ sensitivity to effects of prior-task success. Conclusion: Our findings further our understanding of mechanisms underlying effects of prior-task success and provide new perspectives on how social environment modulates age-related differences in cognitive performance.
Posted: July 22, 2019, 9:55 am
Although frailty has been extensively investigated for the last 2 decades, preclinical models of frailty have only been developed over the past decade. Frailty is a concept that helps to explain the difference between chronologic age and biologic age and to discuss health span along with lifespan. In general, a frail individual will be more susceptible to adverse health outcomes than a healthy, nonfrail individual of the same age. However, the biology and mechanisms of frailty are still unclear. The development of preclinical models of frailty and frailty assessment tools are invaluable to geriatric research. This review briefly describes the concept of frailty and discusses the newly developed animal models of frailty, specifically the frailty phenotype- and frailty index-based models. Mouse models are the most common models for preclinical frailty research, but rat and canine models for frailty assessment have also been developed. These models can facilitate the testing of frailty-specific treatments and help to investigate the effects of various interventions on frailty. Similarities and differences between human and animal models, including sex differences in frailty, are also discussed. The availability of animal models of frailty is a valuable and welcome addition to the study of frailty, aging, or the disorders of old age and will enable a better understanding of frailty mechanisms.
Posted: July 22, 2019, 9:53 am
Background: Cognitive frailty has long been defined as the co-occurrence of mild cognitive deficits and physical frailty. However, recently, a new approach to cognitive frailty has been proposed: cognitive frailty as a distinct construct. Nonetheless, the relationship between this relatively new construct of cognitive frailty and other frailty domains is unclear. Objectives: The aims of this study were to explore the prevalence of cognitive frailty in groups with different degrees of cognitive impairment, as well as to explore the associations between frailty domains, and if this varies with level of objective cognitive impairment. Method: Cross-sectional, secondary data from 3 research projects among community-dwelling people aged ≥60 years, with different degrees of objective cognitive impairment, were used: (1) a randomly selected sample (n = 353); (2) a sample at an increased risk of frailty (n = 95); and (3) a sample of memory clinic patients who scored 0.5 on the Clinical Dementia Rating scale – according to the “original” definition of cognitive frailty (n = 47). Multidimensional frailty was assessed with the Comprehensive Frailty Assessment Instrument – Plus and general cognitive functioning with the Montreal Cognitive Assessment. Descriptive statistics and linear regression were used to determine the prevalence of cognitive frailty and to explore the relationship between cognitive frailty and the other types of frailty in each sample. Results: The prevalence of cognitive frailty increased along with the degree of objective cognitive impairment in the 3 samples (range 35.1–80.9%), while its co-occurrence with (one of) the other types of frailty was most frequent in the frail and community samples. Regarding its relationship with the other domains, cognitive frailty was positively associated with psychological frailty’s subdomain mood disorder symptoms in all 3 samples (p ≤ 0.01), while there was no significant association with environmental frailty and social loneliness. The associations between cognitive frailty and the other types of frailty differed between the samples. Conclusion: Psychological and cognitive frailty are strongly associated, irrespective of the objective degree of cognitive impairment. In addition, it is shown that cognitive frailty can occur independently from the other frailty domains, including physical frailty, and therefore it can be seen as a distinct concept.
Posted: July 22, 2019, 8:35 am
Background: Assistive technology (AT) has the potential to support and enhance self-management of people living with dementia. However, a range of special and heterogeneous needs must be considered when designing and deploying AT for people with dementia, and consequently the involvement of end-users throughout the design process is essential to provide usable and effective AT solutions. Objective: The ReACT study was conducted to investigate how a tailor-made app, the ReACT app, can be designed and deployed to meet the needs of people with dementia in relation to self-management. Methods: This paper presents 4 steps of an iterative user-involving app design process. In the first step, a pilot study was conducted to explore the potential benefits and challenges of using existing off-the-shelf apps to support self-management when living with early-stage dementias. In the second step, focus group interviews provided in-depth understanding of the perspectives and needs of potential end-users of the app. The third step was a product benchmarking process, which served to further qualify the design process. Finally, results from these first 3 steps were included in the fourth step where the ReACT app was designed through an iterative codesign process. In total, 28 people with dementia, 17 family caregivers, and 10 professional caregivers were involved through these 4 iterative steps. Results: The functionalities and the design of the ReACT app directly reflect the perspectives and needs of end-users in relation to self-management. Support of memory and structure in daily living were identified as main needs, and the ReACT app was designed as a holistic and adaptable solution with a tailor-made calendar as a key feature. Conclusion: Based on this extensive iterative user-involving design process, the ReACT app has great potential to support and enhance self-management of people living with dementia. Further studies are needed to test and validate the usability and impact of the app, and methods for deployment and adoption of AT for people with dementia also need to be considered.
Posted: July 2, 2019, 9:28 am
Background: Associations between lower limb muscle strength and balance performance in adults have previously been reported. However, the function of the foot muscles for postural control has not been understood, yet. Objective: The purpose of the present study was to investigate associations between pronator and supinator muscle strength, subtalar range of motion (ROM) and postural stability while standing under various conditions in young versus old adults. Methods: Using a custom-built apparatus equipped with a force transducer and an electrogoniometer, maximum voluntary isometric subtalar pronator and supinator strength as well as ROM tests were administered to 30 young (mean age: 25.1 years) and 30 old (mean age: 65.2 years) volunteers. Total active subtalar ROM, peak pronator and peak supinator torques were measured. While standing on a force plate, limits of stability (LOS) were determined during anterior–posterior (AP) and medio-lateral (ML) leaning tasks. Furthermore, sway distance and velocity during single-legged standing were measured. Correlation and regression analyses were conducted. Results: In both age groups, subtalar pronator muscle strength was related to AP-LOS (young: r = 0.36; old: r = 0.49). In young adults, subtalar supinator muscle strength was associated with ML-LOS (r = 0.41). The regression analyses revealed that summed subtalar muscle strength predicts 13 and 20% of the variance of AP-LOS in young and old adults, respectively. Summed subtalar muscle strength was found to predict 18% of the variance in ML-LOS in young but not in old adults. There were no correlations and no predictors found concerning subtalar muscle strength and postural sway during single-legged standing for both age groups. Conclusions: Longitudinal studies have to proof whether pronator muscle strength training might positively affect balance performance during AP leaning, specifically in old adults.
Posted: July 2, 2019, 9:24 am
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