Cognitive activity and risk of alzheimer's disease

Recent research suggests that frequent participation in cognitively stimulating activities may reduce risk of Alzheimer's disease in old age. We review epidemiological evidence of such an association. We then consider whether cognitive activity can account for the association between higher educational and occupational attainment and reduced risk of Alzheimer's disease. Finally, we discuss the behavioral and neurobiological mechanisms that may underlie the association between cognitive activity and risk of Alzheimer's disease.     

Does physical activity reduce risk for Alzheimer's disease through interaction with the stress neuroendocrine system?

Lack of physical activity (PA) is a risk factor for Alzheimer's disease (AD), and PA interventions are believed to provide an effective non-pharmacological approach for attenuating the symptoms of this disease. However, the mechanism of action of these positive effects is currently unknown. It is possible that the benefits may be at least partially mediated by the effects on the neuroendocrine stress system. Chronic stress can lead to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, leading to aberrant basal and circadian patterns of cortisol secretion and a cascade of negative downstream events. These factors have been linked not only to reduced cognitive function but also increased levels of amyloid-β plaques and protein tau "tangles" (the neuropathological hallmarks of AD) in the non-demented mouse models of this disease. However, there is evidence that PA can have restorative effects on the stress neuroendocrine system and related risk factors relevant to AD. We explore the possibility that PA can positively impact upon AD by restoring normative HPA axis function, with consequent downstream effects upon underlying neuropathology and associated cognitive function. We conclude with suggestions for future research to test this hypothesis in patients with AD.     

Association of television violence exposure with executive functioning and white matter volume in young adult males

Prior research has indicated that self-reported violent media exposure is associated with poorer performance on some neuropsychological tests in adolescents. This study aimed to examine the relationship of executive functioning to violent television viewing in healthy young adult males and examine how brain structure is associated with media exposure measures. Sixty-five healthy adult males (ages 18–29) with minimal video game experience estimated their television viewing habits over the past year and, during the subsequent week, recorded television viewing time and characteristics in a daily media diary. Participants then completed a battery of neuropsychological laboratory tests quantifying executive functions and underwent a magnetic resonance imaging (MRI) scan. Aggregate measures of executive functioning were not associated with measures of overall television viewing (any content type) during the past week or year. However, the amount of television viewing of violent content only, as indicated by both past-year and daily diary measures, was associated with poorer scores on an aggregate score of inhibition, interference control and attention, with no relationship to a composite working memory score. In addition, violent television exposure, as measured with daily media diaries, was associated with reduced frontoparietal white matter volume. Future longitudinal work is necessary to resolve whether individuals with poor executive function and slower white matter growth are more drawn to violent programming, or if extensive media violence exposure modifies cognitive control mechanisms mediated primarily via prefrontal cortex. Impaired inhibitory mechanisms may be related to reported increases in aggression with higher media violence exposure.     

Use it or lose it: engaged lifestyle as a buffer of cognitive decline in aging?

Data from the Victoria Longitudinal Study were used to examine the hypothesis that maintaining intellectual engagement through participation in everyday activities buffers individuals against cognitive decline in later life. The sample consisted of 250 middle-aged and older adults tested 3 times over 6 years. Structural equation modeling techniques were used to examine the relationships among changes in lifestyle variables and an array of cognitive variables. There was a relationship between changes in intellectually related activities and changes in cognitive functioning. These results are consistent with the hypothesis that intellectually engaging activities serve to buffer individuals against decline. However, an alternative model suggested the findings were also consistent with the hypothesis that high-ability individuals lead intellectually active lives until cognitive decline in old age limits their activities.     

Keynote lectures

According to the Cognitive reserve hypothesis, several factors related to mental engagement, such as level of education, type of occupation, leisure activities and social network, appear to affect the risk of developing clinical dementia. The present article provides an overview of the studies that have investigated the effects of mental engagement and cognitive stimulation specifically on dementia of the Alzheimer’s type (AD). Mental training and cognitive stimulation interventions in AD have been shown to be useful in increasing patients’ ability in performing activities of daily living (ADL), allowing them to maintain relative independence. Since cognitive engagement and stimulation are known to modify the brain processes to perform tasks, by recruiting alternative and more efficient networks, this review is especially focused on cognitive rehabilitation in AD patients, which has been shown to improve their global functioning and cognition. This perspective stresses the idea that cognitive reserve is not a fixed factor, but can be continuously modified by life experiences, even when the brain is already affected by neuropathology.     

Motivational reserve: motivation-related occupational abilities and risk of mild cognitive impairment and Alzheimer disease

Midlife motivational abilities, that is, skills to initiate and persevere in the implementation of goals, have been related to mental and physical health, but their association with risk of mild cognitive impairment (MCI) and Alzheimer's disease (AD) has not yet been directly investigated. This relation was examined with data from the German Study on Ageing, Cognition, and Dementia in Primary Care Patients (AgeCoDe). A total of 3,327 nondemented participants (50.3% of a randomly selected sample) aged 75-89 years were recruited in primary care and followed up twice (after 1.5 and 3 years). Motivation-related occupational abilities were estimated on the basis of the main occupation (assessed at follow-up II) using the Occupational Information Network (O* NET) database, which provides detailed information on worker characteristics and abilities. Cox proportional hazards models were used to evaluate the relative risk of developing MCI and AD in relation to motivation-related occupational abilities, adjusting for various covariates. Over the 3 years of follow-up, 15.2% participants developed MCI and 3.0% developed AD. In a fully adjusted model, motivation-related occupational abilities were found to be associated with a reduced risk of MCI (HR: 0.77; 95% CI: 0.64-0.92). Motivation-related occupational abilities were associated with reduced risk of AD in ApoE ε4 carriers (HR: 0.48; CI: 0.25-0.91), but not in noncarriers (HR: 0.99; CI: 0.65-1.53). These results suggest that midlife motivational abilities are associated with reduced risk of MCI in general and with reduced risk of AD in ApoE ε4 carriers. Revealing the mechanisms underlying this association may inform novel prevention strategies for decelerating cognitive decline in old age.     

Background Television as an Inhibitor of Cognitive Processing

Proposed and tested is a causal process that could account for empirical relationships between television viewing and academic achievement. It is argued that television, when used as a secondary activity, interferes with performance on otherwise intellectually demanding tasks. Performance on seven different cognitive processing tests were examined for respondents in four television-viewing conditions and a no-TV control group. Dependent variables included measures of short-term memory, linguistic processing speed, reading comprehension, complex problem-solving abilities, and mental flexibility. Predictions based on four mechanisms were tested. Significant performance decrements in television conditions occurred for measures of reading comprehension, spatial problem solving, and cognitive flexibility. Results were most consistent with the idea that background television influences performance by causing cognitive processing capacity limits to be exceeded on difficult and complex tasks.     

Personality and risk for Alzheimer's disease in adults 72 years of age and older: a 6-year follow-up

[Correction Notice: An erratum for this article was reported in Vol 26(2) of Psychology and Aging (see record 2011-05802-001). This article contains an error in the Discussion, under the Implications, Caveats, Future Directions heading. The third paragraph includes the sentences that should have been removed. The corrected paragraph appears in the correction.] We conducted secondary analyses to determine the relationship between longstanding personality traits and risk for Alzheimer's disease (AD) among 767 participants 72 years of age or older who were followed for more than 6 years. Personality was assessed with the NEO-FFI. We hypothesized that elevated Neuroticism, lower Openness, and lower Conscientiousness would be independently associated with risk of AD. Hypotheses were supported. The finding that AD risk is associated with elevated Neuroticism and lower Conscientiousness can be added to the accumulating literature documenting the pathogenic effects of these two traits. The link between lower Openness and AD risk is consistent with recent findings on cognitive activity and AD risk. Findings have implications for prevention research and for the conceptualization of the etiology of AD.     

Emotional experience and facial expression in Alzheimer's disease

Emotional experiences and facial muscle activity of individuals with Alzheimer's Disease (AD) (n = 13) and healthy elderly control subjects (n = 21) were measured while viewing emotion-eliciting images. Alzheimer's disease and control groups rated their emotional experiences similarly and in the expected directions on dimensions of valence and arousal. Change in corrugator activity while viewing images, compared to baseline, was comparable across groups and was greatest while viewing negative images. Change in zygomatic activity, however, was significantly different between AD and control groups, with AD subjects demonstrating an inverted pattern of activity compared to controls. These findings are discussed as possible consequences of frontal cortical system involvement accompanying the disease process.     

休闲活动对我国老年人认知功能的影响

本文通过分析中国老年健康影响因素跟踪调查(CLHLS)2011年的数据,研究了参与休闲活动对老年人认知功能的影响。研究发现,参与各项休闲活动比例较高的老年人,其认知功能缺损的比例相对较低。回归分析结果表明,当控制了样本的人口特征(包括年龄、受教育程度、性别、居住地)、社会经济地位、健康状况、以及生活习惯等变量以后,参与社交类、益智类、以及轻度户外活动的程度越高,我国老年人认知功能缺损的可能性就越低。这些发现鼓励我国老年人在晚年积极参与上述几类休闲活动从而降低其认知功能衰退的风险。     

The role of cardiovascular risk factors in Alzheimer's disease

The distinction between Alzheimer's disease and vascular dementia, the two most common types of dementia, has been undermined by recent advances in epidemiologic, clinical, imaging, and neuropathological studies. Cardiovascular risk factors, traditionally regarded as distinguishing criteria between the two entities, have been shown to be associated with both AD and vascular dementia. In this article, we propose mechanisms of action of cardiovascular risk factors in AD, suggest possible explanations for the overlap with vascular dementia and discuss the implications this might have on future differential diagnosis, research, and treatment strategies.     

The Effects of Estrogen Replacement Therapy on Neuropsychological Functioning in Postmenopausal Women With and Without Dementia: A Critical and Theoretical Review

We review 42 studies examining the effects of estrogen replacement therapy (ERT) on memory and cognition in nondemented postmenopausal women. Although there are an appreciable number of nonsignificant findings, the number of significant findings favoring ERT users considerably outnumbers the rare findings of better performance in controls. Experimental studies demonstrate a consistent beneficial effect on verbal memory, but these are short-term studies of the more acute effects of ERT. The observational studies suggest that there may be a long-lasting effect of continued ERT on cognitive functioning, but these studies need to be interpreted with caution because of the lack of random assignment and a possible healthy user bias. We also summarize findings from studies on the effects of ERT on Alzheimer's disease (AD). ERT is associated with a decreased risk for dementia, but there is little evidence for a positive effect on cognition in women with AD. Definitive answers to questions about the long-term effects of ERT on cognitive aging and risk of developing AD should be provided by 3 ongoing clinical trials.     

媒体与婴儿的认知发展

随着电视、网络、DVD视频等媒体设备的普及,媒体对婴儿发展的影响越来越受到父母和研究者的关注。电视等媒体与婴儿注意、语言和学习的相关研究是婴儿媒体研究中非常重要的内容。婴儿期对电视的注意随着年龄的增长而增长;婴儿的语言发展依赖于他们收看的电视节目类型及自身特征;当将视频学习和现实中等价学习进行比较时,非常年幼的儿童从视频中学习得更少。媒体对婴儿发展产生的影响是积极还是消极,缺少一个权威性的答案。鉴于这一点,本文从关注媒体的内容和形式、新的研究视角、以及国内研究现状等方面提出未来研究的趋势。     

The Impact of Adolescents' News and Action Movie Viewing on Risky Driving Behavior: A Longitudinal Study

Traffic crashes remain an important cause of injury and death among young people. The aim of the current study was to examine whether adolescents' viewing of particular television genres predicted later risky driving. Data were collected with a two‐wave panel survey (N = 426); structural equation modeling was used to examine the relationships between television viewing and self‐reported risky driving. Theoretically, the study was framed within cultivation theory and the theory of planned behavior. In line with the hypotheses, more news viewing appeared to be an indirect negative predictor of reckless driving, whereas more exposure to action programs was associated with more risk taking in traffic. This relationship was mediated by risk‐taking attitudes and intentions. The implications for prevention are discussed.     

Enhanced cognitive activity--over and above social or physical activity--is required to protect Alzheimer's mice against cognitive impairment, reduce Abeta deposition, and increase synaptic immunoreactivity

Although social, physical, and cognitive activities have each been suggested to reduce the risk of Alzheimer's disease (AD), epidemiologic studies cannot determine which activity or combination of activities is most important. To address this question, mutant APP transgenic AD mice were reared long-term in one of four housing conditions (impoverished, social, social+physical, or complete enrichment) from 1(1/2) through 9 months of age. Thus, a stepwise layering of social, physical, and enhanced cognitive activity was created. Behavioral evaluation in a full battery of sensorimotor, anxiety, and cognitive tasks was carried out during the final 5 weeks of housing. Only AD mice raised in complete enrichment (i.e., enhanced cognitive activity) showed: (1) protection against cognitive impairment, (2) decreased brain beta-amyloid deposition, and (3) increased hippocampal synaptic immunoreactivity. The protection provided by enhanced cognitive activity spanned multiple cognitive domains (working memory, reference learning, and recognition/identification). Cognitive and neurohistologic benefits of complete enrichment occurred without any changes in blood cytokine or corticosterone levels, suggesting that enrichment-dependent mechanisms do not involve changes in the inflammatory response or stress levels, respectively. These results indicate that the enhanced cognitive activity of complete enrichment is required for cognitive and neurologic benefit to AD mice-physical and/or social activity are insufficient. Thus, our data suggest that humans who emphasize a high lifelong level of cognitive activity (over and above social and physical activities) will attain the maximal environmental protection against AD.     

Low diversity and low frequency of participation in leisure activities compromise working memory efficiency in young adults

People perform leisure activities (LA) every day; pursuits that entail applying cognitive, physical and social abilities. As in old age, doing LA during early and middle adulthood is related to a reduced risk of dementias, probably by generating a cognitive reserve. As it is possible that a relation between doing LA and working memory (WM) efficiency exists in young adults, we assessed whether the diversity and frequency of LA are related to WM efficiency in this population. Ninety-three healthy young subjects solved the n-back task at two levels of difficulty (2, 3), and answered an LA questionnaire on the activities in which they had participated in the month prior to the experiment. Subjects were classified separately on their scores for (1) diversity (high/low) and (2) frequency (high/low) in order to test the relation between each variable and WM efficiency. Though no differences were found, a subsequent analysis of the average of diversity and frequency ratios of LA performance taken together-the diversity/frequency index-showed that low diversity plus low frequency was significantly associated with reduced WM efficiency at this age; results that suggest that frequent participation in diverse LA during youth is related to WM efficiency.     

Effect of television viewing on social–emotional competence of young Thai children

Exposure time, program content and cultural context may affect the impact of television (TV) on the social–emotional competence (SEC) of children. This study examined the effects of TV viewing on the SEC of Thai infants. The study was based on a Thai birth cohort study from which duration and content of TV viewing and data from the Modified Infant–Toddler Social and Emotional Assessment instrument at 1 and 3 years of age were available. Generalized estimating equations were used to examine whether scores below the 10th national percentile were associated with TV viewing duration. The relationship between viewing duration and SEC risk was quadratic rather than linear. Viewing duration of 30–120 min/day was associated with a decreased risk of low overall SEC compared to non-viewers after adjustments for confounding factors. However, the beneficial effect diminished when the duration exceeded 120 min/day. Viewing educational programs was associated with a risk reduction of having low overall SEC compared to non-educational programs. These results suggest that a short period of TV viewing may be beneficial for the SEC of Thai infants, especially if the programs are educational.     

Effects of television exposure on developmental skills among young children

BackgroundLiterature addressing the effects of television exposure on developmental skills of young children less than 36 months of age is scarce. This study explored how much time young children spend viewing television and investigated its effects on cognitive, language, and motor developmental skills.MethodsData were collected from the Pediatric Clinics at University Medical Center in Southern Taiwan. The participants comprised 75 children who were frequently exposed to television and 75 children who were not or infrequently exposed to television between 15 and 35 months old. The age and sex were matched in the two groups. The Bayley Scales of Infant Development-second edition and Peabody Developmental Motor Scales-second edition were used to identify developmental skills. Independent t-tests, χ² tests, and logistic regression models were conducted.ResultsAmong 75 children who were frequently exposed to television, young children watched a daily average of 67.4 min of television before age 2, which was excessive according to the American Academy of Pediatrics. Viewing television increased the risk of delayed cognitive, language, and motor development in children who were frequently exposed to television. Cognitive, language, and motor delays in young children were significantly associated with how much time they spent viewing television. The type of care providers was critical in determining the television-viewing time of children.ConclusionWe recommend that pediatric practitioners explain the impacts of television exposure to parents and caregivers to ensure cognitive, language, and motor development in young children. Advocacy efforts must address the fact that allowing young children to spend excessive time viewing television can be developmentally detrimental.     

Stimulation cognitive chez les personnes âgées : effets d’une méthode de stimulation cognitive par les jeux sur les fonctions cognitives et l’estime de soi

The purpose of this study was to examine the effects of a cognitive stimulation program with games on scores to cognitive tests (processing speed, mental flexibility, working memory, inhibition) and how this program can benefit to a psycho-affective measure, self-esteem in older adults. Forty-eight participants over 60 years old took part in the experiment. They were divided into two groups: 1 group followed a program of cognitive stimulation using leisure activities with games and 1 control group in which people gathered every week. There were 8 sessions of cognitive stimulation using leisure activities like games, one-hour session a week. Measures have focused on speed of processing and executive functions (shifting, updating and inhibition). They have been evaluated before and after the training program. Results show that the cognitive stimulation program using leisure activities with games is effective on speed of processing, memory span, inhibition and self-esteem but shows no benefits on shifting and updating. These results indicate that it seems to be possible to enhance cognitive resources, inhibition and self-esteem using leisure activities with games as a tool for cognitive stimulation.