There is enormous interest in designing training methods for reducing cognitive decline in healthy older adults. Because it is impaired with aging, multitasking has often been targeted and has been ...shown to be malleable with appropriate training. Investigating the effects of cognitive training on functional brain activation might provide critical indication regarding the mechanisms that underlie those positive effects, as well as provide models for selecting appropriate training methods. The few studies that have looked at brain correlates of cognitive training indicate a variable pattern and location of brain changes--a result that might relate to differences in training formats. The goal of this study was to measure the neural substrates as a function of whether divided attentional training programs induced the use of alternative processes or whether it relied on repeated practice. Forty-eight older adults were randomly allocated to one of three training programs. In the single repeated training, participants practiced an alphanumeric equation and a visual detection task, each under focused attention. In the divided fixed training, participants practiced combining verification and detection by divided attention, with equal attention allocated to both tasks. In the divided variable training, participants completed the task by divided attention, but were taught to vary the attentional priority allocated to each task. Brain activation was measured with fMRI pre- and post-training while completing each task individually and the two tasks combined. The three training programs resulted in markedly different brain changes. Practice on individual tasks in the single repeated training resulted in reduced brain activation whereas divided variable training resulted in a larger recruitment of the right superior and middle frontal gyrus, a region that has been involved in multitasking. The type of training is a critical factor in determining the pattern of brain activation.
Given that aging is associated with higher risk of cognitive decline and dementia, improving early detection of cognitive impairment has become a research and clinical priority. The Montreal ...Cognitive Assessment (MoCA) is a screening instrument used to assess different aspects of cognition. Despite its widespread use, norms adjusted to the sociodemographics of Quebec-French people are not yet available. Such norms are however important because performance on neuropsychological tests varies according to sociodemographic variables including age, sex, and education. As such, the present study aimed to establish normative data for the MoCA in middle-aged and elderly Quebec-French population.
For that purpose, 1,019 community-dwelling older adults aged between 41 and 98 were recruited. Participants from 12 recruiting sites completed the MoCA. Regression-based normative data were produced and cross-validated with a validation sample (n = 200).
Regression analyses indicated that older age, lower education level, and male sex were associated with poorer MoCA scores. The best predictive model included age (p < .001), education (p < .001), sex (p < .001), and a quadratic term for education (education X education; p < .001). This model explained a significant amount of variance of the MoCA score (p < .001, R2 = 0.26). A regression equation to calculate Z scores is presented.
This study provides normative data for the MoCA test in the middle-aged and elderly French-Quebec people. These data will facilitate more accurate detection and follow-up of the risk of cognitive impairment in this population, taking into account culture, age, education, and sex.
Increasing evidence associates apathy with worsening in cognitive performance and greater risk of dementia, in both clinical and healthy older populations. In older adults with neurocognitive ...disorders, apathy has also been related to specific fronto-subcortical structural abnormalities, thus differentiating apathy and major depressive disorder. Yet, the neural mechanisms associated with apathy in healthy older adults are still unclear. In the present study, we investigated the frontal cortical response during a dual-task walking paradigm in forty-one healthy older adults with and without apathy symptoms, controlling for depressive symptoms. The dual-task walking paradigm included a single cognitive task (2-back), a single motor task (walking), and a dual-task condition (2-back whilst walking). The cortical response was measured by means of functional Near-Infrared Spectroscopy (fNIRS). The results revealed that participants with apathy symptoms showed greater activation of subregions of the prefrontal cortex and of the premotor cortex compared to healthy controls during the single cognitive component of the dual-task paradigm, whilst cognitive performance was equivalent between groups. Moreover, increased cortical response during the cognitive task was associated with higher odds of exhibiting apathy symptoms, independently of depressive symptoms. These findings suggest that apathy may be related to differential brain activation patterns in healthy older individuals and are in line with previous evidence of the distinctiveness between apathy and depression. Future research may explore the long-term effects of apathy on the cortical response in healthy older adults.
Epidemiological studies have revealed that behavioral and psychological (or non-cognitive) symptoms are risk factors for cognitive decline in older adults. This study aimed to systematically review ...the literature and determine which behavioral and psychological symptoms are most predictive of future cognitive decline among individuals with no pre-existing cognitive impairments. The selected studies included middle-aged or older adults without cognitive impairments. The predictors were assessed using behavioral and psychological questionnaires, or diagnostic interviews, to identify non-cognitive symptoms or psychiatric clinical conditions. The follow-up period was at least one year, and the design of the selected studies was either retrospective or prospective. This study compared individuals with and without non-cognitive manifestations and resulted in one of three outcomes: (a) a score change on a cognitive measure, (b) a diagnosis of mild cognitive impairment, or (c) a diagnosis of Alzheimer’s disease or dementia. Four online databases were searched for eligible studies from the database inception to January 17, 2017: MEDLINE (PubMed), Embase (OVID), PsycINFO, and Web of Science. Pooled effect sizes were estimated using a random-effect model. Higgins I
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, the Q statistic, and tau-squared were used to quantify the observed heterogeneity between the studies. Results indicate that depression and sleep duration (long and short) were the most consistent associations between behavioral or psychological symptoms and cognitive decline. This meta-analysis supports the need to assess behavioral and psychological symptoms in cognitively intact older adults to identify those who are at risk for cognitive decline.
An increasing number of studies have relied on brain imaging to assess the effects of cognitive training in healthy aging populations and in persons with early Alzheimer’s disease or mild cognitive ...impairment (MCI). At the structural level, cognitive training in healthy aging individuals has been associated with increased brain volume, cortical thickness, and density and coherence of white matter tracts. At the functional level, task-related brain activation (using fMRI and PET) and fluorodeoxyglucose positron emission tomography (FDG-PET) were found to be sensitive to the effects of training. In persons with MCI, cognitive training increased brain metabolism and task-related brain activation, whereas healthy older adults showed patterns of increased and decreased activation. Further studies are required to generalize these findings to larger groups and to investigate more diverse training protocols. Research will also need to address important methodological issues regarding the use of biomarkers in cognitive aging, including reliability, clinical validity, and relevance to the pathophysiological process.
Autobiographical memory (AM) is built up from various kinds of knowledge, from general to specific, via generative processes. Aging seems to particularly affect the episodic autobiographical ...information while preserving information that is more semantic. However, the mechanism of this deficit has not yet been thoroughly tested in relation to working memory. This study is designed to investigate, in a group of 100 subjects, the relationships between age, accessibility to different levels of AM specificity, and two main components of working memory: the central executive and the episodic buffer. We used a new task composed of four embedded verbal autobiographical fluencies (VAF) – from low to highest specificity levels – exploring lifetime periods, general events, specific events, and details, plus tasks exploring free recall of episodic AM and updating, shifting, inhibition, and feature binding in working memory. The results demonstrate that age-related difficulties increase with level of specificity of autobiographical knowledge, i.e., from semantic to episodic aspects. Moreover, regression analyses mainly show that increase in age-related deficit with level of specificity of AM is largely mediated by performance on executive functions (updating and inhibition) and to a lesser extent feature binding in working memory. The results confirm in episodic AM the executive/working memory aging hypothesis, and for the first time highlight the role of episodic buffer in associating the various different details of specific events that elicit the conscious recollection.
•Hyperactivation relates to memory-related network dysfunction in SCD+ and MCI.•Hippocampal hyperactivation and connectivity relate to worst memory performance.•In contrast, neocortical ...hyperactivation and connectivity may reflect compensation.
The goal of this study was to assess how task-related hyperactivation relates to brain network dysfunction and memory performance in individuals at risk of Alzheimer’s disease (AD). Eighty participants from the CIMA-Q cohort were included, of which 28 had subjective cognitive decline plus (SCD+), as they had memory complaints and worries in addition to a smaller hippocampal volume and/or an APOE4 allele, 26 had amnestic mild cognitive impairment (MCI) and 26 were healthy controls without memory complaints. Functional magnetic resonance imaging (fMRI) activation was measured during an object-location memory task. Seed-partial least square analyses (seed-PLS) were conducted in controls and in the SCD+/MCI groups to yield sets of orthogonal latent variables (LVs) assessing the triple association between: i) seed activity in brain regions found to be hyperactive in individuals at risk of AD (left hippocampus, left superior parietal lobule, right inferior temporal lobe), ii) latent patterns of whole-brain task-related activation, and iii) associative memory performance. Three LVs in the SCD+ and MCI groups (67.88% of total covariance explained) and two LVs in the controls (77.85% of total covariance explained) were significant. While controls and SCD+/MCI groups shared a common pattern of memory-related connectivity, patterns of hyperactivation-networks interactions were unique to the clinical groups. Interestingly, higher hippocampal connectivity was associated with poorer memory performance whereas higher neocortical connectivity predicted better memory performance in SCD+ and MCI groups. Our data provides empirical evidence that early dysfunction in brain activation and connectivity is present in the very early stages of AD and offers new insights on the relationship between functional brain alterations and memory performance.
Some complex cognitive activities impacted by aging (future thinking, problem-solving, creative thinking) have been shown to rely on episodic retrieval, suggesting that cognitive interventions aiming ...to improve retrieval have the potential to induce transfer effects to these activities. Prior studies have shown that a brief one-session technique called Episodic Specificity Induction (ESI) can transiently improve episodic retrieval and induce transfer effects to complex tasks that rely on episodic retrieval in older adults. In the present proof-of-concept study, we assessed whether a training program consisting of repeated practice of the ESI technique can improve episodic retrieval and transfer to complex tasks. Fifteen healthy older adults completed a six-session intervention where they received repeated ESI practice. Before and after the intervention, nearest transfer effects were assessed using free recall, near transfer effects using recognition and associative recognition, and far-transfer effects using mean-ends problem-solving and divergent creative thinking. Before the intervention, typical ESI effects were observed (better performance after an ESI than after a control task), indicating that the ESI operated as expected in our sample. When examining the intervention effects, performance was increased after the intervention on free recall and recognition (nearest- and near-transfer) as well as problem-solving and divergent creative thinking (far transfer). These results indicate that an intervention relying on the ESI technique can produce both near and far transfer. These findings support the use of the ESI in the design of interventions that could improve retrieval and have a broad impact on a range of complex tasks.
Consumption of a prudent dietary pattern rich in healthy nutrients is associated with enhanced cognitive performance in older adulthood, while a Western dietary pattern low in healthy nutrients is ...associated with poor age-related cognitive function. Sex differences exist in dietary intake among older adults; however, there is a paucity of research examining the relationship between sex-specific dietary patterns and cognitive function in later life. The current study aimed to investigate sex differences in the relationship between sex-specific dietary pattern adherence and global cognitive function at baseline and over a 3-year follow-up in 1268 community-dwelling older adults (M.sub.age = 74 years, n = 664 women, n = 612 men) from the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge). A 78-item Food Frequency Questionnaire was used to estimate dietary intake over the previous year. Sex-specific dietary pattern scores were derived using principal component analysis. Global cognition was assessed using the Modified Mini-Mental State Examination (3MS). Adjusted linear mixed effects models indicated that a healthy, prudent dietary pattern was not associated with baseline cognitive performance in men or women. No relationship was found between Western dietary pattern adherence and baseline cognitive function in women. Among men, adherence to an unhealthy, Western dietary pattern was associated with poorer baseline cognitive function (beta = - 0.652, p = 0.02, 95% CI - 1.22, - 0.65). No association was found between prudent or Western dietary patterns and cognitive change over time in men or women. These findings highlight the importance of conducting sex-based analyses in aging research and suggest that the relationship between dietary pattern adherence and cognitive function in late life may be sex-dependent.
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