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Background & Aims: Dual-task walking is an emerging marker of cognitive impairment. However, there is uncertainty regarding which dual-task test and measure to use. The aims of this study were to determine the association between three different dual-tasks and 1) global cognition and 2) individual cognitive domains., Methods: Participants (n = 91) were adults aged between 56-83 years (mean 68.8, SD 6.7). Under single- and dual-task, gait speed was obtained using a computerized mat. For the dual-task there were three conditions: 1) reciting alternate letters of the alphabet (DT-alpha); 2) counting backwards in 3 s (DT-counting); and 3) recalling words from a shopping list (DT-recall). Dual-task interference in gait and cognition were calculated as: (dual task-single task)/single task×100 and summed to obtain total interference. The cognitive domains of executive function, processing speed, working memory, verbal fluency, visuospatial function and verbal memory (recall and recognition) were assessed using a battery of neuropsychological tests. Raw test scores were subjected to principal component analysis to derive a global cognition score. Partial correlations were used to determine the strength of associations between single- and dual-task measures and cognitive scores, adjusting for age, sex and education., Results: The strongest significant associations for each cognitive outcome variable were between greater total interference under DT-alpha and lower global cognition (r = 0.25), working memory (r = 0.28) and verbal memory [recognition] (r = 0.21), greater gait interference under DT-alpha and slower processing speed (r = 0.43) and single-task gait speed and verbal fluency (r = 0.23). Associations between dual-task measures and cognition were generally weaker under the DT-counting and DT-recall., Significance: Calculating total and gait interference during DT-alpha may be the most useful in order to identify adults with poorer cognition., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The apolipoprotein (APOE) ε4 allele and the Met variant of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism are associated with reduced cognitive function in older adults. The aim of this study was to examine the independent and interactional effect of the APOE ε4 allele and BDNF Val66Met polymorphism on cognitive function in a cohort of healthy older adults who had undertaken further university level education. Multiple group latent growth curve modeling revealed no change in cognitive function over time in APOE ε4-carriers or in BDNF Met-carriers, nor in carriers of both APOE-ε4 and BDNF-Met alleles. Further, the results indicate that allelic variation in either APOE or BDNF does not modify the beneficial effects of a university-based education intervention on cognitive function over a 4-year period following the intervention., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Genetic polymorphisms of apolipoprotein E (APOE) and brain-derived neurotrophic factor (BDNF) have shown inconsistent associations with healthy adult cognitive functions. Recent investigations have suggested that APOE polymorphisms do not contribute to non-pathological cognitive function and that any effect is likely due to prodromal Alzheimer's disease (AD). Similarly, although BDNF Val66Met polymorphisms affect hippocampal morphology and function, associations with learning and/or memory have not always been found. This study sought to determine whether APOE and BDNF polymorphisms were associated, either independently or in combination, with adult cognition. Comprehensive neuropsychological assessments were conducted on 433 older adults, aged 50-79 years (M=62.16, SD=6.81), which yielded measures of episodic memory, working memory, executive function, and language processing. Participants underwent comprehensive neuropsychological assessment to ensure that only cognitively intact individuals comprised the sample. APOE and BDNF polymorphic data were used as predictors in general linear models that assessed composite cognitive domain variables, while covarying for education and age. Although no main effects for APOE or BDNF were found, the analysis identified a significant APOE×BDNF interaction that predicted episodic memory performance (p=.02, η(2)=.02). Post-hoc analyses demonstrated that in BDNF Val homozygotes, the cognitive consequences of APOE polymorphisms were minimal. However, in BDNF Met carriers, the hypothesized beneficial/detrimental effects of APOE polymorphisms were found. Our data show that concurrent consideration of both APOE and BDNF polymorphisms are required in order to witness a cognitive effect in healthy older adults., (Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.)

Cognitive decline is a major factor in lowering the quality of life in older populations, and contributes substantially to social, economic, and health costs. As humans age, cognitive function decreases differentially, and individual differences in cognitive ageing are likely attributed to a range of causes, including environmental and genetic influences. The current study included 360 participants (240 females and 120 males) aged between 50 and 79years from the Tasmanian Healthy Brain Project. The brain-derived neurotrophic factor (BDNF) Val66Met and Catechol-O-Methyltransferase (COMT) Val158Met polymorphisms were examined for their association with visual and auditory episodic memory performance. The polymorphisms were also investigated for their association with reported life-long engagement in complex cognitive activity using a retrospective questionnaire. Relative to the demographic variables, the gene variations were found to have no association with episodic memory performance, with the exception of the COMT polymorphism on a single measure of auditory memory (RAVLT). Several other studies also demonstrated that these polymorphisms have no, small, or inconsistent effects on memory function. The BDNF Val66Met and COMT Val158Met polymorphisms were also found to be of little significance to active engagement in complex cognitive activity throughout most of the lifespan. An association was detected between BDNF Val66Met and engagement in cognitive activity in early life (p=.04, d=.23), however this did not reach significance when adjusted for multiple comparisons. The biological mechanisms that underlie engagement in cognitive activity are elusive, thus the potential relationship between BDNF Val66Met genotype and early life cognitive engagement warrants further investigation., (Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.)

Introduction: Neurofilament light (NfL) is a blood biomarker of neurodegeneration. While serum NfL levels have been demonstrated to increase with normal ageing, the relationship between serum NfL levels and normal age-related changes in cognitive functions is less well understood. Methods: The current study investigated whether cross-sectional serum NfL levels measured by single molecule array technology (Simoa®) mediated the effect of age on cognition, measured by a battery of neuropsychological tests administered biannually for 8 years, in a cohort of 174 unimpaired older adults (=50 years) from the Tasmanian Healthy Brain Project. Mediation analysis was conducted using latent variables representing cognitive test performance on three cognitive domains - episodic memory, executive function, and language (vocabulary, comprehension, naming). Cognitive test scores for the three domains were estimated for each participant, coincident with blood collection in 2018 using linear Bayesian hierarchical models. Results: Higher serum NfL levels were significantly positively associated with age (p < 0.001 for all domains). Cognitive test scores were significantly negatively associated with age across the domains of executive function (p < 0.001), episodic memory (p < 0.001) and language (p < 0.05). However, serum NfL levels did not significantly mediate the relationship between age and cognitive test scores across any of the domains. Discussion: This study adds to the literature on the relationship between serum NfL levels and cognition in unimpaired older adults and suggests that serum NfL is not a pre-clinical biomarker of ensuing cognitive decline in unimpaired older adults. [ABSTRACT FROM AUTHOR]

Objectives: Unequal access to cognitive assessments is a major barrier to timely diagnosis, especially for those living in rural or remote areas. 'One‐stop' cognitive clinic models are a proposed solution, but few such clinics exist. We evaluate the implementation of a new one‐stop State‐wide clinic model in Tasmania, Australia, where 27% of people live in rural/remote areas. Methods: A novel single‐visit protocol has been developed, comprising interdisciplinary medical and cognitive assessments, research participation, consensus diagnosis and management plan. A cross‐sectional evaluation was undertaken using the RE‐AIM (reach, effectiveness, adoption, implementation, maintenance) framework and results benchmarked against the national Australian Dementia Network Registry. Results: Over the first 52 consecutive weekly clinics: Reach: 130 adults were assessed (mean age [SD] 70.12 years [10.31]; 59.2% female) with 40 (36.8%) from rural/remote areas. Effectiveness: 98.5% (128/130) received a same‐day diagnosis: 30.1% (n = 40) Subjective Cognitive Decline, 35.4% (46) Mild Cognitive Impairment, 33.1% (43) dementia and one case inconclusive. Adoption: 22.9% (156) of General Practitioners referred patients. Implementation: Nearly all 'ideal' diagnostic clinical practices were met and >90% of surveyed patients reported 'good/very good' clinic experience. The wait from referral to diagnosis was 2 months shorter than other national Registry clinics (78 vs. 133 days). Conclusions: This 'one‐stop' model provides an interdisciplinary consensus cognitive diagnosis quickly and is well accepted; this may reduce health inequities especially for people living in rural/remote areas. This cognitive clinic model may be of relevance to other centres worldwide and also provides a rich data source for research studies. Key points: Access to cognitive assessments is unequal, especially for people living in rural areas.A 'one‐stop' cognitive clinic resulted in 98.5% same‐day diagnosis, 2 months earlier than the national averageOne‐third of people assessed were from rural/remote areas.This model may inform service design for centres worldwide and provides rich data for research. [ABSTRACT FROM AUTHOR]

Background: Up to 40% of incident dementia is considered attributable to behavioral and lifestyle factors. Given the current lack of medical treatments and the projected increase in dementia prevalence, a focus on prevention through risk reduction is needed. Objective: We aim to increase dementia risk knowledge and promote changes in dementia risk behaviors at individual and population levels. Methods: The Island Study Linking Aging and Neurodegenerative Disease (ISLAND) is a long-term prospective, web-based cohort study with nested interventions that will be conducted over a 10-year period. Target participants (n=10,000) reside in Tasmania and are aged 50 years or over. Survey data on knowledge, attitudes, and behaviors related to modifiable dementia risk factors will be collected annually. After each survey wave, participants will be provided with a personalized dementia risk profile containing guidelines for reducing risk across 9 behavioral and lifestyle domains and with opportunities to engage in educational and behavioral interventions targeting risk reduction. Survey data will be modeled longitudinally with intervention engagement indices, cognitive function indices, and blood-based biomarkers, to measure change in risk over time. Results: In the initial 12 months (October 2019 to October 2020), 6410 participants have provided baseline data. The study is ongoing. Conclusions: Recruitment targets are feasible and efforts are ongoing to achieve a representative sample. Findings will inform future public health dementia risk reduction initiatives by showing whether, when, and how dementia risk can be lowered through educational and behavioral interventions, delivered in an uncontrolled real-world context. [ABSTRACT FROM AUTHOR]

The calcium binding protein parvalbumin is expressed in interneurons of two main morphologies, the basket and chandelier cells, which target perisomatic domains on principal cells and are extensively interconnected in laminar networks by synapses and gap junctions. Beyond its utility as a convenient cellular marker, parvalbumin is an unambiguous identifier of the key role that these interneurons play in the fundamental functions of the cortex. They provide a temporal framework for principal cell activity by propagating gamma oscillation, providing coherence for cortical information processing and the basis for timing-dependent plasticity processes. As these parvalbumin networks mature, they are physically and functionally stabilised by axonal myelination and development of the extracellular matrix structure termed the perineuronal net. This maturation correlates with the emergence of high-speed, highly energetic activity and provides a coherent foundation for the unique ability of the cortex to cross-correlate activity across sensory modes and internal representations. [ABSTRACT FROM AUTHOR]

Introduction: Declining cognition in later life is associated with loss of independence and quality of life. This decline in cognition may potentially be reduced or reversed through engaging in cognitively stimulating activities. This study examined the potential for university attendance in later life to enhance cognitive function in older adults. Methods: Cognitively unimpaired adults (n = 485, 69% female, median age 60 years) were given the opportunity to undertake free university study. Repeated neurocognitive assessment was performed over 7 years. Results: Participants in the university education group (n = 383) improved z = .02 SD (.01, .03) per year of the study compared to controls (P = .001; averaged across a battery of cognitive tests). The largest improvements were observed on tests of language and verbal learning, memory, and episodic memory. Discussion: Later-life university study was associated with improved cognitive trajectories. Later-life education may preserve cognitive function, specifically for functions associated with communication, social interaction, and maintaining independence. [ABSTRACT FROM AUTHOR]

Cognitive reserve (CR) is a theoretical construct describing the underlying cognitive capacity of an individual that confers differential levels of resistance to, and recovery from, brain injuries of various types. To date, estimates of an individual's level of CR have been based on single proxy measures that are retrospective and static in nature. To develop a measure of dynamic change in CR across a lifetime, we previously identified a latent factor, derived from an exploratory factor analysis of a large sample of healthy older adults, as current CR (cCR). In the present study, we examined the longitudinal results of a sample of 272 older adults enrolled in the Tasmanian Healthy Brain Project. Using results from 12-month and 24-month reassessments, we examined the longitudinal validity of the cCR factor using confirmatory factor analyses. The results of these analyses indicate that the cCR factor structure is longitudinally stable. These results, in conjunction with recent results from our group demonstrating dynamic increases in cCR over time in older adults undertaking further education, lend weight to this cCR measure being a valid estimate of dynamic change in CR over time. [ABSTRACT FROM AUTHOR]

The association between level of educational attainment and cognitive performance is well studied. People with higher education perform better across a broad range of cognitive tasks. However, there is uncertainty as to whether education moderates the trajectory of age-related cognitive decline. This review paper addresses the potential link between education and age-related cognitive decline by evaluating relevant research published since 2000. Studies reporting data on education and its association with the rate of cognitive decline across various cognitive domains were reviewed. A total of 10 studies were identified with a mean follow-up period of 7.6 years; each contained a population-based, non-demented sample. In the majority of studies, results showed that education did not moderate age-associated cognitive decline. The few studies that did find an association between education and decline in specific cognitive functions should be interpreted with caution because of methodological issues. The literature reveals little consistent evidence that normal age-related cognitive decline is moderated by education attainment. This supports a passive theory of cognitive reserve: people with a higher level of education will continue to perform at a higher level of cognitive functioning than their lower educated peers, which may delay the onset of impairment in the future. [ABSTRACT FROM AUTHOR]

Background:Cognitive reserve (CR) is a protective factor that supports cognition by increasing the resilience of an individual's cognitive function to the deleterious effects of cerebral lesions. A single environmental proxy indicator is often used to estimate CR (e.g. education), possibly resulting in a loss of the accuracy and predictive power of the investigation. Furthermore, while estimates of an individual's prior CR can be made, no operational measure exists to estimate dynamic change in CR resulting from exposure to new life experiences.Methods:We aimed to develop two latent measures of CR through factor analysis: prior and current, in a sample of 467 healthy older adults.Results:The prior CR measure combined proxy measures traditionally associated with CR, while the current CR measure combined variables that had the potential to reflect dynamic change in CR due to new life experiences. Our main finding was that the analyses uncovered latent variables in hypothesized prior and current models of CR.Conclusions:The prior CR model supports multivariate estimation of pre-existing CR and may be applied to more accurately estimate CR in the absence of neuropathological data. The current CR model may be applied to evaluate and explore the potential benefits of CR-based interventions prior to dementia onset. [ABSTRACT FROM PUBLISHER]