Cognition

Specific cognitive functions are associated with grip strength, a reliable marker of biological vitality. This paper explored cognitive dispersion, i.e. a dispersion score derived from multiple cognitive tests, and its relationship to grip strength. A relationship between wider cognitive dispersion scores and weaker grip strength was noted in men but not women. The results provide evidence of a sex-specific biological vitality association with cognitive dispersion and grip strength. These findings highlight the importance of gender in health promotion and intervention research.

This paper examined the cognitive trajectories of 1,662 older adults by grouping individuals based on their cognitive profiles using a latent variable approach.  Baseline cognitive classes of older adults were associated with distinct longitudinal trajectories of cognitive decline that did not converge during an average of 8 years of follow-up. Identifying subgroups with different trajectories of cognitive decline are crucial for isolating the biologic mechanisms which underlie these groupings. This type of approach offers the potential of identifying more homogeneous groups of older adults with similar initial cognitive profiles and patterns of cognitive decline.

Functional brain connectivity of the resting-state networks has gained recent attention as a possible biomarker of Alzheimer’s Disease (AD). This paper reviews the literature of functional connectivity differences in young adults and middle-aged cognitively intact individuals with non-modifiable risk factors of AD (n = 17). The evidence from the literature indicated early vulnerability of functional connectivity across different at-risk groups. The authors conclude that while resting-state functional connectivity markers have great potential to identify at-risk individuals, implementing more data-driven approaches, further longitudinal and crossvalidation studies, and the analysis of greater sample sizes are likely to be necessary to fully establish the effectivity and utility of resting-state network-based analyses.​​

This is the protocol for the EDP hosted CHARIOT PRO Substudy. The rationale, methods, ethics and analyses are described.

With the likely rise of remote research following the COVID-19 pandemic, an increasing number of researchers may opt to conduct telephone or videoconference mediated cognitive assessment. This review examines the current evidence for how reliable these cognitive tests are when completed remotely versus when completed in person, in neurologically healthy individuals and those with MCI or dementia. This work will offer guidance for future remote research design.

There is evidence of vascular dysregulation in preclinical Alzheimer’s disease. This study used MRI data from the APOE-E4 carriers from the PREVENT study providing further evidence of cerebral differences (i.e. blood flow and cerebrovascular resistance index) compared to non-APOE-E4 carriers, in midlife healthy individuals. 

There is a growing consensus that patient reported outcomes should be used in Alzheimer’s disease trials so that the patient can assess if they observe a meaningful change to them. The study wanted to identify what themes and topics are relevant to the patient, particularly focused on pre-dementia stages. They collected free-text responses from 5808 people and used natural language processing techniques to group the responses. The paper describes the key themes identified and analysed according to demographics.  The aim is to develop an app with robust psychometric properties to be used as a patient reported outcome measure in clinical trials.

Imaging data from the PREVENT study is correlated with Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) scores providing evidence of reduced brain volumes in middle-aged healthy participants who have a greater risk of dementia. These findings highlight the possibility and significance of early Alzheimer’s disease intervention through modifiable midlife vascular risk factors.

Cognitive lapses (we’re all guilty right!) are common in cognitive disorders, but what about the general healthy population? The answer will be useful when determining what is normal when evaluating patients attending memory diagnostic services. McWhirter and her University of Edinburgh Medical Students found that around a quarter of middle-aged healthy adults reported having fair to poor memory, and, surprisingly, that 89% met criteria on the Functional Memory Disorder inventory. The data suggest the self-reported memory lapses are, alone, not a good indicator of abnormal memory functioning.

This study explored the reasons behind the transition experienced by older persons who can often move between Mild Cognitive Impairment (MCI) and normal cognitive functioning. Findings indicated that membership of these transition groups was affected by age, cardiovascular disease, and number of depressive symptoms.  Findings that higher baseline depressive symptoms increase the likelihood of reverting from MCI to healthy cognition indicate that there may be an important role for the treatment of depression for those with MCI.

Mak and colleagues investigate “estimated years to onset of dementia” (EYO) as a marker of preclinical disease progression and its associations with neuroimaging biomarkers in the PREVENT cohort. Amongst cognitively normal midlife adults with a family history of dementia, a shorter hypothetical proximity to dementia onset may be associated with incipient brain abnormalities, characterised by white matter disruptions and perfusion abnormalities, particularly amongst APOE-ε4 carriers. The findings also confer biological validity to the construct of EYO as a potential stage marker of preclinical progression in the context of sporadic dementia. ​​​​​

Prevalence of anxiety disorders remains high in older populations; however, little is known about their association with hippocampal changes in this age group. A diagnosis of generalized anxiety disorder was positively associated with larger hippocampal volume. No other anxiety disorder was significantly associated with hippocampal volume.

There is substantial experimental evidence for dysregulation of several microRNA (miRNA) expression levels in Alzheimer’s disease (AD). The authors identified a set of brain-enriched miRNAs in a monocentric cohort of cognitively normal individuals with subjective memory complaints, a condition associated with increased risk of AD. They then investigated the association of clinical markers on miRNA plasma concentrations. In addition, they explored the cross-sectional and longitudinal association of the miRNAs plasma concentrations with regional brain metabolic uptake using PET imaging. The results, coupled with existing experimental evidence, suggest a potential protective anti-Aβ effect of miRNA-15b and a biological link between miRNA-125b and Aβ-independent neurotoxic pathways.

Multiple chronic health conditions commonly coexist simultaneously, this is referred to as multimorbidity. Cases of multimorbidity have been increasing in recent years, partially due to an ageing population. In light of this, research has begun to focus on ways of better understanding multimorbidity. Measuring multimorbidity is tricky, as a simple count of the number of conditions proves to be too simplistic and does not account for factors such as the severity of the conditions. Accordingly, some measurement indices combine a count of chronic conditions with more informative information.

This systematic review identified multimorbidity indices which include more than a simple disease count, with a particular focus on those which included information on mental health. After reviewing more than 5000 research papers, 35 measures were identified which fit the description. Each of these measurement indices measure multimorbidity in slightly different, but equally valid ways. This review’s outcomes provide valuable information for clinicians and researchers who require an effective measure of multimorbidity.