White matter microstructural decline and cognitive performance in older adults: the influence of cardiovascualr health
Bibliographic record
Abstract
Age-related cognitive decline is well documented, especially in memory, speed of processing and executive functions. Structural brain changes are also well documented but often do not directly map onto the mild cognitive decline seen in otherwise healthy older adults. Recent work has focused on whether cognitive ageing is associated with decline in the strength of structural connectivity between neural regions, using diffusion magnetic resonance imaging (dMRI). Reduced integrity of white matter microstructure across the whole brain and in regions of interest, as measured by fractional anisotropy (FA), has been shown to be associated with cognitive decline in older adults who show no signs of dementia. This thesis uses dMRI tractography to examine the association between multiple measures of white matter microstructure across the whole brain and in 18 major white matter tracts and cognitive performance on a range of tasks that vary in process specificity. Seventy non-demented older adults (aged 43-87y) with varying degree of white matter disease completed a comprehensive cognitive and imaging assessment. Cognitive functioning was assessed at three levels: Firstly, global cognitive functioning was assessed using the Montreal Cognitive Assessment (MoCA). Then through the use of standardised neuropsychological tests, more specific cognitive domains of working memory, episodic memory, executive function and processing speed were assessed. An experimental task switching paradigm was then used to assess more specific components of executive function relating to proactive and reactive control processes. These showed that ability to detect the impact of tract-specific changes in white matter microstructure on cognitive performance was dependent on the specificity of the cognitive test. Although, irrespective of the level of cognitive assessment, the relationship between decline in white matter microstructural integrity and cognitive performance was specific only to participants with poor cardiovascular health. These findings suggest that cognitive and brain ageing profiles in older adults vary as a function of cardiovascular health and have strong implications for theories of cognitive ageing. They also emphasise the importance of cardiovascular health in prevention or delay in onset of cognitive decline in old age.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".