Independent Cognitive Effects of Atrophy and Diffuse Subcortical and Thalamico-Cortical Cerebrovascular Disease in Dementia
Bibliographic record
Abstract
BACKGROUND AND PURPOSE: Brain atrophy, cortical infarction, and subcortical ischemic vasculopathy have all been associated with cognitive dysfunction. The interrelationships between these pathologies and their independent contributions to cognitive function remain unclear. Despite the high frequency of Alzheimer disease (AD) in those with clinically diagnosed vascular dementia, and the frequent findings of vascular disease in those with clinically diagnosed AD, many studies of brain-behavior relationships in dementia consider these populations separately. The present study sought to identify the correlates of independent domains of cognitive impairment in an unselected sample across a large range of severity and overlap of AD and VaD. METHODS: Two hundred five individuals from the Sunnybrook Dementia Study recruited from a university Memory clinic had detailed neuropsychological testing and MRI quantification using a multi-step postprocessing algorithm. A factor analysis of the cognitive protocol yielded a 3-factor solution, provisionally labeled: (1) short-term memory and language, (2) attention and working memory, and (3) mental flexibility. RESULTS: A factor analysis of brain measures identified 3 independent factors with measures of (1) brain atrophy, (2) subcortical vascular disease, and (3) strategic infarcts (anterior-medial thalamus and cortical infarcts). After accounting for the effects of age and education, measures of brain atrophy were the strongest correlates of all cognitive domains. Small vessel disease was independently associated with general severity, impaired short-term memory/language, and reduced mental flexibility, but not with poor working memory, presumably through disruption of frontal-subcortical connections. In contrast, strategic infarcts to anterior-medial thalamus and cortical gray matter were associated with poor short-term and working memory, but not with impairments in mental flexibility or global severity measures. CONCLUSIONS: These data support the hypothesis that the thalamico-cortical network subserves both short-term and working memory. The findings also suggest that each type of pathology (atrophy, small vessel disease, and strategic infarcts) contribute independently to the pattern of cognitive disabilities associated with dementia. Particular attention to cerebrovascular disease in deep white or gray matter structures of the thalamico-cortical system is certainly warranted.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".