Anterior-medial thalamic lesions in dementia: frequent, and volume dependently associated with sudden cognitive decline
Bibliographic record
Abstract
BACKGROUND: The anterior-medial thalamus (AMT), which is associated with memory processing, is severely affected by Alzheimer's disease pathology and, when damaged, can be the sole cause of dementia. OBJECTIVE: To assess the frequency of magnetic resonance imaging (MRI) hyperintensities affecting the AMT, and their relationship with sudden cognitive decline. METHODS: 205 consecutive participants from a university cognitive neurology clinic underwent clinical evaluation, neuropsychological testing and quantitative MRI. RESULTS: AMT hyperintensities >5 mm3 occurred in 0 of 34 normal controls but were found in 5 of 30 (17%) participants with cognitive impairment with no dementia (CIND), 9 of 109 (8%) patients with probable Alzheimer's disease, 7 of 17 (41%) with mixed disease and 8 of 15 (53%) with probable vascular dementia (VaD). AMT hyperintensities occurred more often in participants with stepwise decline than in those with slow progression (chi2 = 31.7; p<0.001). Of the 29 people with AMT hyperintensities, those with slow progression had smaller medial temporal width (p<0.001) and smaller anterior-medial thalamic hyperintensities (p<0.001). In a logistic regression model, both variables were significant, and the pattern of decline was correctly classified in 86% of the sample (Cox and Snell R2 = 0.56; p<0.001). Those with AMT hyperintensities >55 mm3 were likely to have stepwise decline in cognitive function regardless of medial temporal lobe width; in contrast, those with smaller AMT hyperintensities showed a stepwise decline only in the absence of medial temporal lobe atrophy. All patients with VaD had left-sided AMT hyperintensities, whereas those with CIND had right-sided AMT hyperintensities. CONCLUSIONS: AMT hyperintensities >55 mm3 probably result in symptomatic decline, whereas smaller lesions may go unrecognised by clinicians and radiologists. Only half of those with AMT hyperintensities had diagnoses of VaD or mixed disease; the other AMT hyperintensities occurred in patients diagnosed with Alzheimer's disease or CIND. These silent hyperintensities may nevertheless contribute to cognitive dysfunction. AMT hyperintensities may represent a major and under-recognised contributor to cognitive impairment.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".