P2‐359: Hippocampal and entorhinal volumetry in amnestic mild cognitive impairment and late‐life depression
Bibliographic record
Abstract
Amnestic mild cognitive impairment (aMCI) and late-life depression (LLD) are two conditions associated with preclinical Alzheimer's disease (AD). We wished to review if a) reported volumetric reductions, when compared to controls, were similar for the hippocampus (HC) and the entorhinal cortex (ERC) in both conditions; and b) if any study had assessed these structures in aMCI subjects with concomitant depression. We searched MEDLINE and found 57 articles describing MRI studies of HC and ERC in patients with aMCI or LLD; twenty-six met our inclusion criteria, 16 on aMCI and 10 on LLD. We found that 1) total HC atrophy is reported as significant in all aMCI and LLD studies; 2) HC volume loss in LLD studies (5.5% to 13.8%) is reported similar to aMCI studies (7.1% to 19.0%); 3) total ERC atrophy is stated as significant in seven aMCI studies with volume losses ranging from 12.5% to 29.4%; 4) no LLD studies measured total or lateral ERC; 5) volume loss is reported more important in the ERC than for the HC in aMCI studies (e.g. 25.4% volume reduction for total ERC versus 15.9% for total HC in one study); and 6) no volumetric studies on aMCI subjects with concomitant depression were done. HC and ERC volumetric measurements vary considerably within and between aMCI and LLD groups (e.g. a factor of 2.3 when comparing lowest and highest total HC volume losses in aMCI). This may result from differences in terms of inclusion and exclusion criteria, demographic characteristics, but more importantly technical characteristics, especially segmentation protocols. HC volume loss in LLD studies is reported similar to the one observed in aMCI studies. No LLD studies measured the ERC. In aMCI studies, ERC volume loss appears more important that HC volume loss. The variability of measurements between aMCI and LLD studies raises the important issue of comparability. Future volumetric studies could benefit from using standardized segmentation protocols. No volumetric studies focusing on aMCI subjects with concomitant depression were found, and hence are needed in order to validate our interpretations.
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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 | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.008 | 0.009 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".