Measuring olfactory‐related brain region volume loss in MCI and AD using structural MRI
Bibliographic record
Abstract
Abstract Background Alzheimer disease (AD) is a chronic disorder that affects millions of individuals worldwide. Olfactory dysfunction is a common symptom of several neurological disorders including AD. Olfactory dysfunction can be an early alteration heralding the presence of AD. Studying the pattern of alterations in olfaction‐related brain regions might help detection of neurodegenerative diseases at an earlier stage. Objectives of this study are to assess the volume of olfactory areas associated with odour processing in healthy elderly, MCI and AD populations using structural MRI scans. To test whether there are any differences in the volume of olfactory related regions between patients and healthy controls. To determine whether there is an effect of sex on olfactory‐related brain regions’ volume loss. Method Neurologically healthy participants aged 66‐85 (n = 95), MCI aged 58‐86 (n = 81) and mild probable AD aged 55‐88 (n = 37) participants were recruited. T1‐ weighted MRI scans acquired at 1.5T were processed using SPM12. Smoothed images were used to extract the volume of olfactory cortex, hippocampus, parahippocampus, amygdala, orbitofrontal cortex and entorhinal cortex. Result One‐way ANOVA analyses showed a significant reduction in all olfaction‐related brain regions (p≤0.0001). Post‐hoc multiple comparison tests showed a significant reduction in volume in the AD group in all olfaction‐related brain regions. In the MCI group, a significantly smaller volume than the healthy controls was found in four of the selected olfactory‐related brain regions (namely, hippocampus, parahippocampus, amygdala and entorhinal cortex) for the total and left volume in the female group only. Additionally in the female MCI, the volume of the right entorhinal cortex however, was also significantly smaller than that of the control group. When adjusting for MMSE, however, between group differences in all olfaction‐related brain regions were no longer significant. Conclusion These preliminary data show a significant reduction in grey matter volume in all olfaction‐related brain regions. Grey matter volume loss in these regions appears to be a good proxy of disease severity.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".