[P1–359]: ASSESSING INTERACTIVE EFFECTS OF ALZHEIMER's DEMENTIA SEVERITY AND PARKINSONISM ON STRIATAL MORPHOMETRY
Bibliographic record
Abstract
Alzheimer's and Parkinson's diseases (AD/PD) are the two most prevalent neurodegenerative disorders. Having distinct primary etiologies, the two conditions nonetheless share a number of co-morbidities. Concomitant with AD, Lewy Body Dementia (DLB) shares the major symptoms of classic AD, with markedly different patterns of neurofibrillary tangles (NFT). About one third of AD patients present parkinsonian symptoms. As well, patients with confirmed PD frequently develop Parkinson's Disease Dementia (PDD), believed to be caused by Lewy Body pathology in the limbic regions. This suggest the possibility of interaction between NFTs and Lewy Body pathology. We assess interaction effects on subcortical morphometry between dementia and Parkinsonism as a proxy to primary etiology. We used 198 (104M/94F) control and 140 (71M/69F) AD patients from the ADNI dataset; 166 (108M/58F) controls and 357 (227M/130F) PD patients from the PPMI dataset. T1 weighted MRI scans were processed with the ENIGMA-Shape package. The shape of 7 bilateral subcortical regions was described vertex-wise with 2 measures: thickness, and surface dilation [2]. Parkinsonism effect (UPDRS scale), and its interaction with Montreal Cognitive Assessment (MoCA) were assessed in the PPMI dataset. We then assessed AD-control group differences in ADNI. We controlled for intracranial volume, age, and sex in both cases, and clinical scores in the interaction test. False discovery rate was used to correct for multiple comparisons (alpha=0.05). Assessing the concordance of the interaction effects with Alzheimer's dementia, we sampled spatial correlations of the significant effect maps over an empirical spatial map distribution, obtaining a concordance value (between -1 and 1), and a non-parametric p-value. Shape of all 7 subcortical regions differed significantly between AD and control subjects. The left caudate head, thalamus, pallidum, nucleus accumbens expanded significantly with higher UPDRS. Dementia and Parkinsonism had a significant multiplicative effect on left caudate and left putamen, over and above additive effects (see figures for all FDR critical p-values). AD and symptom interaction maps had a significant concordance (p=0.0019, C=0.078).
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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 | 0.007 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.003 |
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".