A comparative study of Amyloid positive and negative individuals with “Alzheimer Syndrome”
Bibliographic record
Abstract
Abstract Background Outside academic centres, the diagnosis of probable Alzheimer’s Disease remains a clinical diagnosis supported by basic blood work and structural brain imaging. It has already been documented, approximately 1/3rd of individuals meeting clinical criteria for probable AD, do not show underlying amyloidopathy on PET or cerebrospinal fluid. Thus, the clinical “Alzheimer Syndrome” encompasses individuals with abnormal amyloid (Amyloid positive: A+), as well as “amyloid negative” individuals lacking amyloidopathy. Finding ways to distinguish these subgroups clinically will become increasingly important as anti‐amyloid therapies become more available. It is not yet clear if these two groups have any clinical or imaging features that might distinguish them. Our objective was to find out if there are any clinical or imaging pointers towards amyloid biomarker status. Methods A retrospective chart review of 23 patients screened for anti‐amyloid clinical trials was performed, of whom 13 were (A+) and 10 were (A‐). The following information was collected from the chart review‐ demography, medical history, clinical presentation, course of disease and rate of progression, neuropsychological test scores, blood work, brain scans, and any other relevant investigations. Relevant data were subjected to appropriate statistical analysis. Results This is an ongoing study and the results are derived from interim analysis. Comparison of the (A+) and (A‐) groups revealed no statistically significant difference in terms of age, sex, amnestic presentation and cognitive decline rate. We did not find evidence (in this small group) that (A‐) subjects had a greater vascular load ‐ no difference in Hachinski score or Fazekas score. The only statistically significant difference between the groups was found in their NPI scores, with the A+ group showing a higher score (2.92 versus 0.80, p = 0.008). Conclusion Amyloid positive individuals are more likely to have neuropsychiatric manifestations during the course of their cognitive decline than their Amyloid negative counterpart. Work is ongoing to delineate biological and biomarker differences that account for the cortical dementia (Alzheimer Syndrome) in Amyloid negative subjects. Delineating differences in clinical presentation may prove useful in specifying which of these individuals are actually Amyloid positive. Confirmation in a larger group of subjects will be necessary.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.002 | 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".