Neuropsychological Profiles and Trajectories in Preclinical Alzheimer’s Disease
Bibliographic record
Abstract
OBJECTIVES: The present study investigated the independent and synergistic effects of amyloid beta (Aβ1-42) and phosphorylated tau (Ptau) pathologies on neuropsychological profiles and trajectories in cognitively normal older adults. METHODS: Alzheimer's Disease Neuroimaging Initiative participants identified as cognitively normal at baseline underwent longitudinal assessment (N=518; 0, 12, 24, 36 months), baseline lumbar puncture and follow-up cognitive exams. Cerebral spinal fluid (CSF) biomarker profiles (Aβ-Ptau-, Aβ+Ptau-, Aβ-Ptau+, Aβ+Ptau+) were compared on baseline profiles and trajectories for memory (Rey Auditory Verbal Learning Test), attention/executive function (Trail Making Test, A and B), language (Animal Fluency, Vegetable Fluency, Boston Naming Test) and processing speed (Digit Symbol) using multilevel models. RESULTS: The Aβ+Ptau+ group exhibited significantly worse baseline performance on tests of memory and executive function relative to the Aβ-Ptau+ and Aβ-Ptau- groups. The Aβ+Ptau- group fell between the Aβ+Ptau+ participants and the Aβ-Ptau- and Aβ-Ptau+ groups on all three cognitive domains and exhibited worse baseline executive function. The Aβ-Ptau+ group performed worse than Aβ-Ptau- participants on processing speed. Over 36-month follow-up, the Aβ+Ptau+ group exhibited the greatest declines in memory and semantic fluency compared to all other groups. CONCLUSIONS: Cognitively normal older adults with both Aβ and Ptau pathology exhibited the weakest profile, marked by the worst memory decline compared to the other groups. Other subtle changes in this group included declines in executive function and semantic fluency. Those with Ptau pathology alone showed slowed processing speed, and those with Aβ pathology alone showed worse attention and executive function compared to biomarker negative participants. (JINS, 2018, 24, 693-702).
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".