P4‐330: Association of brain amyloidosis and metabolism with the Trail Making Test in MCI and Alzheimer's disease
Bibliographic record
Abstract
Alzheimer's disease is a process characterized by cognitive decline secondary to progressive amyloidosis and neurodegeneration. Making Test B-A latency (TMTB-AL) is a method to measure executive dysfunction in individuals with presymptomatic dementia. Aims: To investigate the association between TMTB-AL and regional patterns of amyloidosis ([18 F]AV45 retention) and synaptic dysfunction ([18 F]FDG uptake) in individuals with early mild cognitive impairment (EMCI), late mild cognitive impairment (LMCI) and Alzheimer's dementia (AD). We analyzed a subsample of participants from ADNIGO and ADNI2, with clinical, neuropsychological, [18F]AV45, [18F]FDG data collected in the same study visit. Diagnosis of cognitively normal (CN), EMCI, LMCI and AD was adjusted to study visit according to ADNI2 guidelines. PET scans were registered to the MRI. PET uptake ratios (UR) were calculated by dividing [18F]AV45 and [18F]FDG scans by the median counts of cerebellar GM and pons, respectively. PET images were registered to the MNI space using the previously defined non-linear transformations. Voxel-based (age-corrected) regression between PET images and TMTB-A delayed recall were calculated with PET-UR resampled and blurred with a 6mm Gaussian filter. Demographic and PET data is summarized in Table 1. Positive correlation was found between global [18 F]AV45 and TMPB-A across all groups (p< 0.0001, r= 0.243). Global [18 F]FDG-UR and TMPB-A was negatively correlated in all subjects (p < 0.0001, r= 0.268). Across the entire population, voxel-based analysis showed cortical [18 F]AV45 were associated with TMPB-A, while correlations with [18 F]FDG-UR were found in dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), inferior parietal cortex (IPC), and posterior cingulated cortex (PCC). Association between TMPB-AL and [18 F]AV45 was observed in the left DLPFC and precuneus, in EMCI and LMCI, respectively. Areas associated with [18 F]FDG-UR and TMPB-A in EMCI and LMCI were found in IPC and DLPFC, while PCC was also present in AD. In EMCI and LMCI, decline in TMPB-AL is linked to the synaptic degeneration of IPC-DLPFC circuits underlying executive function whereas in demented individuals the PCC synaptic degeneration also significantly contribute to executive deficits. Decline in TMPB-AL is not associated to a specific regional pattern of amyloid deposition. In figure it is shown Aβ (1–42) where Aβ (13–23) is illustrated in silver.
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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 | 0.002 |
| 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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".