Neural and behavioral substrates of disorientation in mild cognitive impairment and Alzheimer's disease
Bibliographic record
Abstract
BACKGROUND: The neural and cognitive substrates of measures of orientation as used in clinical trials and examinations have not been comprehensively examined. METHODS: We studied 473 subjects diagnosed with mild cognitive impairment (MCI) and Alzheimer's disease (AD) at baseline in Alzheimer's Disease Neuroimaging Initiative. Regression analyses at baseline were conducted to find significant predictors of orientation score among cognitive, brain morphometry, and glucose metabolism measures. Mixed model longitudinal analysis was performed to examine consequences of orientation on functional decline, and Cox hazard models examined the risk of conversion to AD in the MCI group. RESULTS: In MCI and AD subjects, orientation was predicted by poorer neurocognitive performance on immediate and delayed episodic memory and attention and processing speed. Among magnetic resonance imaging measures, orientation was predicted by entorhinal cortex thickness, hippocampal volume, and inferior temporal cortex thickness. Glucose metabolism in both middle-inferior temporal cortex and hippocampus were also predictive of orientation score. Functioning was significantly lower in disoriented subjects after 4 years of follow-up, and MCI patients who also were disoriented showed a higher rate of conversion to AD with a hazard ratio of 1.5. CONCLUSIONS: Orientation is associated with medial temporal lobe structure, temporal lobe glucose metabolism, and episodic memory function. In MCI individuals orientation was a risk factor for progression to AD, also associated with rapid functional decline and worse prognosis. Thus, orientation may serve as a surrogate for episodic memory in clinical examination. These results have direct implications for the use of orientation in MCI and AD clinical trials including ceiling effects in healthy controls and issues of redundancy with measures of memory, when both are used in composite scores.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".