P2–324: Greater frontal than cingulate magnetic resonance spectroscopy abnormalities in early Alzheimer's disease
Bibliographic record
Abstract
Recently there has been a great emphasis put on finding early imaging markers for Alzheimer's Disease (AD). In previous imaging studies, abnormal magnetic resonance spectroscopic signals have been found to be limited to the posterior cingulate regions (Kantarci et al, 2000). These studies did not examine other cortical areas. In early AD, executive function has been shown to be deteriorated when compared to normal age matched subjects. We hypothesized that frontal metabolic abnormalities demonstrated by magnetic resonance spectroscopy (MRS) might actually exceed those demonstrated for posterior cingulated cortex. MRS was performed in the left Brodman area (Ba) 44 (inferior frontal gyrus), left Ba 37 (posterior temporal), and left precuneus (this included the mid posterior cingulate gyrus and precuneus areas) in 10 normal elderly controls (NEC) (mean age = 77.9, 4M : 6F, mean MMSE = 27.56) and 6 mild AD patients (mean age = 81.5, 5M : 1F, mean MMSE = 24.00). The N–acetylaspartate and N–acetylaspartylglutamate (NAA+NAAG) / Creatine (Cr) ratios were calculated for these three areas. There was no significant difference found in the Ba 37 region between normal and AD subjects. The precuneus area had minimal significance (p<0.061). The Ba 44 region showed the most significant (p<0.01) difference between AD patients and NEC subjects. MRS performed in the frontal area might demonstrate earlier changes in mild AD patients and may prove to be useful in prognostication. Frontal cortex MRS should be assessed in a pre–dementia state such as Mild Cognitive Impairment (MCI).
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".