Fluorodeoxyglucose positron emission tomography in semantic dementia after 6 months of memantine: an open‐label pilot study
Bibliographic record
Abstract
OBJECTIVES: To follow up on the increases we reported in normalized metabolic activity in salience network hubs from a 2-month open-label study of memantine in frontotemporal dementia (FTD). METHODS: We repeated fluorodeoxyglucose positron emission tomography (FDG-PET) after 6 months of drug use and subjected the data to Statistical Parametrical Mapping (SPM) analysis to reveal clusters of significant change from baseline. We also sought correlations between changes in behavioral disturbances on the Frontal Behavioral Inventory (FBI) and the PET signal. RESULTS: Recruitment of one progressive nonfluent aphasia and one behavioral variant FTD precluded statistical analysis for any FTD subtype other than semantic dementia (SD). The baseline-to-6-month interval showed increased normalized metabolic activity in the left orbitofrontal cortex (p < 0.002) for five participants with SD. The 2-6-month interval revealed a late increase in normalized metabolic activity in the left insula (p < 0.013), right insula (p < 0.009), and left anterior cingulate (p < 0.005). The right anterior cingulate showed both an initial increase and a delayed further increase (2-6 months, p < 0.016). FBI scores worsened by 43.3%. One participant with SD opted not to continue memantine beyond 2 months yet showed similar FDG-PET increases. CONCLUSIONS: Increases in normalized cortical metabolic activity in salience network hubs were sustained in SD over a 6-month period. Because one participant without medication also showed these changes, further investigation is recommended through a double-blind, placebo-controlled study with FDG-PET as an outcome measure.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".