Neuronal viability/astrocyte activity ratio in the dorsolateral prefrontal cortex as a biomarker of Alzheimer’s dementia: A proton magnetic resonance spectroscopy study
Bibliographic record
Abstract
Abstract Background N‐acetyl‐aspartate (NAA) and myo‐inositol (mI) are neurometabolites reflecting neuronal viability and astrocyte activity, respectively. These can be quantified in vivo using proton magnetic resonance spectroscopy (1H‐MRS). Previous studies have suggested that these metabolites could serve as biomarkers for Alzheimer’s disease dementia (AD). NAA and mI levels were compared in the dorsolateral prefrontal cortex (DLPFC) between AD and cognitively healthy control participants to assess for significant differences, assess if NAA/mI ratio can distinguish the two groups, and to explore the relationship between metabolites and cognition. Method Participants with AD and HCs over 55 years old were included. Bilateral NAA and mI levels were quantified in the DLPFC using 3T proton magnetic resonance spectroscopy (point‐resolved spectroscopy, echo time=35ms). NAA and mI levels were estimated using LCmodel version 6.3 and reported in H2O ratios i.e. NAA/ H2O or mI/H2O. Result The study included 64 participants, 41 with AD (mean (SD) age = 75.2 (7.2) years, females = 58.5%), and 23 HC (age = 72.2 (7.7) years, females = 60.1%). Bilateral NAA levels in the DLPFC were lower in AD vs. HC, (t(62)=‐2.5, p =0.02); however, mI levels in the DLPFC did not differ between the two groups t(62)=1.0, p=0.35. NAA/mI ratio was lower in AD vs. healthy (t(62)= ‐2.368, p =0.02). The NAA/mI ratio at a cut off value of 1.69 showed 59% sensitivity and 87% specificity at distinguishing AD from HC. NAA levels were associated positively with global cognition. Conclusion DLPFC NAA is decreased in AD and is associated with cognition. NAA/mI ratio shows good specificity in distinguishing AD from the control group, suggesting its role in complementing other biomarkers in ascertaining AD. Future studies should prospectively evaluate the clinical utility of NAA/mI ratio as a biomarker in AD.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".