A study of alpha desynchronization, heart rate, and MRI during stroop testing unmasks pre‐symptomatic Alzheimer’s disease
Bibliographic record
Abstract
Abstract Background Alzheimer’s disease (AD) studies suggested the need to detect pre‐symptomatic stage, when cognitive challenges reveal changes of alpha power (brain hyperactivity). Heart rate (HR) regulates brain oxygen supply, is regulated by the brain (eg. hippocampus and amygdala), and correlated with resting state alpha power. We aimed to compare alpha power, HR, and hippocampal and amygdala volume between pre‐symptomatic AD and normal, aging individuals. Method We employed quantitative electroencephalography (qEEG) to monitor brain activity during resting and during Stroop interference testing. Cognitively healthy (CH) study participants (demographically matched) were recruited from the local community, consisting of two subgroups based on cerebrospinal fluid (CSF) proteins: with normal amyloid/tau ratio (CH‐NAT, n=20) or pathological amyloid/tau ratio (CH‐PAT, equals pre‐symptomatic AD, n=21). Cognition was assessed using Montreal Cognitive Assessment (MoCA) and Mini‐Mental State Examination‐7 (MMSE‐7). Participants were presented a series of colored words and asked to respond to each word for the color of the ink, including low load (congruent trials, when color matches the word) and high load (incongruent trials, when color does not match the word). Comparisons between two groups include: alpha desynchronization and alpha spectral entropy (SE), as well as the relationships of alpha desynchronization, HR after Stroop testing, and hippocampal and amygdala volumes (1.5T MRI, demographically balanced subgroups). Result No alpha differences were found during the resting state. Occipital alpha desynchronization of CH‐PATs was more negative than in that of CH‐NATs (p=0.024) during the congruent trials (Figure 1), indicating hyperactivity during low load. CH‐PATs had higher alpha SE during congruent trials (p=0.042 frontal, p=0.039 occipital), and lower frontal SE change from congruent to incongruent trials (p=0.012) (Figure 2), supporting reduced functional reserve. Alpha desynchronization positively correlated with HR in CH‐PATs but not CH‐NATs; alpha desynchronization correlated with hippocampal or amygdala differently between CH‐NATs and CH‐PATs (Figure 4). Multiple spectral frequencies revealed correlations in MMSE‐7 & MoCA that differed between CH‐NATs and CH‐PATs. Conclusion These results suggest that hyper‐excitability during low load challenge and limited brain reserve is manifest with increasing interference load in pre‐symptomatic AD. We also find brain‐heart coupling is altered in pre‐symptomatic AD.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".