Resting state EEG Theta rhythms in healthy aging and Alzheimer's disease
Bibliographic record
Abstract
BACKGROUND: Healthy aging and cognitive decline in Alzheimer's Disease (AD) and its precursor, Mild Cognitive Impairment (MCI), are linked to changes in resting-state EEG power spectral density (PSD). Theta band (3-7 Hz) power decreases with normal aging but increases with cognitive decline. However, frequency content does not always indicate true oscillatory activity. Oscillations reflect power concentration at a specific frequency, appearing as peaks in the frequency domain and visible rhythms in the time domain. Rhythmicity analysis quantifies oscillation persistence (percentage of time observed) independently of power. This study examined Theta power and Theta rhythms in healthy controls (HC) versus individuals with MCI/AD. METHOD: Participants included 32 AD, 88 MCI, and 115 and age- matched HC, who completed 5-minutes of resting-state eyes-closed EEG at their baseline visit. PSD was computed for one-second epochs. Relative Theta power was defined as the proportion of total power in the Theta band, averaging across epochs. Theta rhythm duration was defined as the percentage of epochs with Theta oscillations. Baseline differences and longitudinal changes were analyzed for a subset of participants: 28 MCI and 5 AD with at least one follow-up visit, and 25 HC with at least two follow-ups. RESULT: At baseline, the MCI/AD group exhibited significantly higher relative Theta power (p <0.01, df=233, ES=0.35 at T6) and a greater Theta rhythm duration (p <0.01, df=231, ES=0.41 at T6) compared to HC. Longitudinally, HC exhibited a significant reduction in Theta power by the second follow-up (p <0.05, df=24, ES=0.51 at Cz), with no significant changes in Theta rhythms duration. In contrast, MCI/AD showed a significant increase in Theta rhythm duration (and not power) at first follow-up visit (p < 0.05, df =32, ES=0.30 at T3). CONCLUSION: Theta power and Theta rhythm duration are both linked to cognitive decline in MCI and AD but differ from healthy aging patterns. While Theta power reflects age-related changes, Theta rhythms duration may serve as a specific biomarker for disease progression in MCI and AD. These findings support the value of Rhythmicity analysis in EEG-based biomarkers of cognitive decline.
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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 | 0.000 | 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".