Associations between REM‐sleep EEG spectral power, the cholinergic basal forebrain volume and episodic memory in ageing
Bibliographic record
Abstract
Abstract Background Our research team has demonstrated that quantitative electroencephalography (qEEG) slowing during rapid‐eye movement (REM) sleep is a more powerful tool to discriminate patients with mild cognitive impairment (MCI) or Alzheimer Disease (AD) from healthy controls than waking EEG. Cortical activation during REM sleep highly depends on the cholinergic basal forebrain system (BFCS) neurons, while other neuronal systems are less active compared to wakefulness. However, the BFCS degenerates early in AD. Here, we tested the hypothesis that REM sleep EEG activity could be strongly associated with neurodegeneration of the BFCS, before the onset of dementia. Method 134 participants (mean age 68.45 ± 7.8 years; 52 women; 61 with MCI) underwent a polysomnography, structural magnetic resonance imaging, and a neuropsychological evaluation. T1‐weighted images were preprocessed using CAT12 and the DARTEL algorithm, and the JuBrain Anatomy Toolbox was used to extract bilateral BFCS volumes (i.e., Ch1‐2‐3, Ch4 and total volume). Based on prior evidence, theta (4‐8Hz) and alpha (8‐13Hz) absolute EEG power during REM sleep were computed on temporal electrodes (T3‐T4‐T5‐T6). A composite episodic memory score was calculated as the mean of Z‐scores obtained on the Rey Auditory Verbal Learning Test immediate and delayed free recalls. Multiple regressions were performed between (i) spectral power values or (ii) episodic memory performance, and basal forebrain volumes controlling for age, sex, the apnea‐hypopnea index, and the total intracranial volume. Complementary analyses were performed by stratifying the cohort by sex. Result Both Ch4 (r=0.24, p=0.006) and total BFCS (r=0.25, p=0.005) volumes were positively associated with episodic memory performance. Ch4 (r=‐0.21; p=0.025) and total BFCS (r=‐0.22; p=0.02) volumes were negatively associated with temporal theta power. Moreover, total BFCS (r=‐0.22; p=0.023) volumes were negatively associated with temporal alpha power. Sex‐stratified analyses revealed that the associations between BFCS volumes, REM‐sleep spectral power and episodic memory were significant in women, but not in men. Conclusion These results confirmed that cortical activation during REM sleep is sensitive to volume loss in the BFCS, a cholinergic region known to degenerate early in AD. Why this association was only observed in women is intriguing and will need further investigation.
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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".