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Beyond reduced alpha power: a weaker temporal link between alpha and other brain rhythms in Alzheimer’s disease
Wei J, Zhou C.. medRxiv, 2026-10-26
Topic: Brain imaging, connectivity and assessment
Background Reduced alpha power is among the most consistently reported resting electroencephalography (EEG) features of Alzheimer’s disease (AD). However, alpha activity also interacts with other rhythms over time, a dynamic aspect that power measures do not capture. Whether AD weakens this temporal interaction, and whether such a change carries information beyond reduced alpha power, remains unclear. Methods We analyzed public eyes-closed resting EEG from 29 healthy controls (HC), 36 patients with AD and 23 with frontotemporal dementia (FTD). After separating periodic from aperiodic activity, we tracked the aperiodic exponent and periodic theta, alpha, beta and gamma activity in consecutive 1-s windows. A vector autoregressive model predicted these five measures from the preceding window. Alpha’s predictive contribution ( G α ) was the increase in prediction error for theta, beta and gamma when the model was refitted without alpha as a predictor, with training and testing on separate time blocks of each recording. AD–HC differences were adjusted for age and sex, then for alpha expression (periodic alpha power) and signal quality (dynamic range and spatial reliability), with alpha self-persistence (alpha’s carry-over between windows) as a benchmark. We also tested whether expression and G α each added information about AD beyond the other. An exploratory Jansen–Rit-family circuit model examined whether expression and G α can change partly independently. Results G α was lower in AD than in HC (adjusted difference in 10³ G α , −3.19; 95% confidence interval −5.25 to −1.13; p = 0.0035), with a consistent direction across sensitivity analyses. Adjustment for alpha expression and signal quality retained 75.8% of this difference but only 4.4% of the self-persistence difference. Expression and G α each added information beyond the other (Holm-adjusted p = 0.012 for both). FTD contrasts were inconclusive. In the circuit model, reducing local recurrent excitation lowered alpha expression without an estimated decrease in G α , whereas reducing downstream input lowered G α with a smaller change in expression. Conclusions At the group level, the resting alpha abnormality in AD comprises two partly nonredundant dimensions: reduced expression and a weaker temporal link between alpha and subsequent multi-rhythm activity. Quantifying this temporal link may complement conventional spectral markers of AD.
Key findings
- Results G α was lower in AD than in HC (adjusted difference in 10³ G α , −3.19; 95% confidence interval −5.25 to −1.13; p = 0.0035), with a consistent direction across sensitivity analyses.
Study details
- Participants36
- Effect size75.8%; 4.4%
- Evidence strengthLow
How this study scored 16/100
Preprint — not yet peer-reviewed. It scored 31 on the same rubric, but non-peer-reviewed sources are capped at 16, so it shows as 16. Scored zero for study design and randomised / blinded because the record does not state it. We have no data on times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 19 of the 62 points we could judge it on, which is 31 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 2 / 10 | Tier 4 — not a peer-reviewed journal (medRxiv) |
| Journal's citation record | 0 / 4 | Not a journal article, so the journal's record does not count |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 4 / 10 | Preprint — not yet peer-reviewed. Hosted on a preprint server. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 1 / 4 | 36 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 1 / 2 | Not in PubMed, but has a DOI |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 19 / 62 | Scored on 12 of 20 parts. We have no data for the rest, so they are left out: 19 of the 62 points we could judge it on is 31 out of 100. |
| Total | 31 / 100 | Capped to 16 because this is not a peer-reviewed article. |
What each of these 20 components measures, and what this score is not →
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APA 7th
Wei, J., & Zhou, C. (2026). Beyond reduced alpha power: a weaker temporal link between alpha and other brain rhythms in Alzheimer’s disease. medRxiv. https://doi.org/10.64898/2026.10.23.26366296
Vancouver
Wei J, Zhou C. Beyond reduced alpha power: a weaker temporal link between alpha and other brain rhythms in Alzheimer’s disease. medRxiv. 2026. doi:10.64898/2026.10.23.26366296.
BibTeX
@article{wei2026-e81ed845,
author = {Wei, J. and Zhou, C.},
title = {{Beyond reduced alpha power: a weaker temporal link between alpha and other brain rhythms in Alzheimer’s disease}},
journal = {medRxiv},
year = {2026},
doi = {10.64898/2026.10.23.26366296},
url = {https://doi.org/10.64898/2026.10.23.26366296}
}