Flanigan, M J, Morehouse, R L, Shapiro, C M · Sleep · 1995
Many ME/CFS patients have been reported to show a particular brain wave pattern called 'alpha intrusion' during sleep, which may contribute to poor sleep quality. This study examined whether the way researchers measure brain waves during sleep affects whether they can detect this pattern. The researchers found that the type of electrode placement and reference point used significantly influenced whether alpha waves were observed, suggesting that previous findings about alpha intrusion in ME/CFS patients may depend heavily on the measurement method used.
Sleep disturbances are a hallmark symptom of ME/CFS, and understanding whether 'alpha intrusion' is a genuine biological feature requires reliable measurement methods. This study highlights that the technical choices researchers make about electrode placement can dramatically influence their conclusions, which is crucial for interpreting conflicting findings in the literature and for developing validated diagnostic or research tools.
This study does not prove that alpha intrusion does or does not occur in ME/CFS patients—in fact, it demonstrates that the presence or absence of this finding may be an artifact of measurement technique rather than a true biological difference. It also does not establish whether alpha intrusion, if real, contributes to fatigue or other CFS symptoms. The study is a technical evaluation of measurement methodology, not a clinical outcome study.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Flanigan, M J, Morehouse, R L, & Shapiro, C M (1995). Determination of observer-rated alpha activity during sleep.. Sleep. https://pubmed.ncbi.nlm.nih.gov/8560138/
BibTeX
@article{mecfsatlas-flanigan-1995-determination-observer,
author = {Flanigan, M J and Morehouse, R L and Shapiro, C M},
title = {Determination of observer-rated alpha activity during sleep.},
journal = {Sleep},
year = {1995},
note = {PubMed: 8560138},
url = {https://www.mecfsatlas.com/evidence/flanigan-1995-determination-observer},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/flanigan-1995-determination-observer
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