{
  "abstract": "Objective: The theta/alpha ratio, an index of electroencephalographic slowing, has been proposed as a marker of cognitive impairment, but estimates may depend on preprocessing, spectral, spatial, and statistical decisions. We used multiverse analysis to evaluate its robustness across plausible pipelines. Methods: Two resting-state EEG datasets were analyzed. Dataset 1 included 49 controls and 100 participants with Parkinson's disease spanning normal cognition to dementia. Dataset 2 included 29 controls, 36 patients with Alzheimer's disease, and 23 with frontotemporal dementia. Eight decisions were varied: filtering, artifact correction, independent component analysis (ICA), referencing, spatial summary, alpha-band definition, spectral method, and covariate adjustment, yielding 1,280 specifications (universes). Results: Findings varied across the unrestricted multiverse. In Dataset 1, all universes in the exploratory family combining ICA with absolute fast Fourier transform (FFT) or Welch power yielded p < 0.05 for comparisons of controls and cognitively normal Parkinson's disease with Parkinson's disease dementia and produced significant associations with Montreal Cognitive Assessment scores in more than 95% of universes. In Dataset 2, absolute FFT or Welch power supported control versus Alzheimer's disease differences in more than 95% of universes, while ICA with absolute power yielded significant Mini-Mental State Examination associations in all specifications. Higher theta/alpha ratios were consistently associated with greater cognitive impairment. Conclusions: The theta/alpha ratio is a promising but specification-dependent marker of cognitive impairment, contingent particularly on ICA and spectral power quantification. Significance: Identifying the analytic conditions under which theta/alpha findings remain stable supports standardized, reproducible evaluation of quantitative EEG markers of cognitive impairment.",
  "abstract_shown": true,
  "affiliations": [
    "Beth Israel Deaconess Medical Center"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "name": "J. Chang"
    },
    {
      "affs": [
        0
      ],
      "name": "S. H. Song"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3bc9kj13ygm8x.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.03.749187",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.09.03.749187v1.full",
  "id": "3bc9kj13ygm8x",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.09.03.749187v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "neuroscience"
    ],
    [
      "openalex",
      "2738|Dementia and Cognitive Impairment Research"
    ]
  ],
  "openalex": "W7211995995",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.09.03.749187v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-03",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3bc9kj13ygm8x.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:25Z",
      "native_id": "10.64898/2026.09.03.749187",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.09.03.749187v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:neuroscience",
      "subfield": "neuroscience"
    }
  ],
  "title": "Specification dependence of EEG theta/alpha ratio associations with cognitive impairment: a multiverse analysis",
  "title_text": "Specification dependence of EEG theta/alpha ratio associations with cognitive impairment: a multiverse analysis",
  "type": "preprint",
  "updated_at": "2026-10-30T12:20:25Z",
  "url": "https://research.draconitic.com/paper/3bc9kj13ygm8x",
  "venue": "bioRxiv",
  "versions": []
}