EEG features associated with Alzheimer’s disease and Frontotemporal dementia are not reflected by processed indices used in anesthesia monitoring

Topic: Amyloid, tau and blood-test diagnosis

Patients with dementia face increased risks after general anesthesia. Improved perioperative electroencephalogram (EEG) monitoring techniques could aid in identifying vulnerable patients. However, current technology relies on processed indices to measure "depth-of-anesthesia". Analyzing OpenNeuro Dataset ds004504, we compared resting-state, eyes-closed EEG recordings of healthy controls (n = 27) with patients diagnosed with Alzheimer's disease (AD, n = 35) and Frontotemporal dementia (FTD, n = 23). We focused on prefrontal recordings. Analysis included spectral analysis, the "fitting-oscillations&-one-over-f"-algorithm for aperiodic and periodic signal features, as well as calculations of openibis, permutation entropy (PeEn), spectral entropy (SpEn), and spectral edge frequency (SEF). Spectral differences were pronounced, including a higher alpha/theta-ratio of controls (2.62 [95%CI: 1.54-3.62]) compared to both AD (0.55 [95%CI: 0.26-1.92], P < 0.001, AUC: 0.765 [0.642-0.888]) and FTD (0.83 [95%CI: 0.33-1.65], P = 0.007, AUC: 0.779 [0.652-0.907]). Oscillatory peak detection within the alpha frequency band was more robust in control (versus AD: P = 0.003, Cramér's V = 0.374; versus FTD: P = 0.003, Cramér's V = 0.414). Processed index parameters did not show a clear trend. FTD was associated with a higher prefrontal openibis (95.53 [95%CI: 93.43-97.39]) than control (91.98 [95%CI: 89.46-96.27], P = 0.033, AUC: 0.717 [0.572-0.862]) and an elevated SEF (23.68 [95%CI: 14.10-25.57] Hz) compared to AD (16.60 [95%CI: 14.22-22.22] Hz, P = 0.041, AUC: 0.676 [0.532-0.821]). AD and FTD are associated with EEG baseline abnormalities, and a standard prefrontal montage, as used intraoperatively, could present a promising technical screening approach for cognitive vulnerability. However, these EEG features are obscured by processed index parameters currently used in neuroanesthesia monitoring. OpenNeuro Dataset ds004504 "A dataset of EEG recordings from: Alzheimer's disease, Frontotemporal dementia and Healthy subjects" (doi: https://doi.org/10.18112/openneuro.ds004504.v1.0.7 ).

Key findings

• Spectral differences were pronounced, including a higher alpha/theta-ratio of controls (2.62 [95%CI: 1.54-3.62]) compared to both AD (0.55 [95%CI: 0.26-1.92], P < 0.001, AUC: 0.765 [0.642-0.888]) and FTD (0.83 [95%CI: 0.33-1.65], P = 0.007, AUC: 0.779 [0.652-0.907]).
• Oscillatory peak detection within the alpha frequency band was more robust in control (versus AD: P = 0.003, Cramér's V = 0.374; versus FTD: P = 0.003, Cramér's V = 0.414).
• FTD was associated with a higher prefrontal openibis (95.53 [95%CI: 93.43-97.39]) than control (91.98 [95%CI: 89.46-96.27], P = 0.033, AUC: 0.717 [0.572-0.862]) and an elevated SEF (23.68 [95%CI: 14.10-25.57] Hz) compared to AD (16.60 [95%CI: 14.22-22.22] Hz, P = 0.041, AUC: 0.676 [0.532-0.821]).
• AD and FTD are associated with EEG baseline abnormalities, and a standard prefrontal montage, as used intraoperatively, could present a promising technical screening approach for cognitive vulnerability.

Why it matters

Resting-state EEG showed spectral differences in people with Alzheimer's disease and frontotemporal dementia compared to controls, but processed indices used in anesthesia monitoring did not show a clear trend. This suggests current anesthesia depth monitors may not reflect these dementia-related EEG features, which is relevant to monitoring rather than treatment.

Study details

• Participants27
• Effect sizeAUC: 0.765; AUC: 0.779; AUC: 0.717
• Evidence strengthLow

Read the original

• DOI: 10.1007/s10877-025-01294-y
• PubMed: 40259140
• Original source →
• Free full text: Journal of Clinical Monitoring and Computing →

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

@article{schwerin2025-40259140,
  author  = {Schwerin, Stefan and Dragovic, Srdjan Z. and Ostertag, Julian and Nguyen, Duy-Minh and Schneider, Gerhard H. and Kreuzer, Matthias},
  title   = {{EEG features associated with Alzheimer’s disease and Frontotemporal dementia are not reflected by processed indices used in anesthesia monitoring}},
  journal = {Journal of Clinical Monitoring and Computing},
  year    = {2025},
  doi     = {10.1007/s10877-025-01294-y},
  pmid    = {40259140},
  url     = {https://doi.org/10.1007/s10877-025-01294-y}
}

Studies this one cites

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• Mini-Mental State Examination (MMSE) for the detection of dementia in clinically unevaluated people aged 65 and over in community and primary care populations The Cochrane database of systematic reviews · 2016-01-13 · usefulness score 76/100 · Getting a diagnosis
• Resting state EEG biomarkers of cognitive decline associated with Alzheimer's disease and mild cognitive impairment PloS one · 2021-02-05 · usefulness score 62/100 · Mild cognitive impairment
• Frontotemporal dementia Lancet (London, England) · 2015-10-01 · usefulness score 59/100 · Getting a diagnosis
• Neural biomarker diagnosis and prediction to mild cognitive impairment and Alzheimer's disease using EEG technology Alzheimer's research & therapy · 2023-02-10 · usefulness score 57/100 · Mild cognitive impairment
• Alzheimer's Disease and Frontotemporal Dementia: A Robust Classification Method of EEG Signals and a Comparison of Validation Methods Diagnostics (Basel, Switzerland) · 2021-08-09 · usefulness score 50/100 · Digital health tools

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