Quantitative EEG correlates of visual background slowing in routine EEG

Nur Türkmen; Duygu Engez Hancı; Güray Koç

Quantitative EEG correlates of visual background slowing in routine EEG

Abstract

Aims: Background slowing on routine electroencephalography (EEG) is a clinically relevant nonepileptiform finding. This study aimed to determine how visually identified pathological background slowing is represented by interpretable quantitative EEG (qEEG) parameters. Methods: This retrospective study included 56 adults who underwent routine EEG between 2023 and 2026. Recordings were classified by two epileptologists blinded to the qEEG results as normal background activity (n=30) or pathological background slowing (n=26). Quantitative analysis included relative delta, theta, alpha, and beta power from 19 scalp channels, together with the delta/alpha ratio (DAR), the (delta+theta)/(alpha+beta) ratio (DTABR), dominant frequency, and generalized slowing percentage. Results: Compared with the normal group, the pathological slowing group showed higher relative delta and theta power and lower relative alpha and beta power (all p<0.001). DAR (4.38 vs. 0.53), DTABR (5.47 vs. 0.61), and generalized slowing percentage (98.56% vs. 7.63%) were significantly increased, whereas dominant frequency was reduced (2.56 vs. 9.12 Hz; p<0.001). DTABR showed the strongest correlation with visual slowing grade (Spearman rho=0.772; p<0.001). Exploratory receiver operating characteristic analysis showed the highest within-sample discrimination of visual EEG classification for DTABR [area under the curve (AUC)=1.000], followed by DAR (AUC=0.978) and dominant frequency (AUC=0.871). These findings reflect concordance with visual assessment rather than independent diagnostic validation. Conclusion: Visually identified pathological background slowing is consistently represented by interpretable qEEG parameters. DAR, DTABR, dominant frequency, and generalized slowing percentage are measurable correlates of visual background slowing. Quantitative EEG should complement expert visual interpretation rather than serve as an independent diagnostic tool.

Keywords

Supporting Institution

nothing to declare

Ethical Statement

This study was approved by the Ankara Bilkent City Hospital Ethics Committee (decision no: TABED 1-26-2247, date: 25.02.2026). The study was conducted in accordance with the principles of the Declaration of Helsinki. Informed Consent: Due to the retrospective design of the study, the requirement for informed consent was waived by the ethics committee.

Thanks

The authors thank Prof Dr Barkın İlhan for his technical assistance with the MATLAB programming used in this study.

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Details

Primary Language

English

Subjects

Clinical Sciences (Other)

Journal Section

Research Article

Authors

Nur Türkmen ^*
0000-0001-5863-7010
Türkiye

Duygu Engez Hancı
0000-0001-6672-5774
Türkiye

Güray Koç
0000-0002-2477-5244
Türkiye

Publication Date

October 25, 2026

Submission Date

August 5, 2026

Acceptance Date

October 8, 2026

Published in Issue

Year 2026 Volume: 9 Number: 6

IZ

https://izlik.org/JA43GZ59YX

Cite

RIS / Bibtex

APA

Türkmen, N., Engez Hancı, D., & Koç, G. (2026). Quantitative EEG correlates of visual background slowing in routine EEG. Journal of Health Sciences and Medicine, 9(6), 1826-1833. https://izlik.org/JA43GZ59YX

AMA

1.Türkmen N, Engez Hancı D, Koç G. Quantitative EEG correlates of visual background slowing in routine EEG. J Health Sci Med / JHSM. 2026;9(6):1826-1833. https://izlik.org/JA43GZ59YX

Chicago

Türkmen, Nur, Duygu Engez Hancı, and Güray Koç. 2026. “Quantitative EEG Correlates of Visual Background Slowing in Routine EEG”. Journal of Health Sciences and Medicine 9 (6): 1826-33. https://izlik.org/JA43GZ59YX.

EndNote

Türkmen N, Engez Hancı D, Koç G (October 1, 2026) Quantitative EEG correlates of visual background slowing in routine EEG. Journal of Health Sciences and Medicine 9 6 1826–1833.

IEEE

[1]N. Türkmen, D. Engez Hancı, and G. Koç, “Quantitative EEG correlates of visual background slowing in routine EEG”, J Health Sci Med / JHSM, vol. 9, no. 6, pp. 1826–1833, Oct. 2026, [Online]. Available: https://izlik.org/JA43GZ59YX

ISNAD

Türkmen, Nur - Engez Hancı, Duygu - Koç, Güray. “Quantitative EEG Correlates of Visual Background Slowing in Routine EEG”. Journal of Health Sciences and Medicine 9/6 (October 1, 2026): 1826-1833. https://izlik.org/JA43GZ59YX.

JAMA

1.Türkmen N, Engez Hancı D, Koç G. Quantitative EEG correlates of visual background slowing in routine EEG. J Health Sci Med / JHSM. 2026;9:1826–1833.

MLA

Türkmen, Nur, et al. “Quantitative EEG Correlates of Visual Background Slowing in Routine EEG”. Journal of Health Sciences and Medicine, vol. 9, no. 6, Oct. 2026, pp. 1826-33, https://izlik.org/JA43GZ59YX.

Vancouver

1.Nur Türkmen, Duygu Engez Hancı, Güray Koç. Quantitative EEG correlates of visual background slowing in routine EEG. J Health Sci Med / JHSM [Internet]. 2026 Oct. 1;9(6):1826-33. Available from: https://izlik.org/JA43GZ59YX