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Journals / Celal Bayar Üniversitesi Fen Bilimleri Dergisi / 2026 / Cilt: 22 Sayı: 2

Spatiotemporal EEG Dynamics Across Early and Late Preictal Periods in Pediatric Focal Epilepsy

Hasan Fehmi Özel(MANİSA CELÂL BAYAR ÜNİVERSİTESİ)0000-0003-1676-0648
Pages
284–294
Publication Date
2026-06-30
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

Conclusion: These findings indicate that cortical networks experience a collapse in long-range temporal correlations and a reorganization of the aperiodic spectral structure as seizure onset approaches.

📌 3 Key Takeaways

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Objective & Hypothesis:Objective: This study aimed to quantify the temporal and spatial dynamics of preictal cortical networks in pediatric refractory focal epilepsy using scale-independent EEG measurements.
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Key Findings & Data:Method: For this purpose, the preictal (−35 to −5 min), interictal, early preictal (−35 to −20 min), and late preictal (−20 to −5 min) periods were examined in long-term scalp EEG recordings from pediatric patients in the CHB–MIT database.
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Conclusion & Impact:Conclusion: These findings indicate that cortical networks experience a collapse in long-range temporal correlations and a reorganization of the aperiodic spectral structure as seizure onset approaches.
🔬Design:Araştırma Makalesi
📍Scope:Comprehensive Sample
⚙️Variables:Aperiodic 1/f activity · EEG dynamics · epilepsy

Abstract

Objective: This study aimed to quantify the temporal and spatial dynamics of preictal cortical networks in pediatric refractory focal epilepsy using scale-independent EEG measurements. Method: For this purpose, the preictal (−35 to −5 min), interictal, early preictal (−35 to −20 min), and late preictal (−20 to −5 min) periods were examined in long-term scalp EEG recordings from pediatric patients in the CHB–MIT database. For the selected segments, the detrended fluctuation analysis (DFA) scale exponent, median power frequency (MPF), and aperiodic 1/f exponent (β) were calculated using SpecParam/FOOOF and IRASA. The metrics were summarized on an individual basis and analyzed using two-way repeated measures ANOVA with Šídák-corrected post-hoc tests and topographic mapping. Findings: The preictal period was characterized by increased DFA-α and MPF in fronto-temporal regions compared to the interictal period; during the interictal period, MPF foci shifted to posterior areas. Aperiodic β values showed steepening in frontal regions during the preictal period and exhibited a posterior-temporal gradient during the interictal period. Critically, during the transition from the early to late preictal period, fronto-temporal DFA-α and MPF values decreased, accompanied by a posterior-to-anterior spread of aperiodic β steepening. Conclusion: These findings indicate that cortical networks experience a collapse in long-range temporal correlations and a reorganization of the aperiodic spectral structure as seizure onset approaches. The observed loss of complexity, spectral slowing, and frontal aperiodic steepening, occurring simultaneously, suggest a heterogeneous nature of the preictal process and highlight the potential of scale-independent metrics in monitoring seizure risk.

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Cite This Article

Özel, H. F. (2026). Spatiotemporal EEG Dynamics Across Early and Late Preictal Periods in Pediatric Focal Epilepsy. Celal Bayar Üniversitesi Fen Bilimleri Dergisi, Cilt: 22 Sayı: 2, 284–294. https://doi.org/10.18466/cbayarfbe.1829844

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