Impaired brain-heart axis in focal epilepsy: Alterations in information flow and implications for seizure dynamics

Q: What are the key findings of this study?

Focal epileptic seizures significantly reduced postictal heart-to-brain functional interplay compared to preictal periods, particularly from HRV-LF to delta and theta EEG bands (p<0.01).

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Focal epilepsy (n=14). Intervention: Postictal period (10-minute window following seizure offset) vs. Preictal period (10-minute window preceding seizure onset). Primary outcome: Directional functional brain-heart interplay (BHI) between EEG frequency bands (delta, theta, alpha, beta) and HRV frequency bands (LF, HF) quantified via a synthetic data generation (SDG) model (p=<0.01).

Q: What does this research mean for the field?

Focal epileptic seizures significantly reduce postictal heart-to-brain functional interplay compared to preictal periods, particularly from low-frequency heart rate variability to delta and theta EEG bands. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To evaluate directional brain-heart interplay dynamics across preictal and postictal periods in patients with focal epilepsy.

Lorenzo Frassineti; Vincenzo Catrambone; Antonio Lanatà; Gaetano Valenza

doi:10.1162/netn_a_00367

January 1, 2024Network NeuroscienceOpen Access

Impaired brain-heart axis in focal epilepsy: Alterations in information flow and implications for seizure dynamics

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Key result

Focal seizures are linked to reduced postictal heart-to-brain functional interplay, primarily affecting delta and theta bands.

P<0.01
n=14

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Why the study?

The study aimed to elucidate functional brain-heart interplay dynamics and causal interactions between cortical and autonomic nervous system oscillations during interictal periods before and after focal epilepsy seizures.

Does focal epileptic seizure activity alter directional functional brain-heart interplay between cortical EEG oscillations and cardiac autonomic HRV dynamics when comparing preictal and postictal periods?

Key Points

To evaluate directional brain-heart interplay dynamics across preictal and postictal periods in patients with focal epilepsy.
Evaluated concurrent electroencephalography and heart rate variability series from 47 seizure events across 14 individuals using the open-access Siena Dataset.
Quantified directional causal interactions across cortical oscillations (delta, theta, alpha, beta) and cardiac rhythms (low-frequency and high-frequency bands) across 1- to 10-minute windows via Wilcoxon testing.
Significant differences between preictal and postictal periods occurred predominantly in the heart-to-brain direction, with diffuse alterations in low-frequency cardiac interactions targeting delta, theta, and alpha brain waves (minimum p = 4.07e-5).
Brain-to-heart communication targeting cardiac low-frequency oscillations showed no significant changes across all derivations, while changes targeting high-frequency oscillations were restricted to central delta and theta bands.
Spatiotemporal analyses demonstrated lateralization toward the right hemisphere, with preictal values consistently higher than postictal values before converging toward baseline 3 minutes after seizure termination.

Study Design

Type

Observational (n=14)

Multicenter

No

Structured PICO

Does focal epileptic seizure activity alter directional functional brain-heart interplay between cortical EEG oscillations and cardiac autonomic HRV dynamics when comparing preictal and postictal periods?

P

Population

14 adults (age range 20-71 years, 35.7% female) with confirmed focal epilepsy from the University of Siena dataset (13 subjects and 38 seizures analyzed across 10-minute preictal and postictal windows).

E

Exposure

Postictal interictal state (10-minute simultaneous multichannel scalp EEG and ECG/HRV recording window immediately following clinically labeled seizure offset) evaluated using a synthetic data generation (SDG) directional brain-heart interplay model.

C

Comparator

Preictal interictal state (10-minute simultaneous multichannel scalp EEG and ECG/HRV recording window immediately preceding clinically labeled seizure onset) and distant interictal periods (1 hour prior to the first ictal event).

O

Outcome

Bidirectional functional brain-heart interplay (BHI) indices—brain-to-heart (BtH) and heart-to-brain (HtB)—across EEG frequency bands (delta 1-4 Hz, theta 4-8 Hz, alpha 8-12 Hz, beta 12-30 Hz) and HRV frequency bands (LF 0.04-0.15 Hz, HF 0.15-0.4 Hz) over 10-minute preictal vs. postictal windows.surrogate

Main Result

p-value: p=<0.01

Demonstrates that focal epileptic seizures significantly disrupt directional brain-heart axis communication—especially bottom-up sympathovagal heart-to-brain information flow—highlighting autonomic nervous system involvement in postictal dynamics.

Limitations

Limited number of subjects (14 total, 13 analyzed) and seizure events (47 total, 38 analyzed)
Focuses primarily on focal temporal lobe epilepsy in adults, limiting generalizability to generalized seizures or pediatric/neonatal populations
Effect of anti-epileptic medications on brain-heart interplay dynamics was not evaluated
Inability to analyze brain-heart interplay during the ictal phase itself due to movement artifacts and unreliable ECG/EEG recordings
Limited postictal recording duration prevented evaluation of long-term recovery (e.g., 1 hour post-seizure)
Small sample size of 14 subjects (13 analyzed) and 47 seizure events (38 analyzed)
Restricted primarily to adult focal temporal lobe epilepsy, limiting generalizability to generalized epilepsy or pediatric/newborn cohorts
Confounding effects of anti-epileptic medications on BHI dynamics were not assessed
Ictal phase recordings could not be analyzed due to movement artifacts and unreliable ECG/EEG signals
Absence of extended postictal data prevented assessment of whether BHI returns to baseline 1 hour after seizures

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Implication

Reduced postictal heart-to-brain interplay after focal seizures may signal autonomic dysregulation; leaves open prospective validation for clinical use.

Abstract

This study delves into functional brain-heart interplay (BHI) dynamics during interictal periods before and after seizure events in focal epilepsy. Our analysis focuses on elucidating the causal interaction between cortical and autonomic nervous system (ANS) oscillations, employing electroencephalography and heart rate variability series. The dataset for this investigation comprises 47 seizure events from 14 independent subjects, obtained from the publicly available Siena Dataset. Our findings reveal an impaired brain-heart axis especially in the heart-to-brain functional direction. This is particularly evident in bottom-up oscillations originating from sympathovagal activity during the transition between preictal and postictal periods. These results indicate a pivotal role of the ANS in epilepsy dynamics. Notably, the brain-to-heart information flow targeting cardiac oscillations in the low-frequency band does not display significant changes. However, there are noteworthy changes in cortical oscillations, primarily originating in central regions, influencing heartbeat oscillations in the high-frequency band. Our study conceptualizes seizures as a state of hyperexcitability and a network disease affecting both cortical and peripheral neural dynamics. Our results pave the way for a deeper understanding of BHI in epilepsy, which holds promise for the development of advanced diagnostic and therapeutic approaches also based on bodily neural activity for individuals living with epilepsy.

Discussion

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Cite This Study

Frassineti et al. (2024) conducted an observational in Focal epilepsy (n=14). Postictal period (10-minute window following seizure offset) vs. Preictal period (10-minute window preceding seizure onset) was evaluated on Directional functional brain-heart interplay (BHI) between EEG frequency bands (delta, theta, alpha, beta) and HRV frequency bands (LF, HF) quantified via a synthetic data generation (SDG) model (p=<0.01). Focal epileptic seizures significantly reduced postictal heart-to-brain functional interplay compared to preictal periods, particularly from HRV-LF to delta and theta EEG bands (p<0.01).

synapsesocial.com/papers/6a7ba546c06c4f060a75d5ac https://doi.org/10.1162/netn_a_00367

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Impaired brain-heart axis in focal epilepsy: Alterations in information flow and implications for seizure dynamics

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Impaired brain-heart axis in focal epilepsy: Alterations in information flow and implications for seizure dynamics

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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