Club Exco: clustering brain extreme communities from multi-channel EEG data

TL;DR

Club Exco is a novel clustering method based on extreme value theory that identifies brain communities with co-occurring high-amplitude EEG events, providing new insights into seizure dynamics.

Contribution

It introduces a new extreme-value based clustering approach for EEG data, focusing on tail behavior to detect neural communities during extreme events.

Findings

Seizure patients show more persistent and variable clustering patterns.

Non-seizure patients have more consistent clustering in adjacent regions.

Club Exco captures distinct seizure-related connectivity patterns.

Abstract

Current methods for clustering brain networks over time often rely on cross-dependence measures computed from the entire range of EEG signals, which can obscure information specific to extreme neural activity. To overcome this, we introduce Club Exco, a novel clustering method grounded in extreme value theory, designed to detect brain communities with co-occurring high-amplitude EEG events. By focusing on tail behavior, Club Exco isolates extreme-value synchrony across channels, offering new insights into seizure dynamics. We apply Club Exco to neonatal EEG recordings from 30 patients (13 seizure-free and 17 with clinically confirmed seizures). Our method identifies robust ``brain extreme communities'' and constructs Extreme Connectivity Persistence matrices that summarize how often channels exhibit synchronous extremes across time. Seizure patients exhibit more persistent and variable clustering among non-adjacent regions, suggesting seizure propagation, while non-seizure patients show more consistent clustering in anatomically adjacent regions. Compared to coherence-based methods (e.g., Hierarchical Cluster Coherence procedure), Club Exco captures distinct, seizure-associated connectivity patterns, especially in high-amplitude segments. These results highlight Club Exco's potential to characterize extreme neural events and inform clinical understanding of seizure localization and spread.