No evidence for critical slowing down prior to human epileptic seizures

TL;DR

This study analyzed long-term brain recordings from epileptic patients to test if early warning signals like variance and autocorrelation reliably predict seizures, finding no evidence supporting critical slowing down as a universal precursor.

Contribution

The paper provides the first comprehensive evaluation of early warning indicators for seizures, challenging the assumption that critical slowing down universally precedes epileptic events.

Findings

No evidence of critical slowing down before seizures

Traditional early warning indicators lack predictive power

Results question the universality of critical slowing down in epilepsy

Abstract

There is a ongoing debate whether generic early warning signals for critical transitions exist that can be applied across diverse systems. The human epileptic brain is often considered as a prototypical system, given the devastating and, at times, even life-threatening nature of the extreme event epileptic seizure. More than three decades of international effort has successfully identified predictors of imminent seizures. However, the suitability of typically applied early warning indicators for critical slowing down, namely variance and lag-1 autocorrelation, for indexing seizure susceptibility is still controversially discussed. Here, we investigated long-term, multichannel recordings of brain dynamics from 28 subjects with epilepsy. Using a surrogate-based evaluation procedure of sensitivity and specificity of time-resolved estimates of early warning indicators, we found no evidence for critical slowing down prior to 105 epileptic seizures.