Predicting epileptic seizures might be more difficult than previously thought

September 24, 2019

WASHINGTON, D.C., September 24, 2019 -- By studying the brain dynamics of 28 subjects with epilepsy, scientists demonstrated there is no evidence for a previously suspected warning sign for seizures known as "critical slowing down."

In 2013, some of the first seizure-prediction devices were developed and successfully tested. Although extensive research efforts have successfully identified predictors of imminent seizures, the concept of critical slowing down as an index for seizure susceptibility has been controversial and remained unproven.

Critical slowing down refers to characteristic changes in the behavior of a complex system that approaches a theoretical tipping point. When this point is exceeded, it can lead to impactful and devastating changes. An epileptic human brain is considered an excellent example of a system such as this, due to the extreme and distressing nature of a seizure.

In a paper published in Chaos, from AIP Publishing, researchers investigated recordings of brain dynamics that captured 105 epileptic seizures using time-resolved estimates of early warning indicators of the seizures.

"In our investigations, we used the most prominent indicators and showed that critical slowing down prior to human epileptic seizures is not verifiable," neurophysicist Thorsten Rings said. "This demonstrates that the concept underlying critical slowing down is too simple of a model for the human brain."

Instead of critically slowing down, the researchers discovered the seizures acted oppositely and critically sped up, indicating the brain dynamics were less sensitive to changes and experienced a faster return to an unperturbed state.

"Similar indicators of critical slowing down can even be observed in relation to daily rhythms, such as sleeping and waking, but we lack clear-cut evidence for critical slowing down preceding such changes," researcher Theresa Wilkat said. "Therefore, it is hard to clearly distinguish between a critical transition into a seizure and a critical transition into other states."

An in-depth model of the transition into a seizure is still missing, but considering their research, Klaus Lehnertz and his team said the concept of critical slowing down is insufficient as a predictive method. They believe future studies should develop improved models and analysis techniques.

"A promising future approach might be to investigate how seizures emerge from large-scale brain networks by taking into account their time-varying structure and function," Lehnertz said.
-end-
The article, "No evidence for critical slowing down prior to human epileptic seizures," is authored by Theresa Wilkat, Thorsten Rings and Klaus Lehnertz. The article will appear in Chaos on Sept. 24, 2019 (DOI: 10.1063/1.5122759). After that date, it can be accessed at http://aip.scitation.org/doi/full/10.1063/1.5122759.

ABOUT THE JOURNAL

Chaos is devoted to increasing the understanding of nonlinear phenomena in all areas of science and engineering and describing their manifestations in a manner comprehensible to researchers from a broad spectrum of disciplines. See https://aip.scitation.org/journal/cha.

American Institute of Physics

Related Seizures Articles from Brightsurf:

Hallucinations in people with seizures may point to suicide risk
A study from scientists at Trinity College Dublin and Royal College of Surgeons in Ireland shows that 8% of individuals with a history of seizures report hallucinations, including experiences of hearing or seeing things that are not based in reality.

Epilepsy: Seizures not forecastable as expected
Epileptic seizures can probably not be predicted by changes in brain wave patterns that were previously assumed to be characteristic precursors.

Predicting epileptic seizures might be more difficult than previously thought
By studying the brain dynamics of 28 subjects with epilepsy, scientists demonstrated there is no evidence for a previously suspected warning sign for seizures known as 'critical slowing down,' which refers to characteristic changes in the behavior of a complex system that approaches a theoretical tipping point; when this point is exceeded, there can be impactful and devastating changes.

Gene protective against fruit fly heat-induced seizures may explain some human seizures
Researchers identified a gene in fruit flies that helps prevent the hyperexcitability of specific neurons that trigger seizures.

Rethinking seizures associated with cardiac disease
Research from Washington University in St. Louis finds that mutations of a gene implicated in long QT syndrome in humans may trigger seizures because of their direct effects on certain classes of neurons in the brain -- independent from what the genetic mutations do to heart function.

UTSA reduces seizures by removing newborn neurons
Epileptic seizures happen in one of every 10 people who have experienced a traumatic brain injury (TBI).

Reducing seizures by removing newborn neurons
Removing new neurons born after a brain injury reduces seizures in mice, according to new research in JNeurosci.

Inducing seizures to stop seizures
Surgery is the only way to stop seizures in 30 per cent of patients with focal drug-resistant epilepsy.

New research could help predict seizures before they happen
A new study has found a pattern of molecules that appear in the blood before a seizure happens.

New drug could help treat neonatal seizures
A new drug that inhibits neonatal seizures in rodent models could open up new avenues for the treatment of epilepsy in human newborns.

Read More: Seizures News and Seizures Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.