Through looking at a certain type of seizure in a mouse model of epilepsy, researchers found that death occurs only when the seizure induces failure of the respiratory system.
This new understanding will allow scientists to further their efforts in developing methods to prevent sudden unexpected death in epilepsy (SUDEP). Based on this new research alone, the University of Virginia (UVA) team has already identified potential ways to stimulate breathing in the mice and prevent death after a seizure. The team is optimistic that this new approach could potentially save lives someday.
“SUDEP is a major concern for patients with epilepsy and their loved ones,” said Manoj Patel, PhD, of UVA’s Department of Anesthesiology. “Our study has identified a sequence of events that takes place during a seizure which can progress and lead to death. Furthermore, we show that intervention during a seizure can rescue death in mice with epilepsy. This project is a long time in the making, and we are excited to share it with the scientific community.”
Although SUDEP is responsible for 8% to 17% of all epilepsy deaths, increasing to as much as 50% in cases of treatment-resistant seizures, many people have never heard of it. Disney star Cameron Boyce passed away due to SUDEP in 2019 at the age of 20.
Scientists have suggested a variety of potential causes for SUDEP, but UVA's research has brought clarity as to why some seizures lead to death while others don't. The research found that as muscles start to stiffen during a seizure, breathing disruption, known as apnea, will also begin. This is because the muscle stiffening includes contraction of the diaphragm, stopping the regular breathing process.
However, not all instances of seizure-induced apnea were fatal, and it was only when their breathing did not recover immediately after the seizure did the mice died. Based on this, the team tested the theory that artificially stimulated breathing would help prevent sudden death after a seizure. Upon testing this theory, they determined that by directly ventilating the mouse, death could be prevented.
The scientists then began to confirm their findings by monitoring the breathing patterns and frequencies in human patients with epilepsy. They discovered that the breathing disruptions during seizures were very similar to those seen in the mice.
“These results implicate respiratory arrest as a major factor in SUDEP and give us targets for future research on intervention,” said researcher Ian Wenker, PhD.