(SACRAMENTO, Calif.) A new study by researchers at UC Davis Medical Center suggests that the sudden unexplained deaths of some epilepsy patients may be a result of their brains not telling their bodies to breathe during seizures.
"Significant drops in blood oxygen levels are more common than we thought in patients with partial seizures," said study senior author Masud Seyal, a professor of neurology at UC Davis Medical Center and director of the UC Davis Comprehensive Epilepsy Program.
The study, published online in the Oct. 24 issue of the journal Brain, studied Sudden Unexpected Death in Epilepsy, what doctors call SUDEP for short, to examine deaths of epileptics not explained by repeated convulsive seizures, accidents or other mishaps.
"What we've known for a long time is that SUDEP appears to be the most important cause of increased mortality in epilepsy patients. What we haven't known is what causes it," Seyal said.
The findings suggest that some cases of SUDEP may result from the brain not signaling the patient to continue breathing during seizures, though more conclusive evidence is needed, he said.
"It may have to do with an abnormal heart rhythm or it just may be that the brain stops sending the proper signals to maintain normal breathing," Seyal said.
In the retrospective study, Seyal and his colleagues examined records of 300 seizures in 57 epilepsy patients with chronic, recurrent, unprovoked seizures. They compared patients with severe convulsive seizures to those with milder symptoms like transient confusion, lip smacking and head turning.
One-third of all seizures were associated with drops in blood-oxygen levels below 90 percent. Seyal said he was surprised to find that 12 percent of these patients' blood oxygen levels actually dropped below 70 percent during their seizures.
They also discovered that seizures in the temporal lobe of the brain are more often associate
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University of California - Davis - Health System