New research from the University of Virginia School of Medicine
reveals why sleep can put people with epilepsy at increased risk of
Both sleep and seizures work together to slow the heart rate, the
researchers found. Seizures also disrupt the body's natural regulation
of sleep-related changes. Together, in some instances, this can prove
deadly, causing sudden unexpected death in epilepsy, or SUDEP.
"We have been trying to better understand the cardiac changes around
the time of a seizure in patients with epilepsy. When we looked at the
heart rates for patients with epilepsy admitted to the hospital, many of
them develop tachycardia [a fast heart rate] following a seizure, but a
subset of patients have a decreased heart rate. This decline was more
pronounced when the patients were asleep," said Andrew Schomer MD of
UVA's Department of Neurology and the UVA Brain Institute. "The
mechanism of SUDEP, or sudden unexpected death in epilepsy, is still not
fully understood. We know there is an increased risk during sleep and
if seizures are poorly controlled. Hopefully with further study we can
try to identify individuals who are at an increased risk and work to
prevent this devastating outcome."
Understanding SUDEP in Sleep
Doctors have been unsure how seizures in sleep can cause death, such
as was the case with young Disney Channel star Cameron Boyce in 2019.
He died of SUDEP while sleeping at age 20. (While SUDEP can occur when
patients with epilepsy are awake, the majority of cases occur during
To better understand the effect of sleep seizures, UVA researchers
led by Schomer and Mark Quigg, MD, MSc, monitored the brain and heart
activity of people with epilepsy as they slept. The patients were
admitted to the UVA Epilepsy Monitoring Unit between February 2018 and
August 2019, and all were 17 or older.
In total, the researchers evaluated 101 sleep seizures in 41
patients, with a median age of 40.5 years. The participants were, on average,
diagnosed more than 20 years previously.
The researchers monitored how deeply the patients were sleeping when
the seizures occurred. Some seizures caused heart rates to increase.
But the greater sleep depth prior to a seizure, the slower the patient's
heart rate was likely to become, the scientists found.
The results suggest that seizures during sleep are more likely to
lead to dangerously slow heart rate. The effect of the seizure is
secondary to the natural slowing of the heart rate during sleep, the
researchers believe, but the two together can, in some instances, prove
More study is needed to better understand the variables involved and
to better determine what is occurring in individual patients, the
researchers say. But the findings represent an important advance in the
effort to prevent SUDEP during sleep.
"People with poorly controlled seizures have the greatest risk of
SUDEP, and seizures during sleep may hold the higher risk," said Quigg,
of UVA's Department of Neurology and the UVA Brain Institute. "Our
findings can direct further research to determine how the heart's and
lung's control systems fail during sleep-related seizures in order to
help prevent SUDEP."
Source: News Release
University of Virginia Health System
May 6, 2021