Epilepsy Research Reveals Why Sleep Increases Risk of Sudden Death

Summary: Both sleep and seizures reduce heart rate, a new study into mortality and epilepsy reveal. Seizures also disrupt the natural regulation of sleep-related changes. This can sometimes prove deadly and increase the risk of sudden death in epilepsy patients.

Source: UVA Health

New research from the University of Virginia School of Medicine reveals why sleep can put people with epilepsy at increased risk of sudden death.

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 sleep.)

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. 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.

This shows the outline of a head and brain
Both sleep and seizures work together to slow the heart rate, the researchers found. Image is in the public domain

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 deadly.

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.”

Findings Published

The researchers have published their findings in the scientific journal Epilepsia. The research team consisted of Schomer, Morgan Lynch, Stephanie Lowenhaupt, Juliana Leonardo, Valentina Baljak, Matthew Clark, Jaideep Kapur and Quigg.

Funding: The work was supported by the National Institute of Health’s National Institute of Neurological Disorders and Stroke via its NeuroNEXT program, grant 4U10NS077260-07.

About this epilepsy research news

Source: UVA Health
Contact: Josh Barney – UVA Health
Image: The image is in the public domain

Original Research: Closed access.
Synergistic effect of sleep depth and seizures correlates with postictal heart rate” by Andrew Schomer et al. Epilepsia


Synergistic effect of sleep depth and seizures correlates with postictal heart rate

Our objective was to determine the effect of sleep on heart rate following a recorded seizure. We prospectively acquired heart rate data in hospitalized epilepsy monitoring unit patients.

We analyzed heart rate trends for multiple seizures (n = 101) in patients (n = 42) with electroencephalographically confirmed events.

The patient’s sleep state was scored for the 5 min preceding each seizure and correlated with the postictal nadir heart rate (PINHR). The depth of sleep during the 5 min before a seizure correlated (correlation coefficient [CC] = −.229, p < .05) with PINHR.

This result was more significant and strengthened (CC = −.272, 95% confidence interval = −.392 to −.152, p < .001) when adjusted for covariates of age, generalized tonic–clonic seizures, and baseline heart rate. Sleep depth is an independent predictor of the change in heart rate following a seizure.

Diminished heart rate following a seizure in the setting of sleep is likely secondary to non‐rapid eye movement sleep’s synergistic effect on parasympathetic tone.

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  1. I once had a 16 year old girl found dead in her bed at a boarding school. She had a history of seizures. There was some blood on her pillow and she had braces on her teeth. I don’t know what the autopsy found but it appeared to me that she had probably smothered during sleep probably during a seizure.



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