Novel research suggests that sleep may encode seizures in the brain by repurposing the processes used to consolidate memories, potentially making these neurological events more difficult to treat or prevent. However, the study as well proposes a potential way to counter this effect: using electrical stimulation to prevent the brain from “memorizing” the seizure, researchers say.
“This opens up a completely new world of therapeutic options tailored to each patient,” said Dr. Vatslav Kremen, a neurologist at the Mayo Clinic. He added that electrical stimulation could be customized to fit each individual’s unique seizure pattern.
Sleep and Seizures
People often struggle with memory consolidation after seizures, and research in animal models indicates this happens because the brain’s memory storage system strengthens the neural connections that lead to seizures rather than solidifying memories. Understanding the relationship between epilepsy, memory, and sleep in humans has been challenging, however, as most studies have only measured brain activity for a few days and were typically conducted in clinical settings, which aren’t conducive to natural sleep. This new research addresses those limitations.
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“Hospital stays can alter sleep and seizure patterns due to medication adjustments, stress, noise, and disrupted routines,” explained Dr. Irene Conrad, a neurologist at the University of Pennsylvania, who was not involved in the work.
In the new study, published March 4 in the Journal of Neuroscience, electrodes were implanted for months or even years in participants as they slept at home. This allowed researchers to collect data over an extended period without disrupting natural sleep. “This gives a more realistic picture of how sleep changes after seizures in everyday life,” Conrad said.
The team analyzed data from two groups of participants with drug-resistant epilepsy who participated between 2010 and 2011 at the University of Melbourne in Australia, or between 2019 and 2023 at the Mayo Clinic in Minnesota. One group had deep brain stimulation devices implanted that could detect and reduce seizure activity, although the other received an investigational seizure monitoring system that recorded brain signals but did not attempt to interrupt seizures. The study was relatively small, involving 11 participants, so the findings may not generalize to all people with epilepsy, Kremen noted. However, the research provides evidence of how changing brain patterns during sleep could underlie the relationship between epilepsy and memory.
The researchers found that participants slept approximately 24 minutes less on nights following a seizure, but not all sleep stages were affected equally.
If the theory holds, these types of adaptive closed-loop systems could grow a new way to personalize treatment
Dr. Irene Conrad, neurologist at the University of Pennsylvania
Rapid eye movement (REM) sleep, which is important for emotional processing and dreaming, was shortened by about 12 minutes on nights following a seizure compared to seizure-free nights. Dr. Laurent Schüpbach, a neurologist at the University of Geneva, who was not involved in the work, said in an email that “12 minutes may not sound like much, but consider that the total duration of REM sleep isn’t very long either—typically around 1 hour and 40 minutes—so the decrease is meaningful.”
Conrad noted that what replaces the lost minutes of REM sleep is also important. The team found an increase in the length and intensity of a deeper stage of sleep, called slow-wave sleep, which is crucial for memory storage. One hypothesis is that the brain is using memory-formation pathways to “remember” how to have seizures in the future, but observations from this study alone cannot prove that Here’s the case.
Forecasting Seizures Using Sleep Patterns
In future work, the team needs to determine whether prolonging memory consolidation during sleep actually reinforces seizures by “memorizing” seizure pathways.
“Using brain devices that adjust stimulation based on seizures and sleep patterns is an exciting possibility,” Conrad said. These devices apply electrodes to record brain activity and deliver electrical pulses to stop a seizure once it’s detected. They use a closed-loop feedback system to improve detection over time as the system learns an individual’s seizure patterns.
“This type of approach could help test the central idea of the study by determining whether changing brain activity associated with sleep after a seizure reduces the chance of future seizures,” Conrad added. “If the theory holds, these types of adaptive closed-loop systems could become a new way to personalize treatment.”
Kremen said the findings suggest that electrical brain stimulation that disrupts the formation of seizure memories could be a future add-on treatment alongside medication for patients with drug-resistant epilepsy. “We are really investing in trying to find treatments for very sick people with epilepsy who have no hope with usual drug treatments.”
This article is for informational purposes only and is not intended to be a substitute for medical advice.
