Epileptic seizures alter sleep by prolonging the stage that's central to
memory formation, potentially predisposing the brain to "remember" how
to trigger subsequent seizures more easily, a small human study
suggests.
Sleep could encode
epileptic seizures in the brain by repurposing the processes used to
solidify memories, potentially making seizures harder to treat or
prevent, new research suggests. But the new study also suggests a
possible way to counter the effect: using electrical stimulation to keep
the brain from "memorizing" the seizure, the researchers say.
"It opens a whole new realm of therapeutic options tailored to each patient," said study co-author Vaclav Kremen,
a neuroscientist at the Mayo Clinic. He added that electrical
stimulation could be personalized to each individual’s unique seizure
profile.
Sleep and seizures
People often struggle to store memories after epileptic seizures, and research in rats
suggests this occurs because the brain’s memory storing system
solidifies neuronal connections that trigger seizures in lieu of locking
in memories. However, the link between epilepsy, memory and slumber
hasn't been adequately assessed in humans because most of these studies
involve measuring brain activity for only a few days and the research
usually takes place in clinics, which don't lend themselves to a good
night's sleep.
"Hospital stays can change sleep
and seizure patterns because of medication adjustments, stress, noise,
and disrupted routines," Dr. Erin Conrad, a neuroscientist at the University of Pennsylvania who was not involved with the work, told Live Science in an email.
In the new study, published March 4 in The Journal of Neuroscience,
electrodes were implanted for months or years into participants who
slept at home, allowing the researchers to collect data over a long
period without disturbing sleep. "That gives a more realistic picture of
how sleep changes after seizures in everyday conditions," Conrad said.
The team analyzed 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 was implanted with deep
brain stimulation devices that can detect and reduce seizure activity,
while the other got an investigational seizure advisory system that
records brain signals but does not try to interrupt seizures. The study
was small, totaling 11 participants, so the findings may not be
generalizable to all epilepsy patients, Kremen told Live Science.
Nonetheless, the work provides clues as to how changing brain patterns
during sleep could underlie the link between epilepsy and memory.
The
team found that people slept approximately 24 minutes longer on nights
following epileptic seizures, yet not all stages of sleep were
prolonged.