Anli Liu, MD: Responsive Neurostimulation System for Cognition in Epilepsy

"One of the ways in which we can improve the way that we test for memory both in clinical neuropsychology as well as in cognitive neuroscience is by probing for memory function over longer timescales."

In patients with epilepsy, one of the less-often discussed issues are those of declining cognitive function—specifically memory issues. For Anli Liu, MD, the focus in measuring these abilities needs to shift toward long-term memory, such as the ability to recall encounters from a day ago, or longer.

To address this, she and colleagues have suggested probing for memory over longer periods of time when testing patients’ ability. To do this, they developed a proof-of-concept trial with patients using NeuroPace's Responsive Neurostimulation System (RNS), an FDA-approved therapy to treat medically refractory focal seizures in adults, which they adapted for this memory task. They used some research accessories to allow allowed them to interface with the clinical system to deliver trigger artifacts to time the testing with electroencephalography (EEG), as well as to allow for continuous EEG recording.

At the American Neurological Association’s 143rd annual meeting in Atlanta, Georgia, Liu sat with NeurologyLive to discuss this work and the findings of this proof-of-principle trial. Her presentation detailed that some patients with medically refractory focal epilepsy who are chronically implanted with a brain‐responsive neurostimulation device (the RNS System), which then allows for neurophysiological measurements at millisecond resolution, which allows for adaptation in order to measure hippocampal dynamics time‐locked to cognitive tasks. She illustrated the technique in 3 patients previously implanted with the RNS System as they engaged in an associative memory task, measured months apart.