April 5, 2023

Can Electrical Stimulation Prod Memory in Epilepsy Patients?

Article published by  UCHealth Today

Is it possible to prod the brain to remember better? That is the subject of a study recently begun at the University of Colorado – Anschutz Medical Campus. The multi-center trial, funded by the National Institute of Neurological Disorders and Stroke, tests whether timed pulses of electrical stimulation, delivered to targeted areas of the brain, could improve a person’s ability to store and retrieve the elements that are the stuff of memory.

Dr. Aaron Geller, assistant professor in the Department of Neurology at the University of Colorado School of Medicine, leads the study at CU. He noted that “epilepsy and memory intersect in multiple ways.” For example, tonic-clonic seizures (often called grand mal) nearly always interfere with memory, simply because they can render a person unconscious, he said.

Focal onset impaired awareness seizures (or partial complex), which affect a small area of the brain, can cause relatively brief periods of unawareness that also contribute to memory loss. These seizures create abnormal brain rhythms that disrupt areas “critical for being conscious and processing the flow of information,” Geller said. The result is a “temporary disruption in forming new memories.”

Finally, epilepsy can cause long-term memory loss in people who suffer seizures in the brain’s temporal lobe, a frequent site of attacks. The temporal lobe lies near the hippocampus – the brain’s “most important memory circuitry,” Geller said. Repeated seizures in this area can cause brain damage that wipes away memories over an extended period of time.

The memory study’s subjects are those for whom anti-seizure medications have been ineffective – about one-third of all epilepsy patients, Geller said. The patients are enrolled in a separate surgical plan that requires intracranial electroencephalography (EEG) monitoring. The procedure involves drilling holes through the skull and placing electrodes on or in the brain. The aim: detect and monitor brain waves – the signs of the electrical weather in the brain.

Rather than surgical planning, Geller and other memory study researchers aim to use the electrical mapping to scrutinize the brain waves that may pinpoint areas of diminished memory power. The hypothesis – grounded in studies previously conducted at the University of Pennsylvania – is that low-performing memory areas of the brain can be improved with electrical stimulation – a “nudge,” as Geller puts it.

Geller’s research team observes the patient’s brain rhythms during memory tests while they undergo EEG monitoring. The first tests occur without any stimulation. The team analyzes that data to build a computer model, based on the rhythms, that predicts whether the patient is in “high-performance or low-performance memory states,” Geller said.