Inducing Epileptic Seizures Prior to Surgery Aids in Locating Source

The findings of a study published in JAMA Neurology suggest that inducing seizures before surgery on patients with epilepsy may pinpoint the brain region where the seizures are located.

Approximately 20% of epileptic patients require electrodes inserted directly into their brains. These patients frequently undergo cortical stimulation, a procedure which administers electrical current to induce seizures for better understanding of epileptic functioning. The current study marked the first to systematically address whether inducing seizures in preparing of surgery is as effective as depending on spontaneous seizures.

In this cohort study, researchers assessed data from 103 (52.4% female, mean age, 31, 57.3% with induced seizures) patients with focal drug-resistant epilepsy who went underwent stereo electroencephalography (SEEG) between January 2007 and January 2017 from two tertiary epilepsy centers: Montreal Neurological Institute in Montreal, Quebec, Canada, and Grenoble-Alpes University Hospital in Grenoble-Alpes University Hospital in Grenoble, France. Eligibility criteria included cortical stimulation during implantation, and subsequently, an open surgical procedure with a follow-up of one or more years. The study’s outcomes and measures comprised cortical stimulation induced seizures, resection volume, and the percentage of resected electrodes inducing a seizure, as well as spontaneous seizure onset regions. All measures were correlated to either good or poor surgical outcomes.

Findings May Reduce Hospital Time

Following an analysis of all electronical characteristics correlated with cortical induced seizures, results of the study showed that the percentage of patients with cortical stimulation–induced electroclinical seizures was higher in the good outcome group when juxtaposed to the poor outcome group (70.5% vs 47.5%), indicating that patients with induced seizures experienced better outcomes. Moreover, the resected contacts surrounding the cortical stimulation–informed seizure-onset zone were linked with surgical outcome (percentage in good vs poor outcome: 63.2% vs 33.3%] with similar results observed for spontaneous seizures (percentage in good vs poor outcome (57.1% vs 32.7%). Moreover, prolonged time since the most recent seizure was correlated with a greater likelihood of inducing seizures.

“I think it would be a huge advantage if this procedure was done in the first days of a patient’s stay,” said Dr. Birgit Frauscher, lead researcher of the study, in a press release. “It’s not a new procedure, but the approach is new in the sense that now we know it’s very similar to a spontaneous seizure, so we can reduce hospital time. Instead of being in hospital for two weeks, patients can maybe be there for 48 or 72 hours and we only need to record maybe one additional spontaneous seizure and not several, and that is a huge difference.”

Image source: The Neuro