Score may predict which patients with epilepsy should get SEEG

A validated score was able to predict among which patients with epilepsy stereoelectroencephalography was unlikely to identify a focal seizure-onset zone, according to results of a cohort study published in JAMA Neurology.

“There is a worldwide increasing trend toward the use of stereoelectroencephalography (SEEG), which offers the advantage of a 3-dimensional exploration of the epileptogenic network with coverage of deep and bilateral brain structures without large craniotomies,” Alexandra Astner-Rohracher, MD, of the Montreal Neurological Institute and Hospital at McGill University in Canada, and colleagues wrote. “Demonstration of the seizure-onset zone, defined as the area of the cortex that initiates clinical seizures, currently offers the best approximation of the epileptogenic zone and identification of a focal resectable seizure-onset zone is the primary goal of SEEG. However, up to 42% of patients are not eligible for subsequent epilepsy surgery because their epilepsy is not focal or the generator is located in eloquent cortex or cannot be identified.”

According to the researchers, this presents problems due to SEEG being invasive with procedure-related complications, time-consuming and resource intensive. In the current study, they aimed to examine the five-point 5-SENSE score for predicting focality of the seizure-onset zone in SEEG, with score development preceding multicenter validation. Patient selection occurred between February 2002 and October 2018 and between May 2202 and December 2019. Follow-up lasted a year or longer.

Researchers examined 128 patients with drug-resistant epilepsy (44.5% were women; median age, 31 years) who underwent SEEG at a single institute, with selection criteria including two or more seizures in electroencephalography and availability of complete neuropsychological and neuroimaging data sets. Further, they included for validation patients from nine epilepsy centers who met these criteria. They grouped patients as focal and nonfocal seizure-onset zone according to SEEG results.

In the score, researchers used predictive variables that included focal lesion on structural MRI, absence of bilateral independent spikes in scalp electroencephalography, localizing neuropsychological deficit, strongly localizing semiology and regional ictal scalp electroencephalography onset. Results showed an optimal mean probability cutoff for identification of a focal seizure-onset zone of 37.6 for the 5-SENSE score. Astner-Rohracher and colleagues noted area under the curve of 0.83, specificity of 76.3% and sensitivity of 83.3%, with validation showing 76% specificity and 52.3% sensitivity.

“The 5-SENSE score provides an easily applicable tool to guide clinicians in predicting if SEEG will unlikely identify a focal seizure-onset zone,” the researchers wrote. “Thereby, patients with small likelihood to benefit from this invasive and resource-intensive investigation can be identified earlier avoiding unnecessary procedure-related burden on patients and overutilization of health care resources.”