Novel Tool May Prevent Unnecessary Brain Surgery for Epilepsy

Megan Brooks

December 08, 2021

Researchers have developed and validated a quick, non-invasive, web-based tool that identifies patients with epilepsy who are unlikely to benefit from invasive stereoelectroencephalography (SEEG).

The 5-SENSE score includes five variables that predict the seizure-onset zone: focal lesion on structural MRI, absence of bilateral independent spikes in scalp electroencephalography (EEG), localizing neuropsychological deficit, strongly localizing semiology, and regional ictal scalp EEG onset.

Available online, the 5-SENSE score is a "simple and useful tool for assisting clinicians to reduce unnecessary invasive diagnostic burden on patients and overutilization of limited healthcare resources," the researchers note.

"It takes about 1 minute to complete and can be directly used in the clinic," study investigator Birgit Frauscher, MD, PhD, Montreal Neurological Institute and Hospital, McGill University, Canada told Medscape Medical News.

The findings were published online December 6 in JAMA Neurology.

A Reliable Indicator

"SEEG has become the criterion standard in case of inconclusive, noninvasive presurgical epilepsy workup. However, up to 40% of patients are subsequently not offered surgery because the seizure-onset zone is less focal than expected or cannot be identified," the investigators write.

The 5-SENSE score was developed in a cohort of 128 patients (57 women; median age, 31 years) with drug-resistant epilepsy undergoing SEEG at the Montreal Neurological Institute to identify a focal seizure-onset zone.

In the development cohort, the 5-SENSE score differentiated those whose SEEG identified a defined seizure source from those that did not. Area under the curve, specificity, and sensitivity were 0.83, 76.3% and 83.3%, respectively.

The researchers validated the score on a larger cohort of 207 patients (97 women, median age, 32) from nine different tertiary epilepsy centers, finding that it reliably predicted the patients in whom SEEG was unable to identify a focal seizure onset zone. In the validation cohort, specificity was 76% and sensitivity was 52.3%.

Helpful Tool

Reached for comment, David Burkholder, MD, neurologist with the Mayo Clinic, Rochester, Minnesota, noted that selection of epilepsy patients with phase 2 intracranial monitoring and surgery is a "time-intensive process and can be difficult, so scores like this can be helpful in the process."

"In the case of phase 2 intracranial monitoring, and SEEG in particular, it is important to have a detailed understanding of the patient’s epilepsy because there is significant risk of sampling error resulting in failure to achieve the desired outcome if there is a lack of understanding or misinterpretation of data," Burkholder, who was not involved with the research, told Medscape Medical News.

The 5-SENSE tool "forces the user to consider their hypothesis in the context of other objective data. A strong hypothesis is probably the most important thing to have prior to implantation, and adding readily available objective information to that helps provide further clinical context," Burkholder said.  

"It allows some degree of standardization for decision-making in a process that can often be affected by different cognitive biases of those in the driver’s seat, and anything we can do to remove bias from our decision making is helpful," he added.

Regarding the 5-SENSE score in particular, Burkholder cautioned that the "sensitivity and specificity scores seen in the validation group are less than ideal when it comes to definite clinical utility. It really highlights how difficult it is to make these decisions and come up with good tools to help us."

This research was funded by the Montreal Neurological Institute, the Fonds de Recherche du Québec–Santé, and the Austrian Chapter of the International League against Epilepsy. Frauscher reported a salary award from Fonds de Recherche du Québec and grants from Montreal Neurological Institute; personal fees from Eisai and UCB; grants from Eisai; and her research program is supported by the Canadian Institutes of Health Research, the Canadian Foundation for Innovation, the Natural Sciences and Engineering Research Council of Canada, the Savoy Epilepsy Foundation, the Hewitt Foundation, and start-up funding of the Montreal Neurological Institute. Burkholder has disclosed no relevant financial relationships.

JAMA Neurology. Published online December 6, 2021. Abstract

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