BALTIMORE – , according to data presented at the annual meeting of the American Epilepsy Society. In addition, improvements in functional status are strongly associated with improvements in global cognitive performance.
Dr. Daniel Drane
Previous data have indicated that SLAH results in superior cognitive outcomes, compared with selective and standard open resection, in the treatment of medial temporal lobe epilepsy. The rates of seizure freedom following these procedures are equivalent. Daniel Drane, PhD, associate professor of neurology at Emory University in Atlanta, and colleagues hypothesized that the preservation of cognitive skills following SLAH would be apparent in real-world settings. To test this hypothesis, they investigated changes in functional status following SLAH.
Functional status correlated with neurocognitive change
Dr. Drane and colleagues compared functional outcomes in 53 patients who underwent SLAH at the Emory University Epilepsy Center and 20 patients who underwent open resection at the same center. The investigators created a hierarchical classification of functional status using the following criteria (from best to worst): employed and independent with all activities of daily living (ADLs), unemployed and independent with all ADLs, unemployed and independent with lower ADLs only (i.e., independent with self-care, but not with management of finances, medications, etc.), and unemployed and unable to manage any ADLs without assistance. Dr. Drane and colleagues rated all patients on these criteria at baseline and at 1 year after surgery. They classified patients as improving, declining, or remaining stable in functional status. Finally, the investigators used Fisher’s exact test to compare the proportional ratings of change between surgical procedures.
At baseline, the proportions of patients in each functional group were similar between patients who later underwent SLAH and those who later underwent open resection. Significantly more patients who underwent SLAH, however, had functional improvement, compared with patients who underwent open resection (13.2% vs. 0%). Furthermore, fewer patients who underwent SLAH had functional decline, compared with those who underwent open resection (3.7% vs. 35%).
Dr. Drane and colleagues found a strong correlation between functional status and global ratings of neurocognitive change, but no correlation between functional status and seizure-freedom status. Patients who underwent SLAH were less likely to have a decline in employment status than were patients who underwent open resection were (4.2% vs. 45.4%).
Weighing surgical options for a given patient
“This study provides a real-world metric of meaningful change following surgery, which is, critically, independent of seizure freedom outcome,” said Dr. Drane. “If a patient becomes seizure free but declines in functional status, presumably due to compromised cognitive function, this outcome is likely not going to lead to a better quality of life. Overall, our data suggest that functional status is driven more by cognitive outcome than by seizure freedom, and that it is an equally important metric for determining whether or not surgery has been successful. We would hope that the epilepsy surgical team would try to balance the desire to achieve seizure freedom against the potential risks and benefits of surgery on cognitive performance and functional status.”