Sainburg, Lucas E.; Roche, Alexandra; Makhoul, Ghassan S.; Rogers, Baxter P.; Roberson, Shawniqua Williams; Meletti, Stefano; Vaudano, Anna E.; Chang, Catie; Englot, Dario J.; Morgan, Victoria L. (2026).听.听Epilepsia. Advance online publication.听
Accurately identifying the聽epileptogenic zone (EZ)鈥攖he area of the brain where seizures begin鈥攊s essential for planning surgery in people with聽medication-resistant epilepsy. While combining聽electroencephalography (EEG)听飞颈迟丑听functional magnetic resonance imaging (fMRI)聽can help locate this region, the technique requires specialized equipment and is not widely available. In this study, the researchers developed a new fMRI-based measure called the聽dynamic functional connectivity (dFC) peak index, which aims to identify seizure-related brain activity without the need for simultaneous EEG. They evaluated the method in 62 patients with focal epilepsy, most of whom had聽temporal lobe epilepsy (TLE), and compared the results with those from 109 healthy volunteers. The dFC peak index was elevated in brain regions known to be involved in temporal lobe epilepsy, particularly the medial temporal lobe. Patients whose surgeries removed areas with higher dFC peak index values were more likely to have better seizure outcomes, including those whose standard MRI scans did not show visible abnormalities. These findings suggest that the dFC peak index may provide valuable additional information for identifying the epileptogenic zone and could help guide surgical planning for people with medication-resistant epilepsy.
FIGURE 1
Negative dFC聽peaks. (A) Description of negative dFC peaks. Temporally Z-scored timeseries for the DMN聽and a region are shown. The two timeseries are multiplied together at each timepoint to calculate the dFC timeseries between the two regions. Negative dFC peaks are highlighted with black circles, with solid circles denoting peaks of interest (DMN deactivation) and dotted circles denoting peaks of no interest (DMN activation). (B) Examples of negative dFC peaks following interictal epileptic discharges in a patient with left medial temporal lobe epilepsy (top) and right lateral temporal lobe epilepsy (bottom). The EEG-based interictal epileptic discharge activation maps are shown on the left along with a map of the DMN. The timeseries for the DMN, the activated region from the interictal discharges, and the dFC between the two regions are shown in red, yellow, and blue, respectively. DMN, default mode network; dFC, dynamic functional connectivity; EEG: electroencephalography; fMRI, functional magnetic resonance imaging.