The SIGFRIED (SIGnal modeling For Real-time Identification and Event Detection) software provides real-time functional mapping (RTFM) of eloquent cortex for epilepsy patients preparing to undergo resective surgery. The current study presents the first application of paradigms used in functional magnetic resonance (fMRI) and electrical cortical stimulation mapping (ESM) studies for shared functional cortical mapping in the context of RTFM. Results from the three modalities are compared. A left-handed 13-year old male with intractable epilepsy participated in functional mapping for localization of eloquent language cortex with fMRI, ESM, and RTFM. For RTFM, data were acquired over the frontal and temporal cortex. Several paradigms were sequentially presented: passive (listening to stories) and active (picture naming and verb generation.) For verb generation and story processing, fMRI showed atypical right lateralizing language activation within temporal lobe regions of interest (ROI) and bilateral frontal activation with slight right lateralization. Left hemisphere ESM demonstrated no eloquent language areas. RTFM procedures using story processing and picture naming elicited activity in the right lateral and basal temporal regions. Verb generation elicited strong right lateral temporal lobe activation as well as left frontal lobe activation. RTFM results confirmed atypical language lateralization evident from fMRI and ESM. We demonstrated the feasibility and usefulness of a new RTFM stimulation paradigm implementation during pre-surgical evaluation. Block design paradigms used in fMRI may be optimal for this purpose. Further development is needed to create age-appropriate RTFM test batteries.

The results of the quantitative "next-neighbor" RTFM evaluation were concordant to those from ESM and fMRI. The RTFM correlates well with localization of hand motor function provided by ESM and fMRI, which may offer added localization in the operating room and guidance for extraoperative ESM mapping. Real-time functional mapping correlates with fMRI language activation when ESM findings are negative. It has fewer limitations than ESM and greater flexibility in activation paradigms and measuring responses.

Accurate language localization expands surgical treatment options for epilepsy patients and reduces the risk of postsurgery language deficits. Electrical cortical stimulation mapping (ESM) is considered to be the clinical gold standard for language localization. While ESM affords clinically valuable results, it can be poorly tolerated by children, requires active participation and compliance, carries a risk of inducing seizures, is highly time consuming, and is labor intensive. Given these limitations, alternative and/or complementary functional localization methods such as analysis of electrocorticographic (ECoG) activity in high gamma frequency band in real time are needed to precisely identify eloquent cortex in children. In this case report, the authors examined 1) the use of real-time functional mapping (RTFM) for language localization in a high gamma frequency band derived from ECoG to guide surgery in an epileptic pediatric patient and 2) the relationship of RTFM mapping results to postsurgical language outcomes. The authors found that RTFM demonstrated relatively high sensitivity (75%) and high specificity (90%) when compared with ESM in a “next-neighbor” analysis. While overlapping with ESM in the superior temporal region, RTFM showed a few other areas of activation related to expressive language function, areas that were eventually resected during the surgery. The authors speculate that this resection may be associated with observed postsurgical expressive language deficits. With additional validation in more subjects, this finding would suggest that surgical planning and associated assessment of the risk/benefit ratio would benefit from information provided by RTFM mapping.

OBJECTIVE The goal of this study was to assess the success rate and complications of stereo-electroencephalogra-phy (sEEG) and laser interstitial thermal therapy (LITT) in the treatment of nonlesional refractory epilepsy in cingulate and insular cortex. METHODS The authors retrospectively analyzed the treatment response in 9 successive patients who underwent insular or cingulate LITT for nonlesional refractory epilepsy at their center between 2011 and 2019. Localization of seizures was based on inpatient video-EEG monitoring, neuropsychological testing, 3-T MRI, PET scan, magnetoencephalography scan, and/or ictal SPECT scan. Eight patients underwent sEEG, and 1 patient had implantation of both sEEG electrodes and subdural grids for localization of epileptogenic zones. LITT was performed in 5 insular cases (4 left and 1 right) and 3 cingulate cases (all left-sided). One patient also underwent both insular and cingulate LITT on the left side. All of the patients who underwent insular LITT as well as 2 of the 3 who underwent cingulate LITT were right-hand dominant. The patient who underwent insular plus cingulate LITT was also right-hand dominant. RESULTS Following LITT, 67% of the patients were seizure free (Engel class I) at follow-up (mean 1.35 years, range 0.6–2.8 years). All patients responded favorably to treatment (Engel class I–III). Two patients developed small intracranial hemorrhages during the sEEG implantation that did not require surgical management. One patient developed a large intracranial hemorrhage during an insular LITT procedure that did require surgical management. That patient experienced aphasia, incoordination, and hemiparesis, which resolved with inpatient rehabilitation. No permanent neurological deficits were noted in any of the patients at last follow-up. Neuropsychological status was stable in this cohort before and after LITT. CONCLUSIONS sEEG can be safely used to localize seizures originating from insular and cingulate cortex. LITT can successfully treat seizures arising from these deep-seated structures. The insula and cingulum should be evaluated more frequently for seizure onset zones.

Simultaneous bilateral onset and bi-synchrony epileptiform discharges in electroencephalogram (EEG) remain hallmarks for generalized seizures. However, the possibility of an epileptogenic focus triggering rapidly generalized epileptiform discharges has been documented in several studies. Previously, a new multi-stage surgical procedure using bilateral intracranial EEG (iEEG) prior to and post complete corpus callosotomy (CC) was developed to uncover seizure focus in non-lateralizing focal epilepsy. Five patients with drug-resistant generalized epilepsy who underwent this procedure were included in the study. Their bilateral iEEG findings prior to complete CC showed generalized epileptiform discharges with no clear lateralization. Nonetheless, the bilateral ictal iEEG findings post complete CC indicated lateralized or localized seizure onset. This study hypothesized that brain functional connectivity analysis, applied to the pre CC bilateral iEEG recordings, could help identify focal epileptogenic networks in generalized epilepsy. The results indicated that despite diffuse epileptiform discharges, focal features can still be observed in apparent generalized seizures through brain connectivity analysis. The seizure onset localization/lateralization from connectivity analysis demonstrated a good agreement with the bilateral iEEG findings post complete CC and final surgical outcomes. Our study supports the role of focal epileptic networks in generalized seizures.