Localizing Value of TIRDA in a Presurgical Evaluation Based on Invasive EEG and Post-surgical Outcomes
Abstract number :
3.151
Submission category :
3. Neurophysiology / 3A. Video EEG Epilepsy-Monitoring
Year :
2022
Submission ID :
2204444
Source :
www.aesnet.org
Presentation date :
12/5/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:25 AM
Authors :
Brin Freund, MD – Mayo Clinic Florida; Valerie Davis, R.EEG – Mayo Clinic Florida; Anteneh Feyissa, MD – Mayo Clinic Florida; Sanjeet Grewal, MD – Mayo Clinic Florida; Anthony Ritaccio, MD – Mayo Clinic Florida; Sofia Sanchez Boluarte, MD – Instituto Nacional de Ciencias Neurologicas, Peru.; Joseph Sirven, MD – Mayo Clinic Florida; William Tatum, DO – Mayo Clinic Florida; Priya Sharma, DO – Mayo Clinic Florida and Nemours
Rationale: Most cases of drug resistant focal epilepsy arise from the temporal lobe, and mesial temporal lobe epilepsy (mTLE) in particular is often drug-resistant and presurgical evaluation in these cases is recommended. Patient selection for surgery using EEG and MRI data is vital in localizing and/or lateralizing the seizure onset zone (SOZ) and interictal scalp EEG plays a key role in planning invasive EEG (iEEG) and surgical treatment. In particular, temporal intermittent rhythmic delta activity (TIRDA) is an EEG pattern felt to strongly predict seizures in patients with temporal lobe epilepsy (TLE) but its localizing value has been questioned. However, the largest prior study on TIRDA omitted iEEG to correlate the SOZ.
Methods: We reviewed the EMU database of the Mayo Clinic Florida patients who previously underwent iEEG from September 2018 to July 2021. Prior scalp EEG during Epilepsy Monitoring Unit (EMU) admission performed at our institution was reviewed in this cohort to select those with TIRDA. Charts were reviewed to obtain clinical data and review iEEG.
Results: A total of 41 patients underwent iEEG. Seven (3 females) were found to have TIRDA. All were unilateral, 4 on the left and 2 on the right. Of these patients, 4 underwent iEEG with a combination of grids, strips, and depth electrodes and 3 were evaluated with stereo-EEG. On iEEG, the SOZ was located in the ipsilateral hippocampus in 2, was contralateral in 1 and arose from the temporal neocortex in 2. One of the patients with neocortical TLE had seizures arise from a concomitant periventricular nodular heterotopia (PVNH). One had a SOZ in the parahippocampal gyrus, and one in the frontal lobe. LITT was performed in the mesial temporal lobe in all 2/3 patients with hippocampal seizures, in the frontal lobe in 1 case, and PVNH in another. Temporal lobectomy was performed in the remaining 2 patients. Mean follow up after surgery was 21.9 months. Following surgery, 5 patients had at least a 50% reduction in baseline seizure frequency.
Conclusions: TIRDA reflected temporal lobe localization in 5/7 cases based on invasive EEG data and surgical outcome. Though TIRDA has a high correlation with a temporal SOZ, it may not be specific for mTLE with iEEG localizing to temporal neocortex and may be seen with extratemporal epilepsy with TIRDA masquerading as a “pseudotemporal” feature on scalp EEG.
Funding: None
Neurophysiology