Synergy of MEG Spike Analysis, High Density Scalp EEG, and Stereo EEG Leading to Successful Functional Mapping and Epileptogenic Network Analysis in a Pediatric Patient with Porencephaly
Abstract number :
3.135
Submission category :
3. Neurophysiology / 3D. MEG
Year :
2023
Submission ID :
1188
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Yashwanth Reddy Pulluru, MD – University of Nebraska Medical Center
Erin Dennis, MD – University of Nebraska Medical Center; Valentina Gumenyuk, PhD – University of Nebraska Medical Center; Oleg Korzyukov, PhD – University of Nebraska Medical Center; Sookyong Koh, Md, PhD – University of Nebraska Medical Center; Spriha Pavuluri, MD – University of Nebraska Medical Center
Rationale: Traditional methods for functional mapping and identification of epileptogenic zones may not be reliable or feasible for all patients with medically refractory epilepsy. Specifically, pediatric patients and those with developmental delay affecting cognition, language, and behavior may be unable to cooperate with and tolerate these diagnostic tests. Large structural brain abnormalities present an added technical challenge to precise localization. We present a case and literature review to highlight the strength of combining multiple modalities, specifically MEG and stereo EEG (SEEG), in surgical work up for these challenging populations. We need to be able to model dynamic neurophysiological interactions to understand the complex process of seizure onset and propagation. Relying solely on intracranial monitoring, which has limited spatial sampling, can limit our understanding of a dynamic process, carrying inherent risks for surgical planning.
Methods: An obligatory right-handed male who was born at 32 weeks gestation with right hemispheric grade IV intraventricular hemorrhage developed cerebral palsy with left spastic hemiparesis, febrile seizures at age two, global developmental delay associated with continuous spikes in non-REM sleep and epilepsy. He then developed focal motor and focal to bilateral tonic clonic seizures at age four. Seizures became medically refractory, occurring up to six times per month despite appropriate trials of seven antiseizure medications. He had a large right frontoparietal porencephalic cyst on MRI, and seizures with right frontal ictal onset on scalp EEGs with high burden of right > left frontal discharges, most prominently in sleep. At age eight surgical work up was initiated. PET demonstrated right frontal hypometabolism along the anterolateral margin of the lateral ventricle. Dipole analysis initially localized a MEG cluster to the right medial parietal dipole, however spontaneous SEEG analysis and subsequent SEEG stimulation of this cluster did not reveal a definite seizure onset zone. This shed light on the limitations of dipole cluster analysis in abnormal pediatric brains. We proceeded with combining multiple complimentary datasets (MRI, MEG, EEG, and SEEG) using CURRY® analysis and were able to create a more dynamic representation of the patient’s epileptogenic network.
Results: He had laser interstitial thermal therapy to the right hippocampus and frontal rim of the cyst, resulting in a lower seizure frequency of one per month, and now seizure freedom for seven weeks to date. He has also had significant improvements in motor skills, cognition, and mood.
Conclusions: This case highlights the potential pitfalls of traditional methods of epileptogenic zone identification and functional mapping in pediatric patients with medically refractory epilepsy, global developmental delay, and structural brain abnormalities. MEG analysis of the interictal network and eloquent functions can lead to more accurate SEEG implantation, especially in in patients with abnormal brain anatomy, and ultimately combining multiple modalities can lead to more objective source localization and better understanding of the epileptogenic network.
Funding: None
Neurophysiology