Authors :
Presenting Author: Christina Tran, BS – Kaiser Permanente School of Medicine
EISHA CHRISTIAN, MD, FAANS, FCNS – Kaiser Permanente School of Medicine
Jane Hwang, MD – Kaiser Los Angeles Medical Center
Dean Sarco, MD – Kaiser Los Angeles Medical Center
Jingtian Wang, MD – Kaiser Los Angeles Medical Center
Emily McGinnis, MD – Kaiser Los Angeles Medical Center
Rationale:
Temporal lobe epilepsy (TLE) is the most common seizure disorder, affecting 50 million people worldwide. The more common subtype, mesial temporal lobe epilepsy (MTLE), is often refractory to antiepileptic drugs, but is amenable to surgical treatment, making up a large proportion of cases referred for epilepsy surgery.
Presurgical evaluation aims to determine lateralization and localization of the seizure onset zone (SOZ), with interictal epileptiform discharges in a location being highly suggestive of epileptogenic zone in that region. Magnetoencephalography (MEG) can be a useful adjunct to electroencephalography (EEG), offering source localization of interictal data with spatial resolution.
The objective of this study is to evaluate the effectiveness of MEG in the management of TLE.
Methods:
We performed an IRB-approved retrospective review of patients with TLE who underwent MEG as part of their workup at Los Angeles Medical Center from 2017 to 2023. Inclusion criteria were patients with MEG, EEG, and MRI data who had undergone confirmatory invasive intracranial monitoring with either SEEG or responsive neurostimulation (RNS). Patients diagnosed with non-temporal or generalized epilepsy were excluded. Results:
this case series included 8 patients with a mean age at seizure onset of 15.38 years (±12.14), a mean age at time of MEG recording of 26.88 years (SD ±13.77), and a mean duration of epilepsy of 11.50 years (SD ±10.63).
EEG indicated bitemporal onset in 7/8 patients. MEG showed bilateral temporal spikes in 4/8 and no spikes in 1/8. MEG helped predict seizure laterality in 5/8 cases (63%), but only correlated with SOZ in 3/8 (38%)
Conclusions:
MEG can be helpful in predicting seizure laterality and although it is a useful adjuvant, it does not replace invasive intracranial recordings for prediction of epileptogenic zone. Nonlesional cases may benefit more from MEG localization, as 2/3 nonlesional cases had MEG findings that correlated with the consensus of presurgical evaluation and accurately predicted seizure laterality.
Funding: None