Authors :
Presenting Author: Holly Skinner, DO, MS – Advent Health Orlando
James Baumgartner, MD – epilepsy neurosurgeon, Pediatric neurosurgery, Advent Health Orlando; Richard Beegle, MD – Neuro-radiologist, Radiology, Advent Health Orlando; Eduardo Castillo, PhD – Director of MEG, Neuroscience, Advent Health Orlando; Elakkat Gireesh, MD – Epileptologist, Neurology, Advent Health Orlando; Joo Hee Seo, MD – Pediatric Epileptologist, Pediatric Neurology, Advent Health Orlando; Christina Wombles, ARNP – Nurse Practioner, Neurology, Advent Health Orlando; Angel Claudio, MD – Epileptologist, Neurology, Advent Health Orlando; Ammar Hussain, MD – Pediatric Epileptology, Pediatric Neurology, Advent Health Orlando; Ki Lee, MD – Director of Epilepsy Program, Pediatric Neurology, Advent Health Orlando
Rationale:
Seizures arising from the cingulate gyrus are difficult to localize on scalp EEG due to the cingulate’s medial and deep position, diffuse projections, and diverse ictal spread patterns. Both scalp EEG and magnetoencephalography (MEG) have previously been reported to not provide accurate ictal onset zone localization in patients with cingulate epilepsy. Nonetheless, data from these two modalities may be useful in prognosticating outcomes prior to epilepsy brain surgery. We hypothesis a positive relationship between unilateral scalp EEG onset and unilateral source localization of interictal discharges on MEG with better seizures outcomes using International League Against Epilepsy (ILAE) classification.
Methods:
The data for this case series was obtained via retrospective chart review. Patients were selected using the following criteria: 1) Drug resistant epilepsy (documented, continued seizures despite trial of at least two antiepileptic drugs); 2) ictal scalp EEG followed by stereo EEG recording documenting seizure originating from the cingulate regions; and 3) cingulate surgery. All patients underwent laser interstitial thermal therapy (LiTT) surgery of the cingulate between January 1, 2018, and June 30, 2022. All patients completed a presurgical workup included a scalp video-EEG evaluation; magnetic resonance imaging (MRI) of brain, positron emission tomography (PET), and neuropsychological evaluation to localize the epileptogenic zones. Then, patients underwent placement of sEEG electrodes including electrodes in the cingulum, and underwent cingulate LiTT. We compared scalp EEG patterns and source localization of interictal discharges on MEG for patients with ILAE 1-2 outcomes versus ILAE 3-5 outcomes using chi-square tests.
Results:
Twenty-one patients underwent presurgical work-up including MEG, scalp, and sEEG recordings with sEEG electrodes in the cingulum, and cingulate LiTT (Table 1). Bilateral cingulate sEEG recording was performed for 15 patients (71.4%) and unilateral for six. There were 10 patients with ILAE outcomes 1 or 2 including nine patients with an outcome score of 1 (42.9%), and one patient with an outcome score of 2 (4.8%). There 11 patients with ILAE outcome 3-5 including four patients each with scores 3, and 5 (19.0% each) and 3 ILAE 4 patients (14.3%). Bilateral ictal onset on scalp EEG was a common finding occurring in six (60%) of the ILAE 1-2 group and seven (63.6%) of ILAE 3-5 groups. However, bilateral source localization of interictal discharges on MEG was significantly different between the groups. In the ILAE 1-2 group, a single patient (10%) had bilateral discharges noted, but seven (63.6%) had bilateral discharges in the ILAE 3-5 group, p=0.0237.
Conclusions:
We found no significant relationship between bilateral ictal onset on scalp EEG and ILAE outcomes. However, there was a significant relationship between unilateral localization of interictal discharges on MEG and good (1-2) ILAE outcomes. These results suggest pre-operative MEG data may be useful in prognosticating seizures freedom prior to unilateral cingulate surgery.
Funding: None