Regional Connectivity Changes According to Seizure Outcome of Temporal Epilepsy Surgery- A Magnetoencephalography Study

Abstract

Objective: Temporal lobectomy is often successful in treatment of patients with medically intractable temporal lobe epilepsy (TLE), but prediction of its long-term outcome is of great interest. Here, we investigated usefulness of comparison analysis of pre- and post-surgical magnetoencephalopgrahy data in predicting prognosis of temporal lobectomy.

Methods: The authors retrospectively analyzed pre-and post-operative MEG and presence of any seizures after temporal lobectomy in 8 patients with TLE. Spectral powers averaged from spike-free epochs in each condition (pre- and post-operation) were compared between 4 patients free from seizures and the other 4 with recurrent seizures. We also performed connectivity analysis based on phase locking values (PLVs) around resection margins of possible epileptogenic focus as regions of interest.

Results: Spectral analysis on peri-lesional areas demonstrated relative increase of delta power in the patients without seizure freedom. On connectivity analysis, decrease of PLVs between other areas and temporal lobe focus after surgery were noted in patients with good surgical outcome while persistence or increase were found in patients with recurred seizures.

Conclusion: This pilot study on comparison of power spectrum and connectivity metrics between pre- and post-op MEG exhibits a potential for predicting seizure outcome after TLE surgery.