Distinct dual cortico-cortical networks successfully identified between supplemental and primary motor areas during intracranial EEG for drug-resistant frontal lobe epilepsy

Epilepsy Behav Rep. 2021 Jan 19:15:100429. doi: 10.1016/j.ebr.2021.100429. eCollection 2021.

Abstract

We present a case of drug-resistant focal motor seizures in which separate cortico-cortical epileptic networks within the supplementary motor area (SMA) proper and primary motor area (PMA) were proven by ictal high-frequency oscillation (HFO) and cortico-cortical evoked potential (CCEP). A 12-year-old girl presented with two types seizures: type A, tonic extension and subsequent clonic movements of the right arm; and type B, tonic and clonic movements of the right leg. MRI was normal and karyotype genetic analysis revealed 46,X,t(X;14)(q13;p12). She underwent placement of chronic subdural electrodes over the left hemisphere. We recorded a total of nine seizures during 10 days of epilepsy monitoring. Type A seizures started from the lower part of the left SMA proper and early spread to the hand motor area of the PMA. Type B seizures started from the upper part of the SMA proper and early spread to the leg motor area of the PMA. CCEPs of both SMA proper and PMA activated two identical routes for evoked potentials correlating with separate pathways. Corticectomy of the left SMA proper and PMA achieved seizure-free without hemiparesis. Within a small homunculus of the SMA proper, separate epileptic networks were proven and validated by seizure semiology, ictal HFO, and CCEP.

Keywords: CCEP, cortico-cortical evoked potential; Cortico-cortical evoked potential; ECoG, electrocorticogram; EEG, encephaloelectrography; Epilepsy surgery; FDG-PET, 18F-fluorodeoxyglucose positron emission tomography; FIQ, full intelligent quotient; HFO, high-frequency oscillation; High-frequency oscillation; IVEEG, intracranial video electroencephalography; LC, lateral central; MC, mesial central; MEP, motor evoked potentials; MRI, magnetic resonance imaging; PMA, primary motor area; Primary motor area; SISCOM, subtraction ictal single-photon emission computed tomography co-registered to MRI; SMA, supplementary motor area; SPES, single-pulse electrical stimulation; Supplementary motor area.

Publication types

  • Case Reports