Invasive Evaluation for Epilepsy Surgery Lesional Cases NO DISCLOSURES. Mr. Johnson. Seizures at 29 Years of Age. Dileep Nair, MD Juan Bulacio, MD

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1 Invasive Evaluation for Epilepsy Surgery Lesional Cases NO DISCLOSURES Dileep Nair, MD Juan Bulacio, MD Mr. Johnson Seizures at 29 Years of Age Onset of seizures at 16 years of age bed wetting episodes Took antiepileptic medication until 19 years of age, then stopped Seizures recurred at 21 years of age Staring, decreased responsiveness, hand automatisms 3 per day Evolution to generalized tonic clonic convulsion 1 to 3 per 3 months Trials of multiple antiepileptic medications Repetitive Spikes, Left Fronto Central EEG onset: Left Fronto-Central region

2 EEG Seizure, +10 sec - Left Fronto-Central End of EEG Seizure, +30 sec Etiology? Question #1 Normal neurological examination No epilepsy risk factors Earlier MRI interpreted as normal In children or young adults with no epilepsy risk factors and drug-resistant focal epilepsy, the most likely subtle finding on an otherwise normal brain MRI is focal cortical dysplasia. 1. True 2. False Question #1 Transmantle Malformation of Cortical Development In children or young adults with no epilepsy risk factors and drug-resistant focal epilepsy, the most likely subtle finding on an otherwise normal brain MRI is focal cortical dysplasia. 1. True 2. False R Coronal FLAIR

3 Transmantal MCD Language Activation Overlying the Area of Dysplasia Word generation Listening Rhyming R Axial FLAIR Question #2 Question #2 When comparing subdural and stereotactic depth electrodes, which of the following is false? When comparing subdural and stereotactic depth electrodes, which of the following is false? 1.Subdural electrodes may afford more extensive mapping of eloquent cortex 1.Subdural electrodes may afford more extensive mapping of eloquent cortex 2.Stereotactic depth electrodes may afford more precise recording from deeper regions away from the cortical surface 2.Stereotactic depth electrodes may afford more precise recording from deeper regions away from the cortical surface 3.Subdural electrodes have a lower risk of complications than stereotactic depth electrodes 3.Subdural electrodes have a lower risk of complications than stereotactic depth electrodes 3D reconstruction of subdural and depth electrodes Question #3 Which of the following is the most highly significant and characteristic electrocortigraphic finding of focal cortical dysplasia? 1. Continuous repetitive discharges Intraoperative photograph showing the left hemisphere covered by subdural and depth electrodes 2. High amplitude spikes 3. High frequency oscillations 4. EEG seizures with no clinical signs

4 Question #3 Repetitive Spikes, Left Inferior Frontal Which of the following is the most highly significant and characteristic electrocortigraphic finding of focal cortical dysplasia? 1. Continuous repetitive discharges 2. High amplitude spikes 3. High frequency oscillations 4. EEG seizures with no clinical signs EEG Seizure, Onset With Clinical Signs 4 recorded Repetitive Spikes SB 39 EEG Seizure (SB35-39 and depths) EEG Seizure, +15 sec

5 EEG Seizure, Onset (SB 35-39) EEG Seizure, + 10 sec Without Clinical Signs 1 to 2 per hr Question #4 Question #4 Which of the following conditions should be met for speech arrest during cortical stimulation to reliably indicate that the electrode overlies language-eloquent cortex? 1. No effect on tongue mobility Which of the following conditions should be met for speech arrest during cortical stimulation to reliably indicate that the electrode overlies language-eloquent cortex? 1. No effect on tongue mobility 2. No significant EEG after-discharge 3. Non-eloquent reference electrode 2. No significant EEG after-discharge 3. Non-eloquent reference electrode 4. All of the above 4. All of the above

6 Early spread, EEG seizure Early spread, EEG seizure Speech LLA Early spread LLA 9,10 SA 16,12, LLP SB 39,35 18 Speech SB 31 (15 ma), SB 28 (15 ma) Patient Management Conference Neurosurgical Consultation 13 LLA Stimulated electrodes (underlined) Sublobar Resection, Left Pars Orbitalis Outcome No seizures since surgery (early 2015) No epileptiform discharges on postoperative EEG No postoperative language deficit Pathology: Type II cortical dysplasia Focal cortical architectural disorganization Dysmorphic neurons and balloon cells

7 Case Highlights Finding the Lesion Case Highlights When Invasive Evaluation is Needed Focal cortical dysplasia is an important cause of drug-resistant surgically-remediable epilepsy, which may be subtle or invisible on MRI Subdural electrodes - close spatial resolution of the epileptogenic zone in relation to eloquent cortex Stereotactic depth electrodes - recording from deeper regions Case Highlights When Invasive Evaluation is Needed Subdural electrodes - close spatial resolution of the epileptogenic zone in relation to eloquent cortex Stereotactic depth electrodes - recording from deeper regions The choice of either or both techniques must be individualized in every case