EEG is used to monitor brain function and can detect normal, complex, chaotic, or seizure brain activity. Current epilepsy surgery standards include cranial resection surgery and multiple subpial transections. Vagus nerve stimulation reduces seizure frequency over 50% in 65% of patients, but carries risks of infection and stroke. Future directions include responsive neurostimulation, which is undergoing FDA approval, and deep brain stimulation, while indirect drug application, cortical cooling, and optogenetics represent more distant possibilities.

1. EPILEPSY SURGERY: CURRENT STANDARDS FUTURE DIRECTIONS Werner Doyle, MD Associate Professor Department of Neurosurgery NYU Langone Epilepsy Center

2. EEG used to monitor brain processes (brain function) Normal Complex Chaotic Seizure Simple Rhythmic

3. Surgical Methods Resection (craniotomy) Disconnection (MST, callosotomy) Alteration chemical / drugs electrical stimulation magnetic stimulation other (experimental) Local (direct) Diffuse (less direct) Open loop (fixed duty cycle) Closed loop (responsive)

4. CURRENT STANDARDS Cranial Surgery

5. Multiple SubpialTransections

6. CURRENT STANDARDS Vagus Nerve Stimulation 65% of patients achieve 50% or greater reduction in seizure frequency

7. Vagus Nerve Stimulation

8. Benefits / Outcome Surgical outcome Stroke & Hemorrhage = 1% Infection = 3.5% Quality of life Cognition Driving Daily activities Family life Work School Sports & recreation Neurological Status Side effects Memory Cognition

9. Risk / Benefit Risk Benefit Seizure risks Seizures No surgery No surgery Surgery Surgery Surgical risks No seizures Seizure risks >= Surgical risks Surgical Sz control >> Non-surgical Sz control

10. Probably available in the very near future

11. Responsive Neurostimulation (RNS) – in FDA approval process

12. RNS : NeuroPace

13. FUTURE DIRECTIONS : RNS

14. Probably available in the very near future Responsive VNS

15. DBS : Deep Brain Stimulation – possible near future

16. Future Surgical Directions Indirect drug (intrathecal) application Direct drug application Cortical cooling Opto-genetic Other . . .

17. Summary Today : Surgery is available, relatively safe and very effective - Limitation is what can safely be resected Near future : increased the number of people who are candidates for surgery using reversible augmenting techniques such as responsive stimulation Distant future : other less invasive, non-destructive and reversible techniques such as opto-genetics and direct drug delivery