Seizure freedom following VNS implantation and prior to activation
Abstract number :
3.169
Submission category :
4. Clinical Epilepsy / 4C. Clinical Treatments
Year :
2016
Submission ID :
197587
Source :
www.aesnet.org
Presentation date :
12/5/2016 12:00:00 AM
Published date :
Nov 21, 2016, 18:00 PM
Authors :
Najib Murr, Southern Illinois University School of Medicine, Springfield, Illinois
Rationale: Vagal nerve stimulator (VNS) therapy is approved by the FDA as an adjunctive therapy for refractory partial epilepsy, mostly in patients who are not candidates for respective epilepsy surgery. Seizure frequency could be reduced by 25% after 3 months of treatment. We report two cases of refractory partial epilepsy with frequent almost daily seizures that experienced seizure freedom following VNS implantation and prior to activation. Methods: -Case 1: 22 yo female with history of epilepsy since the age of 16 years and a diagnosis of Prader Willi syndrome. Most seizures consist of tonic activity and staring or drop attacks. She only had one generalized tonic-clonic seizure in her lifetime. She has tried multiple anti-seizure medications and continued to experience daily seizures despite taking valproic acid 500 mg TID and rufinamide 400 mg bid per first clinic visit. Following VNS implantation she was seizure free for 4 months with seizure recurrence afterwards. VNS was not turned on until 2 weeks after implantation. VNS titration, addition of lacosamide and the start of Low glycemic index diet have reduced the seizure frequency to 2-3 a week. -Case 2: 61 yo woman with history of meningitis and seizures since the age of 7 years that became intractable to medical treatment at the age of 19 years. She has short-term memory deficit. Her brain MRI revealed a right mesial temporal sclerosis and EEG demonstrated bilateral temporal epileptiform discharges in addition to left temporal epileptogenicity. VNS was implanted and activated 6 months later. She was seizure free for 4 months prior to activation with seizure recurrence later on. Results: Following the implantation of the VNS pulse generator and leads, the first patient became seizure free and remained so for 3 months. The activation of the VNS did not take place until 2 weeks following the implantation. The second patient was seizure free for 4 months prior to activation of the VNS. Conclusions: There is a strong evidence to suggest close to 25% reduction in seizure frequency following 3 months of VNS therapy (Murphy 1999). Placebo effect from Sham surgeries has been very well documented due to some identified and other non-identified mechanisms (Brim et al., 2013). Seizure freedom with placebo effects following the implantation of a VNS pulse generator and leads and prior to activation, has not been well documented. Further research is needed to either accept or refute this hypothesis. One limitation of this report is the poor short-term memory in case 2, which makes seizure information by history not very accurate. References: - Murphy J. Left vagal nerve stimulation in children with medically refractory epilepsy. The pediatric VNS study group. J Pediatr. 1999 May;134(5):563-6. - Brim R, Miller F. The potential benefit of placebo effect in sham-controlled trials: implications for risk-benefit assessments and informed consent. J Med Ethics. 2013 Nov;39(11):703-7 Funding: no funding
Clinical Epilepsy