Abstracts

Rationale: Neuromodulation is increasingly used for the treatment of drug-resistant epilepsy. We present the outcome of the patients that had Deep Brain Stimulation (DBS) or Chronic Cortical Stimulation (CCS) at King’s College Hospital. Methods: Data were collected retrospectively from medical documentation up to the last time of follow up. The number of seizures prior to and after neuromodulation was extracted from the seizure diaries that are kept as part of clinical record. The patient age, the percentage of improvement in seizure frequency (no improvement, >50%, >70% and seizure freedom), the follow-up duration and the major adverse effects were analyzed. Results: A total number of 29 patients have undergone DBS or CCS at KCH since 2004.Six patients with focal epilepsy had DBS at the Anterior Nucleus of the Thalamus. Mean age at implantation date was 33 years, and mean follow-up was 18 months. One patient showed no improvement, three had >50% and two >70% improvement. No patient became seizure free.Fourteen patients had DBS at the Centromedian Nucleus of the Thalamus (CMN). Among them, nine had Genetic Generalized Epilepsy, three epilepsy with combined generalized/focal seizures, and two focal frontal epilepsy (mean age 32 years; mean follow-up 60 months). Four patients showed no improvement, two had >50% and four had >70% improvement. Four became seizure free for periods longer than 24 months (one with recurrence of 50% seizures frequency and one died at 9 years after implantation from unknown cause).Two patients with refractory status epilepticus (rSE), showing focal and generalized seizures, had CMN DBS. The rSE (generalized seizures) was stopped in both cases (>50% and >70% improvement in focal seizures).Three patients had chronic Hippocampal Stimulation (HS). Their mean age at implantation was 41 years and the mean follow-up was 12 months. One patient had >50% and two had >70% improvement.Four patients had chronic cortical stimulation (CCS), three for Epilepsia Partialis Continua (EPC) and one for focal epilepsy (mean age 30 years; mean follow-up 38 months). From the cases with EPC, one patient became seizure free and on the other two the EPC resolved, but they have <50% of days with occasional focal seizures. The single patient with focal epilepsy  had >70% improvement.Six cases of infection were recorded. In one case the infection resolved and in five cases the electrodes had to be removed. Re-implantation was carried out in one case and in another, re-implantation is pending. One child with DBS of the ANT had  >70% improvement in seizure frequency, but reported significant behavioral issues. Conclusions: Neuromodulation is a promising treatment for patients with drug-resistant epilepsy who are not suitable candidates for resective surgery or have generalized epilepsy. Our data show that a significant number of patients can be benefited, with 70% of the patients showing >50% improvement. The most favorable outcome is seen in patients with GGE that had DBS of the CMN with 66.7% of them achieving >70% improvement in their seizure frequency. Funding: No funding was received by the authors in support of this study.