INTRODUCTION: Responsive neurostimulation (RNS) is efficacious in treating medically refractory epilepsy arising from neocortical foci. During clinical trials, most patients with neocortical seizure foci received cortical strip leads, perhaps due to intracranial monitoring with subdural grids/strips. Stereo-electroencephalography (sEEG) has become more widely utilized since the trials, resulting in increased placement of neocortical RNS depth leads. This is also an appealing approach when dural adhesions make strip lead implantation difficult. METHODS: We conducted retrospective chart review of adult patients with refractory epilepsy at seven institutions who underwent placement and connection of at least one RNS depth lead in the neocortex. RESULTS: 61 neocortical depth leads were connected to the RNS neurostimulator in 53 patients. 33 patients had additional depth leads in a non-neocortical focus, and 12 had an additional neocortical strip lead. Median follow-up was 2.2 years (range: 0.4 – 5.2 years). Median clinical seizure reduction in seizures was 63% at 1 y and 75% at last follow-up. 12 patients (23%) were seizure-free at last follow-up; a majority of these (83%) were seizure-free for >6 mo, with five patients seizure-free for >1 y. There were two (3.8%) scalp infections. One patient (1.9%) had each of the following: chemical meningitis, epidural hematoma, post-surgical status epilepticus (resolved with stimulation), new-onset non-epileptic seizures, and stimulation-related nausea (resolved with programming). CONCLUSIONS: Our multicenter series of 53 patients with neocortical-onset epilepsy treated with neocortical RNS depth leads demonstrated 75% median seizure reduction at 2 y of follow-up with a similar safety profile to placement of deep brain electrodes for movement disorders. Neocortical depth leads may be preferred with the RNS system following sEEG evaluation and/or if strip placement poses increased surgical risk.

BACKGROUND: Patients with bitemporal lobe epilepsy are generally not considered for surgical resection. Fortunately, responsive neurostimulation provides another avenue for the management of this challenging disease process. In conjunction with our epileptologist, we consider responsive neurostimulation for patients who have clinical features of temporal lobe epilepsy without clear localization on imaging and stereoelectroencephalography. METHODS: Here we describe our technique for implanting a responsive neurostimulator (NeuroPace, NeuroPace Inc., Mountain View, California) with depth electrodes monitoring the hippocampus and para-hippocampus using stereotactic robotic guidance (ROSA, Medtech SA, Montpeillier, France). RESULTS: We have used this technique with 5 patients without morbidity. Four of 5 patients have received clinical benefit (Engel classification I-III). Promisingly, long-term seizure monitoring with use of the NeuroPace system has suggested lateralizing information on 3 of these patients that was not apparent on previous invasive monitoring. CONCLUSIONS: Robotically implanted responsive neu-rostimulation is a safe and effective treatment for bitemporal epilepsy and can possibly lead to valuable diagnostic information to guide future surgical management in patients who previously were not considered candidates for resective or ablative surgery.

INTRODUCTION:Myoclonus may be a rare complication of stem cell transplant but has limited discussion in the scientific literature. CASE:We present a case of an acute myeloid leukemia survivor who developed refractory myoclonic epilepsy four years after graft versus host disease (GVHD) developed six days following matched unrelated allogeneic hematopoietic stem cell transplant. DISCUSSION:Graft versus host disease occurs in 30-50% of allogenic hematopoietic stem cell transplant patients and may cause pharmacoresistant myoclonic epilepsy; however, the mechanisms by which GVHD leads to recurrent myoclonic seizures are not well understood (Lee, 2005) [1]. The paucity of clinical reports of such manifestation makes it difficult to diagnose and effectively manage these patients.