Responsive neurostimulation as a treatment for super-refractory focal status epilepticus: a systematic review and case series.

OBJECTIVE: Super-refractory status epilepticus (SRSE) has high rates of morbidity and mortality. Few published studies have investigated neurostimulation treatment options in the setting of SRSE. This systematic literature review and series of 10 cases investigated the safety and efficacy of implanting and activating the responsive neurostimulation (RNS) system acutely during SRSE and discusses the rationale for lead placement and selection of stimulation parameters. METHODS: Through a literature search (of databases and American Epilepsy Society abstracts that were last searched on March 1, 2023) and direct contact with the manufacturer of the RNS system, 10 total cases were identified that utilized RNS acutely during SE (9 SRSE cases and 1 case of refractory SE [RSE]). Nine centers obtained IRB approval for retrospective chart review and completed data collection forms. A tenth case had published data from a case report that were referenced in this study. Data from the collection forms and the published case report were compiled in Excel. RESULTS: All 10 cases presented with focal SE: 9 with SRSE and 1 with RSE. Etiology varied from known lesion (focal cortical dysplasia in 7 cases and recurrent meningioma in 1) to unknown (2 cases, with 1 presenting with new-onset refractory focal SE [NORSE]). Seven of 10 cases exited SRSE after RNS placement and activation, with a time frame ranging from 1 to 27 days. Two patients died of complications due to ongoing SRSE. Another patient's SE never resolved but was subclinical. One of 10 cases had a device-related significant adverse event (trace hemorrhage), which did not require intervention. There was 1 reported recurrence of SE after discharge among the cases in which SRSE resolved up to the defined endpoint. CONCLUSIONS: This case series offers preliminary evidence that RNS is a safe and potentially effective treatment option for SRSE in patients with 1-2 well-defined seizure-onset zone(s) who meet the eligibility criteria for RNS. The unique features of RNS offer multiple benefits in the SRSE setting, including real-time electrocorticography to supplement scalp EEG for monitoring SRSE progress and response to treatment, as well as numerous stimulation options. Further research is indicated to investigate the optimal stimulation settings in this unique clinical scenario.

The Ambiguous Nature of Fast Ripples in Epilepsy Surgery.

Removing High-Frequency Oscillations: A Prospective Multicenter Study on Seizure Outcome Jacobs J, Wu JY, Perucca P, et al. Neurology. 2018;91(11):e1040-e1052. OBJECTIVE: To evaluate the use of interictal high-frequency oscillations (HFOs) in epilepsy surgery for prediction of postsurgical seizure outcome in a prospective multicenter trial. METHODS: We hypothesized that a seizure-free outcome could be expected in patients in whom the surgical planning included the majority of HFO-generating brain tissue, while a poor seizure outcome could be expected in patients in whom only a few such areas were planned to be resected. Fifty-two patients were included from 3 tertiary epilepsy centers during a 1-year period. Ripples (80-250 Hz) and fast ripples (250-500 Hz) were automatically detected during slow-wave sleep with chronic intracranial EEG in 2 centers and acute intraoperative electrocorticography in 1 patient. RESULTS: There was a correlation between the removal of HFO-generating regions and seizure-free outcome at the group level for all patients. No correlation was found, however, for the center-specific analysis, and an individual prognostication of seizure outcome was true in only 36 (67%) patients. Moreover, some patients became seizure-free without removal of the majority of HFO-generating tissue. The investigation of influencing factors, including comparisons of visual and automatic analysis, using a threshold analysis for areas with high HFO activity, and excluding contacts bordering the resection, did not result in improved prognostication. CONCLUSIONS: On an individual patient level, a prediction of outcome was not possible in all patients. This may be due to the analysis techniques used. Alternatively, HFOs may be less specific for epileptic tissue than earlier studies have indicated.

Brain-responsive neurostimulation in patients with medically intractable seizures arising from eloquent and other neocortical areas.

OBJECTIVE: Evaluate the seizure-reduction response and safety of brain-responsive stimulation in adults with medically intractable partial-onset seizures of neocortical origin. METHODS: Patients with partial seizures of neocortical origin were identified from prospective clinical trials of a brain-responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2-6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. Additional analyses considered safety and seizure reduction according to lobe and functional area (e.g., eloquent cortex) of seizure onset. RESULTS: There were 126 patients with seizures of neocortical onset. The average follow-up was 6.1 implant years. The median percent seizure reduction was 70% in patients with frontal and parietal seizure onsets, 58% in those with temporal neocortical onsets, and 51% in those with multilobar onsets (last observation carried forward [LOCF] analysis). Twenty-six percent of patients experienced at least one seizure-free period of 6 months or longer and 14% experienced at least one seizure-free period of 1 year or longer. Patients with lesions on magnetic resonance imaging (MRI; 77% reduction, LOCF) and those with normal MRI findings (45% reduction, LOCF) benefitted, although the treatment response was more robust in patients with an MRI lesion (p = 0.02, generalized estimating equation [GEE]). There were no differences in the seizure reduction in patients with and without prior epilepsy surgery or vagus nerve stimulation. Stimulation parameters used for treatment did not cause acute or chronic neurologic deficits, even in eloquent cortical areas. The rates of infection (0.017 per patient implant year) and perioperative hemorrhage (0.8%) were not greater than with other neurostimulation devices. SIGNIFICANCE: Brain-responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including adults with seizures of neocortical onset, and those with onsets from eloquent cortex.

Crisis parciales complejas del lóbulo temporal aspectos neurológicos y psiquiátricos / Temporal lobe complex partial seizures neurologic and psychiatric aspects

Las crisis complejas (CPC) pertenecen al grupo de las crisis focales, caracterizándose por presentar alteraciones en la conciencia, la presencia de un aura y sintomatología psicosensorial, cognoscitiva, afectiva y psicomotora. Constituyen el 30% de las crisis convulsivas en el adulto y más del 70% se originan en el lóbulo temporal. Algunos aspectos fisiológicos del sistema límbico son útiles para comprender las características clínicas y electroencefalográficas de las CPC. Las estructuras que con mayor frecuencia están involucradas son la amígdala y el hipocampo. Ambas presentan actividad elétrica intrínseca, lo cual las distingue del resto de las estructuras cerebrales, y tienen importancia en los mecanismos que originan y propagan las descargas elétricas. Estas dos estructuras influencia al sistema autónomo, a la corteza somatomotora y a los diferentes aspectos del comportamiento y la memoria. Algunos estudios neurofisiológicos apoyan la hipótesis de que estas estructuras consitituyen el sustrato funcionales que permite al individuo relacionar estímulos externos con experiencias pasadas para generar estados motivacionales. La etiología de los focos epileptogénicos del lóbulo temporal se divide en lesiones focales discretas, lesiones circunscritas y anormalidades menores. Existe controversia en cuanto a la existencia de manifestaciones psiquiátricas en los períodos interictales. Los problemas metodológicos constituyen la base para la discrepancia en los diferenes hallazgos reportados. Ejemplos de estos son: la falta de grupos control adecuados; la falta de estandarización de los instrumentos de evaluación y las diferentes connotaciones asignadas al término "psicopatología". De la literatura revisada se puede concluir que la incidencia de psicopatología es similar en los grupos de pacientes con CPC y en aquellos con epilepsia generalizada. Aunque el diagnóstico de las epilepsias se basa en la clínica, el electroencefalograma (EEG) es el instrumento diagnóstico con que se comparan los demás métodos diagnósticos, aunque carece de sensibilidad y especificidad...