No abstract

Background: Vagus nerve stimulation (VNS) functions through neuromodulatory mechanisms to provide quality of life improvements to those with drug-resistant epilepsy. Responsive VNS (rVNS) generators are designed to further reduce seizure burden by detecting ictal tachycardia and aborting seizures soon after their onset.Methods: Electronic medical records were accessed from January 2015 to December 2018 to identify patients with epilepsy managed with rVNS generators. Data were collected on seizure burden before and after rVNS implantation. Seizure burden was compared using t-tests, and monthly seizure reductions were gauged with the McHugh scale. Twenty-seven individuals met inclusion criteria; 10 were eliminated due to prior VNS implantation or undocumented seizure frequencies.Results: The average seizure burden prior to rVNS implantation was 24.78 seizures/month. Following generator placement, the mean seizure frequencies at three months, six months, 12 months, and 18 months were 6.81, 16.57, 5.65, and 5.78 seizures/month, respectively. However, despite documented reductions in the average monthly seizure frequency, we found no statistically significant differences in seizure frequency relative to baseline. Conclusion: While many participants showed individual reductions in seizure burden, this study was unable to definitively conclude that rVNS therapy leads to statistically significant reduction in seizure burden.

Background: Individuals with stroke due to high-degree intracranial stenosis (i.e. > 70% by WASID criteria have a high 1-year risk of stroke recurrence. Whether high-degree intracranial stenosis in stroke-free individuals increases the risk of vascular events is less certain. We hypothesized that high-degree intracranial stenosis in stroke-free individuals is associated with risk of death and vascular events. Methods: Participants in the population-based Northern Manhattan Study (NOMAS) with available time-of-flight MRA were included in this study. We rated intracranial stenosis using WASID criteria and defined high-degree intracranial stenosis if the lumen was reduced by > 70% in the anterior, middle, or posterior cerebral arteries or in the basilar, vertebral or intracranial carotid arteries. Death and vascular events were prospectively ascertained, blinded to stenosis status. Stroke outcomes were subtypes according to the Trial of Organon in Acute Stroke Trial (TOAST) criteria. Results: We included 1,206 NOMAS participants (mean age 70.6±9 years, 60.5% women, 65.7% Hispanic). The participants were followed for an average of 10.4 years (IQR 9.5-12.6). The prevalence of high-degree intracranial stenosis was 3.5% (74% isolated anterior circulation, 21% isolated posterior circulation, and 5% anterior and posterior circulation). In univariate analysis, high-degree intracranial stenosis was associated with older age (P=0.003), hypertension (P=0.02) and diabetes (0.02). The risk of vascular death and stroke was higher among stroke-free individuals with high-degree intracranial stenosis (table), and in particular with strokes due to large artery atherosclerosis. Conclusions: Evidence of high-degree intracranial stenosis among stroke-free individuals identifies those at risk of vascular events and may be used to select individuals for testing aggressive measures to reduce vascular risks.