T Vandekerckhove

Programmed and magnet-induced vagus nerve stimulation for refractory epilepsy

Summary Vagus nerve stimulation (VNS) is an effective alternative treatment for patients with refractory epilepsy. The generator produces intermittent stimulation trains and does not require patient intervention. Using currently available technology, continuous stimulation is incompatible with a reasonable battery life. Because earlier studies have demonstrated the persistence of a stimulation effect after discontinuation of the stimulation train, we intended to evaluate the clinical efficacy of VNS in both the programmed intermittent stimulation mode and the magnet stimulation mode. Patients, companions, and caregivers were instructed on how to administer additional stimulation trains when an aura or a seizure onset occurred. We assumed that patients or caregivers could recognize habitual seizures and were able to evaluate sudden interruption of these seizures. During a mean follow-up of 35 months, 46% of patients became responders, with a reduction in seizure frequency of more than 50%. Twenty-nine percent of patients stopped having convulsive seizures. In two thirds of patients who were able to self-administer or receive additional magnet stimulation, seizures could be interrupted consistently or occasionally. More than half of the patients who reported a positive effect of magnet stimulation became responders. Only three patients were able to use the magnet themselves. In most cases, support from caregivers was necessary. This study is the first to document the efficacy of magnet-induced VNS in a larger patient population during long-term follow-up. The magnet is a useful tool that provides patients who are treated with VNS and mainly caregivers of such patients with an additional means of controlling seizures. To further confirm the self-reported results from our patients, additional studies comparing programmed stimulation and magnet-induced stimulation during monitoring conditions are needed.

Acute single photon emission computed tomographic study of vagus nerve stimulation in refractory epilepsy

Summary: Purpose: Left‐sided vagus nerve stimulation (VNS) is an efficacious treatment for patients with refractory epilepsy. The precise mechanism of action remains to be elucidated. Only limited data on VNS‐induced changes in regional cerebral blood flow (rCBF) are available. The aim of this study was to investigate rCBF changes during initial VNS with single‐photon emission computed tomography (SPECT).

Dipole Modeling in Epilepsy Surgery Candidates

Summary: Purpose: The validity and clinical significance of dipole modeling in epilepsy surgery candidates is not fully established.

Long-term results of vagus nerve stimulation in refractory epilepsy

Vagus nerve stimulation (VNS) is an adjunctive antiepileptic treatment for patients with refractory epilepsy. Limited information on long-term treatment with VNS is available. The purpose of this paper is to present our experience with VNS with a follow-up of up to 4 years. Twenty-five patients (13 females and 12 males) with refractory partial epilepsy were treated with VNS. The first 15 patients with a mean age of 30 years and a mean duration of epilepsy of 17.5 years have sufficient follow-up for analysis. Mean post-implantation follow-up was 29 months and mean stimulation output 2.25 mA. There was a mean seizure frequency reduction from 14 complex partial seizures (CPS) per month before implantation to 8 CPS per month after implantation (P = 0.0016; Wilcoxon signed-rank rest (WSRT)). The mean maximum CPS-free interval changed from 9 to 312 days (P = 0.0007; WSRT). Six patients were free of CPS for at least one year. In one patient, one antiepileptic drug (AED) was tapered; in 10 patients, AEDs remained unchanged; in four, one adjunctive AED was administered. Side effects occurred in six patients, three of whom required a temporary reduction of output current. Nine patients reported no side effects at all. Treatment with VNS remains effective in the long-term. In this series 4 / 15 (27%) patients with highly refractory epilepsy experienced entirely seizure-free intervals of 12 months or more.

VAGUS NERVE STIMULATION FOR MEDICALLY REFRACTORY EPILEPSY; EFFICACY AND COST-BENEFIT ANALYSIS

Summary Introduction. Vagus nerve stimulation is a novel treatment for patients with medically refractory epilepsy, who are not candidates for conventional epilepsy surgery, or who have had such surgery without optimal outcome. To date only studies with relatively short follow-up are available. In these studies efficacy increased with time and reached a maximum after a period of 6 to 12 months. Implantation of a vagus nerve stimulator requires an important financial investment but a cost-benefit analysis has not been published. Patients and Methods. Our own experience with VNS in Gent comprises 15 patients with mean age of 29 years (range: 17–44 years) and mean duration of epilepsy of 18 years (range: 4–32 years). All patients underwent a comprehensive presurgical evaluation and were found not to be suitable candidates for resective epilepsy surgery. Mean post-implantation follow-up is 24 months (range: 7–43 months). In patients with follow-up of at least one year, efficacy of treatment in terms of seizure control and seizure severity was assessed one year before and after the implantation of a vagus nerve stimulator. Epilepsy-related direct medical costs (ERDMC) before and after the implantation were also compared. Results. A mean reduction of seizure frequency from 14 seizures/month (range: 2–40/month) to 8 seizures/month (range: 0–30/month) was achieved (Wilcoxon signed rank test n=14; p=0.0016). Five patients showed a marked seizure reduction of ≥50%; 6 became free of complex partial seizures, 3 of whom became entirely seizure free for more than 12 months; 2 patients had a worthwhile reduction of seizure frequency between 30–50%; in 2 patients seizure frequency reduction has remained practically unchanged. Seizure freedom or ≥50% seizure reduction was achieved within the first 4 months after implantation in 6/11 patients. Before the implantation, the mean yearly epilepsy-related direct medical costs per patient were estimated to be 8830US

Steroid treatment in acute ischaemic stroke. A comparative retrospective study of 556 cases.

(n=13; range: 1879–31129US

Dipole modelling and intracranial EEG recording: Correlation between dipole and ictal onset zone.

; sd=7667); the average number of hospital admission days per year was 21 (range: 4–100; sd=25.7). In the 12 months after implantation, ERDMC had decreased to 4215US

Cervical chordoma with vertebral artery encasement mimicking neurofibroma: MRI findings.

(range: 615–11794US

Rupture of a cervical spinal cord arteriovenous malformation: a rare complication of endovascular embolization.

; sd=3558) (Wilcoxon signed rank test n=13; p=0.018) and the average number of admission days to 8 (range: 0–35) (Wilcoxon signed rank test n=13; p=0.023). Conclusion. VNS is an effective treatment of refractory epilepsy and remains effective during long-term follow-up. Cost-benefit analysis suggests that the cost of VNS is saved within two years following implantation.

Vagus nerve stimulation for refractory epilepsy

The files of 556 patients with a history of ischaemic stroke were reviewed. The disability and mortality rates were compared between 277 patients with a steroid treatment in the acute stage and 279 without. Comparison of the whole group showed that the steroid-treated patients had less improvement of their disability and a higher mortality rate than the non-steroid group. However, in the former more patients with a severe stroke were present. Statistical analysis of a subset of 208 patients with completed stroke in the middle cerebral artery territory showed no marked difference in the outcome and the adverse reactions between the steroid- and non-steroid-treated patients.