A prospective, multicenter study of cardiac-based seizure detection to activate vagus nerve stimulation.

PURPOSE: This study investigates the performance of a cardiac-based seizure detection algorithm (CBSDA) that automatically triggers VNS (NCT01325623). METHODS: Thirty-one patients with drug resistant epilepsy were evaluated in an epilepsy monitoring unit (EMU) to assess algorithm performance and near-term clinical benefit. Long-term efficacy and safety were evaluated with combined open and closed-loop VNS. RESULTS: Sixty-six seizures (n=16 patients) were available from the EMU for analysis. In 37 seizures (n=14 patients) a ≥ 20% heart rate increase was found and 11 (n=5 patients) were associated with ictal tachycardia (iTC, 55% or 35 bpm heart rate increase, minimum of 100 bpm). Multiple CBSDA settings achieved a sensitivity of ≥ 80%. False positives ranged from 0.5 to 7.2/h. 27/66 seizures were stimulated within ± 2 min of seizure onset. In 10/17 of these seizures, where triggered VNS overlapped with ongoing seizure activity, seizure activity stopped during stimulation. Physician-scored seizure severity (NHS3-scale) showed significant improvement for complex partial seizures (CPS) at EMU discharge and through 12 months (p<0.05). Patient-scored seizure severity (total SSQ score) showed significant improvement at 3 and 6 months. Quality of life (total QOLIE-31-P score) showed significant improvement at 12 months. The responder rate (≥ 50% reduction in seizure frequency) at 12 months was 29.6% (n=8/27). Safety profiles were comparable to prior VNS trials. CONCLUSIONS: The investigated CBSDA has a high sensitivity and an acceptable specificity for triggering VNS. Despite the moderate effects on seizure frequency, combined open- and closed-loop VNS may provide valuable improvements in seizure severity and QOL in refractory epilepsy patients.

Vagus nerve stimulation for drug-resistant epilepsy: a European long-term study up to 24 months in 347 children.

OBJECTIVE: To gain insight into the long-term impact of vagus nerve stimulation (with VNS Therapy) in children with drug-resistant epilepsy, we conducted the largest retrospective multicenter study to date over an extended follow-up period of up to 24 months. METHODS: The primary objective was to assess change in seizure frequency of the predominant seizure type (defined as the most disabling seizure) following VNS device implantation. Treating physicians collected data from patient records from baseline to 6, 12, and 24 months of follow-up. RESULTS: The analysis population included 347 children (aged 6 months to 17.9 years at the time of implant). At 6, 12, and 24 months after implantation, 32.5%, 37.6%, and 43.8%, respectively, of patients had ≥ 50% reduction in baseline seizure frequency of the predominant seizure type. The responder rate was higher in a subgroup of patients who had no change in antiepileptic drugs (AEDs) during the study. Favorable results were also evident for all secondary outcome measures including changes in seizure duration, ictal severity, postictal severity, quality of life, clinical global impression of improvement, and safety. Post hoc analyses demonstrated a statistically significant correlation between VNS total charge delivered per day and an increase in response rate. VNS Therapy is indicated as adjunctive therapy in children with focal, structural epilepsies, who for any reason are not good candidates for surgical treatment following the trial of two or more AEDs. Children with predominantly generalized seizures from genetic, structural epilepsies, like Dravet syndrome or Lennox-Gastaut syndrome, could also benefit from VNS Therapy. SIGNIFICANCE: The results demonstrate that adjunctive VNS Therapy in children with drug-resistant epilepsy reduces seizure frequency and is well tolerated over a 2-year follow-up period. No new safety issues were identified. A post hoc analysis revealed a dose-response correlation for VNS in patients with epilepsy.

Mortality and suicide risk in treatment-resistant depression: an observational study of the long-term impact of intervention.

Major depressive disorder is a common global disease that causes a significant societal burden. Most interventional studies of depression provide a limited assessment of the interventions on mortality and suicide risks. This study utilizes data from an observational registry of patients with major depressive disorder to determine the impact of intervention (vagus nerve stimulation or standard pharmacological/non-pharmacological therapy) and a latent factor, patient trajectory toward response, on mortality, suicide and suicidal ideation. A total of 636 patients were available for an intent-to-treat analysis of all-cause mortality, suicide and suicidal ideation. Patients treated with vagus nerve stimulation in addition to standard therapies experienced lower, but not statistically significant, all-cause mortality (vagus nerve stimulation 4.93 per 1,000 person-years vs. 10.02 per 1,000 patient years for treatment as usual) and suicide rates (vagus nerve stimulation 0.88 per 1,000 person-years vs. 1.61 per 1,000 patient years for treatment as usual). Treatment with vagus nerve stimulation produced a statistically lower relative risk of suicidal ideation 0.80, 95% confidence interval (0.68,0.95). Further, patients that responded to either treatment saw a 51% reduction in relative risk of suicidal behavior; relative risk and 95% confidence interval of 0.49 (0.41,0.58). In summary, we find that treatment with adjunctive vagus nerve stimulation can potentially lower the risk of all-cause mortality, suicide and suicide attempts.