Search

Objective: Vagus nerve stimulation (VNS) is a nonpharmacologic therapeutic option for patients who have pharmaco-resistant Dravet syndrome (DS). Plentiful efforts have been made for delivering VNS to DS patients, but its effectiveness still requires further verification. We investigated the effectiveness of the VNS treatment of DS patients using brain connectivity analysis with electroencephalography (EEG)., Approach: Twenty pharmaco-resistant DS patients were selected to undergo VNS implantation and classified into responder and non-responder groups after 24 months post-VNS. The effect of VNS between 6 months pre- and 6, 12, and 24 months post-VNS in all patients, responders, and non-responders on four different frequency categories of four brain parameters were compared using resting-state EEG., Main Results: In alpha and beta bands, all patients showed positive results for characteristic path length (CPL), global efficiency (GE), and transitivity after VNS treatment, and changes in betweenness centrality (BC) were not significant. The difference in transitivity between responders and non-responders is more pronounced than those in CPL and GE are, in both the alpha (p < 0.015) and beta (p < 0.001) bands. There was an obvious change in BC, especially in the alpha band, as the hubs tended to move from frontal lobe to parietal lobe for responders; however, there was no change for the non-responders., Significance: We investigated the alteration in brain connectivity of DS patients in alpha and beta bands during a long-term follow-up and found the responders have a decreased transitivity after the VNS treatment. Moreover, the hubs with high values in the alpha band tended to move from frontal lobe to parietal lobe for responders after VNS treatment.

Rationale: Dravet Syndrome (DS) is a severe epileptic encephalopathy of childhood involving intractable seizures, recurrent status epilepticus and cognitive decline. Because DS is a rare disease, available data is limited and evidence-based treatment guidelines are lacking. Vagus nerve stimulation (VNS) is an established neurostimulation treatment for intractable epilepsy, however little evidence is published on its efficacy in patients with DS., Methods: We performed a meta-analysis of all peer-reviewed English language studies reporting seizure outcomes of patients with DS treated with adjunctive vagus nerve stimulation. The primary and secondary outcome measures were ≥50% reduction of seizures or of the most-debilitating seizure type and seizure reduction per patient., Results: 13 studies comprising 68 patients met the inclusion criteria of which 11 were single-center retrospective case series, one was a multi-center retrospective analysis and one was a case report. 52.9% of patients experienced a ≥50% reduction of seizures and the average seizure reduction, which could only be assessed in n=28 patients was 50.8%. 7 out of 13 studies reported additional benefits of VNS, however this could not be assessed systematically., Conclusion: Vagus nerve stimulation appears to reduce seizure frequency in patients with DS. Based on this preliminary analysis, controlled trials of VNS in this rare condition using patient-centric outcome measures are indicated., (Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Background: Dravet syndrome (DS) is a rare genetic epilepsy syndrome which is particularly pharmacoresistant. Vagus nerve stimulation (VNS) is commonly used in the treatment of DS as an adjunct to medical therapy. A meaningful assessment of post-surgical outcomes with VNS is difficult given the rarity of the condition., Objective: In a novel approach, we used social media to contact patients with DS to gather data on post-surgical seizure reduction and overall satisfaction with VNS., Methods: A survey consisting of 10 questions was posted to a social media webpage for a DS support group moderated by the Dravet Syndrome Foundation. The results were analyzed and percentages reported using the integrated SurveyMonkey analytical software., Results: 49 responses were received. We found that 28.5% of patients had a >50% reduction in seizure frequency after VNS placement, 55.8% felt that VNS therapy had helped to reduce seizure frequency, and 83.7% felt that seizure severity had improved. Of the respondents, 75% felt that they would undergo VNS implantation again for similar outcomes., Conclusions: We employed the novel technique of using social media to gather the largest set of self-reported outcomes of VNS therapy for Dravet syndrome. As corroborated by prior studies of VNS effectiveness in Dravet syndrome, there is significant albeit limited improvement in seizure control. Our study shows that despite this limitation, it is still considered a useful treatment adjunct from a caregiver's perspective., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Epilepsy is a common disease in the world. Around 10-40% of patients who suffer epilepsy will have intractable seizures. When resective epilepsy surgery is not possible, vagus nerve stimulation (VNS) can be an option. The most common side effects associated with VSN therapy are hoarseness, throat pain and coughing. Cardiac arrhythmia has been reported during lead tests performed during implantation of the device, but few cases during regular treatment. We report a new child where vagally induced bradyarrhythmia, perfectly correlated with the stimulation periods., Clinical Report: 13-year-old girl with refractory myoclonic-astatic epilepsy since the age of two. When she was five years old, a VNS was implanted with complete resolution of her seizures. But when she was 13, she began with sudden falls with loss of consciousness lasting less than 10 s, which were similar to her previous epileptic drop-attacks. Continuous ECG recording was normal but electrocardiography showed a bradycardia of 45 bpm with a syncope-like episode. It was necessary to turn off the VNS., Conclusions: To our knowledge, there are just three pediatrics and four adults patients described in the literature with this severe and life-threatening side effect. Cardiac complications of VNS therapy are very infrequent but should alert clinicians to its possibility. A cardiac evaluation is mandatory before VNS implantation and periodically thereafter (probably between one or three years)., (Copyright © 2016 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Unlabelled: There is strong evidence for the use of the ketogenic diet (KD) in Dravet syndrome (DS). The purpose of this study was to evaluate both effectiveness and tolerability in comparison with various antiepileptic drugs (AEDs)., Methods: 32 children (19 males) with genetically confirmed DS treated at our center since 1999 were analyzed retrospectively. Data collected from patients' files included type of mutation, age at treatment initiation and treatment lag, overall seizure frequency and frequency of different seizure types, especially prolonged seizures and status epilepticus (SE). Efficacy and safety of the KD were evaluated. In addition, the effect on seizure count was compared with that of various AED regimen and the vagus nerve stimulation (VNS)., Results: Overall response to the KD was 70% at 3 months and 60% at 12 months. No SE occurred while patients were on the diet, and the frequencies of prolonged generalized and myoclonic seizures were reduced. No severe side effects requiring withdrawal of the KD were observed. Although the effect of the KD was independent of age at initiation, it had to be withdrawn due to noncompliance more frequently in solid fed older children compared with infants treated with the liquid ketogenic formula. The KD was not significantly inferior to the current gold standard AED triple combination of Stiripentol+Valproate+Clobazam (89%), Bromides (78%), Valproate alone (48%), Topiramate (35%) and VNS (37%) and significantly more effective than Levetiracetam (30%; p=0.037, Pearson's Chi-square)., Significance: These data suggest that the KD ranks among currently used AEDs as an effective treatment for seizures in DS. According to our results (good effect on SE and prolonged seizures, good tolerability, less compliance problems due to formula treatment) the KD should be considered as an early treatment option in infants with DS., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Myoclonic astatic epilepsy (MAE) is characterized by multiple seizure types, which are often refractory. Although vagus nerve stimulation (VNS) is an alternative treatment for medically intractable seizures, its exact mechanism of action remains unclear. Herein, we report the case of a 4-year-old boy with intractable MAE who has been in a seizure-free status for 2 years and 3 months since 6 months after the implantation of a vagus nerve stimulator (Model 103, Cyberonics, Inc., Houston, TX). Various test results 6 months after VNS were compared with those before VNS. Results of an electroencephalograph revealed disappearance of epileptiform discharges and an increased beta-gamma spectrum rhythm. The brain diffusion-tensor imaging showed an increased ratio of fraction anisotropy in the right fimbria-fornix, indicating improved diffusion of the white matter tract, and (18)F-fluorodeoxyglucose positron emission tomography revealed globally improved cerebral glucose metabolism. His cognitive and social-emotional performances also improved at 2 years after VNS. To the best of our knowledge, this is the first report to describe the effects of VNS on fimbria-fornix and glucose metabolism in MAE., (Copyright © 2013. Published by Elsevier B.V.)

We report on a patient who developed, from 5 months of age, multiple seizure types, including myoclonic, associated with severe psychomotor delay, leading to the diagnosis of Dravet syndrome. Over the years, he developed refractory epilepsy and was implanted with a vagus nerve stimulator at the age of 19. After 3 months, he experienced a progressive improvement of partial and generalized seizures, with a >90% reduction, and better alertness. This meaningful clinical improvement is discussed in the light of the sudden unexpected death in epilepsy risk, which is high in this setting, and seems remarkably diminished in our patient in view of the reduction of generalized convulsions., (Copyright © 2012 S. Karger AG, Basel.)

Aim: We discuss the effectiveness, tolerability, and safety of vagus nerve stimulation (VNS) as adjunctive therapy in 64 paediatric patients with refractory epilepsies., Materials and Methods: Sixty-four patients (34 male and 30 female) implanted with VNS for refractory epilepsy were analysed. Electroclinical features were compatible with Lennox-Gastaut syndrome in 46 patients, focal epilepsies in 10 patients, Dravet syndrome in three patients, epilepsy with myoclonic-astatic seizures in three patients, and West syndrome in two. The NeuroCybernetic Prosthesis (NCP) system (Cyberonics, Webster, TX, USA) was employed and the following stimulation parameters were used: output current of 1 to 2.5mA, signal frequency of 30Hz, signal pulse width of 500μs, and signal "on" and "off" times of 30  seconds and 5  minutes, respectively., Results: Of 46 patients with LGS, 30 cases showed a significant improvement in seizure control, with a reduction in seizure frequency of at least 50%. Ten patients with focal epilepsy, three patients with myoclonic-astatic seizures, two patients with Dravet, and two patients with West showed a significant improvement in seizure control, with a reduction in seizure frequency of at least 50%. A good clinical response was evident early and efficacy progressively improved with the duration of treatment up to 36 months. In a significant number of patients, reduced seizure severity and shorter recovery time and hospital stay were also observed. VNS was well tolerated in all patients., Conclusion: VNS is an effective and well-tolerated treatment for paediatric patients with refractory epilepsies, improving quality of life and neuropsychological performance.

We present an update of our experience with the ketogenic diet (KD) in patients with Dravet syndrome (DS) to evaluate the efficacy and tolerability and our short experience with vagus nerve stimulation (VNS) in the treatment of this syndrome. Between March 1, 1990 and May 31, 2007, 59 patients who met diagnostic criteria for DS were studied in our department. Twenty-four of them were placed on the KD and were followed up for a minimum of 2 years. Three patients were treated with VNS. Sixteen (66.6%) of 24 patients remained on the diet. Two patients (12.5%) became seizure free, 10 children (62.5%) had a 75-99% decrease in seizures, and the remaining 4 children (25%) had a 50-74% decrease in seizures. Six patients have been off the diet for >2 years; one of them is seizure free, two have sporadic seizures, and three, who abandoned the diet after 3 years of adhering to it, relapsed. As to the efficacy of VNS, two patients had a 50-74% decrease in seizures and in the other seizure frequency remained unchanged. The device was well tolerated in all patients without significant complications. Considering the severity and refractarity of seizures in patients with DS, the fact that 12 of 16 children who remained on the diet had a significant reduction in number of seizures shows that the KD is at present an interesting therapeutic option. VNS may be a good alternative treatment for DS., (Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.)

Medical treatment of Dravet syndrome is disappointing. Ketogenic Diet and neurostimulation procedures as Vagus Nerve Stimulation (VNS) and Deep Brain Stimulation are in ongoing evaluation. In the present study, the long-term effectiveness of VNS on seizures, cognition and behavior was retrospectively evaluated in eight young patients with DS and medically refractory epilepsy (mean age at VNS implant: 10.28 years, range: 5-25). The average duration of treatment was 54 months (range: 12-120). Compared to baseline (mean: 55; standard deviation: 83, range: 4-200), the mean number of monthly seizures after VNS implantation was 39 ± 67 at 3 months, 42 ± 67 at 6 months and 38 ± 69 at twelve months (not significant comparisons). In particular, VNS produced a mean seizure rate reduction of 12% at three months, 6% at six months, and 31% at twelve months. All patients but three experienced some reduction in seizure burden (range: 33-61%) at twelve months. Seizure outcome after one year of stimulation was rated as Mc Hugh class II (50-79% reduction in seizure frequency) in four patients, class III (<50% reduction) in one patient and class V (no improvement) in three patients. In this small case series of patients with DS, VNS therapy had a clinically significant effect in reducing seizures at twelve months in four of the eight patients. Even in patients in whom seizure reduction was not dramatic, a slight improvement in alertness and communicative skills was seen. The long-term clinical course of two selected cases is discussed., (© 2010 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)