Vagus nerve stimulation for drug-resistant epilepsy in children case series
A total of 46 children with drug-resistant epilepsy, who underwent VNS at the Pediatric Epilepsy Center, Peking University First Hospital between March 2017 and June 2018, were enrolled into the study. Participants were assigned (non-randomized) into an outpatient programming group or remote programming group (where VNS parameters were adjusted through the internet) by parental choice. The responder rate, expenditure for VNS programming and adverse events were compared between the two groups. The median age at VNS implantation was 5.17 years (3.83-6.71), with the median epileptic course being 3.79 years (2.65-4.90). Twenty-four patients were assigned to the outpatient programming group and 22 were assigned to the remote programming group. Baseline data were comparable between the two groups, with the exception of the remote group having a longer distance between their place of residence and the hospital. The median time from VNS implantation to last follow-up was 1.33 years (1.25-1.75) and 1.46 years (1.17-1.58) in the outpatient and remote groups, respectively. In the outpatient programming group, 15 patients (62.5 %,) were VNS responders and four patients (16.6 %) became seizure-free. In the remote programming group, 16 patients (72.7 %) were VNS responders and four (17.4 %) became seizure-free. Cough and hoarseness were common adverse events in both the outpatient and remote groups (33.3 % vs. 18.2 %). There were no significant differences between the two groups in terms of adverse events. The median cost of each follow-up visit per patient in the outpatient group was 192.4 US dollars ($120.0-$376.5), of which travelling expenses were the major component, followed by accommodation fees, outpatient service fees and indirect costs. Whereas, patients in the remote programming group only needed to pay for the remote programming expense, which totaled 75.8 US dollars per person each time. The efficacy and adverse events were both comparable between the outpatient and remote programming patients. Remote programming was found to be a more cost-effective treatment, especially for patients living further away from centers specializing in epilepsy. 1).
Fifty-six children, comprising discovery (n = 38) and validation (n = 18) cohorts, were recruited from 3 separate institutions. Diffusion tensor imaging was used to identify group differences in white matter microstructure, which in turn informed beamforming of resting-state magnetoencephalography recordings. The results were used to generate a support vector machine learning classifier, which was independently validated. This algorithm was compared to a second classifier generated using 31 clinical covariates.
Treatment responders demonstrated greater fractional anisotropy in left thalamocortical, limbic, and association fibers, as well as greater connectivity in a functional network encompassing left thalamic, insular, and temporal nodes (p < 0.05). The resulting classifier demonstrated 89.5% accuracy and area under the receiver operating characteristic (ROC) curve of 0.93 on 10-fold cross-validation. In the external validation cohort, this model demonstrated an accuracy of 83.3%, with a sensitivity of 85.7% and specificity of 75.0%. This was significantly superior to predictions using clinical covariates alone, which exhibited an area under the ROC curve of 0.57 (p < 0.008).
This study provides the first multi-institutional, multimodal connectomic prediction algorithm for VNS, and provides new insights into its mechanism of action. Reliable identification of VNS responders is critical to mitigating surgical risks for children who may not benefit and to ensure cost-effective allocation of health care resources 2).
The purpose was to assess the outcome of the AspireSR® in a patient population managed in a pediatric neurology unit.
The records of patients who underwent transplantation during 2015-2017 and are continuously followed in one pediatric-epilepsy clinic, were retrospectively analyzed. Collected information included demographics, use of antiepileptic drugs and seizure type, frequency and duration before and after VNS implantation.
46 patients ages 5-31 years (mean 15.7 ± 5.8), mean age at implantation 14 ± 5.8 years, were included. 29 patients (63%) were new insertions and 17 of the patients (37%) underwent a VNS replacement to the AspireSR® model. Mean follow-up was 13 ± 7.5 months (range 2-29 months). The total cohort responder rate (patients with ≥50% reduction in seizure frequency compared to the pre-implantation period) was 60.9%. (62% in the new insertion group; while 59% in the replacement group had additional benefit over their former VNS model, p = 0.981). Epilepsy etiology, age, age at implantation and type of seizures pre-implantation showed no correlation to response-rate. Five patients (10.9%) experienced complete seizure-freedom following implantation (4/5 in the “new insertion” group). Responses were reported at median follow up of 5 ± 1.3 months post-implantation. 67.4% experienced shorter seizure duration post-implantation.
The results suggest that the AspireSR® device provides an early and meaningful benefit to drug-resistant epilepsy patients, which is relevant for both patients with new insertions and those with replacements of former VNS devices 3).
A study of Gedela et al. explored the effect of Vagus Nerve Stimulator (VNS) on Status Epilepticus (SE) in children with medically intractable epilepsy.
A retrospective review was conducted in children with a history of at least two SE, who had VNS implantation and had at least one year follow up after the procedure.
Sixteen patients met inclusion/exclusion criteria. The median age of seizure onset and surgery was 1.3 years and 9.0 years, respectively. Prior to VNS implantation, 81% (13/16) of patients had ≥one seizure per month when all seizure types were combined. 75% (12/16) of patients experienced ≥one generalized convulsive seizure per month. The median number of SE prior to VNS was three (2-9), and 63% (10/16) had at least one SE during a year prior to implantation. The proportion of patients who did not have any SE one year after VNS implantation increased compared to the year prior (75% vs. 37%, p = 0.07). The seizure frequency decreased in a minority of patients when all seizure types were combined (20% at one year, p = 1.00, 44% at the last follow up, p = 0.55), but generalized convulsive seizure decreased in 69% of patients at one year (p = 0.01) and 75% of patients at last follow up (p = 0.01).
VNS appears to have favorable impact on SE and generalized convulsive seizures in children with medically intractable epilepsy 4).