In a prospective, multicenter study published in Acta Epileptologica, 124 adults with drug-resistant epilepsy were followed for a full year after receiving the implant, with assessments scheduled at 1, 3, 6, 9, and 12 months. The headline result is striking: the proportion of patients achieving at least a 50 percent reduction in seizure frequency climbed steadily from 35.5 percent at one month to 76.6 percent at twelve months, and the researchers report a significant cumulative effect, meaning the benefits grew the longer the device was active.
The study, led by Chenyang Zhao and colleagues with senior authorship by Dong Zhou, enrolled patients at 83 sites nationwide between January 2022 and December 2024. All participants had been diagnosed with drug-resistant epilepsy according to the 2010 criteria of the International League Against Epilepsy, meaning their seizures persisted despite two appropriately chosen and well-tolerated anti-seizure medications. The cohort was predominantly young and had lived with epilepsy for a long time: the mean age was 28.3 years, the mean age at seizure onset was 14.5 years, and the mean duration of epilepsy was 14.8 years. Seventy-seven of the 124 patients were male and 47 were female.
Vagus nerve stimulation works by delivering electrical pulses to the left cervical vagus nerve in the neck. These afferent signals travel to the nucleus tractus solitarius in the brainstem, which in turn activates the locus coeruleus and other brain regions involved in modulating seizure activity. The therapy was approved by the United States Food and Drug Administration in 1997 as an adjunctive treatment for pharmacoresistant epilepsy, and it has been introduced into clinical practice in China since 2008. The domestic Chinese VNS device used in this study, manufactured by PINS in Beijing, completed its clinical trial registration in 2014 and entered clinical use in 2016. Today, more than 140 hospitals in China offer the therapy, and nearly 5,000 epilepsy patients have received it.
The design of the new study set it apart from much of the existing literature. Before implantation, each patient underwent a 12-week prospective baseline period during which seizure frequency, quality of life, and demographic and clinical information were systematically recorded. After surgery, follow-up visits at 1, 3, 6, 9, and 12 months captured the same measures using standardized case report forms. The primary endpoint was the change in seizure frequency from baseline, with responders defined as patients achieving a reduction of at least 50 percent. Secondary endpoints included changes in the 31-item Quality of Life in Epilepsy Inventory (QOLIE-31) score, the overall anti-seizure medication load, and adverse events. Importantly, medication choices and device parameter settings were left to each patient’s treating physicians, reflecting genuine clinical practice rather than a tightly controlled protocol.
The seizure outcomes showed a clear pattern of accumulation over time. Beyond the responder rates of 35.5, 41.6, 62.2, 64.2, and 76.6 percent at the successive follow-up visits, the seizure-free rates also rose, from 2.4 percent at one month to 10.9 percent at twelve months, with the intermediate values at 2.7, 9.2, and 8.6 percent. The researchers report that both the trend toward greater seizure freedom and the rising responder rate were statistically significant across the follow-up period. The authors note that this dynamic follow-up design allowed them to directly compare outcomes at successive time points, addressing a question that earlier pooled analyses had left open, since a previous meta-analysis had found only a non-significant trend toward greater benefit with longer follow-up.
Quality of life improved in parallel with seizure control. Mean QOLIE-31 score improvements from baseline were 2.93 points at one month, 4.27 at three months, 4.69 at six months, 6.68 at nine months, and 9.32 at twelve months, with each improvement statistically significant and the benefit growing over the year. The authors calculated a mean improvement of 5.58 points across the follow-up period. Correlation analyses revealed that the number of anti-seizure medications taken before implantation was positively associated with the quality-of-life improvement at three months, and that being a responder at the last visit correlated with larger quality-of-life gains at the 3, 6, 9, and 12 month assessments. No other clinical characteristic, including age, sex, epilepsy duration, or seizure frequency, showed a significant correlation with the quality-of-life changes.
One perhaps counterintuitive finding concerned medication use. Despite the substantial improvements in seizure outcomes, the overall anti-seizure medication load, defined as the sum of each drug’s dosage relative to its standard dose referenced from World Health Organization definitions, showed no significant difference between baseline and any follow-up visit, with only a slight, non-significant upward trend. The authors suggest a plausible explanation: in patients who achieve substantial but incomplete seizure reduction, clinicians may cautiously optimize or even slightly increase the existing medication regimen in pursuit of complete seizure freedom. Medication adjustments were made in 37 of the 124 patients, yet the overall load for the cohort remained statistically unchanged from baseline throughout the year.
Safety results were reassuring. At least one adverse event was reported in 34 patients, or 27.4 percent of the cohort, and no severe or life-threatening events occurred, nor were there any events that led to removal of the device. The most commonly reported problems were voice changes or hoarseness, accounting for 76.5 percent of all adverse events, and cough, accounting for 32.4 percent. All documented adverse events occurred at the start of the stimulation phase and were generally transient and reversible. The authors note that this overall incidence compares favorably with other reports, which have ranged from 45.8 percent to 71.4 percent, and with a meta-analysis that found hoarseness in 37.2 percent of patients and cough in 14.2 percent.
The study’s findings align with a growing international literature. A recent systematic review of 11 studies reported a mean responder rate of 56.9 percent, while a multicenter study from Japan reported mean seizure-free and responder rates of 6.4 percent and 52.9 percent respectively, and a Belgian multicenter study with a mean follow-up of 44 months reported a seizure-free rate of 9 percent and a responder rate of 59 percent. The new Chinese data, with a mean responder rate of 56.0 percent and a mean seizure-free rate of 6.8 percent across the follow-up visits, sit comfortably within this range while adding the weight of a nationwide, prospective design with more than 100 patients, something the authors identify as previously lacking in China.
The authors are candid about the limitations of their work. The dosing of anti-seizure medications and the adjustment of stimulation parameters were not standardized and were left to the discretion of individual physicians, although the authors argue that this reflects the reality of clinical practice. There was loss to follow-up at every visit, which the authors acknowledge may introduce a potential selection bias, particularly as the dropout rate rose with longer follow-up duration. The maximum follow-up period was 12 months, leaving longer-term effects and cumulative benefits unexplored. The cohort was also restricted to adults between 18 and 75 years of age. The team states that future research will involve longer-term, rigorous follow-up to assess the long-term effects of vagus nerve stimulation on seizure outcomes and quality of life. For now, the study offers patients and clinicians in China and beyond a detailed, prospectively gathered picture of what the first year with a vagus nerve stimulator typically looks like: gradual, accumulating gains in seizure control and quality of life, achieved without a net increase in medication burden and with a manageable profile of mostly transient side effects.
Subject of Research: Vagus nerve stimulation as an add-on therapy for drug-resistant epilepsy in China
Article Title: Vagus nerve stimulation as an add-on therapy in patients with epilepsy: a prospective, multicenter, real-world study in China
Article References: Zhao, C., Zhang, E., Zhang, H., Yan, R., Le, Z., Chen, Y., Liu, W., Xiong, W., Wu, X., & Zhou, D. (2026). Vagus nerve stimulation as an add-on therapy in patients with epilepsy: a prospective, multicenter, real-world study in China. Acta Epileptologica, 8(1), Article 30. https://doi.org/10.1186/s42494-026-00272-4
Image Credits: AI Generated
DOI: 10.1186/s42494-026-00272-4
Keywords: epilepsy, vagus nerve stimulation, drug-resistant epilepsy, neuromodulation, quality of life, anti-seizure medications, seizure freedom, adverse events, prospective study, China, QOLIE-31, real-world study
News Source: Kendall Mcintyre. (October 28, 2026). Vagus Nerve Stimulation Cuts Seizures and Lifts Quality of Life in Chinese Epilepsy Study. Scienmag.
