Transcutaneous auricular vagus nerve stimulation (taVNS), a novel self-care technique to noninvasively stimulate the vagus nerve as a treatment option for drug-resistant epilepsy, had a relatively modest feasibility and the limitations are likely to be related to the practical usability of the device, according to study results published in Epilepsy Research.
While there are data to suggest that the tolerability of taVNS is similar to that of traditional implanted VNS, limited data are available on the feasibility of the therapy. The objective of the current study was to assess potential clinical benefits of taVNS and to determine the adaptation, compliance, and usability of the device.
The trial consisted of 8 weeks baseline phase, a 6-month phase with fixed antiseizure medication and antidepressant drugs and a subsequent 12 months follow-up phase. The primary outcome was 6 months user retention rate of taVNS therapy.
The trial was prematurely terminated after 45 months due to recruitment problems and the rapid and high number of participants who dropped out. At that point, the prospective, multicenter, clinical trial included 37 patients with drug-resistant epilepsy of whom 22 completed the first endpoint (6 months). As the study turned out to be inadequately powered to detect any statistically significant results or conclusions of the clinical benefits of taVNS on seizure frequency or psychometric outcomes, assessment of practical usability and lifestyle issues was completed, including reasons for dropping out early.
Of the 22 patients who completed the 6-month phase, most (14 patients) were willing to continue into the open phase follow-up. In total, 6 patients (16%) completed the following 12 months follow-up and used taVNS for a total of 18 months. These 6 patients gave higher scores for the device usability and lifestyle fit already at the first telephone visit.
The reasons for discontinuation were a mixture of medical and practical issues of which the majority was related to a combination of both. Finding time to use the device for 4 hours every day and electrode connection issues were the most common reported challenges regarding the usability and lifestyle fit of taVNS.
The study had several limitations, including small sample size and the study was not designed to measure the effectiveness of taVNS.
“The results of this study stress the importance of generating data based on patients experiences at an early stage during the development phase and when designing clinical trials on medical devices that depend on patient’s active participation and motivation,” concluded the researchers.
Disclosure: This research was supported by Inge Berthelsens Foundation, Odense, Denmark. Please see the original reference for a full list of disclosures.
Sabers A, Aumüller-Wagner S, Christensen LR, et al. Feasibility of transcutaneous auricular vagus nerve stimulation in treatment of drug resistant epilepsy: a multicenter prospective study. Epilepsy Res. Published online September 25, 2021. doi: 10.1016/j.eplepsyres.2021.106776