Ear your heart: transcutaneous auricular vagus nerve stimulation on heart rate variability in healthy young participants

Abstract

Background Transcutaneous auricular vagus nerve stimulation (taVNS) stimulating the auricular branch of the vagus nerve along a well-defined neuroanatomical pathway, has promising therapeutic efficacy. Potentially, taVNS can modulate autonomic responses. Specifically, taVNS can induce more consistent parasympathetic activation and may lead to increased heart rate variability (HRV). However, the effects of taVNS on HRV remain inconclusive. Here, we investigated changes in HRV due to brief alteration periods of parasympathetic-vagal cardiac activity produced by taVNS on the cymba as opposed to control administration via the helix. Materials and Methods We compared the effect of 10 min of active stimulation (i.e., cymba conchae) to sham stimulation (i.e., helix) on peripheral cardiovascular response, in 28 healthy young adults. HRV was estimated in the time domain and frequency domain during the overall stimulation. Results Although active-taVNS and sham-taVNS stimulation did not differ in subjective intensity ratings, the active stimulation of the cymba led to vagally mediated HRV increases in both the time and frequency domains. Differences were significant between active-taVNS and both sham-taVNS and resting conditions in the absence of stimulation for various HRV parameters, but not for the low-frequency index of HRV, where no differences were found between active-taVNS and sham-taVNS conditions. Conclusion This work supports the hypothesis that taVNS reliably induces a rapid increase in HRV parameters when auricular stimulation is used to recruit fibers in the cymba compared to stimulation at another site. The results suggest that HRV can be used as a physiological indicator of autonomic tone in taVNS for research and potential therapeutic applications, in line with the established effects of invasive VNS. Knowledge of the physiological effect of taVNS short sessions in modulating cardiovagal processing is essential for enhancing its clinical use.

Modifying functional brain networks in focal epilepsy by manual visceral-osteopathic stimulation of the vagus nerve at the abdomen

“…For the latter, similar observations were made for chronic invasive stimulation of the left cervical vagus nerve as an add-on treatment for medically refractory epilepsy ( Constantinescu et al, 2019 ; Wu et al, 2021 ). Studies on cardiac effects of short-term (minutes to hours) taVNS have so far been performed in healthy subjects only, however, with conflicting findings ( De Couck et al, 2017 ; Badran et al, 2018 ; Capilupi et al, 2020 ; Keute et al, 2021 ; Machetanz et al, 2021a ; Machetanz et al, 2021b ; Wolf et al, 2021 ; Forte et al, 2022 ). These can probably be related to stimulation-parameter-dependent influences that act on brain-heart couplings ( Cerritelli et al, 2021 ; Keute et al, 2021 ).…”

Brief periods of transcutaneous auricular vagus nerve stimulation improve autonomic balance and alter circulating monocytes and endothelial cells in patients with metabolic syndrome: a pilot study

“…Prior studies, which have investigated effects of vagus nerve stimulation on HRV, have generated various results depending on the study design, such as included population, the region of stimulation and its duration, and methods of HRV analysis. Some studies using TAVNS for shorter periods (5 or 10 min) in healthy subjects have also showed significant improvement in HRV parameters of parasympathetic activity (Forte et al 2022;Geng et al 2022). However, regarding the LH component, it is suggested that prolonged TAVNS stimulation (30 -60 min) is required to decrease its power (Tran et al 2019).…”

Modulation of vagal activity may help reduce neurodevelopmental damage in the offspring of mothers with pre-eclampsia

“…Recognized as a potentially safe and feasible treatment, it is imperative for upcoming research on taVNS to meticulously evaluate any adverse events (73). Moreover, there is evidence indicating that taVNS can amplify cardiac vagal activity, reflected by heart rate variability (HRV) (74). Consequently, we speculate that, unlike the invasive implanted VNS, taVNS might serve as a pivotal tool in future studies on preeclamptic women to potentially alleviate their symptoms and possibly mitigate neurodevelopmental damage in their offspring.…”