Articles

Acoustic Voice Changes Induced by Transcutaneous Auricular Vagus Nerve Stimulation

AUTHOR
Seong Hee Choi, Woo Sung Choi, Geun Young Han
INFORMATION
2025, Vol. 10, Issue 3 / pp. 143-153
e-ISSN
2508-5948
p-ISSN

ABSTRACT

Purpose Transcutaneous auricular vagus nerve stimulation (taVNS) is being increasingly applied in both clinical and experimental context; however, its effects on vocal function remain poorly understood. This study investigated the short-term effects of bilateral taVNS on voice production in healthy adults using acoustic perturbation, cepstral, spectral, and electroglottographic measures.Methods A total of 39 healthy adults (8 males and 31 females; aged 21–36 years) without voice or neurological disorders were randomly allocated to either an active taVNS group (n = 20) or a sham group (n = 19) in a double-blind design. Participants received a single 30-minute session of bilateral taVNS (25 Hz, 200 μs, 0.5 mA below pain threshold) or sham stimulation. Voice measures were obtained immediately before and after stimulation during sustained vowel phonation and connected speech. Pre- to post-stimulation changes were compared between groups, and subjective symptoms were monitored.Results No consistent effects of taVNS were observed across acoustic, electroglottographic, or cepstral–spectral measures. Fundamental frequency, perturbation indices, vocal fold contact measures, and overall cepstral–spectral metrics remained stable following stimulation in both groups. A significant change was observed only in the low-to-high spectral ratio during sustained phonation in the taVNS group, with no corresponding effects observed during connected speech.Conclusions Under the tested stimulation parameters, short-term bilateral taVNS did not produce robust or systematic changes in objective measures of voice production in healthy adults. These findings suggest that acute taVNS has limited immediate influence on vocal fold function and overall voice quality.

Keyword
transcutaneous auricular vagus nerve stimulation (taVNS) voice acoustics healthy adults voice safety cepstral measures perturbation measures

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