Effects of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) on Verbal Working Memory, Word Fluency, and Verbal Episodic Memory in Healthy Young Adults

Objectives: The purpose of this study was to investigate the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on verbal working memory, word fluency, and verbal episodic memory in healthy young adults. Methods: Thirty-nine healthy participants aged 20-30 years were randomly assigned to either an active taVNS group (N=20) or a sham group (N=19), and the experiment was conducted in a single-blind design. Participants completed verbal working memory tasks (digit and word forward/backward span), a word fluency task (animal naming), and verbal episodic memory tasks (immediate recall, delayed recall, recognition) before and after stimulation. Data were analyzed using twoway mixed ANOVAs. Results: The active taVNS group showed significant improvements after stimulation in the digit backward span, word forward/backward spans, and word fluency tasks, whereas the sham group showed no significant differences. However, both groups showed significant post-stimulation improvements in digit forward span and verbal episodic memory tasks, with no significant differences between groups. Conclusion: These findings suggest that taVNS has potential as a non-invasive electroceutical therapy for enhancing verbal working memory and word fluency performance in healthy young adults. In particular, the effects were more pronounced in tasks requiring higher cognitive load, implying that taVNS may enhance cognitive processing by activating prefrontal cortex and language-related neural networks associated with working memory.