taVNS Effect on Central Auditory Processing

Transcutaneous auricular vagus nerve stimulation (taVNS) is an emerging non-invasive therapy that modulates brain activity by delivering electrical impulses to the auricular branch of the vagus nerve at the outer ear (Badran et al., 2018). taVNS subsequently stimulates the nucleus of tractus solitarius via the afferent vagus nerve fibers. The nucleus solitarius sends outputs to the hypothalamus, which is critical for sensory processing, including auditory processing, and also activates various brain regions, including the locus coeruleus, resulting in the release of neurotransmitters such as norepinephrine and serotonin, which are involved in neural plasticity and cognitive function, which is important for CAP. Another theory for taVNS effects is the release of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, which may further help to balance abnormal neural activity in auditory circuits.

the control group received sham stimulation with the stimulator closed and electrodes placed in their left ear