Therapeutic potential of transcutaneous auricular vagus nerve stimulation in cognitive impairment: insights from preclinical and clinical studies

Transcutaneous auricular vagus nerve stimulation (taVNS) is being investigated as a non-invasive neuromodulatory approach for cognitive impairment (CI). This review evaluates the existing preclinical and clinical evidence regarding its potential efficacy and mechanisms of action in conditions such as mild cognitive impairment, post-stroke cognitive impairment, and other forms of CI. Preclinical models suggest that taVNS may influence multiple pathways, including neurotransmitter regulation, neuroinflammation, apoptosis, and synaptic plasticity. Clinically, some small-scale studies report modest improvements in cognitive metrics, but the evidence remains preliminary due to methodological limitations such as small sample sizes, heterogeneous parameters, and short intervention durations. Significant challenges, including the lack of standardized protocols, inadequate sham controls, and an underdeveloped mechanistic understanding, currently hinder the interpretation and translation of findings. Future research necessitates large-scale, rigorously controlled trials and deeper mechanistic studies to determine whether taVNS has a definitive role in the clinical management of cognitive impairment.