Galvanic Vestibular Stimulation and Its Effects on Sympathetic Nervous System Activation

Cardiovascular modulation in response to movement and gravitational forces can be influenced by vestibular input or peripheral baroreflex mechanisms. Galvanic vestibular stimulation (GVS) is a widely used, noninvasive method for activating neural pathways within the vestibular system, as well as associated pathways such as vestibulo-spinal, oculomotor, and vestibulo-autonomic circuits. Research on vestibulo-autonomic function via GVS has primarily focused on its effects on cardiovascular modulation and sympathetic muscle and nerve activity. However, inconsistencies in GVS application protocols across studies have made it challenging to reach a consensus regarding its effectiveness in modulating the vestibulo-autonomic pathway. Evidence suggests that GVS induces transient autonomic changes by stimulating a neural pathway sensitive to otolith input. This review collates the parameters used in GVS application and examines their effects on autonomic neural pathways by analyzing variations in amplitude, frequency, and electrode montage to understand their impact on autonomic responses, including changes in heart rate (HR), blood pressure (BP), and sympathetic muscle or nerve activity (MSNA). By analyzing stimulation parameters and experimental protocols, we aim to determine their impact on autonomic activation and evaluate their potential for precise autonomic modulation. Finally, based on the evidence generated in populations with neurological disorders and motion sickness, we discuss the potential of GVS as a complementary neuromodulation strategy to treat autonomic dysregulation.