Therapeutic Effects of Electrical Vestibular Stimulation (EVS) on Balance and Gait

Background and Rationale

Standing balance and stable gait are maintained through the integration of sensory feedback from the visual, somatosensory (muscle, skin, tendon, and joint receptors), and vestibular systems. The quality of this feedback, and the ability of the central nervous system (brain and spinal cord) to integrate these signals and generate appropriate motor responses dictates balance and gait performance. Age-related balance decline, clinically known as presbystasis, is one of the most visible and debilitating signs of aging. More than 60 million people in the U.S. over the age of 40 live with age-related balance impairments that increase their risks of fall-related injuries and make it increasingly difficult to continue living actively and independently. 1-in-3 adults above the age of 65 falls each year and falls are the leading cause of death in seniors. But there are less than 20,000 clinical specialists in the U.S. with the tools to diagnose balance impairments, so for most people, little is done to address declining balance until after a fall-related injury occurs. The solution offered to most older adults is a mechanical balance aid such as a walker, whose prolonged use only further destabilizes balance.

Vestibular dysfunction has been identified as the primary cause of balance decline in more than 55% of adults over age 50, or around 34 million people in the U.S. This dysfunction impacts both the peripheral vestibular organs in the inner ear and central vestibular processing in the brain, and it has also been linked to cognitive decline. Current therapeutic options to restore lost balance function are limited to high-risk surgical vestibular implants. The current standard of care is exercise-based therapy that aims to help compensate for vestibular balance decline, but there remains a critical gap: no widely available non-invasive solution exists to restore lost vestibular function or prevent further deterioration.

A growing body of research indicates that low-level, non-invasive electrical stimulation of the vestibular balance system (EVS) can induce neuroplastic changes at both cellular and circuit levels, effectively restoring peripheral and central vestibular functions. Restored vestibular function has also been linked to restored cognitive function. The investigators have developed a novel sub-threshold wideband stochastic EVS (swsEVS) neuroplastic stimulation, which targets peripheral and central vestibular pathways. Multiple studies have demonstrated that the swsEVS frequencies and current levels are safe, comfortable, well-tolerated, and have no adverse side effects. These studies have also demonstrated that a therapeutic treatment protocol with 18 twenty-minute swsEVS sessions delivered over a 5-6-week period resulted in significant improvements in balance performance in otherwise healthy adults aged 50-98 years old. These improvements are attributed to neuroplastic restoration of both peripheral and central vestibular function. The observed improvements persisted for at least 3-6 months and were sufficient to recategorize high fall risk individuals to lower fall risk.