Clinical Research Directory

MRI Performance and Risk Factors in Bilateral Vestibular Hypofunction

Bilateral vestibular hypofunction (BVH) is a chronic disorder in which the balance organs or vestibular pathways on both sides do not work normally. People with BVH may experience unsteadiness, blurred or unstable vision during head movement, difficulty walking, and an increased risk of falls. At present, there are limited targeted medical treatments, and the reasons why symptoms are severe in some patients but mild in others are not fully understood. This prospective, multicenter, cross-sectional study will investigate the relationships among vestibular function, brain structure and function, blood biomarkers, patient-reported symptoms, and disease severity in people with BVH. The study will enroll approximately 120 participants from five medical centers in China, including about 80 patients with BVH and 40 age-matched healthy controls. Participants will undergo vestibular function tests, including videonystagmography, caloric testing, sinusoidal harmonic acceleration testing, video head impulse testing, vestibular evoked myogenic potentials, and sensory organization testing. Brain imaging will include resting-state functional magnetic resonance imaging, diffusion tensor imaging, and diffusion kurtosis imaging. Participants will also complete questionnaires related to dizziness, anxiety and depression, daily activities, and symptom severity, and blood samples will be collected for biochemical and inflammatory marker testing. The main hypothesis is that BVH severity is associated with measurable changes in vestibular function, brain functional connectivity and microstructure, inflammatory or metabolic biomarkers, and patient-reported quality of life. By combining clinical testing, neuroimaging, laboratory measures, and symptom scales, this study aims to improve understanding of the mechanisms of BVH and to support future development of more individualized diagnostic and rehabilitation strategies.

Subthreshold Vestibular Stimulation as a Strategy for Rehabilitation

The nervous system responds to changes in external or internal conditions by altering the behavior of neurons through multiple forms of neural plasticity. A specific form of plasticity, "homeostatic plasticity", stabilizes neural activity by driving the excitability of neurons toward a "set-point" level of activity. Over the last six years, new data have come to light showing that the vestibular system also possess a robust capacity to modulate sensitivity to self-motion cues in response to prolonged periods of motion. Collectively, these studies have demonstrated a capacity to use motion perturbations (i.e., low, or high levels of vestibular stimulation) to dynamically adjust the sensitivity of the vestibular system on both the single neuron and behavioral levels. The ability to use subthreshold motion stimuli to drive plasticity in the vestibular system motivates this study. The investigators aim to determine the impact of subthreshold motion on (a) balance performance and (b) balance training in individuals with peripheral vestibular hypofunction.

Vestibular Implantation in Older Adults

Although cochlear implants can restore hearing to individuals who have lost cochlear hair cell function, there is no widely available, adequately effective treatment for individuals suffering chronic imbalance, postural instability and unsteady vision due to bilateral vestibular hypofunction. Prior research has demonstrated that electrical stimulation of the vestibular nerve via a chronically implanted multichannel vestibular implant can partially restore vestibular reflexes that normally maintain steady posture and vision; improve performance on objective measures of postural stability and gait; and improve patient-reported disability and health-related quality of life. This single-arm open-label study extends that research to evaluate outcomes for up to fifteen older adults (age 65-90 years at time of enrollment) with ototoxic or non-ototoxic bilateral vestibular hypofunction.