Direct Assessment of Human Gravity Sensors to Improve Peripheral Vestibular Assessment

About This Grant

PROJECT SUMMARY Dizziness accounts for approximately 10% of all physician visits, making it one of the most common reasons patients seek medical attention. Current vestibular assessments primarily relay on the sequential activation of peripheral sensors, central brainstem relay neurons, and alpha motor neuron pools innervating the neck, extraocular, or postural muscles. This indirect approach often limits the effectiveness of diagnosing peripheral vestibular pathologies. Addressing the limitations of these traditional methods, a non-invasive, direct assessment of vestibular otolithic sensors could greatly advance the field and ultimately improve care for patients with dizziness complaints. We hypothesize that short latency vestibular sensory evoked potentials (VsEPs) can be elicited in humans using linear acceleration transients and recorded non-invasively through far-field evoked potential electrophysiology from the scalp. Building on successful animal models by the PI and collaborators, we propose translating this approach to human clinical use. To support this goal, we have developed a newly designed head motion system and aim to validate the utility of short latency VsEPs in human subjects. As a crucial step toward the long-term goal of developing a direct assessment of vestibular function for clinical use, our proposed studies herein seek to identify the optimal stimulus and effective recording parameters for eliciting human VsEPs. The first specific aim will identify the ideal stimulus profile by systematically varying either acceleration or jerk levels. Our preliminary data suggest that jerk is more crucial than acceleration in activating vestibular signal transduction in human otolithic organs. The second specific aim will determine the best recording and stimulation configuration, beginning with approaches that have proven effective in animal models and incorporating comprehensive multichannel recordings. We will explore key variables such as electrode placement, amplification, filtering, stimulus rate, duration, and head motion direction to enhance the efficiency in assessing the human vestibular system. To complete these aims, we will test young adults with normal vestibular function from four distinct racial groups and both genders, recruited from the University of Rochester and University of Rochester Medical Center, while refining our head motion system for clinical application. The knowledge gained from the proposed studies will outline the physiological design requirements for a prototype VsEP stimulator device for future clinical use. Our findings will also provide a foundation for comparing VsEPs with traditional measures, validating a reliable diagnostic tool for various peripheral vestibular dysfunction including 8th nerve schwannomas, vestibular neuritis, labyrinthitis, and Meniere’s disease. This proposed research has the potential to significantly impact both clinical practice and basic science. We aim to provide the first direct assessment method for peripheral vestibular function. Our findings will offer critical insights for understanding and diagnosing balance disorders.