Every year nearly 25-50% of older adults fall. However fall prevention efforts are not uniformlyeffective and factors contributing to fall risk are not completely understood. The vestibular systempart of the inner ear is a known contributor to fall risk and recent evidence suggests that cognitionmay interact with vestibular function to influence falls. Patients with Alzheimers disease (AD) fall2-3 times more than cognitively healthy adults and those with vestibular dysfunction exhibitchanges in cognition. However these relationships have not been fully elucidated. As thevestibular system is diverse identifying which functional pathways (i.e. reflexive perceptualvisual-vestibular integration) are related to both cognition and imbalance is vital for developmentof targeted interventions to reduce falls. The specific aims examine the extent to which vestibularfunction is associated with sensorimotor behaviors (balance and falls) in AD (Aim 1a) and theextent to which cognition is associated with sensorimotor behaviors in adults with vestibular loss(Aim 1b). Explicit comparisons between those with AD and vestibular loss will also be made (Aim1c) in order to determine potential similarities and inform ongoing fall prevention interventions inthese patient populations. Existing measures will be combined with novel laboratory techniquesin order to directly inform clinical practice and elucidate fundamental mechanisms underlying fallrisk. The K01 award period will enable the PI to build upon her existing clinical and researchexpertise in vestibular science and provide structured training in the following areas: a) aging b)cognition and cognitive impairment c) advanced techniques for assessment of balance and gaitand d) advanced techniques for measuring eye movements. Research and training experiencesduring this award period will help the PI become an independent researcher in vestibularphysiology. The proposed work will take place at University of Arizona under the mentorship ofDr. Dan Merfeld and Dr. Yuri Agrawal in conjunction with subject area specific mentorship fromleaders in their respective fields. The proposed training activities and research plan are consistentwith the NIDCDs strategic plan for research in balance specifically addressing currentunderstanding of self-motion perception in health and disease and factors contributing toimbalance and falls in older adults. The proposed training will be the foundation for future R01applications using advanced vestibular assessment techniques to examine changes in sensoryfunction related to diverse pathologies and relationships to postural control.