We do not possess a clinical test to assess balance pathways to the trunk and lower limbs. This project will use vibration pulses and a gentle electrical pulses to activate inner ear balance organs and evoke a postural response. We will assess healthy volunteers across age groups and dizzy patients . We will develop and disseminate a simplified test for widespread clinical use. Our findings will be used to refine and validate a predictive model of postural responses to electrical stimulation.