Some people experience virtual reality sickness while wearing headsets, and it's similar to motion sickness. Mayo Clinic researchers have developed Galvanic Vestibular Stimulation (GVS) to help with VR sickness, and it may one day help with other balance issues.
Mayo Clinic's GVS technology
"was developed over 10 years by its Aerospace Medicine & Vestibular Research Laboratory (AMVRL) team who are neurovestibular specialists and experts in aerospace medicine, internal medicine, and computational science. vMocion's 3v(TM) Platform features this technology, which adds a complete sense of three-dimensional movement for the first time into a VR/AR environment."
This bonus video explains some of the research behind the project.