Objective
To assess the static balance under the virtual moving surround (VMS) in healthy young and elderly adults. Method: There were twenty four healthy young adults and thirty nine healthy elderly aged 60 and older. Each group was tested with forceplate during quite standing with eyes opened, closed and under the VMS for static balance. The VMS was stimulated with a head-mounted display (HMD). The parameters for static balance were total sway path distance and area. Results: All static balance parameters of healthy elderly were significantly increased in all conditions when comparedwith parameters of young adults. In the young adults and elderly, total sway path distance and sway area were significantly different under the VMS. In the healthy elderly, total sway path distance and sway area were significantly increased under the VMS as much as eyes closed . Conclusion: In the healthy adults, the VMS could provoke the significant postural sway during static standing. VMS can be used as a tool to evaluate and treat of the patients with static balance dysfunction. (J Korean Acad Rehab Med 2006; 30: 254-260)

Objective
To investigate static posturographic characteristics during balance control under virtual moving surround (VMS) using force platform and head mount display (HMD) device in patients with chronic ankle sprain as compared with that of normal adults. Method: Ten patients with chronic ankle sprain and 24 healthy adults participated. Center of pressure (COP) parameters were obtained for 20 seconds using force platform as total path distance and total sway area in following conditions (1) comfortable standing with opened and closed eyes, (2) VMS delivered using HMD with four different moving patterns. The virtual moving patterns composed of close-far, superior-inferior tilting (pitch), right-left tilting (roll) and horizontal rotation (yaw) movement. Results: No significant difference was found between patients with chronic ankle sprain and healthy adults on comfortable standing with both open and closed eyes. But, patients revealed significantly increased total path distance and sway area of COP on all VMS conditions. Conclusion: These results showed that under VMS conditions patients with the weaker balance control problem were more sensitive to balance control than simple comfortable standing conditions with opened and closed eyes. (J Korean Acad Rehab Med 2005; 29: 297-302)