Subjects will complete a mental speed test and will undergo Computerized Dynamic Posturography (CDP) testing using the modified Clinical Testing of Sensory Integration in Balance (mCTSIB) protocol: the subjects will be required to stand on a hard or compliant surface (a 4" tall foam cushion of known mechanical properties) in a comfortable posture, feet shoulder width, with eyes open or closed, head straight and arms to the side and free to move, gazing forward, and breathing normally. Immediately prior to the CDP testing, subjects will have their heart rate, blood pressure and pulse Ox measured. These will constitute the baseline information.