Motor function Changes to motor function with aging include Decreased flexibility, strength, and balance Slowed gait speed and reaction time Medical conditions that can impact motor function include Neurologic impairment (eg, due to stroke, Parkinson disease, amyotrophic lateral sclerosis, or brain tumor) Diabetes that causes sensorimotor impairment and / or amputation Arthritic conditions Frailty and weakness from normal aging or medical disorders Various parameters of physical function can be assessed in the office: Motor speed, reaction time, balance, and coordination can be assessed with the rapid-pace walk test.