Slowness of movement (bradykinesia - pronounced 'bray-dee kin-eesya') is one of the classic symptoms of Parkinson's disease. Over time, patients develop a stooped posture and a slow, shuffling walk. This gait gradually becomes erratic and unsteady, and may lead to falls.
Re: Skirt Board On Existing Stairs. Or....just lay a 1 X 12 on edge running up the stairs, resting on the tips of the treads. Scribe down to the treads the right amount to make it line up with your 4-1/4 base. Use a framing square to mark for riser cuts. Then if the risers are angled back as they sometimes are in a carpeted situation, scribe the skirt board back after it has been scribed down. This will usually require that 2 boards be connected together to cover the entire length of the stairs.
Stair treads usually already have the bullnose shape when you buy them, but you have to take care of that detail yourself if you're making the treads. You do it with a 1/2-inch round-over routing bit.. Put the router base flat against thread and move it to far left. Turn it on and push the machine from left to right along the edge of the tread. After you've routed the edge, go back over it once more to clean up any splinters or ripples.