Hoehn and Yahr scale

Overview
The Hoehn and Yahr scale is a commonly used system for describing how the symptoms of Parkinson's disease progress. The scale allocates stages from 0 to 5 to indicate the relative level of disability.


 * Stage one: Symptoms on one side of the body only.
 * Stage two: Symptoms on both sides of the body. No impairment of balance.
 * Stage three: Balance impairment. Mild to moderate disease.  Physically independent.
 * Stage four: Severe disability, but still able to walk or stand unassisted.
 * Stage five: Wheelchair-bound or bedridden unless assisted.