One of the assessment tools doctors use to evaluate the progression of symptoms and the extent of disability that results from them for the person with Parkinson’s disease. Developed in 1967 by the physicians Margaret Hoehn and Melvin Yahr, this scale primarily assesses mobility and motor function. The scale designates five stages of Parkinson’s disease.
Unlike rating scales for diseases such as cancer, the Hoehn and Yahr stage scale and similar assessment tools do not project the likely progression of symptoms or success of treatment. Parkinson’s stage scales only indicate the current level, relative to the full spectrum of the disease, of a person’s symptoms. The higher the stage, the more significantly the Parkinson’s affects the person’s ability to function.
Many people with Parkinson’s move back and forth among the stages, particularly in the midcourse of the disease. As well, the person’s rating may be stage V during an off-state (at the end of a medication dose’s effectiveness) and stage II during an on-state. See also activities of daily living; instrumental ACTIVITIES OF DAILY LIVING; PARKINSON’S IMPACT scale; staging of Parkinson’s disease.