atrophy (Parkinson’s disease)

The wasting away of body tissue such as organs or muscle. In Parkinson’s disease, atrophy of the substantia nigra occurs as the loss of dopamine-producing cells progresses. When physical activity diminishes in later stages of Parkinson’s disease, muscles also begin to atrophy. Regular exercise, physical therapy, and occupational therapy can help preserve muscle tone and strength because muscle tissue is not actually affected by the disease process as it is in movement disorders such as amyotrophic lateral sclerosis (ALS). Atrophy can be an important distinguishing trait in early diagnosis of movement disorders because it is not a key factor in Parkinson’s disease.