Parkinson's disease is a slowly progressing brain disorder that usually develops after age 50 and is characterized by changes in speech and gait, tremors, and difficulty with balance. Symptoms vary widely, though, so it can be hard to recognize at first. There's no cure yet. But it's usually treatable, with opportunities for symptom relief and a good quality of life for many years. Find out more about how to care for someone with Parkinson's here.