More than half a million Americans suffer from Parkinson's disease, a brain disorder that leads to tremor and difficulty with walking, movement, and coordination. Although not a normal part of aging, Parkinson's occurs most often among people 60 and older, and the risk increases with age. Older adults now can visit the NIHSeniorHealth Web site to learn more about Parkinson's disease at www.nihseniorhealth.gov/parkinsonsdisease/toc.html. The Web site from the National Institutes of Health (NIH) is geared toward older adults and features clear language.