Estimates suggest that about 50,000 Americans are diagnosed with PD each year, although some estimates are much higher. Getting an accurate count of the number of cases is difficult because many people in the early stages of the disease may assume their symptoms are the result of normal aging and do not seek medical attention. Diagnosis is sometimes complicated by the fact that other conditions may produce symptoms of PD and there is no definitive test for the disease. People with PD may sometimes be told by their doctors that they have other disorders, and people with PD-like diseases may be incorrectly diagnosed as having PD.