Because the early symptoms of Parkinson's disease are often very slight and begin slowly, they can be hard to notice. Family members or friends are often the first to spot the early symptoms, such as a constant blank look on the face, shaky hands, decreased arm swinging, a stooped posture, or shorter steps when walking. Parkinson's disease patients may notice that they are weaker or more tired. The disease may eventually involve 2 or more of the 4 main symptoms of Parkinson's disease:

1. Tremors — rhythmic movements or shaking, especially in the hands and particularly when they are at rest
2. Rigid limbs and trunk — muscle tenseness, stiffness, aching, or weakness
3. Slowness of movement — difficulty beginning a task, such as washing or dressing
4. Poor balance and coordination — problems with walking, such as shuffling, which may cause falls

As time goes on, Parkinson's disease sometimes leads to other symptoms, such as depression or anxiety, problems with chewing and swallowing, and speech changes. Some people may have problems with urination or constipation. Others may have trouble sleeping or problems with skin that is too oily or too dry.

It is always important to remember that the symptoms of Parkinson's disease can vary greatly from person to person. For example, one person may have tremors, while another may be very stiff and slow without any tremor.

The diagnosis of Parkinson's disease is usually based on typical signs and symptoms. It is often hard for a healthcare provider to diagnose Parkinson's disease during the early stages when the symptoms are very slight. The healthcare provider will need to observe the patient carefully and take a detailed health history. Family members can also offer important observations. Tests like an MRI may be used to make sure that nothing else is causing the symptoms. It may be helpful to find a healthcare provider who specializes in Parkinson's disease.

People with Parkinson's disease often seek treatment for tremors because they are visible and easily observed. Whether or not a patient has tremors, the healthcare provider will look for the other common symptoms of Parkinson's disease, such as stiffness, poor balance, difficulty walking, and slowness of movement. When several of these symptoms occur, the healthcare provider can often see a pattern that leads to a diagnosis of Parkinson's disease. There is still no medical test or scan approved by the Food and Drug Administration that can diagnose Parkinson's disease.