Low levels of dopamine, a brain chemical (neurotransmitter) involved in controlling movement, cause symptoms of Parkinson’s disease. The shortage of this brain chemical occurs when nerve cells in a part of the brain (substantia nigra) that produces dopamine fail and deteriorate. The exact cause of this deterioration is not known.

The links between Parkinson’s disease and factors such as genetics, aging, toxins in the environment, and free radicals are all under investigation. Although these studies are beginning to provide some answers, experts do not know the exact cause of the disease.

Studies are ongoing to determine whether there is a genetic cause of Parkinson’s disease. Only a small percentage of people with Parkinson’s disease have a parent, brother, or sister who has the disease; however, abnormal genes do seem to be a factor in a few families where early-onset Parkinson’s disease is common.

What Happens?

The symptoms and the course of Parkinson’s disease can vary a great deal from person to person. There is no known cure for Parkinson’s disease. However, drugs, surgery, exercise, and lifestyle changes can relieve some symptoms of the disease.

Emotions may also affect symptoms. Anxiety, tension, and unhappiness may make symptoms worse. Relaxing usually reduces symptoms. Sometimes during stress, a person with Parkinson’s disease has a “paradoxical outburst.” This results in a short symptom-free period when the person may be able to move normally.

Treatment may help control symptoms during the early stages of Parkinson’s disease and is usually started as soon as symptoms begin to affect a person’s ability to work or do daily activities. For instance, a right-handed person with tremor only on the left side may not feel limited by the symptoms and may not feel the need to take drugs until symptoms get worse. A person who cannot do his or her job because of symptoms may want to begin treatment sooner than someone who does not work or whose symptoms do not affect his or her ability to work.

• Symptoms of Parkinson’s disease typically begin appearing between the ages 50 and 60. They develop slowly and often go unnoticed by family, friends, and even the person who has them.
• A small number of people have symptoms on only one side of the body that never progress to the other side.

Drugs can control symptoms to some extent, but as the disease progresses, drugs may become less effective. Parkinson’s disease also can cause a variety of complications as it advances.

Normally, these nerve cells make an important chemical called dopamine. Dopamine sends signals to the part of your brain that controls movement. It lets your muscles move smoothly and do what you want them to do. When you have Parkinson’s, these nerve cells break down. Then you no longer have enough dopamine, and you have trouble moving the way you want to.

Parkinson’s is progressive, which means it gets worse over time. But usually this happens slowly, over a period of many years. And there are good treatments that can help you live a full life.

What causes Parkinson’s disease?

No one knows for sure what makes these nerve cells break down. But scientists are doing a lot of research to look for the answer. They are studying many possible causes, including aging and poisons in the environment.

Abnormal genes seem to lead to Parkinson’s disease in some people. But so far, there is not enough proof to show that it is always inherited.

What are the symptoms?

The four main symptoms of Parkinson’s are:

• Tremor, which means shaking or trembling. Tremor may affect your hands, arms, legs, or head.
• Stiff muscles.
• Slow movement.
• Problems with balance or walking.

Tremor may be the first symptom you notice. It is one of the most common signs of the disease, although not everyone has it. More importantly, not everyone with a tremor has Parkinson’s disease. Tremor often starts in just one arm or leg or only on one side of the body. It may be worse when you are awake but not moving the affected arm or leg. It may get better when you move the limb or you are asleep.

In time, Parkinson’s affects muscles all through your body, so it can lead to problems like trouble swallowing or constipation. In the later stages of the disease, a person with Parkinson’s may have a fixed or blank expression, trouble speaking, and other problems. Some people also have a decrease in mental skills (dementia).

People usually start to have symptoms between the ages of 50 and 60, but in some people symptoms start earlier.

How is Parkinson’s disease diagnosed?

Your doctor will ask questions about your symptoms and your past health and will do a neurological exam. A neurological exam includes questions and tests that show how well your nerves are working. For example, your doctor will watch how you move, check your muscle strength and reflexes, and check your vision. In some cases, your doctor may have you try a medicine. How this medicine works may help your doctor know if you have Parkinson’s disease. He or she will also ask questions about your mood.

There are no lab or blood tests that can help your doctor know whether you have Parkinson’s. But you may have tests to help your doctor rule out other diseases that could be causing your symptoms. For example, you might have an MRI to look for signs of a stroke or brain tumor.

How is it treated?

At this time, there is no cure for Parkinson’s disease. But there are several types of medicines that can control the symptoms and make the disease easier to live with.

Levodopa (also called L-dopa) is the best drug for controlling symptoms of Parkinson’s disease. But it can cause problems if you use it for a long time or at a high dose. For this reason, many doctors use other medicines to treat people in the early stages of the disease. This lets them delay the use of levodopa and postpone the side effects.

You may not even need treatment if your symptoms are mild. Your doctor may wait to prescribe medicines until your symptoms start to get in the way of your daily life. Your doctor will adjust your medicines as your symptoms get worse. You may need to take several medicines to get the best results.

In some cases, a treatment called deep brain stimulation may also be used. For this treatment, a surgeon places wires in your brain. The wires carry tiny electrical signals to the parts of the brain that control movement. These little signals can help those parts of the brain work better.

There are many things you can do at home that can help you stay as independent and healthy as possible. Eat healthy foods. Get the rest you need. Make wise use of your energy. Get some exercise every day. Physical therapy and occupational therapy can also help.

How will Parkinson’s disease affect my life?

Finding out that you have a long-term, progressive disease changes your life. It is normal to have a wide range of feelings. You may feel angry, afraid, sad, or worried about what lies ahead. It may help to keep a few things in mind:

• No one can know for sure how your disease will progress. But usually this disease progresses slowly. Some people live for many years with only minor symptoms, such as a tremor in one hand.
• Many people who have Parkinson’s disease can and do keep working for years. As the disease gets worse, you may need to change how you work. You can get support to learn ways to adapt.
• It is important to take an active role in your health care. Learn all you can about the disease. Find a doctor you trust and can work with. Go to all your appointments, and get all the treatment your doctor suggests.
• Depression is common in people who have Parkinson’s. If you feel very sad or hopeless, talk to your doctor or see a counselor. Antidepressant medicines can help.
• It can make a big difference to know that you are not alone. Ask your doctor about Parkinson’s support groups, or look for online groups or message boards.
• Parkinson’s affects more than just the person who has it. It also affects your loved ones. Be sure to include them in your decisions. Help them learn about the disease and get the support they need.