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How Do I Know If I Have Parkinson's Disease?

Usually, the outward symptoms of Parkinson's are distinctive enough for a diagnosis to be made. The metabolic changes in the brain can be traced with imaging tests such as PET - positron emission tomography. Tests can help your doctor determine whether you have Parkinson's disease or some other type of parkinsonism. If you don't have a response to the drugs used to treat Parkinson's disease, your doctor will probably continue to search for the cause of your parkinsonism.

What Are the Treatments?

Most treatments aim at restoring the proper balance of the neurotransmitters acetylcholine and dopamine by increasing dopamine levels. Drugs are the standard way of doing this, but neurosurgeons have had some success with experiments involving operative procedures. If your parkinsonism is not due to Parkinson's disease, your doctor will select the appropriate treatment for the underlying cause.

Conventional Medicine

Symptoms can be effectively controlled for years with medication. The drug most often prescribed is levodopa — also called L-dopa — which the body metabolizes to produce dopamine. (Direct administration of dopamine is ineffective; the brain's natural protections block its uptake.) To suppress nausea and other possible side effects, levodopa is often used in conjunction with a related drug called carbidopa.

But some patients cannot tolerate carbidopa and so take levodopa alone. If you take only levodopa, it's important not to take it at the same time as food or vitamins containing vitamin B-6, which interferes with its effectiveness.

Most doctors try to postpone starting patients on levodopa as long as possible, because the medication tends to lose effectiveness over time. However, there is some controversy about waiting to begin treatment with levodopa because it can be so beneficial. Researchers have thus investigated ways to offset the loss of effectiveness.

COMT inhibitors such as tolcapone (Tasmar) and entacapone (Comtan) are drugs that are taken with levodopa. They prolong the duration of symptom relief by blocking the action of an enzyme which breaks down levodopa.

Stalevo is a newer combination tablet that combines carbidopa/levodopa, with entacapone. While carbidopa reduces the side effects of levodopa, entacapone extends the time levodopa is active in the brain.

A promising new class of dopamine-like drugs directly imitates dopamine's activity in the brain. Bromocriptine, pergolide, and two newer agents (pramipexole and ropinirole) used alone or in combination with L-dopa are effective in treating the motor symptoms of Parkinson's disease. Other medications prescribed for Parkinson's disease include apomorphine, benztropine, amantadine, selegiline and anticholinergic drugs; all can help control various symptoms — in some cases by releasing dopamine from nerve cells, in others by reducing the effects of acetylcholine rather than increasing the amount of dopamine.

Neurologists and neurosurgeons have explored various ways of grafting dopamine-producing cells in the brain rather than trying to correct the neurotransmitter imbalance with drugs. One promising approach uses fetal-tissue implants. Some improvements have been observed, but because of the source of the cells, the technique is highly controversial. Alternative dopamine-producing cell lines are being developed.

Another surgical technique creates lesions in the globus pallidus or thalamus. These are the parts of the brain involved in Parkinson's disease. Another way to do this without causing permanent damage is with electrical stimulation. This can be turned off and on and may offer dramatic improvements in symptoms.

Scientists are also investigating the use of glial cell-derived nerve growth factor to treat Parkinson's and other neurodegenerative diseases. This substance is produced naturally by tissues throughout the body; some experiments indicate that injections of this nerve growth factor may help preserve and even restore nerve cells in the brain and spinal cord — specifically those that produce dopamine and that help initiate muscle movement.

Some treatments focus on the effects of the disorder rather than the causes. Your doctor might refer you to a physical therapist to restore normal body alignment, enhance your balance and motor responses, and improve your ability to initiate motion. A physical therapist may also give you muscle-strengthening exercises to help with speaking or swallowing.

In many Parkinson's patients, a weakening of social ties because of physical difficulties can lead to depression. Antidepressants can help. In addition, the American Parkinson Disease Association can provide information about support groups and exercise classes in your area - valuable sources of companionship.