The Disease | Incidence | Symptoms and Diagnosis
Treatment | Medications | Surgical Treatments

The Disease

Parkinson's disease is a progressive disorder of the central nervous system affecting more than 1.5 million people in the United States. Clinically, the disease is characterized by a decrease in spontaneous movements, gait difficulty, postural instability, rigidity and tremor. Parkinson's disease is caused by the degeneration of the pigmented neurons in the Substantia Nigra of the brain, resulting in decreased dopamine availability. The major symptoms of the disease were originally described in 1817 by an English physician, Dr. James Parkinson, who called it "Shaking Palsy.” It was not until the 1960's, however, that pathological and biochemical changes in the brain of patients were identified, opening the way to the first effective medication for controlling the symptoms of the disease.

Incidence

Men and women alike are affected. The frequency of the disease is considerably higher in the over-60 age group, even though there is an alarming increase of patients of younger age. In consideration of the increased life expectancy in this country and worldwide, an increasing number of people will be victims of Parkinson's disease.

Symptoms and Diagnosis

The symptoms of Parkinson’s disease may begin so gradually that patients may not even be aware they have the disease. While some may feel they have symptoms, they often do not get checked by a physician until the symptoms become very pronounced. For everyone especially over the age of 50 it is strongly recommended to have regular medical check ups. It is especially important to see a neurologist who can determine early on if a patient exhibits symptoms, even if the patient is unable to notice these symptoms.

A diagnosis of Parkinson’s disease is made when a person shows at least 2 of the primary symptoms of the disease, which include:

• Rigidity
• Tremor
• Slow Movement (bradykinesia)
• Loss of Movement (akinesia)
• Difficulty with balance and walking
• Fixed facial expression
• Gradual loss of spontaneous movement
• Changed handwriting
• Decrease in voice volume
• Disturbances in gait
• Constipation
• Decreased sense of smell
• Depression
• Inability to initiate bodily movement
• A tendency to “freeze” in bodily movement

Treatment

While no cure is currently available for Parkinson’s disease, treatments are available to help control the symptoms. For most early-stage patients, when symptoms are usually mild, treatments may be unnecessary. Once symptoms have progressed to the point of requiring medical intervention, physicians have a variety of available medications, which are customized to each individual patient for his/her symptoms. Physicians may reserve certain medications for particular stages of the disease in order to maximize their effectiveness. Quite often, a patient’s treatment may include a combination of drugs. These treatments have helped many patients maintain their ability to function.

Medications for Parkinson's disease

Administration of the drug levodopa has been the standard treatment for Parkinson’s disease. Once it reaches the brain, levodopa is converted to dopamine, which replaces the same substance not present in sufficient amounts in Parkinson’s patients. However, treatment with levodopa does not prevent the progressive changes of the brain typical of Parkinson’s disease. The drug may also produce side effects in some people, due to its change to dopamine before reaching the brain. The simultaneous administration with levodopa of substances inhibiting this change allows a higher concentration of levodopa to reach the brain and considerably decreases the side effects. Some new drugs have recently been approved offering a wider choice of medications for the patient, while others are under investigation in this country and overseas in an effort to obtain better therapeutic results with fewer side effects.

Surgical Treatments for Parkinson's disease

All major surgical procedures performed to relieve symptoms of Parkinson's disease are done stereotactically. This means that the target cells in the brain, which have been selected for either destruction or stimulation, are reached with the aid of a computerized guidance system through a small hole in the skull. A needle is guided to the appropriately chosen target and the cells in the targeted nucleus (group of cells) are then either destroyed or stimulated electrically.

Deep Brain Stimulation
Deep Brain Stimulation (DBS) targets the subthalamic nucleus, which is located below the thalamus. The procedure involves implanting a thin electrode into the brain. The electrode is connected via a wire running beneath the skin to a stimulator and battery pack in the patient’s chest (similar to a cardiac pacemaker). Small electrical pulses from the device stimulate the brain and block brain signals that cause Parkinson's symptoms. With DBS, the targeted region is inactivated not destroyed. This procedure was FDA approved in January 2002.

Thalamotomy
This procedure destroys a small group of cells in the thalamus, a major area that receives information from the basal ganglia. This procedure is mainly effective in abolishing tremor on the opposite side of the body to the surgery.

Pallidotomy
This procedure destroys a group of cells in the internal globus pallidus, the major area from which information leaves the basal ganglia. This procedure is most effective in relieving dyskinesias and tremor, but also helps some of the other symptoms of advanced Parkinson’s. Much more needs to be learned about the effectiveness of all these procedures. At present, they should be reserved for patients with advanced Parkinson's disease, which is not adequately responding to medications or for patients with very complicated treatment regimens and severe dyskinesias or motor fluctuations.