New hope for Parkinson’s victims

Ever since the British doctor James Parkinson first described the disease that bears his name in 1817, the search for a cure for Parkinson’s has been marked by both hope and disappointment. The disease occurs when nerve cells, or neurons, in a section of the brain called the substantia nigra, die or become impaired for unknown reasons. Normally, these cells produce dopamine, a chemical that transmits signals to produce smooth, purposeful muscle activity. Dopamine helps messages travel across nerve connections in the brain. When this crucial chemical is missing, messages don’t connect. So, as dopamine levels drop, the brain and the muscles are no longer able to communicate properly and they become less coordinated, resulting in shaking and slow movement.

Thus, the malfunction typically causes a resting tremor – one reason the condition was once referred to as "shaking palsy." Other hallmarks of the disorder includes:

• rigidity or stiffness in the muscles

• slowness of movement and a delay in initiating movements

• poor balance, which usually occurs when making a sudden change in the body’s position

• walking problems (which include short, shuffling steps and an inability to take the next step)

• loss of facial expression, slurred speech, slowness of thought, stooped posture, and small, cramped handwriting.

The disease has been in the spotlight recently because of the prominent people it afflicts – which includes former world heavyweight boxing champion Muhammad Ali, TV and movie actor Michael J. Fox, former US Attorney General Janet Reno, and of course, His Holiness, Pope John Paul II.

At this time, there’s no cure for Parkinson’s disease, but it doesn’t need to shorten a victim’s life span either. Many live well into their 80s. Because the disease worsens as one ages, however, it may profoundly affect the victim’s ability to function independently, and the emotional impact is substantial. Today, doctors have far more treatments to help reduce Parkinson’s most debilitating symptoms. And research is yielding new and better therapies every day. Here’s what you need to know if you or someone dear to you develops Parkinson’s.

Clues To The Causes

The disease typically occurs in people older than 50. Only about five percent develop it before age 40. At whatever age it develops, however, it’ll be with you for the rest of your life.

Possible instigators include:

• Familial predisposition. About 15 to 20 percent of people with Parkinson’s have a close relative who has symptoms.

• Accelerated aging. Although the brain ages like the rest of the body, this process may be accelerated in specific brain areas in certain people.

• Exposure to environmental toxins such as pesticides. There’s indirect evidence suggesting this possibility, but there’s no compelling proof.

In its later stages, Parkinson’s disease is easy to recognize because symptoms are unmistakable. But in its early stages, making a definitive diagnosis isn’t easy. In part, that’s because there aren’t any objective blood or laboratory tests available and because symptoms may be very mild. Parkinson’s is strongly suspected if you have a tremor when your limb is relaxed, if your tremor is greater on one side of your body than the other, and if you have a powerful early response to the drug levodopa.

Treating With Medications

The goal with medications is to find the right balance between relieving symptoms and keeping side effects to a minimum. These include:

• Levodopa. This medication is considered the gold standard for treatment. Nerve cells use levodopa to make dopamine to replenish your own diminished supply. Levodopa is combined with carbidopa (Sinemet) to help reduce side effects, especially nausea. Effectiveness of the drug often becomes less consistent after five to 15 years.

• Pergolide, ropinirole, pramipexole and bromocryptine. May be taken alone or with Sinemet. May delay wearing-off effects of levodopa.

• Catechol-O-methyl transferase (COMT) inhibitors (entacapone, tolcapone). Prolong effectiveness of levodopa when these medications are taken with it.

• Selegiline. This makes levodopa slightly more potent. At one time, this drug was thought to slow disease progression, but recent evidence has argued against this.

• Amantadine. Used alone or with levodopa, it may help reduce symptoms and lessen the excessive involuntary movements (dyskinesias) that can be brought on by levodopa therapy.

Surgical Options

When responses to drug therapies are no longer effective, surgery may be an option. Procedures include:

• Pallidotomy. An electrical current passed through a brain probe is used to destroy small amounts of tissue within a part of the brain called the globus pallidus. This area of the brain mediates some of the symptoms of Parkinson’s disease.

• Thalamotomy. Similar to pallidotomy, but the brain tissue destroyed is within the area called the thalamus. It helps reduce tremor.

•Deep brain stimulation (neurostimulation). Electrodes implanted in the brain are connected to a pacemaker-like device, which you can switch on or off to control symptoms. Stimulating the brain in this way suppresses muscle tremors caused by the disease.

The latest FDA approval, issued in January 2002, allows the surgeon to implant the electrodes deeper and in both sides of the brain. This bilateral deep brain stimulation offers more complete control of symptoms. About 80 percent of people who undergo deep brain stimulation report a decrease in their tremors. Studies suggest that the bilateral technique is even more effective. Its rate of complication also appears to be less than that reported with other surgical procedures used for Parkinson’s disease.

Medical Rehabilitation

There’s more to treatment than medications and surgery. Doctors also recommend:

• Physical therapy exercises to improve strength, flexibility, balance and coordination. These may help improve mobility and aid emotional well-being, allowing a person with Parkinson’s disease to live as independently as possible.

• Occupational therapy treatments to improve hand skills and to allow a person with Parkinson’s disease to become as independent as possible in self-care activities.

• Speech therapy if, in the later stage of the disease, difficulty in verbal communication develops.

Research On The Horizon

Parkinson’s disease is an area of active research. Areas under study include :

• Drugs aimed at slowing or halting the disease progression.

• Controlled-release drugs and implantable pumps for continuous supply of levodopa.

• Brain tissue transplants with the use of fetal tissue or genetically engineered cells that can be made to produce dopamine.

• Agents that may prevent dopamine-producing nerve cells from dying. One such compound, called glial-derived neurotrophic factor (GDNF), is a naturally occurring substance that has been found to mentally improve Parkinson’s symptoms in animal studies. GDNF is currently being tested in human trials of individuals with advanced Parkinson’s.

• Gene therapy. Studies show that transferring modified genes into the brains of rats improves survival of dopamine-producing neurons. This therapy though has not been studied in humans yet.

Outlook For Life

There’s no denying the impact that Parkinson’s can have on one’s life. Although it can be devastating, severe incapacity may not happen for decades after the victim is diagnosed. And although doctors still don’t know what causes Parkinson’s or how to cure it, research efforts to find treatments to slow, halt, or even reverse the disease’s relentless progression are more active than ever before. There will be setbacks, of course. But for both investigators determined to find answers and individuals living with the disease, hope springs eternal.