THE SPECIALIST: DR. WARREN OLANOW ON PARKINSON'S DISEASE
Warren Olanow, a professor and past chairman of the Department of Neurology at the Mount Sinai School of Medicine, has dedicated the past 30 years to specializing in Parkinson's disease and related movement disorders.
WHO'S AT RISK
Many people first learned of Parkinson's disease when the actor Michael J. Fox announced he had the illness, but Parkinson's affects more than a million Americans.
"It's an age-related neurodegenerative disease," says Olanow. "It's characterized clinically by a tremor at rest, slowness and stiffness of movement and problems with walking and balance." For 75% to 80% of patients, Parkinson's eventually leads to dementia.
Everyone is at risk of developing Parkinson's disease, and the risk increases with age. "It affects men and women of all races and all occupations, with the mean age of onset of about 60 years," says Olanow. "The older you get, the greater the chances that you will have it."
As the American population ages, the frequency of Parkinson's disease will likely rise, and some doctors predict as much as a fourfold increase within the next few decades. "Parkinson's disease is a major public-health risk, as well as a serious threat to the well-being of individuals and families," says Olanow.
The cause is generally unknown. "Genetic causes are thought to underlie about 10% to 15% of cases, and typically occur in younger individuals," says Olanow. "In older individuals, Parkinson's is mostly sporadic." And though everyone is at risk, some groups have an elevated risk, including people who live in rural areas, drink well water and are exposed to pesticides.
Though Parkinson's can be extremely debilitating, improved treatments can help maintain a good quality of life. "For many patients, we can provide them with satisfactory control so they can live and work in a relatively normal way for years," says Olanow. "The average Parkinson's patient lives about as long as the average individual of the same age who does not have Parkinson's disease."
SIGNS AND SYMPTOMS
The classic symptoms of Parkinson's disease are a tremor that is most prominent when the limb is at rest, slow and stiff movements, gait problems and difficulty maintaining balance. These result mainly from a loss of the dopamine producing cells in a region of the brain called the substantia nigra. There are also many additional signs that are due to degeneration of other cells in the brain, the spinal cord and the autonomic nervous system (which controls the automatic functions of many organs).
"It's now appreciated that Parkinson's has a far broader range of disturbances than was originally [believed], and can include features like depression, sleep disorders, impaired smell, urinary problems, constipation, sexual dysfunction, cognitive impairment and dementia," says Olanow.
Doctors now know that some symptoms can show up before the onset of the classic movement-related features of the disease. Individuals who only have impaired smell, a sleep problem called REM behavior disorder, and constipation likely have an early form of the disease," says Olanow. "We are close to having therapies that can slow the rate of disease progression, and if we could start them early enough, we could theoretically slow the disease down so that the classic motor features never develop."
Because Parkinson's disease is associated with a deficiency of the chemical dopamine in the brain, the standard treatments focus on dopamine replacement.
"Levodopa is the most effective drug we have. It gets into the brain where it is converted to dopamine, and improves the classic motor features of the illness," says Olanow. "This treatment reduces disability, enhances independence and prolongs life span. It has revolutionized the care for patients with Parkinson's disease and brought help to millions of people around the world."
Even so, levodopa has some major limitations and side effects. "About 90% of patients with long-term treatment will eventually develop flinging movements called dyskinesia," says Olanow. The drug's effectiveness also decreases over time. "Patients cycle between on periods where the drug works and off periods where the symptoms recur," according to Olanow. Other drugs like dopamine agonists, COMT inhibitors and MAO-B inhibitors are valuable because they help to prevent, delay or treat the side effects of levodopa.
For those patients with motor complications that can't be controlled with medication, doctors have developed a form of surgery called deep brain stimulation. "When you have dopamine depletion, it upsets the brain's circuitry so that it fires in an abnormal pattern," says Olanow. "Deep brain stimulation involves placing electrodes into specific sites in the circuitry of the brain and stimulating at a high frequency, thus interfering with the abnormal firing patterns and providing dramatic benefit."
This surgery is especially effective for treating motor complications and tremors, but patients continue to develop problems like depression, falling, inability to move and dementia, which are not controlled by levodopa.
"Nothing we have is especially good for those," says Olanow. "But we're making progress investigating many treatments that could be available in the near future."
In the past 50 years, Parkinson's research has achieved several breakthroughs, including the discovery of genetic mutations that can cause the disease. "Recent studies suggest that the accumulation and aggregation of misfolded and unwanted proteins is central to the development of Parkinson's disease," says Olanow. "Finding treatments that prevent these proteins from accumulating might allow us to prevent the disease from forming in the first place." There has also been great interest in the potential value of cell transplantation, stem cells and gene therapy as treatments for Parkinson's, but these remain experimental.
QUESTIONS FOR YOUR DOCTOR
Olanow advises patients to write down their comments and questions in advance and take them to the doctor's office. A good first question for people who are newly diagnosed is, "Can we go over my treatment options together?" Olanow recommends seeing a specialist early on, because "how you treat the disease initially matters." If you want to share your experience and learn from other Parkinson's patients, be sure to ask, "Can you point to me to a support group with patients at a similar stage?" Caregivers can benefit greatly from support groups, too.
WHAT YOU CAN DO
See a Parkinson's specialist. Many people see general physicians or neurologists for day-to-day care, but Dr. Olanow encourages patients to see an expert in PD at the time of diagnosis and periodically after that.
Stay active. Staying mentally and physically active helps preserve the function you have. "Exercise helps to prevent stiffness," says Olanow, "and there are theories suggesting that it may also have protective effects."
Get informed. Your doctor, support groups and various Web sites, can help. There's plenty of misinformation on the Web, though, so be sure to go to trusted sources like the Movement Disorder Society (MovementDisorders.org), the World Parkinson Congress (WorldPDCongress.org) or the Michael J. Fox Foundation (MichaelJFox.org).
Don't forget the caregiver. "Parkinson's is a two-person disease," says Olanow. "The more disabled someone gets, the more work there is for the spouse, who is also getting older. They have an increased risk of depression, and require attention as well as the PD patient."