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- Brain Scan May Predict Course of Parkinson's Disease
- Pramipexole (Mirapex®) for Parkinson's: Safety News from the FDA
Doctors have found that a specific type of brain scan may be useful in predicting the course of Parkinson's disease (PD) in people newly diagnosed with the disease,according to a study published in the September 15 issue of the journal Movement Disorders. Doctors sometimes use brain scans to confirm a diagnosis of Parkinsonism (though the scans cannot distinguish PD from some similar disorders). This new study applies a brain scan to predicting the future course of the disease.
A group of researchers led by Bernard Ravina, M.D., formerly of the University of Rochester and now of Biogen Idec, in Cambridge, MA, examined the brain scan images (performed at time of diagnosis and two years later) and health records of 491 people who were newly diagnosed with PD and had not yet begun medications. The volunteers were all part of the Longitudinal and Biomarker Study in PD (LABS-PD), a project that was funded in part by PDF.
- People with newly diagnosed PD whose initial brain scans showed dopamine transporter levels lower than the average went on to develop more severe PD five and a half years later, including greater motor-related disability, falling and postural instability, cognitive impairment, psychosis and depression.
- People who showed the lowest dopamine levels in their brains in the early stages of PD were three times more likely five and a half years later to experience cognitive impairment — and 12.9 times more likely to develop psychosis — than those who showed the highest levels.
- People who showed large decreases in dopamine levels between the two brain scans had worse motor and cognitive symptoms five and a half years later than those with small decreases.
What Does It Mean?
Some people with PD develop more debilitating symptoms than others, but doctors cannot currently predict ahead of time who will do better and who will do worse. Being able to do so may help them better anticipate and treat severe symptoms. This study provides the best evidence to date that brain scans could be used to predict long-term progression of Parkinson's disease.
Even if the results hold true in later studies, it is important to remember that predictions are not the same as facts — and that an increased risk for severe PD does not mean that everyone who has this risk will go on to develop severe Parkinson's disease.
The United States Food and Drug Administration (FDA), the governmental agency that regulates prescription drugs, issued a cautionary note in September 2012 about the possible risk of heart failure among a small number of people who are receiving pramipexole (Mirapex®), one of the most widely-used medicines for Parkinson's disease (PD). The primary focus of the caution is the possibility of a slight risk of heart failure for individuals who have been taking the drug for less than three months or are older than age 80, especially in individuals witha history of heart disease. The FDA says it will continue to monitor this problem.
Christopher Goetz, M.D., Chair of PDF's Medical Policy Committee and the Chief of Movement Disorders at Rush University Medical Center in Chicago, IL, provided the following statement for people living with Parkinson's disease.
"The evidence available to date does not establish any definitive risk of heart failure from pramipexole exposure — especially for long time users. Nevertheless, the FDA — in my view, very responsibly — believes there is sufficient concern to call for further research.
"As those findings are made public, be assured that PDF will help to interpret them for the Parkinson's disease community. In the meantime, PDF encourages people with Parkinson's disease who are on pramipexole — or whose doctors have recommended pramipexole as a possible treatment — to discuss this report with their doctors. This is especially important for those who have a history of heart failure."
The FDA provides ways for people with PD and health care professionals to report problems or side effects from medications, including pramipexole. Individuals can visit www.fda.gov/MedWatch/report.htm or call (800) 332-1088 to report such problems.
People with Parkinson's disease, family members or health care professionals who have additional questions are invited to contact PDF's toll-free HelpLine at (800) 457-6676 or firstname.lastname@example.org.
For more information about PD medications and their side effects, order a free copy of our "Understanding Parkinson's Medications" fact sheet, or download it from our website at www.pdf.org/factsheets.