Parkinson's disease, which causes tremors, slowness of movement, rigidity and other muscle disorders, isn't normally diagnosed until the movement disorders become obvious, just as Alzheimer's disease normally isn't diagnosed until memory loss becomes troublesome. But researchers now think that both diseases stem from brain degeneration that begins years, and possibly decades, before conspicuous symptoms appear.
A German doctor, Alexandra Gaenslen, asked nearly 100 Parkinson's patients if they recalled any unusual physical changes in the years before their diagnosis, and nearly all of them did. In fact, they remembered an average of nearly eight changes.
"Early unclear motor signs, including stiffness, tremor of the extremities or head, slowed movements, a feeling of lost balance and/or falls were reported by more than 70 percent of individuals in whom Parkinson's disease was diagnosed," Gaenslen reported in an article just published in the journal, Movement Disorders. Most receive a diagnosis of Parkinson's about six years after the early unclear motor signs began.
Unfortunately, detecting Parkinson's disease early doesn't translate into better treatment. As with Alzheimer's, treatment for Parkinson's alleviates the symptoms, but not very well. Slowing the brain degeneration that causes both diseases, or halting it altogether, remains a tantalizing goal far from reach.
But finding signs or "biomarkers" of Parkinson's years before symptoms appear will help with the development of those tantalizing treatments, according to Todd Sherer, CEO of the Michael J. Fox Foundation, named for the actor who developed the disease at the unusually early age of 30.
"Biomarkers could be used in multiple ways in the clinical development of new treatments," Sherer said in an article just published in Science Translational Medicine. "The ability to identify individuals in the earliest stages of the disease using biomarkers would give clinicians the chance to intervene with disease-modifying agents early, reversing symptoms or possibly even preventing them."
So scientists around the world are searching for early signs of the disease. The Parkinson's Associated Risk Study, for example, uses loss of smell, an early symptom of Parkinson's, to identify people who may be at risk for developing Parkinson's. But loss of smell often accompanies normal aging, so researchers also perform a CT scan that can reveal the presence of dopamine active transporter, a protein associated with Parkinson's.
"About 90 percent of Parkinson's patients have abnormal smell, but not everyone who gets abnormal smell will get PD," said Kenneth Marek of the Institute for Neurodegenerative Disorders in New Haven, Conn., and a Parkinson's Associated Risk Study researcher. "However, 10 to 15 percent of people who have abnormal smell and an abnormal DAT scan will probably go on to develop Parkinson's."
Hossam Haick, a professor of chemical engineering in Israel who has developed an electronic "nose" capable of detecting signs of cancer in exhaled air, is trying to use the machine to detect a "breath print" that reveals early signs of Parkinson's disease.
"We believe that this Parkinson's disease breath print could provide a robust, inexpensive biomarker that could be used for diagnosis, tracking of disease progression, and for research into disease-modifying treatments," he said.
So what happens if scientists develop a way to detect signs of Parkinson's disease years before the damage to the brain becomes significant? According to a recent article in Nature Reviews Neurology, researchers at Harvard analyzed health habits of 136,197 people all free of Parkinson's at the start of their study. During six years of observation, 291 developed the disease. Those who took ibuprofen (sold as Advil, Motrin, and Nuprin, among others) more than twice per week lowered their risk of the disease by about 38 percent. Aspirin and acetaminophen (Tylenol) had no such effect. And one big bonus is that use of ibuprofen already has been shown to lower the risk of Alzheimer's, too. However, ibuprofen, although very safe, can cause gastrointestinal bleeding, and should be used only to relieve pain, not to prevent any disease.
How does ibuprofen do this? More study will be needed to answer that question, according to the researchers.
Tom Valeo writes frequently about health matters. He can be reached at [email protected]