Often, the first signs of the disease are symptoms such as tremor in the fingers, chin or lip, loss of smell or a more rigid facial expression. Now an encouraging new test may help to diagnose Parkinson’s before those symptoms appear, when treatments might be more effective.
Researchers from the University of Pennsylvania report in the journal JAMA Neurology that certain proteins appearing the spinal fluid may be the key to identifying affected patients early in the disease process, long before symptoms set in. The results, which came from the five-year Parkinson’s Progression Markers Initiative (PPMI), are the first to find so-called biomarkers unique to Parkinson’s patients.
In this first set of results, the researchers conducted spinal taps on a subset of 102 of the PPMI participants to extract samples of cerebrospinal fluid, which acts as a liquid cushion for the brain and spinal cord. Sixty-three of them had early and untreated Parkinson’s disease, and the team compared their spinal fluid composition to those of 39 matched individuals unaffected by the disease. The researchers focused on five protein biomarkers: amyloid beta, total tau, phosphorylated tau, alpha synuclein and the ratio of total tau to amyloid beta. They found that people with early stage Parkinson’s had lower levels of the biomarkers amyloid beta and alpha synuclein. People with higher levels of motor dysfunction also had lower levels of tau and alpha synuclein while those whose muscles tended to freeze, or people with abnormal gaits who had difficulty walking, showed lower levels of amyloid beta and tau.
The breakdown of proteins could become the foundation for a more sophisticated understanding of how Parkinson’s, which is caused by depletion of the brain chemical dopamine, progresses, and which changes in the body herald new symptoms.
“Parkinson’s disease is very complex and varies from person to person. One of the biggest challenges to improving care and finding better treatments is the lack of a biomarker that can diagnose the disease and predict its progression,” says Beth Vernaleo, senior manager of research programs for the Parkinson’s Disease Foundation, which was not involved with the study. “Although additional research is needed, by demonstrating that cerebrospinal fluid may in fact be a biomarker for Parkinson’s disease, this study brings us closer to our goals of diagnosing Parkinson’s disease earlier and developing individualized treatment plans.”
The results suggest that Parkinson’s may be detectable in the spinal fluid far earlier than is currently possible, which could change the way the neurodegenerative disease is diagnosed and treated. Every year, about 60,000 Americans are newly diagnosed, and the earlier patients are identified, the more likely that new therapies, including targeted drugs that are designed to replenish waning dopamine levels, can be introduced. The hope is that such treatments might eventually reduce or even prevent some of the disease’s more advanced and debilitating symptoms.