Parkinson’s Disease Diagnosis May Come Before Symptoms Appear With New Testing Technique: Study

A new testing technique could revolutionize Parkinson’s disease diagnosis, resulting in detection of the condition years before serious neurological damage begins to result in symptoms.

Not only could diagnosis of Parkinson’s disease come years earlier, but a more effective testing method will also likely result in better treatments at earlier stages of the disease, according to findings published in the latest issue of The Lancet Neurology.

Parkinson’s disease is a progressive neurological disorder which affects about 1 million Americans, and at least 6 million other people worldwide. Symptoms can include tremors, uncontrollable movements, shaking, difficulty talking, balance and coordination problems, which typically begin gradually and worsen over time.

The condition causes nerve cell damage in the brain, which results in dropping dopamine levels. While Parkinson’s medications can help control the symptoms, but there is currently no known cure for the disease.

New Method of Testing for Parkinson’s Disease

In this new study, a group of researchers from the University of Pennsylvania’s Perelman School of Medicine, and Amprion, a brain disease medical diagnosis company, indicate that they have developed a new technique to detect Parkinson’s disease before symptoms begin.

The technique is known as the alpha-synuclein seed amplification assay (SAA), which looks for abnormal protein deposits in the brain linked to Parkinson’s disease. Because these proteins begin building up long before symptoms develop, this could mean detection at much earlier stages.

In the cross-sectional study, the researchers used the SAA technique on 1,123 participants from 33 neurology outpatient practices worldwide. The participants included a mix of patients with sporadic Parkinson’s disease, unrelated movement disorders, people with no signs of Parkinson’s and those with genetic carriers.

The SAA had a 95% accuracy rate, including identifying the healthy control subjects more than 96% of the time. For some types of Parkinson’s disease, the test was also more than 96% accurate. The only place where the test faltered was in various participants who were non-manifesting carriers of certain genetic mutations linked to the disorder.

“Our results show that the assay classifies people with Parkinson’s disease with high sensitivity and specificity, provides information about molecular heterogeneity, and detects prodromal individuals before diagnosis,” the researchers concluded. “These findings suggest a crucial role for the α-synuclein SAA in therapeutic development, both to identify pathologically defined subgroups of people with Parkinson’s disease and to establish biomarker-defined at-risk cohorts.”

The researchers say one of the few limitations is that SAA requires spinal fluid for its diagnosis, but they hope to improve the detection process to eventually be effective with blood samples or even nasal swabs. They also anticipate the new detection system will be used to better map progression of the disease, which would most likely lead to earlier treatments which could potentially slow or lessen its progression before symptoms appear.

In addition to genetics, there are a variety of potential causes of Parkinson’s disease, which can make certain individuals more susceptible to the condition, including exposure to certain environmental toxins or chemicals. Because this new Parkinson’s disease testing method is so effective on those with non-genetic causes, it could help individuals determine whether they may have developed Parkinson’s disease from certain pollutants and substances that research has shown to increase the risk, such as the herbicide Paraquat.

Paraquat Parkinson’s Disease Lawsuits

Paraquat was originally developed in the 1950s by Imperial Chemical Industries, PLC (ICI), which is a legacy company of Syngenta, and the weed killer was first marketed under the brand name Gramoxone in the 1960s. However, over the subsequent decades Syngenta sold Paraquat formulations under a variety of names, and promoted the weed killer without warning users about the long-term side effects they may face from exposure.

Although it has been widely used for decades, and is already heavily restricted in the United States due to the risk of Paraquat toxicity if even a small amount of the weed killer is ingested, there are now a growing number of Paraquat lawsuits being pursued by former users diagnosed with Parkinson’s disease, pointing to a number of studies that have found a two- to five-fold increased risk for individuals regularly handling, mixing and spraying Paraquat, compared to populations that do not have such occupational exposure.

Given common questions of fact and law raised in the litigation, the federal cases have been centralized as part of a Paraquat MDL (multi-district litigation), which is consolidated before U.S. District Judge Nancy J. Rosenstengel in the Southern District of Illinois, for coordinated discovery and pretrial proceedings.

To help the parties gauge how juries may respond to certain evidence and testimony that will be presented throughout the Paraquat litigation, the Court previously set an aggressive schedule that anticipated the first case would go before a jury by late 2022. However, as a growing number of complaints continued to be filed, the start of the first Paraquat trial has been reset to begin in July 2023.

While the outcome of those early trials will not be binding on other plaintiffs, they will be closely watched to gauge the average Paraquat lawsuit payout awarded by juries. Following bellwether trials before Judge Rosenstengel, if the manufacturers fail to negotiate Paraquat settlements or otherwise resolve the litigation, hundreds of individuals claims may be remanded to U.S. District Courts nationwide for individual trial dates in the future.