Researchers at Banner Sun Health Research Institute and Mayo Clinic are continuing to study how to diagnose early Parkinson’s disease. The research team’s most recent article titled, “Peripheral Synucleinopathy in Early Parkinson’s Disease: Submandibular Gland Needle Biopsy Findings” has been recognized by Movement Disorders, the official journal of the International Parkinson and Movement Disorders Society, as the “best original research article” of 2016.

Currently, there is no diagnostic test for Parkinson’s disease. The researchers believe that a procedure termed transcutaneous submandibular gland biopsy may provide the needed accuracy. The test involves inserting a needle into the submandibular gland, which creates saliva and is located under the jaw, and then withdrawing the needle to obtain the core of the gland tissue within. From this test, researchers can compare the tissue extracted from patients with Parkinson’s disease to patients that do not.

“This was the first study demonstrating the value of testing a portion of the submandibular gland to diagnose a living person with early Parkinson’s disease. Making a diagnosis in living patients is a big step forward in our effort to understand and better treat patients,” says study author Charles Adler, M.D., Ph.D., professor of neurology at Mayo Clinic in Arizona. 

As part of the study, 25 Mayo Clinic patients with Parkinson’s disease as well as 10 people without it had the procedure done. Biopsies were taken from one submandibular gland and were completed as an office procedure by Michael Hinni, M.D., and David Lott, M.D., at Mayo Clinic in Arizona. The biopsied tissues were then tested for evidence of the abnormal Parkinson’s protein by study co-author Thomas Beach, M.D., Ph.D., a neuropathologist with Banner Sun Health Research Institute.

The abnormal Parkinson’s protein was detected in 14 of the 19 patients who had enough tissue to study providing very positive results that need further analysis. The research team had previously shown that the biopsy was able to detect the protein in nine of 12 patients with advanced disease.

“This procedure [submandibular gland biopsy] will very likely provide a much more accurate diagnosis of early Parkinson’s disease than what is now available,” said Dr. Beach. “One of the greatest potential impacts of this finding is on clinical trials, as at the present time some patients entered into Parkinson’s clinical trials do not necessarily have Parkinson’s disease and this is a big impediment to testing new therapies.”

“This study provides the first direct evidence for the use of submandibular gland biopsies as a diagnostic test for living patients with early Parkinson’s disease,” Dr. Adler. “This finding, in patients with early Parkinson’s disease, may be of great use since accuracy of diagnosis in patients with early disease is not nearly as good as in those having the disease for more than 5 years.”

The study is now finished but has been followed by a similar Michael J Fox Foundation-funded study (the “S4” study), being done in multiple US and Canadian cities, that will be comparing submandibular gland needle biopsy with biopsies of the colon and skin.  Drs. Adler and Beach are both heavily involved in study planning and analysis, while Drs. Lott and Hinni conducted online training sessions for the participating surgeons.

Parkinson’s disease is a progressive disorder of the nervous system that affects movement as well as sleep, balance, blood pressure, and smell. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. But while tremor may be the best-known sign of Parkinson’s, the disorder also commonly causes stiffness or slowing of movement. Currently, the diagnosis is made based on medical history, a review of signs and symptoms, a neurological examination, and by ruling out other conditions. Up to 55 percent of patients may be misdiagnosed early in the disease.

Although Parkinson’s disease can’t be cured, medications may markedly improve symptoms.

This study was funded by the Michael J. Fox Foundation for Parkinson’s Research.