Saliva May Provide Early Test for Parkinson’s Disease

While no test to date has been able to accurately diagnose Parkinson’s disease, scientists may have discovered a new salivary gland test that could provide early diagnosis. Alarmed that only 4% of Parkinson’s cases are diagnosed before the age of 50—and up to 45% of patients in the early stages of the disease are incorrectly diagnosed—Arizona researchers conducted a search for a protein in the cells that could indicate early Parkinson’s disease.

Researchers performed transcutaneous submandibular gland biopsies, which involve the extraction of gland tissue by inserting a needle into a salivary gland under the jaw. In the first experiment, they found that this biopsy could detect the abnormal protein in 9 out of 12 patients with advanced Parkinson’s. In a second study comprised of patients who had the disease for less than 5 years, the protein was present in 14 out of 19 patients.

Besides being a vast improvement over the existing basis for diagnosis (which involves medical history, hand tremors, stiffness or slowing of movement, a neurological examination and exclusion of other conditions), the submandibular gland biopsy could help diagnose thousands of Americans whose Parkinson’s disease is currently undetected. In addition, the test could significantly increase the efficacy of clinical trials, where testing of new therapies has been difficult due to the fact that some patients who are entered into Parkinson’s clinical trials may not necessarily have the disease.