A saliva gland test could become a new way to test for early Parkinson's disease, according to research published in Movement Disorders.

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Parkinson's disease can go undetected for some time, but the new test could help patients obtain an early diagnosis.

The Parkinson's Disease Foundation (PDF) note that a million Americans may be living with Parkinson's disease, and around 60,000 new cases are diagnosed each year, while thousands go undetected.

Parkinson's mostly manifests in older people, but 4% of cases are diagnosed before the age of 50 years. The risk is one and a half times higher for men than for women.

The degenerative neurological disorder affects movement, sleep, walking, balance, blood pressure and smell. There is no cure, but medications can relieve the symptoms.

The first and best-known sign of the disease is often just a small tremor in one hand. Stiffness or slowing of movement may occur, which gradually gets worse.

No test so far has been able to diagnose Parkinson's disease accurately. The basis for diagnosis is currently medical history, signs and symptoms, a neurological examination and exclusion of other conditions.

Submandibular gland biopsy may provide early diagnosis

Researchers from the Mayo Clinic in Phoenix, AZ, and Banner Sun Health Research Institute in Sun City, AZ, carried out the current study. They had previously found that up to 45% of patients in the early stages may receive an incorrect diagnosis.

The team wanted to see if a procedure termed "transcutaneous submandibular gland biopsy" could provide an answer. In this procedure, a core of gland tissue is extracted by inserting a needle into a salivary gland under the jaw.

The scientists were searching for a protein in the cells that could indicate early Parkinson's disease. They took the biopsies from one salivary gland to test for it. In earlier tests, they had found that that the same biopsy test could detect the abnormal protein in 9 out of 12 patients with advanced Parkinson's.

The new study involved 25 patients who had the disease for less than 5 years and 10 healthy individuals.

Of the 25 subjects, 19 had sufficient tissue for the study. The researchers tested the biopsied tissues to see if they contained the Parkinson's protein. The researchers then compared the results with those of the healthy controls.

The protein was found to be present in 14 out of 19 patients.

Study co-author Dr. Thomas Beach, PhD, a neuropathologist with Banner Sun Health Research Institute, says:

"This procedure will provide a much more accurate diagnosis of Parkinson's disease than what is now available. 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."

Study author Dr. Charles Adler, PhD, neurologist and professor of neurology at the Mayo Clinic, adds that using submandibular gland biopsies to test for early Parkinson's disease may help many people because, currently, testing after 10 years gives a far more reliable diagnosis than early testing.

The team hopes for further studies to expand understanding of the disease and to develop better treatments.

Medical News Today reported recently that having hepatitis C can increase the risk of developing Parkinson's by 30%.