New Study Shows Promise of Test to Detect Parkinson’s Disease Early

In an encouraging development for the treatment of Parkinson’s disease, a new study found that a laboratory test was able to detect the neurological disorder in people at high risk for developing it, even if they were not yet showing symptoms.

The study, published in the May 2023 issue of Lancet Neurology, found that the biomarker test, which analyzes a person’s spinal fluid, had 88% accuracy in identifying Parkinson’s in people already diagnosed with the disease. There is no cure for Parkinson’s, but the promise of the lab test is that it could help doctors start treatment much earlier. Currently, Parkinson’s diagnoses are typically made only after physical symptoms start.

“People in the pre-clinical phase of Parkinson’s who did not yet have symptoms like tremors or stiffness, were tested and showed signs of the disease in their spinal fluid,” says Dr. Miran Salgado, a movement disorder specialist and chief of neurology at NewYork-Presbyterian Brooklyn Methodist Hospital. “This is important because the goal is to identify Parkinson’s disease early and develop treatments that can stop disease development or slow its progression.”

About 1 million people live with Parkinson’s disease in the U.S., according to the Parkinson’s Foundation — a number that could increase to 1.2 million by 2030. Diagnoses typically happen in people 60 years or older, but 4% can be diagnosed before age 50. Actor and Parkinson’s advocate Michael J. Fox was diagnosed with the disease in 1991, at age 29.

Among the 1,123 participants in the research were people who had Parkinson’s disease without a known cause; people experiencing pre-clinical symptoms of the disease, such as hyposmia, an inability to detect odors; and people who carried gene mutations that make them at higher risk for the disease but who had not yet shown clinical symptoms. People with no sign or risk of Parkinson’s also participated.

“The laboratory test, called the alpha-synuclein seeding amplification assay, detected alpha-synuclein in people’s spinal fluid with high accuracy,” says Dr. Salgado. “Alpha-synuclein is a protein in the nervous system, such as in the brain and spinal cord, and people with Parkinson’s disease have abnormal clumps of these proteins in their brain cells.”

For people with Parkinson’s, the brain cells that make dopamine, a chemical responsible for movement, also stop working or die, which can lead to unintended slowness of movements, tremors, stiffness, and difficulty with balance and coordination, among other clinical symptoms that worsen over time. While there is an imaging test to help detect dopamine loss, the research suggests the alpha-synuclein test can help detect Parkinson’s even before significant dopaminergic cell loss.

“The idea is to detect the abnormal proteins before people get advanced Parkinson’s disease that include these clinical symptoms,” says Dr. Salgado. “If we have this test to diagnose early, then we can work to institute various treatments against alpha-synuclein proteins. The laboratory test holds promise because the goal here is early detection and treatment development.”

Miran Salgado, M.D., is a board-certified neurologist at NewYork-Presbyterian Brooklyn Methodist Hospital, where he is a movement disorder specialist and chief of neurology. He works with the Weill Cornell Medicine brain and spine team providing care for patients with Parkinson’s disease and other movement disorders, stroke, and other neurological conditions.