A simple blood test may be as accurate as a spinal fluid test when trying to determine whether symptoms are caused by Parkinson’s disease or another atypical parkinsonism disorder, according to a new study published in Neurology.
In early stages of disease, it can be difficult to differentiate between Parkinson’s disease and atypical parkinsonism disorders (APDs) like multiple system atrophy, progressive supranuclear palsy and corticobasal degeneration, because symptoms can overlap. But identifying these diseases early is important because expectations concerning progression and potential benefit from treatment differ dramatically between Parkinson’s and APDs.
The study found that a nerve protein called neurofilament light chain protein can, when found in the blood, discriminate between Parkinson’s disease and APDs . It is a component of nerve cells and can be detected in the blood stream and spinal fluid when nerve cells die.
For the study, researchers examined 504 people from three study groups. Two groups, had healthy people and people who had been living with Parkinson’s or APDs for an average of four to six years. The third group was comprised of people who had been living with the diseases for three years or less. In all, there were 244 people with Parkinson’s, 88 with multiple system atrophy, 70 with progressive supranuclear palsy, 23 with corticobasal degeneration and 79 people who served as healthy controls.
Researchers found the blood test was just as accurate as a spinal fluid test at diagnosing whether someone had Parkinson’s or an APD, in both early stages of disease and in those who had been living with the diseases longer. The nerve protein levels were higher in people with APDs and lower in those with Parkinson’s disease and those who were healthy.
The researchers say that one limitation of nerve protein testing is that it does not distinguish between the different APDs, however, they note that doctors can look for other symptoms and signs to distinguish between those diseases.
Paper: “Blood-based NfL: A biomarker for differential diagnosis of parkinsonian disorder”
Reprinted from materials provided by the American Academy of Neurology (AAN).