Since a good deal of brain damage occurs before symptoms of Parkinson’s disease appear, it’s vital to come up with a test that can identify the disease in the earliest stages.
Existing lab tests have proven unreliable and even brain scans don’t provide a definitive diagnosis of this independence-robbing disease. But all that may be about to change.
New research points to a promising new marker in the blood that could lead to much earlier diagnosis and treatment.
Although various markers in body fluids have been tested to see if they can provide an early indicator of Parkinson’s, all have fallen short of the mark. But a new blood biomarker might fit the bill. I’m talking about neurofilament light (NfL).
Neurofilament light is a protein that’s released when damage occurs to nerve fibers. Since NfL is released in most neurodegenerative disorders, it has been described as a universal marker of brain inflammation or “the C-reactive protein of neurology.”
Elevated levels are found in Alzheimer’s, Lou Gehrig’s disease, multiple sclerosis, and cerebral vascular disease. Scientists from Rush University, Chicago, wanted to find out whether Parkinson’s could be added to the list.
More Than Doubles the Risk
Their study included data on 1,254 men and women over the age of 65 who participated in the Chicago Health and Aging Project.
During the 16-year study, researchers evaluated participants for the four main signs of Parkinson’s – slowness of movement, tremor, stiff muscles that tighten spontaneously, and balance issues.
Blood samples were collected at the start of the study and the NfL values of the trial members were divided into four quartiles, with the highest having values greater than 37.3 pg/mL and the lowest below 18.5 pg/mL. Blood samples continued to be taken over the duration of the study.
By the end of the trial, 77 participants developed Parkinson’s. The researchers found that a two-fold higher concentration of serum NfL was associated with a 2½-fold increased risk of Parkinson’s and almost the same increased risk of having signs of Parkinson’s. These associations were significant more than five years before diagnosis.
Compared to those in the lowest quartile of NfL, those in the second and third quartiles had an increased risk of Parkinson’s, with the greatest risk occurring in the highest quartile – an increase nearly four times (3 ¾). These higher risks were apparent from the time of diagnosis to more than five years earlier.
Higher NfL was also linked to a faster rate of decline in physical functioning.
May Become the First Test Used
The authors of the paper, published in the journal Neurology in April, concluded by writing, “Our findings suggest that NfL may serve as a potential biomarker for neurodegeneration including Parkinson’s disease outcomes.”
An editorial in the same edition commented on the paper, saying, “This study confirms the potential of NfL to detect a neurological disease years before the clinical picture becomes manifest.”
Sometime in the future, the editors speculated, NfL could become the first test used to diagnose Parkinson’s and other neurological illnesses. However, because NfL is a general test of neurodegeneration, it would have to be followed by a more disease-specific blood or cerebrospinal fluid analysis to indicate if the patient was suffering from Parkinson’s disease or another neurological illness.