Scientists at the National Institutes of Health have developed an accurate test for the early diagnosis of neurodegenerative diseases, including Parkinson’s.
The new NIH test is a refinement of one that detects protein clumping involved in these disorders.
It diagnosed Parkinson’s and dementia with Lewy bodies from 60 cerebral spinal fluid samples with 93 percent accuracy. The 60 people whose samples were tested included 12 with Parkinson’s, 17 with dementia with Lewy bodies, and 31 controls, 16 of whom had Alzheimer’s disease.
In addition to the test being accurate, the results were ready in two days, compared with up to 13 days for other tests.
The study, “Rapid and ultra-sensitive quantitation of disease-associated α-synuclein seeds in brain and cerebrospinal fluid by αSyn RT-QuIC,” was published in the journal Acta Neuropathologica Communications.
Many neurodegenerative diseases stem from misfolded proteins, many of which are identified only by analyzing brain tissue after a person dies. Doctors’ diagnoses involve a combination of looking for symptoms, doing tissue imaging, performing biopsies, and looking at levels of biomarkers in cerebral spinal fluid.
Unfortunately, arriving at an early diagnosis can be difficult. One reason it is hard to diagnose a particular neurodegenerative condition is that the features of many of them overlap.
The NIH team used an improved version of the Real-Time Quaking-Induced Conversion (RT-QuIC) test to diagnose the Parkinson’s and dementia cases. The Rocky Mountain Laboratories of the agency’s National Institute of Allergy and Infectious Diseases has refined the test through the years.
The test does a better job of detecting abnormal α-synuclein protein clumps in rare neurodegenerative disorders known as prion diseases.
Importantly, most of the cerebrospinal fluid specimens that the scientists analyzed were collected early in the course of the diseases.
“The early detection of pathogenic disease-associated forms of α-synuclein is particularly helpful,” the authors wrote. In the first place, “the accuracy of diagnoses based on other clinical indices is poorest in the earlier phases of disease,” they wrote. In addition, “the earlier the diagnosis, the earlier that any appropriately targeted therapies can be initiated before further tissue damage is done.”
The ability to obtain an early diagnosis of these diseases, which can progress for years before symptoms appear, can help scientists develop treatments and identify patients eligible for clinical trials.