Parkinson's Disease Test Is 95% Accurate In Early Human Trial, Provides Hope For Earliest Detection Yet

Aug. 29, 2016

Researchers have developed a test that's able to identify cases of Parkinson's Disease and certain forms of dementia with greater than 90 percent accuracy. Pixabay, Public Domain

A test that’s set to become the standard detection tool for a rare neurological disorder may also someday be able to find cases of Parkinson’s Disease and related disorders earlier than ever before, according to new research published Sunday in the journal Annals of Clinical and Translational Neurology.

Using cerebrospinal fluid taken from patients with a variety of neurological disorders, the researchers’ test was able to identify 19 out of 20 samples belonging to Parkinson’s Disease patients with 95 percent accuracy, and when compared to samples of patients with Alzheimer’s or who were otherwise healthy, it could tell them apart with perfect accuracy. It was also able to identify cases of dementia with Lewy bodies, a progressive disorder likely related to Parkinson’s, with 92 percent accuracy. Importantly, it wasn’t fooled by samples taken from patients with diseases that have little in common with Parkinson's biologically, like progressive supranuclear palsy."We have already used this technique to develop an accurate test for Creutzfeldt Jacob Disease (CJD), another neurodegenerative condition," said senior study author Dr. Alison Green, a principal investigator at the National CJD Research and Surveillance Unit at Scotland’s University of Edinburgh, in a statement. "We hope that with further refinement, our approach will help to improve diagnosis for Parkinson's patients."

The diagnostic technique, called real-time quaking-induced conversion (RT-QuIC), was developed by Green’s group and has been in the works since at least 2010. CJD, an invariably fatal disorder, is caused by the clumping together of abnormally folded proteins called prions that eventually eat away at normal brain tissue. The RT-QuIC was designed to detect these clumps in spinal fluid and has so far proved to be very effective at doing so. While not caused by prions (which can be contagious), there is a similar unhealthy accumulation of the brain protein alpha-synuclein in cases of Parkinson’s Disease. Green’s team theorized that the test could be modified to detect these sticky piles of alpha-synuclein, which are called Lewy bodies.

Though the study represents the earliest stages of research, Green and her colleagues are hopeful for the grander application of their technology. Indeed, while many neurological disorders are caused by the build-up of deformed proteins, finding a reliable diagnostic test for Parkinson’s Disease and dementia with Lewy bodies, the third most common form of dementia, has been a challenge. In many cases, dementia and Parkinson’s can only be completely confirmed with an examination of patients' brains after their death.

The researchers hope to expand human trials of the test. In particular, they want to look at people suffering from REM sleep behavior disorder (RBD), a population that’s at especially high risk of developing a future Lewy body disorder. As much as 80 percent of all RBD sufferers will develop these disorders, and all three RBD patients tested by Green’s group had a positive RT-QuIC response.

"We are also interested in whether it could be used to identify people with Parkinson's and Lewy body dementia in the early stages of their illness," she said. "These people could then be given the opportunity to take part in trials of new medicines that may slow, or stop, the progression of disease,"

Source: Fairfoul G, McGuire L, Pal S, et al. Alpha-synuclein RT-QuIC in the CSF of patients with alpha-synucleinopathies. Clinical and Translational Neurology. 2016.

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