Early Identification of Parkinson’s Leads to New Approaches to Tests, Biomarkers, Biopsies

Ana de Barros, PhD avatar

by Ana de Barros, PhD |

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Working toward early identification of Parkinson's

One of the main topics discussed at the 2nd Congress of the European Academy of Neurology (EAN) in Copenhagen, Denmark, focused on early stages of Parkinson’s disease (PD).

According to Prof. Günther Deuschl of the University Medical Center Schleswig-Holstein in Kiel and the president of the EAN, “new, neuroprotective or disease-modifying therapies against Parkinson’s could be far more effective if administered at an early stage of the disease. Fortunately, we are increasingly able to decipher the mechanisms by which the condition develops, thanks to the latest findings and methods, which enable us to identify persons at risk of developing Parkinson’s early on.”

Deuschl highlighted the growing importance of early detection, particularly in the light of current demographic trends. “Parkinson’s disease affects around 2 percent of over-65’s and is one of the most common neurodegenerative conditions in Europe, with about 1.2 million cases across the continent. In view of increasing life expectancy, the number of sufferers is expected to double by 2030,” Deuschl said in a press release.

“In the EU, some 640,000 healthy years of life are being lost to this disease. Today, Parkinson’s is ranked fifth in the list of the most expensive neurological conditions facing Europe’s health systems. That makes it all the more important to devise innovative approaches that prevent the progression of the disease as effectively as possible,” he added.

Deuschl talked about risk markers, as it seems research is now showing that alpha-synuclein protein plays a key role in the progression of Parkinson’s: “Alpha-synuclein agglutination in the brain is a significant factor. It seems that this pattern of damage is passed on from cell to cell – so future therapies should be aimed at stopping or at least delaying this chain reaction. These findings are opening the door to new approaches for the early recognition and treatment of Parkinson’s disease. Detailed research is under way to establish whether a biopsy of the nerves in the intestines, salivary glands, or skin permits a conclusive early diagnosis of the condition,” he said.

Deuschl praised the recent definition of Parkinson’s disease diagnosis criteria in the prodromal phase – a very early stage when conventional diagnoses based on motor symptoms can’t be confirmed. He believes this is a major step toward better care for Parkinson’s patients.

“The criteria were recently published by the Movement Disorder Society. They are designed to standardize clinical research and provide diagnostic support,” he said. “There are still no reliable tests for early diagnosis of Parkinson’s, so doctors have had to rely on experience alone. But now we have developed a completely novel neurological approach that links clinical examinations and statistical calculations of probability.”

The starting point is that this condition is age-related. Researchers would collect all diagnostic information possible and then evaluate it using a likelihood ratio. The information might include environmental risks as well as genetic factors or prodromal symptoms. This means that risk factors can be considered positive or negative influences.

“The risk assessment system can be extended as required when new tests to support early diagnosis are developed,” the professor explained.

The Second EAN Congress included some studies showing that many symptoms can appear years before the degeneration of nerve cells. These studies suggest that some symptoms can be identifiable before motor impairment begins to show. Symptoms such as hyposmia, constipation, dizziness, and urinary dysfunction, as well as REM-sleep behavior disorder (a condition that makes people physically enact their dreams) are all included on this watch list.

For example, a French study analyzed 40 individuals diagnosed with Parkinson’s and found that their respiratory function is considerably weaker than that of healthy individuals. Another study, led by Italian researchers, looked at the olfactory (sense of smell) performance of Parkinson’s patients at an early, undiagnosed stage of the disease and compared it with the olfactory performance of a control group of healthy individuals. The control group had a stronger sense of smell, which might be related to a better cortical connection to the caudate nucleus – a part of the basal ganglia that also controls voluntary movements.

And a third study, from Russian researchers, analyzed 104 patients and illustrated the prevalence of olfactory dysfunction among Parkinson’s patients. Eight out of 10 people participating in the study suffered from hyposmia while one in five were anosmic. Only two subjects had no olfactory impairment.

“A long line of studies being presented at the EAN Congress confirm the existence of risk markers that are not necessarily associated with Parkinson’s disease at first glance, and as such are easily missed,” Deuschl said.