New Diagnostics for PD Might Allow Early Diagnosis, Prevention

A new way of diagnosing Parkinson’s disease based on manifestations that appear decades before motor symptoms — the current hallmarks for diagnosis — might allow early diagnosis and even prevention.

The study, “From Prodromal to Overt Parkinson’s Disease: Towards a New Definition in the Year 2040,” was published in the Journal of Parkinson’s Disease.

Parkinson’s disease is characterized by progressive loss of coordination and movement. Currently, a person is diagnosed when those symptoms appear. However, there are some risk factors and symptoms that precede motor manifestations and constitute the early stages of the disease (called prodromal).

“Brilliant work of many in different scientific fields has paved the way for the concept of prodromal  [Parkinson’s disease]; that is, a phase of years to decades in which non-motor and subtle motor symptoms may indicate spreading PD pathology, but do not meet the threshold for diagnosis according to the classic motor-based clinical criteria,” researchers said.

The development of new diagnostic criteria that allow the identification of prodromal Parkinson’s might help to better understand disease progression, lead to early diagnosis and treatment, and prevent classic motor symptoms.

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Now, Parkinson’s experts Daniela Berg, MD, Christian-Albrechts-University of Kiel, Germany, and Ronald B. Postuma, MD, MSc, Montreal General Hospital, Canada, have developed a mathematical model that calculates a person’s risk of being in the prodromal phase of the disease. This model is based on three main premises relative to Parkinson’s prodromal phase:

• The fact that the neurodegenerative process in Parkinson’s is slow and continuous, possibly starting in the gut or olfactory system, finally reaching the nervous system;

•  The increased knowledge regarding risk factors and clinical symptoms that occur years or decades prior to motor manifestations. These can be correlated to imaging findings and tissue examinations;

• Studies have found that people who manifest different combinations of risk and prodromal markers can many times progress to Parkinson’s disease.

Currently, however, the model has some limitations. For example, it does not consider age and sex factors, and cannot predict whether or when motor symptoms will appear.

“The prodromal PD criteria are meant to be research criteria and constitute a first step in what should be a continually updated process,” researchers stated.

New Parkinson’s biomarkers — substances present in the body that indicate the occurrence of a condition — are continually being discovered, providing new information that makes the model more reliable. In time, the hallmarks for diagnosis might be based on the presence of biomarkers instead of motor symptoms.

Wearable technology, such as mobile phones, also allows the continuous capture of movement in daily life, which will benefit “from new methods of data handling and analyses,” researchers said.

“With new data arising from objective movement measurements, the earlier detection of motor symptoms will become possible. Objectively measured markers … wearable-based markers of activity … indicate that we can expect to change our understanding of early motor PD,” researchers said.

The model will be available online, allowing doctors to calculate the risk for patients. Additionally, there will be a platform where experts can share information and discuss the new criteria for diagnosis.

With this collaborative model, researchers expect to incorporate the new criteria and have a functional model by 2040. This is expected to allow early diagnosis and treatment and, in time, prevention of clinical symptoms.

“Our review highlights the importance of making an earlier diagnosis of neurodegenerative diseases, and in particular PD, for now primarily to understand the disease better,” Berg and Postuma said in a press release. “However, in the future, once we have preventive therapy, it will become critical to find patients in the earliest stages of the disease so that we can prevent the disease from developing and affecting quality of life.”