Parkinson’s disease (PD) is the fastest growing neurological disorder in the world. It is also the second most common neurodegenerative disorder behind Alzheimer’s disease, affecting around 1 million people in the United States. Unfortunately, diagnosing PD can be difficult because it is similar to other diseases and the symptoms develop over time. However, establishing specific ways to identify PD could aid in early diagnosis and the development of more effective treatments, resulting in better outcomes for patients.
Most people who develop PD are over the age of 60, but 5%–10% of patients are diagnosed before the age of 50. PD is caused by a loss of neurons in the brain that results in problems with movement. Patients experience slow and involuntary movements, tremors, stiffness, loss of balance and coordination, as well as difficulty walking and/or speaking. They can also experience symptoms that are unrelated to movement, including trouble sleeping, pain, dementia, and depression. Over time, these symptoms get worse, leading to a loss of independence and lower quality of life.
PD is clinically diagnosed. This means that doctors rely on medical history, pertinent symptoms, and their examinations to diagnose the disease. Reaching a diagnosis can be challenging because there are several disorders, such as multiple system atrophy, dementia with Lewy bodies, and essential tremor, that have symptoms similar to those of PD. Because of these similarities, misdiagnosis of PD is common, and it often takes years for patients to get a final diagnosis.
To help speed up diagnosis and enable early treatment, some research is focused on identifying biomarkers for PD. Biomarkers are biological traits that are measured to provide information about a patient’s health status. Some biomarkers are physiological features, such as blood pressure or heart rate, and some are molecules that can be detected in tissues or body fluids, such as blood or cerebrospinal fluid. There are also imaging biomarkers that are measured using technologies like computed tomography (CT) and magnetic resonance imaging (MRI). Biomarkers can be used to make a diagnosis, determine the risk of developing disease, or predict disease outcomes. They can also be used to monitor disease or aid in developing a course of treatment.
Currently, there are no known biomarkers that can specifically diagnose PD alone. However, there are biomarkers that can be used to support a PD diagnosis or rule out similar conditions. For example, a special scan that measures the activity of specific neurons that use dopamine in the brain can be used to support a PD diagnosis and rule out essential tremor. Another biomarker is a misfolded protein called alpha-synuclein, which is directly linked to PD. This protein can be measured in body fluids (blood or cerebrospinal fluid) and skin samples using laboratory tests. However, other neurodegenerative disorders, such as multiple system atrophy and dementia with Lewy bodies, also have this protein. This means that this biomarker can support a PD diagnosis but cannot specifically diagnose PD.
Identifying specific biomarkers for PD is a key step to improving patient care and well-being. Having such biomarkers would enable earlier identification and treatment of PD and allow tracking of disease progression over time. It would also help advance research into new treatments that could potentially slow or stop disease progression. Therefore, improving awareness and supporting research of new diagnostic tools for PD is essential for enhancing access to optimal care and improving patient outcomes.
