What Obstacles Are Impeding Early Diagnosis of Parkinson Disease?

Improving on the ability to confirm diagnosis of Parkinson disease (PD) earlier and determining who is at risk for PD were referenced as key factors in further slowing progression of the disease, according to review findings published in Frontiers Neurology.

The complexity of PD can often cause physicians to mistake initial symptoms for those of other conditions. In fact, a poll of patients with PD (PwP) indicated that more than 1 in 4 PwP had been initially misdiagnosed, with 48% of these individuals receiving treatment for the wrong condition.

In slowing the progression of PD, early diagnosis is crucial. As researchers note, “there is a substantial latency between the actual onset of PD pathology and our ability to confirm diagnosis, during which accumulating structural and functional damage might be too advanced for effective modification or protection.”

So, what obstacles are limiting physicians from identifying PD earlier?

As referenced prior, the complexity of PD is a major issue, as researchers are still learning more on the condition. Currently, symptomatic management through efforts to prevent further dopamine deficiency serves as the gold standard of clinical treatment for PD.

While this may be successful in the early stages of the disease, the continued decline of dopaminergic neurons can make this strategy difficult. The frequency of OFF periods, which are characterized by the recurrence of symptoms after a period of symptom control, has been shown to increase as the disease progresses, affecting 70% of PwP after 9 years, up from 40% after 4 to 5 years of diagnosis.

Moreover, nonmotor symptoms in PD are additional factors that researchers note play an integral role in defining the condition at an early stage, but have limited treatment options. These nonmotor symptoms have extensive implications to a myriad of major disorders, ranging from sleep to olfactory issues.

In evolving the ability to diagnose PD at an early stage, researchers highlighted the potential efficacy of biomarkers in identifying those who may be at risk. So far, a growing number of markers have been proposed as effective screening tools for PD, including clinical, imaging, biochemical, and genetic markers, noted the researchers. Although no proposed biomarker can definitively predict PD onset, some markers are focused on the earliest phases of PD, which can provide novel information on the presence and progression of the disease.

The potential of identifying biomarkers within PD pathogenesis can prove a breakthrough in treating patients as physicians can tailor symptomatic approaches based on the individualized symptoms of a PwP. The efficacy of these possible diagnostic tools is still not confirmed, however, with researchers still examining the latest diagnostic, prognostic, and therapeutic methods in PD.

“Fundamentally what is needed to move forward in our search for PD solutions is a better understanding of the natural progression of PD and the underlying pathological processes and mechanisms,” concluded the study authors.

Reference

Poortvliet PC, O’Maley K, Silburn PA, et al. Perspective: current pitfalls in the search for future treatments and prevention of Parkinson's disease. Front Neurol. Published online July 8, 2020. doi:10.3389/fneur.2020.00686