Biomarkers are useful for aiding an accurate diagnosis when clinical symptoms are complex and difficult to interpret, such as in PD.5 For PD, this can be particularly the case during the early, prodromal phase when cardinal features (bradykinesia, muscle rigidity, resting tremor) that strongly suggest a diagnosis of PD are not yet apparent.5 During this time, misdiagnosis may occur, so a reliable diagnostic biomarker that can identify PD before a significant amount of damage has occurred would be invaluable.5
Predictive and diagnostic biomarkers also help scientists to carry out more research during the early stages of a disease, which at the moment can be challenging in PD due to the difficulty of identifying true cases using only clinical examination.5 By studying the disease in its early development, researchers would be more likely to develop therapies in the future that actually prevent neuron loss, rather than merely treating the resulting symptoms.5