[Does early detection of non-motor symptoms facilitate early treatment of Parkinson's disease?].

Parkinson's disease (PD) is the second most common neurodegenerative disorder. The risk of developing of PD increases with age, it is estimated that the prevalence rate is approximately 150/100,000 in Japan. Recently, non-motor symptoms such as anosmia, autonomic failure, sleep disorders, sensory problems, depression, anxiety, cognitive disorders (including dementia), and psychosis are interested in the pathogenetic process of PD. According to the Braak's hypothesis, these non-motor symptoms precede the onset of the classic motor symptoms of PD. Many studies have shown that the number of neurons in the substantia nigra is decreased to approximately -40 to -60% in number when the motorsymptoms of PD are developed. In this article, review of special references regarding the natural history of PD shows that non-motor symptoms are the prodromal signs of PD. If disease modification therapy and/or disease prevention therapy is approved in the future, an early and accurate diagnosis of PD is needed. Accurate early diagnostic biomarkers including symptoms, some compounds, and radiological markers need to be identified.