[Approaches to early diagnosis of Parkinson's disease].

Parkinson's disease (PD) is characterized by a long period of 'latent' course of the neurodegenerative process. Non-motor symptoms, including behavioral dysfunction in the REM sleep phase, hyposmia, constipation, depression, may be detected in patients before the development of movement disorders. The combination of these manifestations can be used to identify the risk group for the subsequent development of PD.