The clinical methods of olfactory testing and color discrimination as well as apparative methods such as transcranial ultrasound, dopamine transporter imaging and MIBG scintigraphy reveal a high sensitivity concerning the diagnosis of idiopathic Parkinson's disease (PD). The specificity of the presented methods, in particular of the dopamine transporter imaging--seems to be limited. All these methods and primarily their combination allow the detection of PD in early and--probably--preclinical stages. This requires sufficient therapeutic strategies to prevent and treat preclinical and early PD.