Clinical symptoms of the idiopathic Parkinson's syndrome (IPS) are numerous. Clinical experience as well as pharmacological research identified symptoms not responsive to dopaminergic stimulation. These symptoms in particular were the target of rehabilitative therapy approaches. Several of these approaches have been evaluated in prospective studies. In the present paper, these studies and the respective therapeutic interventions were categorized and rated concerning their clinical relevance and their study design supporting a differential therapeutic approach. Symptoms were arranged relating to their clinical relevance and specific therapeutic approaches were described and rated. The rating was based on a novel developed approach to check for clinical relevance. In addition, areas in need of further and more intensive scientific research, as depression, cognitive deficits, and tremor, were identified. On the contrary, conclusive therapeutic approaches were available for the treatment of symptoms like gait and postural disturbances and dysarthria. Some advice for the therapy of muscular weakness, dexterity problems and dysphagia was given, but further studies are warranted in these fields.