Imaging of nonmotor symptoms in Parkinson syndromes.

Neuroimaging modalities in Parkinson's Disease (PD) are primarily used for the differential diagnosis of Parkinson syndromes and to understand pathophysiological mechanisms in PD. Neuroimaging of nonmotor dysfunctions in PD mostly consist of functional studies in neuropsychologically impaired PD patients using PET or SPECT techniques. Various studies controversially discuss the probable frontal versus temporal hypometabolism in demented PD patients. Functional studies of PD patients with depression are limited to case reports showing an involvement of left frontal regions. To investigate the pathophysiology of hallucinations with functional imaging may be a promising field of future research.