rCBF SPECT in Parkinson's disease patients with mental dysfunction.
Functional imaging of the brain using SPECT provides information correlative to the alterations of regional blood flow. In this paper we review the literature pertaining to SPECT in Parkinson's disease with and without dementia and depression. Parkinson's disease itself is not associated with a consistent pattern of cerebral blood flow alterations in the basal ganglia, but reduced parietal blood flow is more often reported. The heterogeneity of blood flow changes possibly reflects the multifactorial pathophysiology of the disease. In demented Parkinson's disease patients frontal hypoperfusion is often found or bilateral temporoparietal deficits, probably indicative of concomitant Alzheimer's disease. The SPECT studies undertaken in depressed patients with and without Parkinson's disease show highly conflicting and inconsistent results, probably due to methodological and diagnostic flaws (especially the inclusion of demented Parkinson patients). Several lines of reasoning point to a prefrontal dysfunction and future SPECT studies are planned to study this region in non-demented Parkinson's disease patients with and without major depression.