Hypometabolism in Posterior and Temporal Areas of the Brain is Associated with Cognitive Decline in Parkinson's Disease

Background: Brain metabolic profiles of patients with Parkinson's disease (PD) and cognitive impairment or dementia are now available. It would be useful if data on brain metabolism were also predictive of the risk of a pejorative cognitive evolution - especially in the multidisciplinary management of advanced PD patients. Objective: The primary objective was to determine whether a specific brain metabolic pattern is associated with cognitive decline in PD. Methods: Sixteen advanced PD patients were screened for the absence of cognitive impairment (according to the Mattis dementia rating scale, MDRS) and underwent [F-18]- fluorodeoxyglucose positron emission tomography brain imaging in the "off drug" state. The MDRS was scored again about two years later, categorizing patients as having significant cognitive decline (decliners) or not (stables). The two groups were then compared in terms of their brain metabolism at inclusion. Results: There were six decliners and ten stables. Significant hypometabolism in the two precunei (Brodmann area (BA) 31), the left middle temporal gyrus (BA21) and the left fusiform gyrus (BA37) was found in the decliner group compared with the stables. Conclusion: In advanced PD, a particular metabolic pattern may be associated with the onset of significant cognitive decline.