Changes in Cerebral Glucose Metabolism in Patients with Parkinson Disease with Dementia After Cholinesterase Inhibitor Therapy

We investigated changes in cerebral glucose metabolism after cholinesterase inhibitor (ChEI) therapy in patients with Parkinson disease dementia (PDD) to determine whether cognitive improvements would be reflected in changes of cerebral metabolic patterns, thus offering insight into the neural substrate of cognitive dysfunction in patients with PDD. Methods: We performed a serial PET study before (baseline) and after ChEI therapy on 10 patients with PDD, using statistical parametric mapping. Additionally, covariance analysis was performed to extract regions in which increased change in regional cerebral metabolism correlated significantly with increased Mini-Mental State Examination scores. Results: The statistical parametric mapping analysis indicated that significantly increased cerebral metabolism after ChEI therapy, compared with at baseline, was most evident in the left angular gyrus extending to the supramarginal area and left superior and middle frontal gyri. Additionally, cerebral metabolism was significantly increased in the right superior frontal and left middle orbitofrontal gyri. In contrast, the right fusiform gyrus showed significantly decreased metabolism after ChEI, compared with at baseline. In the correlation analysis, improvements in Mini-Mental State Examination scores after ChEI treatment were significantly associated with increased cerebral metabolism in the left supramarginal, orbitofrontal, and cingulate areas. Conclusion: Our data suggest that prefrontal and parietal association areas may be relevant structures for the pharmacologic response to ChEI in patients with PDD.