Changes in Glucose Metabolism in Cerebral Cortex and Cerebellum Correlate With Tremor and Rigidity Control by Subthalamic Nucleus Stimulation in Parkinson’s Disease: A Positron Emission Tomography Study

Abstract

Objective. Employing [(18) F]fluorodeoxyglucose (FDG) positron emission tomography (PET) to assess the correlation between the effect of deep brain stimulation (DBS) on the subthalamic nucleus (STN) and the regional cerebral metabolic rate of glucose (rCMRGlc) in advanced Parkinson's disease patients (N=8). Materials and Methods. On the basis of patients' diary records, we performed FDG-PET during the off-period of motor activity with on- or off-stimulation by STN-DBS on separate days and analyzed the correlation between changes in motor symptoms and alterations in the rCMRGlc. Result. When FDG-PET was performed, the motor score on the unified Parkinson's disease rating scale (UPDRS) was 64% lower with on-stimulation than with off-stimulation (p<0.001, Wilcoxon single-rank test). STN-DBS increased the rCMRGlc in the posterior part of the right middle frontal gyrus, which corresponded to the premotor area, and the right anterior lobe of the cerebellum (p<0.005, paired t-test). No region exhibited a decrease in rCMRGlc. Among the items of the UPDRS motor score, the changes in resting tremor and rigidity of the left extremities showed a significant correlation with the changes in rCMRGlc observed in the right premotor area (p<0.02 and p<0.05, respectively, Spearman's rank correlation). Conclusions. STN-DBS either activates the premotor area or normalizes the deactivation of the premotor area. These FDG-PET findings obtained are consistent with the idea that STN-DBS modifies the activities of neural circuits involved in motor control.