Determining Factors for the Reduction of Dopaminergic Drugs after Bilateral Subthalamic Nucleus Deep Brain Stimulation

Background: We aimed to investigate the possible factors determining reduction of dopaminergic drugs in patients who received bilateral subthalamic nucleus (STN) deep brain stimulation (DBS). Methods: We studied 33 consecutive Parkinson’s disease (PD) patients who underwent bilateral STN DBS between March 2002 and April 2006. Patients were assessed at baseline and 6 months and 1 year after surgery. Results: The dose of dopaminergic drugs was significantly decreased by 16.5 % (p<0.05) and 14.9 % (p<0.05), at post op 6 months and 12 months respectively. The reduction rate of dopaminergic drugs after bilateral STN DBS was positively correlated with the dopaminergic drug dosage at baseline (p<0.05) and was negatively correlated with the scores of “off”-period UPDRS II (p<0.05), III (p<0.001), and total UPDRS (p<0.001) at baseline. The difference of UPDRS scores between “on ” and “off ” periods on the levodopa challenge test was negatively correlated with the reduction rate of dopaminergic drug dosage after bilateral STN DBS (p<0.001). Conclusions: It is likely that the main determining factors for the reduction of dopaminergic drug dosages after bilateral STN DBS in advanced PD are the UPDRS III score during “off ” periods, difference of the UPDRS III score between “on ” and “off ” periods on the levodopa challenge test and dose of dopaminergic drugs at baseline