Different Modes of Clinical Progress between Parkinsonian Patients with and without Subthalamic Deep Brain Stimulation

Abstract

Parkinson's disease (PD) is a progressive neurodegenerative disorder. The progress of clinical decline, typically assessed using the Unified Parkinson's Disease Rating Scale (UPDRS), parallels the degeneration of dopaminergic neurons. In this study, we retrospectively analyzed differences in the rate of UPDRS score decline between patients who underwent and who did not undergo subthalamic deep brain stimulation (STN-DBS).Methods: Thirty-two patients (22 men and 10 women) with advanced PD were included in pre-surgical analysis. Twenty-seven patients (18 males and 9 females) out of 32 patients completed post-surgical evaluations. Core assessments were made for every patient. During post-surgical examinations, UPDRS scores were recorded during DBS-on and DBS-off periods (both were determined during the levodopa-off period). The effect of STN-DBS was determined by comparing the DBS-on and DBS-off UPDRS scores. Repeated measure analysis of variance (ANOVA) was performed for a comparison between the UPDRS scores in patients when with DBS-on and when with DBS-off.Results: Mean follow-up was 23.4 months after the initiation of STN-DBS. UPDRS scores during DBS-on were significantly lower than scores during DBS-off (43.3±3.2 vs. 71.4±3.8, P=0.03). There was a significant effect of patient age on levodopa-off UPDRS scores over time (P=0.01). There was a borderline significant effect (P=0.06) of PD duration on levodopa-off UPDRS scores.Conclusions: STN-DBS does not restore functional loss of patients with PD, but there are differences in clinical progress between patients with and those without STN-DBS.