Long-term effects of bilateral deep brain stimulation of the subthalamic nucleus on depression in patients with Parkinson's disease

Objective: To study the long-term effects of deep brain stimulation (DBS) of the bilateral subthalamic nucleus (STN) on depression in patients with Parkinson’s disease (PD) and to discuss the mechanism. Methods: A STN–DBS group (n ¼ 27) and anti-Parkinson’s medication control group with paired designing were set up. The evaluation of the depression and motor function was performed a total of six times. Depression was evaluated by the Self-Rating Depression Scale (SDS) and Hamilton Rating Scale for Depression (HAMD). Motor function was evaluated by the third part of the Unified Parkinson’s Disease Rating Scale (UPDRS-III). Results: Compared with the preoperative and the medication control group, the UPDRS-III scores of the STN–DBS group decreased remarkably within 18 months postoperatively (P � 0.001), and the SDS scores decreased notably within 6 months postoperatively (P � 0.05), and the HAMD scores decreased notably within 3 months postoperatively (P � 0.05). The UPDRS-III scores were strongly correlated with their SDS scores within 6 months postoperatively (P � 0.05), especially at 5 weeks postoperation (P � 0.001). UPDRS-III scores were also strongly correlated with HAMD scores at 5 weeks postoperation (P � 0.05). The mean value of the bilateral voltages was obviously correlated with SDS and HAMD scores (P � 0.05) within 18 months postoperatively. Conclusion: The improvement in motor symptoms resulting from STN–DBS can improve depression in PD patients, but its long-term effects were unremarkable. Within the treatment range, the higher the mean value of bilateral voltages then the more severe was the depression in PD patients. 2009 Elsevier Ltd. All rights reserved.