Background: Pain is a well recognized feature of Parkinson disease (PD). Like motor fluctuations, pain in PD may fluctuate as 'non-motor fluctuations'. Subthalamic deep brain stimulation (STN DBS) is an established treatment for motor fluctuations in PD. However, the effect of STN DBS on the pain in PD is only partially investigated.
Methods: PD patients who were considered for STN DBS were asked if they had pain. The severity of pain was scored in each body part. In patients with motor fluctuation, the pain in the 'on' and 'off ' state were recorded separately. Patients were evaluated preoperatively and 3 months after surgery. Some patients were followed for 6 months.
Results: Twenty-three of 29 patients had pain preoperatively. Of 24 with motor fluctuation, 21 had pain, and 18 had fluctuating pain. Pain improved in 20 out of 23 with preoperative pain at 3 months postoperatively. Of 18 with fluctuating pain, 12 reported a decrease in, and 5 complete disappearance of the 'off ' pain. Of 4 with nonfluctuating preoperative pain, 2 reported improvement. Pain was severe and functionally disabling in some. The STN DBS improved pain to a tolerable degree. In 7 of 29, new pain developed during the 3 month follow-up. Sixteen patients were followed for 6 months. All 11 patients who had improvement at 3 months continued to get benefit from STN DBS. Two additional patients who had no improvement at 3 months reported improvement at 6 months.
Conclusions: Pain is frequent in PD and STN DBS improves pain, especially the 'off ' pain in PD.