Outcome of subthalamic nucleus deep brain stimulation on long-term motor function of patients with advanced Parkinson disease

The objective of our study was to assess Unified Parkinson Disease Rating Scale (UPDRS) score in Parkinson disease (PD) patients who underwent subthalamic nucleus (STN) deep brain stimulation (DBS) 6 years after their surgery and to compare their UPDRS score 6 years after DBS with their score before surgery and 6 months after their operation.
In this cross sectional study which was carried out at Neurology Department of Rasool-e-Akram Hospital, Tehran, Iran, affiliated to Iran University of Medical Sciences between 2008 and 2014, 37 patients with advanced PD were enrolled using non-randomized sampling method.
All of the patients underwent STN DBS surgery and one patient died before being discharged, therefore; we started our study with 36 patients. The UPDRS III total score at preoperative state, 6-month follow-up and 6-year follow-up state were compared using repeated-measure analysis of variance.
Thirty-seven patients (26 men and 10 women) with mean age of 50 ± 3 ranging from 32 to 72 years underwent STN DBS surgery. All patients were suffering from advanced PD with mean period of 11.3 ± 1.9 years. All patients except one were followed up for six months. And 14 patients (8 men and 6 women) were included in a six-year follow-up. The UPDRS score measurements before surgery, at
6-month follow-up and 6-year follow-up were
18.22 ± 2.88, 12.80 ± 3.14, 25.0 ± 11.8, respectively. Significant increase in UPDRS score was observed between the preoperative and six-year follow-up period (P In conclusion, this study suggests that total UPDRS score will increase at 5 years following STN DBS and also showed that resting tremor, one of UPDRS sub-scores, will improve over time and the benefit of DBS will be persistent even after 6 years.