title: Factors related to outcomes of subthalamic deep brain stimulation in Parkinson's disease.
abstract: OBJECTIVE
  Subthalamic nucleus (STN) deep brain stimulation (DBS) is an effective treatment of choice for patients with advanced idiopathic Parkinson's disease (PD) who have motor complication with medication. The objectives of this study are to analyze long-term follow-up data of STN DBS cases and to identify the factors related to outcomes.
  
  
  METHODS
  Fifty-two PD patients who underwent STN DBS were followed-up for more than 3 years. The Unified Parkinsons Disease Rating Scale (UPDRS) and other clinical profiles were assessed preoperatively and during follow-up. A linear regression model was used to analyze whether factors predict the results of STN DBS. We divided the study individuals into subgroups according to several factors and compared subgroups.
  
  
  RESULTS
  Preoperative activity of daily living (ADL) and the magnitude of preoperative levodopa response were shown to predict the improvement in UPDRS part II without medication, and preoperative ADL and levodopa equivalent dose (LED) were shown to predict the improvement in UPDRS part II with medication. In UPDRS part III with medication, the magnitude of preoperative levodopa response was a predicting factor.
  
  
  CONCLUSIONS
  The intensity of preoperative levodopa response was a strong factor for motor outcome. And preoperative ADL and LED were strong factors for ADL improvement. More vigorous studies should be conducted to elucidate how levodopa-induced motor complications are ameliorated after STN DBS.
authors.affiliation: Department of Neurosurgery, Brain Korea 21 Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea. ; Department of Neurosurgery, Haeundae Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Hae Yu
authors.initials: HY
authors.lastname: Kim
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Chang
authors.forename: Dong Wan
authors.initials: DW
authors.lastname: Kang
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Sohn
authors.forename: Myung Sik
authors.initials: MS
authors.lastname: Lee
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Chang
keywords: Deep brain stimulation; Parkinson's disease; Subthalamic nucleus