title: Efficacy of bilateral subthalamic nucleus (STN) stimulation in Parkinson's disease.
abstract: BACKGROUND
  Deep brain stimulation (DBS) has, for the most part, replaced irreversible stereotactic coagulations in the surgical treatment of advanced Parkinson's disease. This study was undertaken to evaluate the benefits of bilateral STN stimulation related to its potential risks and side effects.
  
  
  METHODS
  Twenty-nine consecutive Parkinsonian patients treated with STN-DBS were prospectively followed-up. Effects on Parkinsonian symptoms were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS). The evaluation was performed preoperatively and included postoperative follow-up evaluations at one and twelve months. All evaluations were made during the patient's best on-medication phase and postoperative follow-ups were conducted under both stimulator-on and stimulator-off conditions by a blinded neurologist. A neuropsychologist also evaluated the patients at every visit.
  
  
  RESULTS
  Two patients were excluded from the analysis because of severe surgical complications and three for an infection demanding the removal of the stimulator material. Other complications and side effects were clearly milder and temporary. At twelve months after surgery dyskinesia scores in the UPDRS were 53% lower than preoperative values. The results of the UPDRS motor scores improved 31.4% and activities of daily living (ADL) scores increased 19% compared with the preoperative situation. Also, the daily levodopa dose was 22% lower. Neuropsychological changes were minor, except for some deterioration in verbal fluency.
  
  
  CONCLUSIONS
  The majority of Parkinsonian patients experienced significant and long lasting relief from their motor symptoms and an improvement in ADL functions due to DBS-STN therapy when evaluated at the best on-medication phase.
authors.affiliation: Department of Neurosurgery, Oulu University Hospital, Oulu, Finland. erola@pp.inet.fi
authors.forename: T
authors.initials: T
authors.lastname: Erola
authors.forename: E R
authors.initials: ER
authors.lastname: Heikkinen
authors.forename: T
authors.initials: T
authors.lastname: Haapaniemi
authors.forename: J
authors.initials: J
authors.lastname: Tuominen
authors.forename: A
authors.initials: A
authors.lastname: Juolasmaa
authors.forename: V V
authors.initials: VV
authors.lastname: Myllylä
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001479:Basal Ganglia / Q000503:physiopathology; D046690:Deep Brain Stimulation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology; D018570:Risk Assessment; D013378:Substantia Nigra / Q000503:physiopathology; D020531:Subthalamic Nucleus / Q000503:physiopathology*; D016896:Treatment Outcome
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa