title: Long-term evaluation of deep brain stimulation of the thalamus.
abstract: OBJECTIVE
  The effects of thalamic deep brain stimulation (DBS) on essential tremor (ET) and Parkinson disease (PD) have been well documented, but there is a paucity of long-term data. The aim of this study was to evaluate the long-term safety and efficacy of DBS of the ventralis intermedius nucleus (VIM) of the thalamus for PD and ET.
  
  
  METHODS
  Thirty-eight of 45 patients enrolled at five sites completed a 5-year follow-up study. There were 26 patients with ET and 19 with PD undergoing 29 unilateral (18 ET/11 PD) and 16 bilateral (eight ET/eight PD) procedures. Patients with ET were evaluated using the Tremor Rating Scale, and patients with PD were evaluated using the Unified Parkinson's Disease Rating Scale. The mean age of patients with ET was 70.2 years and 66.3 years in patients with PD. Unilaterally implanted patients with ET had a 75% improvement of the targeted hand tremor; those with bilateral implants had a 65% improvement in the left hand and 86% in the right compared with baseline. Parkinsonian patients with unilateral implants had an 85% improvement in the targeted hand tremor and those with bilateral implants had a 100% improvement in the left hand and 90% improvement in the right. Common DBS-related adverse events in patients receiving unilateral implants were paresthesia (45%) and pain (41%), and in patients receiving implants bilaterally dysarthria (75%) and balance difficulties (56%) occurred. Device-related surgical revisions other than IPG replacements occurred in 12 (27%) of the 45 patients.
  
  
  CONCLUSIONS
  Thalamic stimulation is safe and effective for the long-term management of essential and Parkinsonian tremors. Bilateral stimulation can cause dysarthria and incoordination and should be used cautiously.
authors.affiliation: Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA. rpahwa@kumc.edu
authors.forename: Rajesh
authors.initials: R
authors.lastname: Pahwa
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Lyons
authors.forename: Steven B
authors.initials: SB
authors.lastname: Wilkinson
authors.forename: Richard K
authors.initials: RK
authors.lastname: Simpson
authors.forename: William G
authors.initials: WG
authors.lastname: Ondo
authors.forename: Daniel
authors.initials: D
authors.lastname: Tarsy
authors.forename: Thorkild
authors.initials: T
authors.lastname: Norregaard
authors.forename: Jean P
authors.initials: JP
authors.lastname: Hubble
authors.forename: Donald A
authors.initials: DA
authors.lastname: Smith
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hauser
authors.forename: Joseph
authors.initials: J
authors.lastname: Jankovic
mesh_terms: D000203:Activities of Daily Living / Q000145:classification; D000368:Aged; D046690:Deep Brain Stimulation; D004292:Dominance, Cerebral; D020329:Essential Tremor / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D011446:Prospective Studies; D016896:Treatment Outcome; D014481:United States; D020651:Ventral Thalamic Nuclei / Q000503:physiopathology*