title: Unilateral thalamic deep brain stimulation in essential tremor demonstrates long-term ipsilateral effects.
abstract: BACKGROUND
  Deep Brain Stimulation (DBS) of thalamus in essential tremor (ET) is effective for the treatment of contralateral tremors. Bilateral DBS controls tremors on both sides but is associated with increased morbidity and risks. We evaluated if unilateral surgery had ipsilateral benefits on tremors and thus could be a potentially safer alternative to bilateral DBS.
  
  
  METHODS
  Medication refractory ET patients undergoing unilateral thalamic DBS were included and longitudinally followed. Tremor rating scale was used to record total motor, arm tremor and activities of daily living (ADL) scores at baseline, six months and at last visit (three or more years after surgery). Postoperative scores were recorded with DBS turned OFF and ON.
  
  
  RESULTS
  Twenty-two patients with a mean follow-up 3.4 ± 0.14 years were enrolled. When baseline scores were compared to scores with the DBS turned ON, significant improvements were noted in total tremor (40%), ADL (67%) and arm tremor scores both on the ipsilateral and the contralateral side at six months and at the last visit of follow-up (all p < 0.05). Ipsilateral arm tremor (∼56%) improvements were milder compared to the contralateral side (∼73%) tremors.
  
  
  CONCLUSIONS
  Unilateral thalamic DBS in ET demonstrates significant long-term benefits for ipsilateral arm tremors and can be offered to higher risk and to select patients.
authors.affiliation: Department of Neurology, University of Florida, Movement Disorders Center, Gainesville, FL, USA; University for Development, Av. Plaza 680, San Carlos de Apoquindo, Las Condes, Santiago, Chile.
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Peng-Chen
authors.forename: Takashi
authors.initials: T
authors.lastname: Morishita
authors.forename: David
authors.initials: D
authors.lastname: Vaillancourt
authors.forename: Chris
authors.initials: C
authors.lastname: Favilla
authors.forename: Kelly D
authors.initials: KD
authors.lastname: Foote
authors.forename: Michael S
authors.initials: MS
authors.lastname: Okun
authors.forename: Aparna
authors.initials: A
authors.lastname: Wagle Shukla
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D020329:Essential Tremor / Q000628:therapy*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
keywords: DBS; Essential tremors; Thalamus