title: Bilateral Ventral Intermediate Nucleus Thalamic Deep Brain Stimulation in Orthostatic Tremor.
abstract: Orthostatic tremor (OT) is characterized by high-frequency leg tremor when standing still, resulting in a sense of imbalance, with limited treatment options. Ventral intermediate (Vim) nucleus thalamic deep brain stimulation (DBS) has been reported as beneficial in a few cases.
  
  
  
  To report clinical outcomes, lead locations, and stimulation parameters in 2 patients with severe medication-refractory OT treated with Vim DBS.
  
  
  
  The patients underwent surface electromyography (EMG) to confirm the OT diagnosis. Outcomes were measured as change in tolerated standing time at the last follow-up. Lead locations were quantified using postoperative MRI.
  
  
  
  Vim DBS was well tolerated and resulted in improvement in standing time (patient 1: 50 s at baseline to 15 min 16 months after surgery; patient 2: 34 s at baseline to 4.2 min 7 months after surgery). Postoperative surface EMG for patient 1 demonstrated a delayed onset of tremor, lower-amplitude tremor, and periods of quiescence, but an unchanged tremor frequency.
  
  
  
  These cases provide further support for Vim DBS to improve standing time in severe medication-refractory OT. The location of the effective thalamic target for OT does not differ from the effective target for essential tremor.
authors.affiliation: Neurology, University of California San Francisco, San Francisco, Calif., USA.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Coleman
authors.forename: Philip A
authors.initials: PA
authors.lastname: Starr
authors.forename: Maya
authors.initials: M
authors.lastname: Katz
authors.forename: Graham A
authors.initials: GA
authors.lastname: Glass
authors.forename: Monica
authors.initials: M
authors.lastname: Volz
authors.forename: Suketu M
authors.initials: SM
authors.lastname: Khandhar
authors.forename: Jill L
authors.initials: JL
authors.lastname: Ostrem
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D004244:Dizziness / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D014202:Tremor / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D020651:Ventral Thalamic Nuclei / Q000502:physiology / Q000601:surgery*