title: Thalamic DBS with a constant-current device in essential tremor: A controlled clinical trial.
abstract: BACKGROUND
  This study of thalamic deep brain stimulation (DBS) investigated whether a novel constant-current device improves tremor and activities of daily living (ADL) in patients with essential tremor (ET).
  
  
  METHODS
  A prospective, controlled, multicenter study was conducted at 12 academic centers. We investigated the safety and efficacy of unilateral and bilateral constant-current DBS of the ventralis intermedius (VIM) nucleus of the thalamus in patients with essential tremor whose tremor was inadequately controlled by medications. The primary outcome measure was a rater-blinded assessment of the change in the target limb tremor score in the stimulation-on versus stimulation-off state six months following surgery. Multiple secondary outcomes were assessed at one-year follow-up, including motor, mood, and quality-of-life measures.
  
  
  RESULTS
  127 patients were implanted with VIM DBS. The blinded, primary outcome variable (n = 76) revealed a mean improvement of 1.25 ± 1.26 points in the target limb tremor rating scale (TRS) score in the arm contralateral to DBS (p < 0.001). Secondary outcome variables at one year revealed significant improvements (p ≤ 0.001) in quality of life, depression symptoms, and ADL scores. Forty-seven patients had a second contralateral VIM-DBS, and this group demonstrated reduction in second-sided tremor at 180 days (p < 0.001). Serious adverse events related to the surgery included infection (n = 3), intracranial hemorrhage (n = 3), and device explantation (n = 3).
  
  
  CONCLUSIONS
  Unilateral and bilateral constant-current VIM DBS significantly improves upper extremity tremor, ADL, quality of life, and depression in patients with severe ET.
authors.affiliation: Department of Neurologic Surgery, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, United States. Electronic address: wharen.robert@mayo.edu.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Wharen
authors.affiliation: Departments of Neurology and Neurosurgery, University of Florida College of Medicine and McKnight Brain Institute, University of Florida Center for Movement Disorders and Neurorestoration, 3450 Hull Road, 4th Floor, Gainesville, FL 32607, United States. Electronic address: okun@neurology.ufl.edu.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Okun
authors.affiliation: Department of Neurosurgery, University of Alabama Birmingham, School of Medicine, Department of Neurosurgery, 510 20th Avenue South, FOT 1038, Birmingham, AL 35234, United States. Electronic address: bguthrie@uabmc.edu.
authors.forename: Barton L
authors.initials: BL
authors.lastname: Guthrie
authors.affiliation: Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, United States. Electronic address: Uitti.ryan@mayo.edu.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Uitti
authors.affiliation: Department of Neurological Surgery, University of California San Francisco, 1635 Divisadero Street, 5th Floor, Suite 520-530, San Francisco, CA 94115, United States. Electronic address: LarsonP@neurosurg.ucsf.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Larson
authors.affiliation: Departments of Neurological Surgery, University of Florida College of Medicine and McKnight Brain Institute, University of Florida Center for Movement Disorders and Neurorestoration, 3450 Hull Road, 4th Floor, Gainesville, FL 32607, United States. Electronic address: foote@neurosurgery.ufl.edu.
authors.forename: Kelly
authors.initials: K
authors.lastname: Foote
authors.affiliation: Department of Neurology, University of Alabama Birmingham, School of Medicine, 510 20th Avenue South, FOT 1038, Birmingham, AL 35234, United States. Electronic address: hcwalker@uab.edu.
authors.forename: Harrison
authors.initials: H
authors.lastname: Walker
authors.affiliation: Neurology Department, University of Rochester, 919 Westfall Rd., Bldg C, Suite 220, Rochester, NY 14618, United States. Electronic address: Fred.Marshall@ctcc.rochester.edu.
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Marshall
authors.affiliation: Movement Disorder and Comprehensive Epilepsy Centers, Henry Ford Medical Group, 6777 West Maple Road, West Bloomfield, MI 48322, United States. Electronic address: jschwal1@hfhs.org.
authors.forename: Jason
authors.initials: J
authors.lastname: Schwalb
authors.affiliation: Movement Disorder Group, Columbia University Medical Center, 710 West 168th Street, 3rd Floor, #350, New York, NY 10032, United States. Electronic address: BFord@neuro.columbia.edu.
authors.forename: Blair
authors.initials: B
authors.lastname: Ford
authors.affiliation: Department of Neurology, Baylor College of Medicine, 6550 Fannin Street, Suite 1801, Houston, TX 77030, United States. Electronic address: josephj@bcm.tmc.edu.
authors.forename: Joseph
authors.initials: J
authors.lastname: Jankovic
authors.affiliation: Department of Neurosurgery, The Methodist Hospital Physician Organization, 6560 Fannin, Suite 944, Houston, TX 77030, United States. Electronic address: RSimpson@houstonmethodist.org.
authors.forename: Richard
authors.initials: R
authors.lastname: Simpson
authors.affiliation: Department of Neurology, Loma Linda University Medical Center, Division of Movement Disorders, 11370 Anderson St, Suite 2400, Loma Linda, CA 92354, United States. Electronic address: KDashtipour@llu.edu.
authors.forename: Khashayar
authors.initials: K
authors.lastname: Dashtipour
authors.affiliation: Department of Neurology, Vanderbilt University, A-0118 Medical Center North, Nashville, TN 37232-2551, United States. Electronic address: fenna.phibbs@Vanderbilt.edu.
authors.forename: Fenna
authors.initials: F
authors.lastname: Phibbs
authors.affiliation: Department of Neurosurgery, Vanderbilt University, 1211 22nd Ave. S, Nashville, TN 37232, United States. Electronic address: joseph.neimat@Vanderbilt.edu.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Neimat
authors.affiliation: Movement Disorder Center, Texas Health Presbyterian Dallas, 8200 Walnut Hill, Dallas, TX 75231, United States. Electronic address: stewart4765@sbcglobal.net.
authors.forename: R Malcolm
authors.initials: RM
authors.lastname: Stewart
authors.affiliation: Clinical Research Department, St. Jude Medical, 6901 Preston Road, Plano, TX 75024, United States. Electronic address: dpeichel@sjm.com.
authors.forename: DeLea
authors.initials: D
authors.lastname: Peichel
authors.affiliation: Parkinson's Disease and Movement Disorder Center, University of Kansas Medical Center, 3599 Rainbow Blvd, Mailstop 2012, Kansas City, KS 66160, United States. Electronic address: RPAHWA@kumc.edu.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Pahwa
authors.affiliation: Surgical Movement Disorders, Department of Neurology, University of California San Francisco and the San Francisco Veteran's Affairs Medical Center, 1635 Divisadero Street, 5th Floor, Suite 520-530, San Francisco, CA 94115, United States. Electronic address: jill.ostrem@ucsf.edu.
authors.forename: Jill L
authors.initials: JL
authors.lastname: Ostrem
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D046690:Deep Brain Stimulation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D020329:Essential Tremor / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D013788:Thalamus; D016896:Treatment Outcome
keywords: Deep brain stimulation; Essential tremor; Thalamus; Ventralis intermedius nucleus