title: Dynamic decomposition of motion in essential and parkinsonian tremor.
abstract: BACKGROUND
  Treatment options for essential (ET) and Parkinson disease (PD) tremor are suboptimal, with significant side effects. Botulinum toxin type A (BoNT A) is successfully used in management of various focal movement disorders but is not widely used for tremor.
  
  
  METHODS
  This study examines complexity of wrist tremor in terms of involvement of its three anatomical degrees of freedom (DOF) in two common situations of rest and posture. The study examines tremor in 11 ET and 17 PD participants by kinematic decomposition of motion in 3-DOF.
  
  
  RESULTS
  Tremor decomposition showed the motion involved more than one DOF (<70% contribution in one DOF) in most ET (rest: 100%, posture: 64%) and PD (rest: 77%, posture: 77%) patients. Task variation resulted in change in both amplitude and composition in ET, but not in PD. Amplitude significantly increased from rest to posture in ET. Directional bias was observed at the wrist for ET (pronation), and PD (extension, ulnar deviation, pronation). Average agreement between clinical visual and kinematic selection of muscles was 55% across all subjects.
  
  
  CONCLUSIONS
  This study shows the complexity of tremor and the difficulty in visual judgment of tremor, which may be key to the success of targeted focal treatments such as BoNT A.
authors.affiliation: 1London Health Sciences Centre,Western University,London,ON,Canada.
authors.forename: Fariborz
authors.initials: F
authors.lastname: Rahimi
authors.affiliation: 2Department of Neurology,Western University,London,ON,Canada.
authors.forename: Derek
authors.initials: D
authors.lastname: Debicki
authors.affiliation: 3Department of Health Rehabilitation Sciences,Western University,London,ON,Canada.
authors.forename: Angela
authors.initials: A
authors.lastname: Roberts-South
authors.affiliation: 1London Health Sciences Centre,Western University,London,ON,Canada.
authors.forename: Carina
authors.initials: C
authors.lastname: Bee
authors.affiliation: 4Department of Physiology and Pharmacology,Western University,London,ON,Canada.
authors.forename: Priya
authors.initials: P
authors.lastname: Bapat
authors.affiliation: 1London Health Sciences Centre,Western University,London,ON,Canada.
authors.forename: Mandar
authors.initials: M
authors.lastname: Jog
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D004576:Electromyography; D020329:Essential Tremor / Q000175:diagnosis* / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009038:Motion; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D020734:Parkinsonian Disorders / Q000175:diagnosis* / Q000188:drug therapy* / Q000503:physiopathology; D011403:Pronation; D014457:Ulna / Q000503:physiopathology; D014953:Wrist / Q000503:physiopathology
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A
keywords: tremor composition