title: A randomized, double masked, controlled trial of botulinum toxin type A in essential hand tremor.
abstract: OBJECTIVE
  To evaluate the safety and efficacy of botulinum toxin type A injection in essential tremor of the hand.
  
  
  BACKGROUND
  Botulinum toxin type A is an effective treatment for dystonia, spasticity, and other movement disorders and has been found to be useful in open-label studies and one double-masked study of essential hand tremor.
  
  
  METHODS
  One hundred thirty-three patients with essential tremor were randomized to low-dose (50 U) or high-dose (100 U) botulinum toxin type A (Botox) or vehicle placebo treatment. Injections were made into the wrist flexors and extensors. Patients were followed for 16 weeks. The effect of treatment was assessed by clinical rating scales, measures of motor tasks and functional disability, and global assessment of treatment. Hand strength was evaluated by clinical rating and by a dynamometer.
  
  
  RESULTS
  Both doses of botulinum toxin type A significantly reduced postural tremor on the clinical rating scales after 4 to 16 weeks. However, kinetic tremor was significantly reduced only at the 6-week examination. Measures of motor tasks and functional disability were not consistently improved with botulinum toxin type A treatment. Grip strength was reduced for the low- and high-dose botulinum toxin type A groups as compared with the placebo group. Adverse reactions consisted mainly of dose-dependent hand weakness.
  
  
  CONCLUSIONS
  Botulinum toxin type A injections for essential tremor of the hands resulted in significant improvement of postural, but not kinetic, hand tremors and resulted in limited functional efficacy. Hand weakness is a dose-dependent significant side effect of treatment at the doses used in this study.
authors.affiliation: Department of Neurology, Columbia University, New York, NY, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Brin
authors.forename: K E
authors.initials: KE
authors.lastname: Lyons
authors.forename: J
authors.initials: J
authors.lastname: Doucette
authors.forename: C H
authors.initials: CH
authors.lastname: Adler
authors.forename: J N
authors.initials: JN
authors.lastname: Caviness
authors.forename: C L
authors.initials: CL
authors.lastname: Comella
authors.forename: R M
authors.initials: RM
authors.lastname: Dubinsky
authors.forename: J H
authors.initials: JH
authors.lastname: Friedman
authors.forename: B V
authors.initials: BV
authors.lastname: Manyam
authors.forename: J Y
authors.initials: JY
authors.lastname: Matsumoto
authors.forename: S L
authors.initials: SL
authors.lastname: Pullman
authors.forename: A H
authors.initials: AH
authors.lastname: Rajput
authors.forename: K D
authors.initials: KD
authors.lastname: Sethi
authors.forename: C
authors.initials: C
authors.lastname: Tanner
authors.forename: W C
authors.initials: WC
authors.lastname: Koller
mesh_terms: D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D004311:Double-Blind Method; D020329:Essential Tremor / Q000188:drug therapy*; D005260:Female; D006225:Hand; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A