Double-blind controlled study of botulinum toxin in adductor spasmodic dysphonia

Laryngoscope. 1991 Jun;101(6 Pt 1):630-4. doi: 10.1288/00005537-199106000-00010.


The treatment of adductor spasmodic dysphonia using botulinum toxin A was conducted in 13 patients as a double-blind, placebo-controlled study. Patients were diagnosed independently by an interdisciplinary team consisting of speech pathologists, an otolaryngologist, and a neurologist. The toxin or saline was injected into each thyroarytenoid muscle under electromyographic and laryngoscopic guidance. Botulinum toxin A markedly reduced perturbation, decreased fundamental frequency range, and improved the spectrographic characteristics of the voice. Fundamental frequency and phonation time remained unchanged. Patients injected with botulinum toxin A noticed significant improvement in their voices in comparison with the placebo-treated group. Excessive breathiness of the voice occurred in two patients, and mild bleeding in one patient in the botulinum toxin A-treated group. Injection with saline resulted in edema of the vocal cord in one patient. Botulinum toxin A proved to be an effective and safe treatment of adductor spasmodic dysphonia.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Botulinum Toxins / administration & dosage
  • Botulinum Toxins / adverse effects
  • Botulinum Toxins / therapeutic use*
  • Double-Blind Method
  • Humans
  • Injections, Intramuscular
  • Laryngeal Muscles
  • Sound Spectrography
  • Spasm / drug therapy
  • Speech / physiology
  • Voice Disorders / drug therapy*
  • Voice Disorders / etiology
  • Voice Disorders / physiopathology


  • Botulinum Toxins