Differences in botulinum toxin dosing between patients with adductor spasmodic dysphonia and essential voice tremor

J Voice. 2014 Jan;28(1):123-7. doi: 10.1016/j.jvoice.2013.05.008. Epub 2013 Sep 27.


Objectives: To explore possible dose differences in average botulinum toxin (BTX) given to patients with adductor spasmodic dysphonia (ADSD) compared with patients with essential voice tremor (EVT).

Methods: A retrospective study compared the average BTX dose injected in equal doses to the thyroarytenoid (TA) muscles of 51 patients with ADSD with 52 patients with EVT.

Results: Those with ADSD received significantly higher total doses (6.80 ± 2.79 units) compared with those with EVT (5.02 ± 1.65 units). Dose at time of first injection, age at time of first injection, gender, year of first injection, and average time between injections were included in multivariate analysis but did not interact with total average dose findings.

Conclusions: Patients with ADSD may need relatively higher doses of BTX injections to bilateral TA muscles compared with patients with EVT.

Keywords: Botulinum toxin; Dystonia; Dystonic tremor; Essential voice tremor; Spasmodic dysphonia; Tremor.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Botulinum Toxins / administration & dosage*
  • Chi-Square Distribution
  • Drug Dosage Calculations
  • Dysphonia / diagnosis
  • Dysphonia / drug therapy*
  • Dysphonia / physiopathology
  • Humans
  • Injections, Intramuscular
  • Laryngeal Muscles / drug effects*
  • Laryngeal Muscles / physiopathology
  • Multivariate Analysis
  • Neuromuscular Agents / administration & dosage*
  • Retrospective Studies
  • Time Factors
  • Treatment Outcome
  • Voice Quality / drug effects*


  • Neuromuscular Agents
  • Botulinum Toxins