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Botulinum toxin injections for the treatment of spasmodic dysphoniaWatts C, Whurr R, Nye C
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SummaryBotulinum toxin has been shown to benefit some aspects of voice production in speakers with spasmodic dysphoniaBotulinum toxin is currently the gold standard of treatment for patients with spasmodic dysphonia. It has been used over the past two decades to treat both adductor and abductor forms of the disorder. The results of this review of randomised controlled trials indicate that botulinum toxin is effective for some aspects of voice production, including perceptual measures of improvement post-injection, variability of fundamental frequency, vocal intensity and subglottal air pressure. These benefits may be dependent on certain subject variables, such as the amount of voice use immediately post-injection and treatment variables such as dosage and location of injection. These results should currently be interpreted with caution, however, as studies have used small sample sizes and have methodological differences which prevent between-study comparisons.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2009 Issue 4, Copyright © 2009 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This version first published online:
July 19. 2004 AbstractBackgroundThe use of botulinum toxin for the treatment of spasmodic dysphonia is currently the treatment of choice for management of this neurological voice disorder. Over the past 20 years, botulinum toxin has been used to treat both adductor and abductor forms of the disorder, with vocal improvement noted after treatment for both. A large number of studies have attempted to document the efficacy of botulinum toxin for improvement of vocal symptoms in individuals with spasmodic dysphonia. ObjectivesTo determine the effectiveness of botulinum toxin for treating spasmodic dysphonia. Search strategyOur search included the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2 2007), MEDLINE (1950 to April 2007), EMBASE (1974 to April 2007 ) and CINAHL (to April 2007). Reference lists for all the obtained studies and other review articles were examined for additional studies. The date of the last search was April 2007. Selection criteriaAll studies in which the participants were randomly allocated prior to intervention and in which botulinum toxin was compared to either an alternative treatment, placebo or non-treated control group were included. Data collection and analysisTwo authors independently evaluated all potential studies meeting the selection criteria noted above for inclusion. One study met the inclusion criteria and was included in the final analysis. Main resultsOnly one study in the literature met the inclusion criteria. This was the only study identified which reported a treatment/no treatment comparison. It reported significant beneficial effects for fundamental frequency (Fo), Fo range, spectrographic analysis, independent ratings of voice severity and patient ratings of voice improvement. Authors' conclusionsThe evidence from randomized controlled trials does not allow firm conclusions to be drawn about the effectiveness of botulinum toxin for all types of spasmodic dysphonia, or for patients with different behavioral or clinical characteristics. |