Botulinum Toxin B for Laryngeal Dystonia: A Scoping Review

We aimed to comprehensively map the available literature on botulinum toxin B (BoNT-B) for the treatment of laryngeal dystonia.

A comprehensive librarian-designed strategy was used to search EMBASE, MEDLINE, and Web of Science for English-language studies from database inception to December 2025.

A PRISMA-ScR scoping review was registered on Open Science Framework (10.23041/OSF.IJ/R3BG4). Study selection was independently performed by two investigators for all English-language studies of adult patients investigating BoNT-B treatment for laryngeal dystonia. BoNT-B treatment dosing, treatment outcomes (ie, voice breaks/volume, spasms), patient-reported outcomes measures (PROMs), and adverse treatment events (ie, breathiness/dyspnea, dysphagia) were analyzed. Risk of bias was assessed with the ROBINS-I V2 tool.

In total, 188 studies were identified through the database searches, of which four studies met the inclusion criteria following full manuscript review. Two studies were clinical cohort studies in nature, and two were case reports. The total number of participants included in all studies was 47, of which 46 were diagnosed with adductor laryngeal dystonia. Injection dosing regimen ranged from 50-750 units among the included studies. Botulinum toxin treatment outcome reporting was largely subjective but demonstrated efficacy of BoNT-B injection. No study evaluated standardized PROMs in BoNT-B treatment of laryngeal dystonia. No serious adverse events were described among all included studies. Risk of bias was scored as "Serious" for all included studies.

The current study identified a gap within the literature recommending objective clinical evaluation of BoNT-B for the treatment of laryngeal dystonia.