Assessing the effects of botulinum toxin therapy for spasmodic dysphonia: An Austria-Germany registry

The results of this registry showed that BoNT injection, the current off-label treatment of SD symptoms, failed to restore normal voice quality. This registry's outcomes also indicate that the choice of the applied BoNT brand is site-specific and does not appear to be associated with differences in efficacy. We also showed that the effects of the BoNT on the SD symptoms are best described by semi-quantitative outcome measures such as spasm counts and voice strain, and by patients-reported outcome measures (PROMs), such as CPIB and VHI-9i than by more objective parameters such as frequency and dynamic range of the singing voice.