Evaluation of voice quality in adductor spasmodic dysphonia before and after botulinum toxin treatment

In this prospective study. the efficacy of botulinum toxin (Botox) injectio ns in patients with adductor spasmodic dysphonia (AdSD) was assessed by 3 d ifferent modalities: perceptual and acoustic analyses and subjective self-a ssessment. This was done by comparing AdSD patients' pretreatment and postt reatment values and comparing these values with those of normal control spe akers. In contrast to most other studies, the posttreatment status was defi ned as the optimal voice quality as judged by the: patient. The aim of the study was to assess to what extent Botox injections actually improve voice quality and Function. The AdSD subjects rated a significantly improved voic e quality and function after Botox treatment. However. the results were nev er within normal limits. Perceptually, the characteristic and severely impa ired AdSD voice improved, but another "type" of pathological voice was dete cted after Botox treatment. Acoustic analyses demonstrated a significant im provement, as well. Nevertheless, the "optimally" treated AdSD voice still remained significantly deviant as compared to normal voice production. Curr ently, Botox injection is the therapy of first choice for AdSD. Although si gnificant improvement could be measured in our study perceptually, acoustic ally. and subjectively, the optimal voice that was achieved never fully mat ched normal voice quality or function.