[Botulinum toxin efficacy in the treatment of patients with spasmodic dysphonia]

Spasmodic dysphonia (DS) is a disabling speech disturbance appearing as the consequence of dystonic vocal folds contraction. Its intermittent appearance in the laryngeal muscles causes vocal function discontinuation. The quality of life of these patients is significantly disturbed. Surgical and a medical therapy appear to be inadequate and unsuccessful ones of no steady improvement. It is the botulinum toxin therapy that proved to be highly efficacious one, with the established improvement in 80-100% of patients. The aim of our study was to evaluate the efficacy of botulinum toxin therapy in patients with SD and to show our preliminary results.

The study included 10 patients with adductor spasmodic dysphonia. After diagnostic procedures, botulinum toxin was applied either in one or both vocal folds, in doses of 12-16 units each. In our study we applied indirect technique originally developed by Hocevar and Pirtosek. Perceptive voice and speech analysis was performed prior to and after the instillation of botuline toxin as per structured Scale of pathological characteristics of voice and speech appearing in the spasmodic dysphonia.

The majority of our patients experienced both subjective improvement and the improvement in the terms of the quality of life, Voice Henolicap Index--(VHI) that was rated as rather significant one (t = 3.562; p = 0.006).

Regardless unquestionable improvement of definite phonation, further function restitution requires individual vocal therapy and psychotherapy. Vocal therapy includes structural vocal techniques which reduce degree of vocal tension and rapid changes in the power and the height of voice. Further investigations are necessary for the scope of the definition of a standardized therapeutically procedure for spasmodic dysphonia treatment which comprises multidisciplinary approach in diagnosis, therapy and treatment efficacy evaluation.