Objective To investigate the longitudinal effects of botulinum toxin type A (Botox) injections on voice-related quality of life (V-RQOL) for patients with adductory spasmodic dysphonia.
Design Prospective study.
Setting Academic tertiary care referral center.
Participants Forty-two patients who presented to our institution with dysphonia and were diagnosed as having adductory spasmodic dysphonia during a 38-month period.
Intervention Patients received Botox injections into both thyroarytenoid muscles via the cricothyroid membrane. The typical starting dose was 1.0 U per vocal fold. If necessary, the dosage was adjusted in subsequent injections to reduce adverse effects or to enhance duration of benefit.
Main Outcome Measures Patients filled out questionnaires, including the V-RQOL Measure and a self-assessed overall voice rating, before each injection. Postinjection questionnaires were completed 6 to 8 weeks after each treatment. Mean pretreatment and posttreatment scores were calculated for each treatment.
Results The number of treatments per patient ranged from 1 to 7. Statistically significant improvements in mean total and domain V-RQOL scores were calculated for every injection (P<.01) (no postinjection questionnaires were available for the seventh injections). The magnitude of the effect remained constant for later injections. Eighty-two percent of the population recorded at least 1 category of improvement in overall self-assessed voice rating with each injection.
Conclusions Botox has a significant beneficial effect on V-RQOL for at least 6 injection cycles. This study demonstrates the efficacy of Botox for treating patients with adductory spasmodic dysphonia and further illustrates the usefulness and validity of the V-RQOL Measure in evaluating patients with dysphonia.
