Outcomes of Botulinum Toxin Treatment for Patients With Spasmodic Dysphonia

Abstract
SPASMODIC dysphonia (SD) is a focal dystonia of the larynx with characteristic interruptions in voice and visible true and false vocal fold spasms when the larynx is visualized during running speech. Spasmodic dysphonia spasms can result in forceful adduction of the vocal folds during phonation (adductor SD), abduction (abductor SD), or both adduction and abduction during phonation (mixed SD). Adductor SD is much more common than abductor SD, accounting for about 80% of cases. A familial association has been identified in some cases with the isolation of a specific gene in these clusterings.1