Abductor laryngeal dystonia: a series treated with botulinum toxin.

Abductor laryngeal dystonia (LD) is characterized by a hoarse voice quality which is broken up by breathy or whispered portions. Botulinum toxin injection (Botox) has been a safe and effective treatment for adductor laryngeal dystonia and is currently accepted medical therapy. As an extension of the established treatment program, in 1989 treatment of abductor LD was initiated. Thirty-two patients have been treated by sequential percutaneous electromyogram-guided (EMG) injections of the posterior cricoarytenoid (PCA) muscles. Most patients required treatment of both PCA muscles and improved to an average of 70% of normal voice. Patients who had a preexisting tremor, evidence of dystonia in other muscle groups, vocal tremor, or respiratory dysrhythmia had less improvement. Ten patients also required injection of the cricothyroid muscles and/or type I laryngoplasty.