Botulinum toxin injection for adductor spastic dysphonia: Patient self-ratings of voice and phonatory effort after three successive injections

Ten patients (aged 35 to 70 years) with neurologic adductor spastic dysphonia rated themselves on a 7-point scale of severity for degree of voice improvement and physical effort after a series of three injections of botulinum toxin. Symptoms were noticeably reduced 24 and 48 hours after injection; this improvement was followed by considerable fluctuations in voice quality and phonatory effort. With successive injections, patients differed in their postinjection experiences, the time required to reach optimal voice, and the total duration of benefit. The study shows that the course of voice change after botulinum toxin injection is not predictable, uniform, or equal among patients with spastic dysphonia.