Spasmodic dysphonia: onset, course, socioemotional effects, and treatment response.

OBJECTIVES: This investigation explored the onset, progression, socioemotional effects, and treatment outcomes of spasmodic dysphonia (SD).

METHODS: A cross-sectional epidemiological approach was used to examine questionnaire responses from 150 individuals with SD.

RESULTS: Symptoms of SD (mean age at onset, 46 years) began gradually in 76% of cases and were progressive (ie, failed to plateau) in 34% of cases. Botulinum toxin A (Botox) helped to attenuate voice symptoms in 91% of cases; however, the scores on the Voice-Related Quality of Life questionnaire (V-RQOL) were not associated with this effect. The V-RQOL scores improved with time since symptom onset, independent of age and treatment. The patients with only SD experienced onset, course, and progression of symptoms similar to those of the patients with SD and coexisting vocal tremor.

CONCLUSIONS: The symptoms of SD begin gradually and worsen over time. New evidence indicates that SD symptoms may continue to progress without plateau in at least a subset of patients. Individuals with SD and coexisting vocal tremor experience symptom trajectories similar to those of patients with SD only. Although Botox may attenuate voice symptoms, these effects do not appear to be strongly related to the V-RQOL scores. These results provide new and valuable insights regarding the onset, course, progression, and treatment of SD.