Long-Term Follow-Up of Patients with Spasmodic Dysphonia and Improved Voice despite Discontinuation of Treatment.

OBJECTIVE

To evaluate voice function in patients with adductor spasmodic dysphonia (AdSD) who discontinued botulinum toxin (BTX) treatment because they felt that their voice had improved sufficiently.

PATIENTS AND

METHODS

Twenty-eight patients quit treatment in 2004, of whom 20 fulfilled the inclusion criteria for the study, with 3 subsequently excluded because of return of symptoms, leaving 17 patients (11 males, 6 females) included in this follow-up study. A questionnaire concerning current voice function and the Voice Handicap Index were completed. Audio-perceptual voice assessments were done by 3 listeners. The inter- and intrarater reliabilities were r > 0.80.

RESULTS

All patients had a subjectively good stable voice, but with differences in their audio-perceptual voice assessment scores. Based on the pre-/posttreatment auditory scores on the overall degree of AdSD, patients were divided into 2 subgroups showing more and less improvement, with 10 and 7 patients, respectively. The subgroup with more improvement had shorter duration from the onset of symptoms until the start of BTX treatment, and included 7 males compared to only 4 males in the subgroup with less improvement.

CONCLUSION

It seems plausible that the symptoms of spasmodic dysphonia may decrease over time. Early intervention and male gender seem to be important factors for long-term reduction of the voice symptoms of AdSD.