Background and ObjectivesZZBotulinum toxin type A (BTX-A) injection is well known
for its effectiveness in the treatment of “Spasmodic dysphonia”. However, studies on the efficacy
of BTX-A injection have not been attempted in Korea. Therefore, this study was carried
out to investigate the effects of BTX-A.
Subjects and MethodZZThe study examined 12 female patients with ‘adductor spasmodic
dysphonia’. Objective assesments included aerodynamic analysis and electoroglottography
(EGG) of each patient before and after BTX-A. Subjective assessments included using the
Korean-version of Voice Handicap Index-30 (KVHI-30) and a patient self-rating scale.
ResultsZZAerodynamic analysis revealed that only maximum phonation time (MPT) was
significantly shortened after the injection of BTX-A (p<0.05). In the EGG, the mean frequency
distribution was significantly increased, while the mean amplitude and the mean closed
quotient distribution were significantly decreased (p<0.05). The KVHI-30 and patient selfrating
scale scores were significantly decreased (p<0.01) as well, demonstrating the effects
of BTX-A on the quality of life.
ConclusionZZOur results show the effects of BTX-A objectively by comparing voice characteristics,
which were measured through EGG before and after BTX-A injection, as well as
by determining aerodynamic characteristics. The subjective self-assessment on the quality of
life is significant as it may serve as a clinically relevant measure. This study may be helpful in
elucidating treatment efficacy of BTX-A in many ways.