Quality of Life Assessment Following Botulinum Toxin Injection in Patients with Adductor Spasmodic Dysphonia Using the 5-Factor Glasgow Benefit Inventory

Abstract

Objectives/Hypothesis:

Botulinum neurotoxin type-A (BoNT-A) injection into the true vocal cords is an effective treatment for restoring vocal functionality in adductor spasmodic dysphonia (AdSD). The Glasgow Benefit Inventory was developed to measure quality of life change following any otolaryngologic intervention and was recently revised to a 5-factor subdomain (GBI-5F) questionnaire to improve clinical utility. The study aim was to utilize the GBI-5F to measure patient-reported quality of life change in AdSD patients following BoNT-A injection.

Methods:

The GBI-5F questionnaire was administered to patients diagnosed with AdSD who received a BoNT-A vocal cord injection between December 2022 and May 2023. All patients had received multiple prior injections. GBI-5F subdomains and demographics were analyzed to identify areas for patient-reported improvement.

Results:

Sixty-six patients completed the GBI-5F. There were 52 (78.7%) females and average age was 69.4 years. The median total benefit score was +40.0 (interquartile range [IQR], 20.0). Median subdomain scores were +83.3 (IQR, 50.0) for quality of life, +50.0 (IQR, 50.0) for self-confidence, +33.3 (IQR, 33.3) for social involvement, +16.7 (IQR, 50.0) for support, and 0.0 (IQR, 16.7) for general health. Differences in the individual subdomain scores were statistically significant (P < .0001). No significant differences were found in the total GBI-5F score or any subdomain according to sex or presence of vocal tremor (all P > .05). A moderately positive correlation was noted between median total score and percent functional improvement (r = 0.46, P < .001).

Conclusion:

Botulinum injection therapy for AdSD provides overall benefit to patients as measured by the GBI-5F, with particular improvement observed for perceived quality of life, self-confidence, and social involvement. Sex, presence/absence of vocal tremor, and age do not appear to modify benefit, though degree of functional improvement is positively correlated with total score.