Long-lasting benefits of botulinum toxin type B in Parkinson's disease-related drooling

Abstract Purpose To investigate the safety, efficacy and effectiveness of botulinum toxin type-B (BTX-B) injections into the parotid glands to reduce drooling in Parkinson’s disease (PD) subjects. Methods A double-blind, randomised, placebo-controlled study enrolled 36 advanced phase PD subjects who complained of disabling drooling. Patients received either 4000U BTX-B or placebo. Anatomically guided injections were performed. Outcome measures were chosen to assess both the subjective feeling of improvement (i. e. the Drooling Severity and Frequency Scale, DSFS, visuo analogic ratings of familial distress, VAS-FD, and social distress, VAS-SD) and objective saliva reduction (saliva production over five minutes was checked by weighing dental rolls). The Global Impression Score (GIS) was also applied, rating improvement from 0 to 3. Results One month after injections, BTX-B patients showed a meaningful improvement in almost all subjective outcomes. Two-way analysis of variance gave a significant time × treatment effect, F-value being 52.5 (p < 0.0001) for DS-FS, 23.2 (p < 0.0001) for VAS-FD, 29 (p < 0.0001) for VAS-SD, and 28.9 (p < 0.0001) for UPDRSADL drooling item score. All BTX-B subjects declared sialorrhea reduction of any kind (moderate for 44.4 % cases, and dramatic for 33.3 % subjects), at variance with 61.1 % controls who denied any benefit from treatment. (Chi-square = 22.9; p < 0.0001). When present, benefits lasted on average 19.2 ± 6.3 weeks in the BTX-B group compared to 6.7 ± 1.4 weeks in controls (T-value: 26.4; p < 0.0001). Conclusions BTXB represents a safe and efficacious tool for the management of PDrelated drooling, ensuring a longlasting waning of this disabling symptom