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

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 x 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 PD-related drooling, ensuring a longlasting waning of this disabling symptom.