Effect of botulinum toxin in the treatment of drooling: a controlled clinical trial

Abstract

Objective: To investigate the clinical effectiveness of botulinum neurotoxin type A (BoNT) to reduce drooling in children with cerebral palsy (CP).

Methods: A controlled clinical trial was performed in which the results of single-dose BoNT injections in the submandibular glands were compared with treatment with scopolamine. Forty-five children who had CP and experienced severe drooling were enrolled. Drooling severity was measured at baseline, during application of scopolamine, and at different intervals after BoNT injections up to 24 weeks, using the Drooling Quotient (DQ), the Teacher Drooling Scale (TDS), and Visual Analog Scales (VAS).

Results: Drooling was reduced during scopolamine application as well as after BoNT injections. Compared with baseline, the mean DQ showed a significant decrease throughout the study. Greatest reductions were achieved 2 to 8 weeks after BoNT injection. No significant differences were found between scopolamine measurements and those up to 24 months after BoNT injection. Using VAS, parents recorded the effect on drooling in which significant differences were found between baseline VAS score and all follow-up assessments. According to our definition of "success to therapy," demanding a 2-point decrease on the TDS, 61.5% of patients responded to BoNT injections. Analysis of the DQ demonstrated a response rate of 53% of the patients to scopolamine and 48.7% to BoNT until 24 weeks after BoNT injections, the actual duration of this study. As a reaction to scopolamine, 71.1% of the patients had moderate to severe side effects. Only nonsevere, incidental side effects were reported after BoNT injections.

Conclusions: During scopolamine application as well as after intraglandular BoNT injections, a clinically relevant reduction in drooling was achieved in children with CP, demonstrating maximum effect 2 to 8 weeks after injections. This is the first controlled clinical trial that confirmed a significant effect of BoNT injections in the treatment of drooling. General anesthesia was needed for all children. BoNT injections show fewer and less serious side effects than transdermal scopolamine treatment.