Factors in the Efficacy, Safety, and Impact on Quality of Life for Treatment of Drooling with Botulinum Toxin Type A in Patients with Cerebral Palsy

Objective: To assess the efficacy and safety of botulinum toxin A (BoNT-A) injected in both submandibular and parotid versus only in parotid glands as a treatment for drooling in patients with spastic and dyskinetic cerebral palsy (CP), including an assessment of impact on quality of life (QoL) based on items from the International Classification of Functioning, Disability, and Health (ICF) core set. Design: Forty patients with CP 18 years or older (mean, 21.8 years) participated in a prospective, single-center, randomized controlled interventional study. All participants were classified as GrossMotor Function Classification System level III or higher and all had significant drooling as defined in prior studies. One group (group A) was treated with 100 U of BoNT-A, and another group (group B) served as control. In the treatment group, all patients first received combined parotid and submandibular injections, and then parotid injections only. The main outcome variables were a postinjection decrease in the drooling quotient (DQ) of 50% or more, total flow of 30% or more, and QoL as assessed by a set of 10 items related to drooling from the ICF. Results: The proportion of patients who achieved at least 50% reduction in DQ was 45% in group A versus 0.0% in group B; 0.0% (P = 0.0012); and of those who achieved at least 30% reduction in total flow was 90% in group A versus 10% in group B (P < 0.0001). Within group A, 42.1% of the dyskinetic patients versus 58.0% of the spastic ones showed 50% or better response in DQ, which is not a statistically significant difference (P = 0.8045). With regard to ICF questions, group A showed statistically significant improvements in several related items. There did not seem to be a significant difference in overall response for providing parotid-only injections. Additional correlations and uncommon adverse effect experiences are also reviewed. Conclusion: Botulinum toxin A injection of the salivary glands is frequently effective and generally safe for the treatment of drooling in patients with either spastic or dyskinetic CP, both in objective measurement of saliva production and subjective symptoms related to the condition. There does not seem to be a significant advantage of injecting both submandibular and parotid glands over injecting parotid glands alone.