Changes in severity and impact of drooling after submandibular gland botulinum neurotoxin A injections in children with neurodevelopmental disabilities

Abstract

Aims: To examine changes in objective and subjective drooling severity measures after submandibular botulinum neurotoxin A injection in children with neurodevelopmental disabilities, explore their relationship, and evaluate if clinically relevant responses relate to changes in the impact of drooling. Method: This longitudinal, observational cohort study involved 160 children (92 males, 68 females; 3-17y, mean 9y 1mo, SD 3y 6mo) treated between 2000 and 2012 at the Radboud University Medical Center, Nijmegen, the Netherlands. Repeated measures analysis of variance was used to compare the 5‐minute Drooling Quotient (DQ5) and Visual Analogue Scale (VAS) for drooling severity pretreatment and posttreatment, and Pearson’s rho to assess their association. A parent questionnaire was used to assess drooling impact in responders (defined as ≥50% reduction in DQ5 and/or ≥2 SD reduction in VAS for drooling severity 8wks postintervention) and non‐responders. Results: One hundred and twelve children (70%) were responders. Their mean VAS for drooling severity and DQ5 scores were significantly lower 32 weeks postintervention compared to baseline. At baseline, the VAS for drooling severity‐DQ5 relationship was 'weak' (rs=0.15, p=0.060), whereas it was 'fair' at 8 weeks (rs=0.43, p=0.000) and 32 weeks (rs=0.30, p=0.000). For responders, a significant change was found regarding the impact of drooling on daily care and social interactions at 8 weeks after intervention; most of these effects were maintained at 32 weeks. Interpretation: A clinically relevant response based on a combination of objective and subjective measures of drooling severity was accompanied by positive changes regarding the impact of drooling on daily care and social interactions.