Studies were required to include at least 16 participants. The included studies assessed BOTX-A (Allergan), BOTX-A (Dysport) or BOTX-B. Treatment doses varied and assessment ranged from 1 to 24 weeks. The majority of studies bilaterally injected BTX into the protid and/or submandibular glands. All studies involved participants with either cerebral palsy, Parkinson’s disease, multiple system atrophy, amyotrophic lateral sclerosis or corticobasal degeneration. The included studies were conducted in both children and adults.
The included studies used one or more of the following outcomes to assess sialorrhoea (drooling): visual analogue scale, drooling quotient, drooling rating scale, drooling severity and frequency scale, scintigraphy imaging, bibs used, saliva production, dental rolls, counter measurement and the global impression of change questionnaire. The instruments used to measure outcomes varied between the studies.
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.