The purpose of this study is to evaluate the effectiveness of botulinum toxin injection to treat drooling in children with cerebral palsy, and to find the most appropriate dosage, duration of effect and side effects.

Sialorrhea, or drooling, has been reported to be a significant problem in 10%to 37% of patients with cerebral palsy. Excessive drooling may cause skin maceration, increased the burden of caregiver, affect articulation of the patients, and increase the risk of aspiration and dehydration. Many options, including various therapies, medications, surgeries and radiation, have been proposed to treat drooling. Yet none of these is universally successful and many have potential complications. Nerve endings of the parasympathetic post-ganglionic neurons secret aceylcholine. Botulinum toxin should be able to inhibit salivary gland secretion by blocking the release of acetylcholine. Very limited case series had proved fair result of botulinum toxin injection to treat drooling. However, most of the subjects were adult patients with neurological disorders. The purpose of this study is to evaluate the effectiveness of botulinum toxin injection to treat drooling in children with cerebral palsy, and to find the most appropriate dosage, duration of effect and side effects.

Inclusion Criteria:

• diagnosis of cerebral palsy
• severe drooling
• aged 6-21 yrs
• subjects (or their guardian) who are able to understand the requirements of the study and sign the informed consent form

Exclusion Criteria:

• age below 6 yrs or above 21 yrs
• known allergy or sensitivity to the study medication or its component
• diagnosis of myasthenia gravis, amyotrophic lateral sclerosis or any other disease that might interfere with neuromuscular function
• subjects who have prior surgery of the submandibular gland
• subjects who are receiving medication that affect drooling such as anticholinergic drug
• inability to give informed consent