Does botulinum toxin decrease frequency and severity of sialorrhea in Parkinson's disease?

This study analysed if botulinum toxin type A (BTX-A) decreases drooling in 21 Parkinson's disease patients. BTX-A injections were given in the parotid glands. The severity of drooling decreased in 18 (86%) patients, while frequency was reduced in 8 (38%).