Dosage of botulinum toxin in patients undergoing treatment for hemifacial spasm: is there modification during follow-up?

Background:  The movement disorder known as hemifacial spasm is characterized by involuntary contractions of the muscles that are innervated by the facial nerve. The treatment of choice for this condition is botulinum toxin injections.

Objective:  To analyze the botulinum toxin dosage in patients undergoing treatment for hemifacial spasm during a 14-year period.