Botulinum Toxin A in the Treatment of Hemifacial Spasm

Inclusion Criteria: * clinical diagnosis of hemifacial spasm * Scott grading III to IV * hemifacial spasm duration of half or more years * last botulinum toxin A application at least 3 months before the start of the study Exclusion Criteria: * history of facial trauma, congenital facial asymmetry, facial nerve microsurgical decompression * bilateral hemifacial spasm * allergies to botulinum toxin A or to any component of the drug * previous treatment with botulinum toxin A fewer than 3 months * the use of drugs that could interfere with neuromuscular transmission or spasm