Botulinum toxin A for patients with orofacial dystonia: prospective, observational, single-centre study.

The objective of this study was to demonstrate the efficacy of intramuscular botulinum toxin type A (BTX-A) as a method of controlling the symptoms of focal facial dystonia. A prospective, longitudinal, observational, pre-post (case-series) single-centre study was conducted over a period of 3 months, involving 30 patients with focal dystonia. The patients were enrolled on a first-come, first-served basis. For all patients, the abnormal movements were evaluated using the Abnormal Involuntary Movement Scale (AIMS). The AIMS results were recorded immediately before BTX-A injection (primary predictor variable) and after 3 months (the toxin reaches its maximum effect 2 weeks after injection, and the effect is maintained for 3 months). An improvement in AIMS score was the primary outcome variable. Treatment efficacy was evaluated using the Pearson correlation index with a level of significance of P<0.05. The average age of the study subjects was 70.9±12.7years (20 female, 10 male). The mean dose of BTX-A used was 27.4±20.5U. The mean improvement in AIMS score after treatment was 5.2±4.2. A significant correlation was found between the dose applied and the reduction in AIMS score (P<0.05). BTX-A can be used in the treatment of focal dystonia and provides reproducible results.