[Treatment of focal dystonia with botulinum toxin].

Focal dystonia and hemifacial spasms are difficult to treat. Medication and surgery may suppress the dystonic movements but the improvement is not satisfactory. The present article reviews use of Botulinum toxin in cases of focal dystonia. Injections of very small doses of Botulinum A toxin into the affected muscles is a new and efficient therapy for patients with focal dystonia. The toxin acts by inhibiting the release of acetylcholine from the nerve terminal, leading to a localized paralysis of the treated muscle. The effect is temporary and gradually diminishes, but the treatment can be repeated. The use of Botulinum toxin must be applied on the basis of a thorough knowledge of its effect and possible side effects.