[Treatment of focal dystonia with botulinum toxin]

We have studied the effect of botulinum toxin in patients with focal dystonia, not responding sufficiently to medical therapy. Injection of 5-100 units to the muscles, selected by EMG and clinical examination, invariably resulted in reduction of muscle tonus, although to a different degree depending on the dosage. The outcome after the first trial was best when dealing with small muscles in patients with blephalospasm or Meige's syndrome. In contrast, several attempts were required for the treatment of a large muscle as in torticollis, or multiple muscles as in writers' cramps. The effect lasted 1-3 months. With precise selection of the affected muscles and careful regulation of necessary dosages, this type of therapy may contribute to the treatment of focal dystonia.