[Hemifacial spasms. Causes, clinical findings and treatment].

Hemifacial spasm is a condition characterized by involuntary, episodic, synchronous contractions of muscles innervated by the facial nerve in one half of the face. The treatment can be medical or neurosurgical, but the most effective is injections of botulinum toxin. 13 patients who received this treatment for hemifacial spasm are described. The treatment of different forms of focal dystonias has been described before in this journal. The aetiology of hemifacial spasm is different from that of focal dystonia. It is probably due to compression of the facial nerve, causing ectopic generation of impulses. Treatment with botulinum toxin is shown to be effective also for this condition, but the dosage and the duration of effect differ from those reported for focal dystonias. This may be due to differences in the pathophysiological mechanisms of the two conditions.