[Treatment of movement disorders using botulinum toxin]

Intramuscular injections of botulinum toxin (Botox) are followed by a dose-dependent focal paresis which can be used to treat several focal movement disorders. Botox injections are recommended as effective for the treatment of blepharospasm, hemifacial spasm, and cervical dystonia (torticollis). Focal dystonias elsewhere (for example, writer's cramp) can often be treated with similar success. Others, such as oromandibular dystonia, are more difficult to treat. In the case of more generalized dystonias, some focal muscle spasms can be treated with success by local intramuscular injections. New indications are still being investigated, for example in focal tremors and spasticity. Side effects are in general slight and disappear at the end of toxin effect. In general, it is necessary to repeat the injections after a couple of months, due to a cessation of effect after regrowth of nerve terminals. New injections have similar effects even over years of treatment.