Treatment of upper limb dystonia with botulinum toxin

The use of botulinum toxin A (BTX A) in upper limb dystonia is gaining increasing acceptance and it has recently been suggested that it be considered as first line treatment.(1) We have reviewed our experience since 1991 of treating 20 cases of upper limb dystonia. 14 patients had task-specific dystonias (6 simple writer's cramp, 5 dystonic writer's cramp, 3 musician's cramp) and 6 had secondary focal or segmental dystonias (4 with early cortico-basal degeneration). All patients had electromyography to both determine and guide muscle selection. Pre- and post-treatment video as well as questionnaires formed the basis for outcome assessment. Botulinum toxin therapy was clearly beneficial in about two-thirds of those with primary upper limb dystonia, a condition affecting young adults (mean onset 32.9 years). In contrast, BTX A was far less effective in secondary upper limb dystonias which occurred in the elderly (mean onset 71.7 years). Optimal treatment strategies are discussed. In conclusion, botulinum toxin is an effective form of treatment for primary upper limb dystonia; its role in late onset secondary dystonia is mainly palliative.