Evidence-based medicine in botulinum toxin therapy for cervical dystonia

Early controlled studies of botulinum toxin (BTX) in cervical dystonia were unblinded and indicated that BTX injections are more successful than medic ation. In this article, the use of botulinum toxin (BTX) in cervical dyston ia is reviewed according to evidence-based medicine. To document the effica cy of BTX, there have been a number of prospective, placebo-controlled stud ies of the use of BTX in cervical dystonia. Most were double-blind, some in cluded videotapes to provide blinded objective assessments. The more recent studies of BTX in cervical dystonia focused on particular issues such as u tility of EMG guidance, comparison to anticholinergic treatment, BTX seroty pe B in BTX type A resistant and non-resistant patients and different dosag es. Despite the wealth of data generated with prospective placebo-controlle d studies on the effectiveness of BTX in cervical dystonia, there is uncert ainty on which outcome measures to use to express the efficacy of treatment s for cervical dystonia. Disease specific instruments to measure quality of life in cervical dystonia have not been used so far. Data on the use of BT X for cervical dystonia have long been restricted to small series of patien ts reflecting exclusively the experience of individual specialized centers.