QUANTITATIVE ELECTROMYOGRAPHY-GUIDED BOTULINUM TOXIN TREATMENT OF CERVICAL DYSTONIA

The purpose of this study was to investigate the clinical and electrom yographic effect of turn/amplitude analysis (TAA)-guided botulinum tox in administration in patients with cervical dystonia. Involuntary elec tromyographic activity was recorded from both sternocleidomastoidei, b oth splenii capites, and both trapezii muscles of 13 torticollis patie nts, aged 34-73 years, before and after botulinum toxin A (Dysport) ap plication. Dystonic muscles were selected for the injection if mean tu rns/s exceeded a level of 200. Four weeks after treatment with a mean dose of 223 mu/subject, clinical improvement was observed in 12 patien ts (92%) and only one patient reported no effect. Electromyographic im provement could be observed in 10 patients (77%). Both turns/s and the amplitude/turn decreased by 27% on the average after treatment. The e lectromyographic toxin effect showed a good correlation with the clini cal toxin effect (r = 0.6). No dose dependency of the changes in turn/ amplitude parameters could be observed. We found TAA a valuable modali ty for targeting and selecting dystonic muscles and for assessing the therapeutic benefit of the toxin.