TREATMENT OF CERVICAL DYSTONIA - A COMPARISON OF MEASURES FOR OUTCOMEASSESSMENT

There is little agreement on which outcome measures to use to express the efficacy of treatments for cervical dystonia. We analyzed change s cores on various scales of 64 new patients with cervical dystonia befo re and after repeated injections with botulinum toxin. Method: The ass ociation between change in impairment (Tsui), and change in pain (TWST RS-Pain) and functional health (TWSTRS-D, MOS-20) was expressed in per centages of variance explained. Effect sizes of the outcome measures f rom patients who continued botulinum treatment and dropouts were compa red. Performance of outcome measures to distinguish patients who conti nued treatment and dropouts was analyzed with ROC curves and areas und er the curve (AUC). Results: impairments explained less than or equal to 7% of the score variance in functional health. There were no differ ences between the effect sizes of impairment and pain of patients who continued treatment and dropouts (p > 0.60). This suggests a poor refl ection of the treatment efficacy by these outcome measures. Conversely , there were significant differences between the effect sizes of the f unctional status scales of the patients who continued treatment and th e dropouts (p less than or equal to 0.01). ROC curve analysis showed t hat the disability, handicap, and global disease burden scale accurate ly distinguished between the two groups (AUCs > 0.80). Impairments sho wed no discriminative accuracy (AUC = 0.46). Conclusion: Neurologic im pairments have a small impact on the functional health of cervical dys tonia patients. Disability, handicap, and a global measure of disease burden were the most suitable outcome parameters to express the clinic al efficacy of botulinum therapy.