TREATMENT OUTCOMES IN CERVICAL DYSTONIA - A CLINIMETRIC STUDY

We reviewed 21 studies (8 blinded and 13 open) on the treatment of bot ulinum toxin type A for cervical dystonia, directed to the health aspe cts used to evaluate the patients' response to treatment (Medline sear ch 1985-1993, English language literature). The prerequisite for compa ring the treatment results was that studies had to evaluate similar as pects of disease. The ICIDH model, outlined by the World Health Organi zation in 1980, orders the different health outcomes into distinct cla sses of disease consequences. Our aim was to order the health outcomes according to the model and, thus, to study the comparability of treat ment outcomes. Three differences could be identified between the objec tive and the subjective instruments. (a) The aspects measured by the s ubjective instruments varied substantially; of the 22 different subjec tive instruments identified in 18 studies, 8 measured impairments, 5 d isability, and 9 could not be classified according to the ICIDH model. The objective instruments measured impairments. (b) All objective ins truments were multiitem, whereas only 2 of 22 subjective instruments c ould be identified as multiitem. (c) The subjective instruments were g enerally poorly documented with regard to the number of items, score r ange, or grading. We conclude that the treatment outcomes can only be compared on the objective level of assessment and with regard to the p atients with painful dystonia. The subjective instruments, particularl y those focusing on disease-specific disability, deserve further resea rch. The ICIDH model offers a useful framework for selection, improvem ent, and development of outcome instruments. Because the model clearly demarcates the different consequences of disease, adoption will enhan ce the comparability of outcomes in cervical dystonia intervention tri als.