Cervical dystonia severity scale reliability study

Cervical dystonia (CD) is characterized by sustained contractions of the ne ck musculature, resulting in abnormal head postures. The Cervical Dystonia Severity Scale (CDSS) was developed to provide a reliable measure of treatm ent response in patients with CD. The CDSS uses a protractor and wall chart to rate the severity of the head's deviation from neutral in each of three planes of motion (rotation, laterocollis, anterocollis/retrocollis), which is then scored in 5 degree intervals (1 degree to 5 degrees deviation = 1; 86 degree to 90 degrees deviation = 18). To test the reliability of the CDSS, four centers, each with two independen t examiners, evaluated 42 patients with CD. At each site, each of the two e xaminers used the CDSS to evaluate the head position of each patient twice, on the same day, for a total of four evaluations. The kappa value for intr o-examiner agreement was 0.94 (95% confidence limit of 0.900-0.972), indica ting excellent infra-examiner reliability. The kappa value for interexamine r reliability was 0.79 for the first evaluation and 0.86 for the second eva luation (95% confidence limits of 0.668-0.920 and 0.790-0.920) indicating e xcellent interexaminer reliability. Thus, the CDSS was highly reliable in b oth infra-examiner and interexaminer scoring comparisons. (C) 2001 Movement Disorder Society.