Inter and intra-observer reliability in Kurtzke scoring systems in multiple sclerosis

Of the various scoring systems employed to assess the neurological status in Multiple Sclerosis (MS), the Kurtzke functional system and disability status scale are the most used even for international comparisons. In order to assess inter- and intra-observer variability in the employment of Kurtzke's scale, 70 patients with definite MS were scored by 4 neurologists independently: 40 subjects were assessed using the Kurtzke scoring system and 30 patients using the Kurtzke system as modified by the Italian Multicenter MS Case-Control Study Group. Each of the patients was examined by one of the 4 neurologists in turn and in the presence of the other three. The same neurological examination was scored again after 1 month by the same neurologists. Agreement was estimated using the weighted Kappa index. The results indicated a high level of concordance both for intra- and inter-observer comparisons on all the items. No significant difference in reliability was found using the two scales examined.