OBJECTIVE

To assess validity and reproducibility of Russian-language version of the Expanded Disability Status Scale (EDSS) compared to original paper English-language form of this scale.

MATERIAL AND METHODS

The study was conducted in 6 centers of the Russian Federation and approved by the ethical committee. There were 60 adults according to inclusion criteria. Two raters examined all patients at two visits. Neurological status was assessed using the EDSS scale in 30 patients and Russian-language version of the same scale in 30 patients. We assessed the time spent by raters to fill out paper forms of each scale. We used the version of scale translated into Russian by two translators independently of each other with subsequent reverse translation into English.

RESULTS

Both scales have comparable indicators of intra- and inter-expert reliability and internal consistency. Both scales showed high intra-expert reliability both for functional scales and final score (ICC=0.962 [95% CI: 0.937; 0.977] and 0.997 [95% CI: 0.994; 0.998], respectively). Inter-expert reliability within a single visit was higher for the Russian-language version of the scale (ICC >0.9) for final score and individual functional systems. Internal consistency of scales was sufficient (Cronbach’s alpha = 0.78 [95% CI: 0.72; 0.82] and 0.74 [95% CI: 0.68; 0.79], respectively). No significant difference was found in filling time (181 (159.5—204.5) and 200 (167—289) s, respectively, p=0.6282).

CONCLUSION

The Russian-language version of the scale is a reliable and valid equivalent of the EDSS and can be used in routine clinical practice and clinical trials.