Validation of the Neuropathy Impairment Score (NIS) for use in Russian-speaking patients with chronic inflammatory demyelinating polyneuropathy

Background. A clinical application of scales and questionnaires is essential for the objective evaluation of treatment response, disease course, quality of life and the disability level in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Neuropathy Impairment Score (NIS) has become widespread in epidemiological and clinical studies of various polyneuropathies, including CIDP. However, its application in Russia is limited by the absence of its validated version for Russian-speaking patients. Aim. To develop the Russian validated version of the NIS for its application in patients with CIDP. Materials and methods. The study involved 50 patients with CIDP (25 with multifocal variant of CIDP (Lewis–Sumner syndrome) and 25 with typical CIDP). The validation process included two stages: translation and linguocultural ratification of the scale according to the standard protocol and an assessment of its psychometric properties, such as reliability, validity and sensitivity. Results. The developed Russian version of the NIS demonstrated the high level of reliability, sensitivity and validity. Conclusion. The validated Russian version of the NIS can be recommended for application in research and clinical practice.