Validation study of the Overall Neuropathy Limitations Scale (ONLS) in Russia

Background. Polyneuropathies are a heterogeneous group of peripheral nervous system disorders associated with sensory and motor impairment and often leading to disability. Validated assessment tools adapted to specific populations are required to evaluate functional limitations. Although the Overall Neuropathy Limitations Scale (ONLS) is widely used internationally, it has not been validated in a Russian-speaking population. Aim. To perform cross-cultural adaptation of the original ONLS and to evaluate the psychometric properties of the developed Russian-language version. Materials and methods. The study enrolled 60 patients with polyneuropathies: hereditary motor and sensory neuropathy (30 patients), chronic inflammatory demyelinating polyneuropathy (15 patients), and diabetic polyneuropathy (15 patients). The methodology included cross-cultural adaptation of the scale (involving 15 patients in the pilot phase), as well as analysis of its reliability, validity, and sensitivity. Results. A Russian-language version of the ONLS was developed. The tool demonstrated high content validity and criterion validity against the INCAT (Inflammatory Neuropathy Cause and Treatment) scale (r = 0.99), excellent inter-rater reliability and test-retest reliability (intraclass correlation coefficient is 0.97 and 0.99, respectively), as well as high sensitivity in patients with chronic inflammatory demyelinating polyneuropathies (standardized response mean –0.72; Cohen’s d = 0.83). Conclusion. The Russian-language version of the ONLS possesses strong psychometric properties and can be recommended for evaluating functional limitations in patients with polyneuropathies of various etiologies in both clinical and research settings.