Journal of Manipulative and Physiological Therapeutics
Original ResearchValidation of the Neck Disability Index in Serbian Patients With Cervical Radiculopathy
Introduction
Cervical radiculopathy (CR) typically presents as neck pain radiating to the upper extremity and is most commonly due to the compression of a cervical nerve root that causes pain and disability.1 Cervical radiculopathy affects approximately 1 person per 1000 of a population per year and is most often caused by degenerative spondylosis or a disk herniation.1 One study reports that patients with upper arm pain are more disabled and have less improved quality of life compared with patients who have neck pain only.2 Quantification of neck and upper extremity pain-related disability is crucial for the evaluation of the treatment and also for assessing clinical outcomes of disability.3
The Neck Disability Index (NDI) is a questionnaire developed by Vernon and Mior4 that measures problems with neck movements, neck pain intensity, effect of neck pain on concentration, and the level of interference in daily life activities. It has been translated and validated in many study populations and has shown stable psychometric properties.4, 5, 6 To our knowledge, no specific disease questionnaire that assesses disability in patients with neck pain and CR has ever been validated in Serbia. Therefore, the purpose of this study was to translate and validate the NDI in Serbian patients with CR.
Section snippets
Translation and Adaptation
The translation process was in accordance with standard methods that have been adopted internationally.7 The NDI was first translated into Serbian by 2 research study doctors who were fluent in English and blinded to each other. The translation was examined by the study team that included research study doctors and 1 doctor from an English-speaking area (a Serbian doctor living and working in London). The Serbian version of the NDI (NDI-S) was then translated into English again by a
Descriptive Data
Fifty patients with CR who fulfilled inclusion criteria were included in the study: 35 females and 15 males; mean age was 44.5 ± 10 (Table 1). Basic demographic data and lifestyle habits are outlined in the Table 1.
The mean value of NDI-S was 18.9 ± 7.42, denoting moderate disability. Of the 50 participants involved in the study, 17 participants (34%) had 1, the same missing item (“driving”). No missing data occurred across all other items of the NDI-S. No floor or ceiling effects were
Discussion
This study was conducted with the purpose of validating the NDI in Serbian patients with CR. The NDI-S showed acceptable psychometric properties that corresponded to those of translations in other languages. To our knowledge, this study is the first validity study of NDI in Serbian patients. No specific-disease questionnaire that assesses disability in patients with neck pain and CR has ever been validated in Serbia. The sample size in this study was adequate,8, 17 with clear inclusion criteria
Conclusions
The results of this study suggest that NDI-S is a valid questionnaire to measure neck and arm pain-related disability in Serbian patients with CR.
Funding Sources and Conflicts of Interest
No funding sources or conflicts of interest were reported for this study.
Contributorship Information
Concept development (provided idea for the research): M.D.J., L.M.K.
Design (planned the methods to generate the results): M.D.J., L.M.K., A.D.G.
Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): L.M.K., A.D.G., N.D.M., S.M.D.
Data collection/processing (responsible for experiments, patient management, organization, or reporting data): M.D.J., N.D.M., V.Z.J., S.I.K.D., M.K.H., S.M.D.
Analysis/interpretation (responsible for statistical
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