The Neck Disability Index: modification of the “Driving” item of the Russian language version

Objective. 1. To supplement the “Driving” item of the Neck Disability Index (NDI) with information assessing the impact of neck pain on the ability to move around by public and private transport. 2. To evaluate the psychometric properties of the modified version of this questionnaire. Material and methods. The object of the study is a modified (2020) Russian-language version of the NDI. At the first stage, we performed retrospective analysis of filled questionnaires and calculated percentage of omissions for the “Driving” item. At the second stage, the “Driving” item was modified, and psychometric properties of new version were assessed. Study participants were 337 patients (221 women and 116 men) aged 18-65 years with non-specific neck pain, tension type headache, migraine and cervicogenic headache (CeH). Results. A retrospective analysis revealed that the “Driving” item was omitted in 83 (43%) out of 194 questionnaires completed by patients with neck pain. To eliminate omissions, the name of this item was changed to “Using transportation / driving”, and each statement was supplemented with phrase “I use transportation...”, for example: “I use transportation / drive a car without any neck pain at all”. This modification eliminated omissions when filling out the questionnaires. The questionnaire demonstrated good internal consistency: Cronbach’s α=0.89; inter-item correlation coefficient=0.47. Factor analysis revealed a 2-factor structure of the Index. In the 2nd factor, “Headache” (0.878) and “Concentration of attention” (0.876) items had the highest factor loading. Cluster analysis revealed three separate non-overlapping clusters of patients with no, mild, and moderate disability. The group with no disability consisted mainly of patients with non-specific neck pain. The group with moderate disability consisted mainly of patients with chronic migraines, including that combined with chronic CeH. Conclusion. The Russian language version of the Neck Disability Index, modified to assess patients’ ability to use transportation, is a reliable instrument with good psychometric properties, ready for use in everyday practice and clinical trials.