title: The Neck Disability Index-Russian Language Version (NDI-RU): A Study of Validity and Reliability.
abstract: METHODS
  Cross-cultural adaptation and psychometric testing.
  
  
  OBJECTIVE
  To perform a validated Russian translation and then to evaluate the validity and reliability of the Russian language version of the Neck Disability Index (NDI-RU).
  
  
  BACKGROUND
  Neck pain is highly prevalent and can greatly affect daily activity. The Neck Disability Index (NDI) is the most frequently used scale for self-rating of disability due to neck pain. Its translated versions are applied in many countries. However, the Russian language version of the NDI has not been developed yet.
  
  
  METHODS
  Cross-cultural adaptation of the NDI-RU was performed according to established guidelines. Then, the NDI-RU was evaluated for content validity, concurrent criterion validity, internal consistency, test-retest reliability, factor structure, and minimum detectable change.
  
  
  RESULTS
  Two hundred thirty-two patients took part in the study in total: 109 in validity (39.5 ± 10 yr), 123 in reliability (38.4 ± 11 yr; 80 in the test-retest phase). A culturally valid translation was achieved. NDI-RU total scores were distributed normally. Floor/ceiling effects were absent. Good values of Cronbach α were obtained for each item (from 0.80 to 0.84) and for the total NDI-RU (0.83). A 2-factor solution was found for the NDI-RU. The average interitem correlation coefficient was 0.53. Intraclass correlation coefficients for test-retest reliability coefficients ranged from 0.65 to 0.92 for different items and 0.91 for the total NDI-RU. Moderate correlation (Spearman rs = 0.62; P < 0.05) was found between the NDI-RU total score and graphic rating scalepain score. Completion of the NDI-RU takes 3.6 ± 1 minutes.
  
  
  CONCLUSIONS
  The development of a Russian language version of the Neck Disability Index resulted in a valid, reliable instrument that can be used both in clinical practice and scientific investigations.
  
  
  METHODS
  1.
authors.affiliation: *Department of Neurology, Neurosurgery and Medical Genetics, Russian National Research Medical University (named after N. I. Pirogov), and Department of Manual Therapy, Center for Manual Therapy, Moscow, Russia †Canadian Memorial Chiropractic College, Toronto, Ontario, Canada; and ‡Department of Physiotherapy, Moscow City Hospital, Moscow, Russia.
authors.forename: Maxim A
authors.initials: MA
authors.lastname: Bakhtadze
authors.forename: Howard
authors.initials: H
authors.lastname: Vernon
authors.forename: Olga B
authors.initials: OB
authors.lastname: Zakharova
authors.forename: Kirill O
authors.initials: KO
authors.lastname: Kuzminov
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Bolotov
mesh_terms: D000328:Adult; D003431:Cross-Cultural Comparison; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000145:classification / Q000503:physiopathology / Q000523:psychology; D015203:Reproducibility of Results; D012426:Russia; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires / Q000592:standards*; D014177:Translations