title: Reliability and validity study of a Thai version of the Neck Disability Index in patients with neck pain.
abstract: OBJECTIVE
  To evaluate the reliability and validity of the Thai version of the neck disability index (NDI) in neck pain patients.
  
  
  METHODS
  The NDI was translated into Thai. The translation strategy used international standards. Forty-six Thai patients with neck pain were included in the present study. Thai version NDI, short form-36 (SF-36) and visual analogue scale (VAS) were completed by all subjects, twice, one week apart. The reliability and validity were subsequently analyzed.
  
  
  RESULTS
  Intraclass correlation coefficient score for test retest reliability was 0.986. Cronbach's alpha for internal consistency was calculated as 0.925. For concurrent validity, the relation between NDI and VAS was investigated, the r value was 0.886 (p < 0.001). For construct validity, the relation between NDI and the Thai version of SF-36 was -0.427. The mental health component was highest correlated with NDI.
  
  
  CONCLUSIONS
  The Thai version of NDI is a valid and reliable measurement method for evaluating neck pain disability.
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Panya
authors.initials: P
authors.lastname: Luksanapruksa
authors.forename: Thanet
authors.initials: T
authors.lastname: Wathana-apisit
authors.forename: Somyot
authors.initials: S
authors.lastname: Wanasinthop
authors.forename: Sanyapong
authors.initials: S
authors.lastname: Sanpakit
authors.forename: Cholavech
authors.initials: C
authors.lastname: Chavasiri
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis*; D015203:Reproducibility of Results; D013785:Thailand