title: Cross-cultural adaptation, reliability and validity of the Turkish version of the spine functional index.
abstract: BACKGROUND
  The Spine Functional Index (SFI) is a patient reported outcome measure with sound clinimetric properties and clinical viability for the determination of whole-spine impairment. To date, no validated Turkish version is available. The purpose of this study is to cross-culturally adapted the SFI for Turkish-speaking patients (SFI-Tk) and determine the psychometric properties of reliability, validity and factor structure in a Turkish population with spine musculoskeletal disorders.
  
  
  METHODS
  The SFI English version was culturally adapted and translated into Turkish using a double forward and backward method according to established guidelines. Patients (n = 285, cervical = l29, lumbar = 151, cervical and lumbar region = 5, 73% female, age 45 ± 1) with spine musculoskeletal disorders completed the SFI-Tk at baseline and after a seven day period for test-retest reliability. For criterion validity the Turkish version of the Functional Rating Index (FRI) was used plus the Neck Disability Index (NDI) for cervical patients and the Oswestry Disability Index (ODI) for back patients. Additional psychometric properties were determined for internal consistency (Chronbach's α), criterion validity and factor structure.
  
  
  RESULTS
  There was a high degree of internal consistency (α = 0.85, item range 0.80-0.88) and test-retest reliability (r = 0.93, item range = 0.75-0.95). The factor analysis demonstrated a one-factor solution explaining 24.2% of total variance. Criterion validity with the ODI was high (r = 0.71, p < 0.001) while the FRI and NDI were fair (r = 0.52 and r = 0.58, respectively). The SFI-Tk showed no missing responses with the 'half-mark' option used in 11.75% of total responses by 77.9% of participants. Measurement error from SEM and MDC90 were respectively 2.96% and 7.12%.
  
  
  CONCLUSIONS
  The SFI-Tk demonstrated a one-factor solution and is a reliable and valid instrument. The SFI-Tk consists of simple and easily understood wording and may be used to assess spine region musculoskeletal disorders in Turkish speaking patients.
authors: Department of Physiotherapy and Rehabilitation, Baskent University, Faculty of Health Sciences, Ankara, Turkey. etonga@baskent.edu.tr.
authors: Eda
authors: E
authors: Tonga
authors: Faculty of Science, Centre for Healthy Activities, Sport and Exercise, University of the Sunshine Coast, Sunshine Coast, QLD, Australia. cp.gabel@bigpond.com.
authors: Charles Philip
authors: CP
authors: Gabel
authors: Department of Ergotherapy, Hacettepe University, Faculty of Health Sciences, Ankara, Turkey. sedefkarayazgan88@hotmail.com.
authors: Sedef
authors: S
authors: Karayazgan
authors: Department of Physiotherapy, Faculty of Health Science, University of Malaga, Malaga, Spain. acuesta.var@gmail.com.|School of Clinical Science, Faculty of Health, Queensland University of Technology, Kelvin Grove, Australia. acuesta.var@gmail.com.
authors: Antonio I
authors: AI
authors: Cuesta-Vargas
mesh_terms: D000328:Adult; D003431:Cross-Cultural Comparison; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000706:statistics & numerical data*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D013122:Spinal Diseases / Q000175:diagnosis* / Q000453:epidemiology; D011795:Surveys and Questionnaires / Q000592:standards*; D014421:Turkey