Cross-cultural adaptation, reliability and validity of the Turkish version of Patient-Specific Functional Scale in patients with chronic neck pain

Background/aim: Current clinical guidelines recommend to use both clinical and self-reported measurements for evaluation of chronic neck pain. Among the self-reported outcomes, Neck disability index and patient-specific functional scale are the most widely used and recommended instruments. The purpose of our study was to determine the test-retest reliability and validity of patient-specific functional scale which was not validated in Turkish language previously. Materials and methods: Translation and adaptation process had conducted according to the Beaton et al. Sociodemographic data, Turkish version of patient-specific functional scale and neck disability index were recorded at the initial assessment. Retest assessment was produced for reliability analyses and intraclass correlation coefficient (ICC3,2) was determined. The correlations between patient- specific functional scale and neck disability index and hypothesis testing were examined for the convergent and construct validity analysis. Results: The final form was completed by 110 chronic neck pain patients (Male: 33; mean ages: 43.13 ± 13.75 years, Female: 77; mean ages: 44.45 ± 14.38). Test-retest reliability of patient-specific functional scale was found good level (ICC: 0.85). The relationship between patient-specific functional scale and neck disability index was found moderate level (P < 0.05, rho: –0.578). The median score of PSFS-T in the low disability group was significantly higher than the high disability group in the hypothesis testing of construct validity (P < 0.001). Conclusion: The Turkish version of the patient-specific functional scale is a valid and reliable scale for evaluating functional status in patients with chronic neck pain.