Data from this study show that there is excellent inter- and intra-rater reliability and inter-rater agreement for curve type and each modifier. The high degree of reliability demonstrates that applying the classification system is easy and consistent.

The Persian versions of the ODI, RDQ, and QDS are reliable and valid instruments to measure functional status in Persian-speaking patients with LBP. They are simple and fast scales, and the use of them can be recommended in a clinical setting and future outcome studies in Iran.

The Iranian versions of the NDI and NPDS are reliable and valid instruments to measure functional status in Persian-speaking patients with neck pain in Iran. They are simple and easy to use and now can be applied in clinical settings and future outcome studies in Iran and other Persian speaking communities.

No abstract