Back Pain and Body Posture Evaluation Instrument for Children and Adolescents (BackPEI-CA): Expansion, Content Validation, and Reliability.

The Back Pain and Body Posture Evaluation Instrument (BackPEI) was created in 2013 to assess back pain and its risk factors in school children. However, it does not assess neck pain or the habits of mobile device usage, which are aspects that are often part of school children's lives. Therefore, we aimed to update the BackPEI questionnaire to include new questions assessing aspects related to neck pain and the use of mobile devices and to test the content validity and reliability of the new questions. The updated questionnaire was named Back Pain and Body Posture Evaluation Instrument for Children and Adolescents (BackPEI-CA). The content was validated by eight experts using the content validity index (CVI). To assess reliability, the BackPEI-CA questionnaire was applied at two different times in 105 school children, and Cohen's kappa (k) and intraclass correlation coefficient (ICC) were calculated. All aspects assessed regarding content validity had a CVI higher than 0.8. The new questions presented moderate and good kappa values and excellent ICC values. The updated version of BackPEI-CA can be used as a clinic tool for assessing the presence, frequency, and intensity of back and neck pain and their risk factors.