Validity and Reliability of the Persian Version of “Identification of Functional Ankle Instability” Questionnaire in People With Lateral Ankle Sprain

Purpose: The Identification of Functional Ankle Instability (IdFAI) questionnaire is a valid and reliable tool to identify ankle instability, but this questionnaire is written in English and Persian speakers have difficulties in using it. Therefore, this study aimed to translate the IdFAI questionnaire in Persian and evaluate its validity and reliability. Methods: The present study is a non-experimental, analytical, and descriptive study. After translating the IdFAI questionnaire with a standard policy, it was given to 100 individuals with a history of at least 1 ankle sprain and 45 participants who had no history of an ankle sprain. The Cumberland Ankle Instability Tool (CAIT) was also distributed to the participants to examine the validity of IdFAI. After 1 week, a questionnaire was distributed among several participants to determine the repeatability of the test-retest of the Persian version of the questionnaire. After collecting the data, intraclass correlation, the Standard Error of Measurement (SEM), and the Cronbach alpha coefficient of the questionnaire were calculated in SPSS version 20. Results: The correlation of the IdFAI questionnaire with the CAIT was 0.71. The Cronbach alpha coefficient of 0.88 showed an acceptable level for the reliability of the questionnaire. Also, the correlation coefficient of the test-retest was 0.95, indicating a high degree of repeatability of the Persian version of the questionnaire. The SEM was 2.35, and the factor analysis showed that the questionnaire’s items could be classified into three categories, with a maximum of 72.5% variance coverage. Conclusion: The Persian version of the IdFAI questionnaire has excellent reliability and validity in identifying Persian-speaking participants with functional ankle instability. This questionnaire can be used for people with ankle sprain injuries in future studies, clinical examinations, and evaluations.