Translation and validation of the Arab version of the Late-Life Function and Disability Instrument: a cross sectional study.

Background: The Late-Life Function and Disability Instrument (LLFDI) provides a comprehensive, reliable, and valid assessment of physical function and disability in community-dwelling adults. There does not appear to be a validated, comprehensive instrument for assessing function and disability in Arabic. The objective of the present study was to translate and culturally adapt the LLFDI to Arabic, and to determine its test-retest reliability and validity.

Methods: The LLFDI was translated to Arabic through a forward and backward translation process, and approved by a bilingual committee of experts. Sixty-one (26 male and 35 female) Arabic speaking, healthy, older adults, ages 65-88, living in northern Israel participated in the study. To determine test-retest reliability, the questionnaire was administered twice to 41 subjects with a 6 to 8day interval. Construct validity was examined by correlating the LLFDI responses with the 10-item physical function (PF-10) subscales of the General Health Survey (SF-36), with the physical component of SF-36 (SF-36 PCS), and with two performance measures, the Berg Balance Scale (BBS) and Time Up and Go (TUG) test. Additionally, gender and fall related differences in the LLFDI were also examined.

Results: Internal consistency (Cronbach's alpha) was good to excellent (0.77 to 0.97). Test-retest agreement was good to very good (function component: 0.86-0.93, disability component: 0.77-0.93). Correlation with the SF-36 PCS and PF-10 was moderate to strong for both LLFDI components (function, r = 0.53-0.65 and r = 0.57-0.63, and LLFDI disability, r = 0.57-0.76 and 0.53-0.73, respectively). Significant, moderate-to-strong correlations between the LLFDI and BBS (r = 0.73-0.87) and a significant, moderate, negative correlation between LLFDI and TUG test (r = -0.59- -0.68) were noted. The standard error of measure was 6-12%, and the smallest real difference was 18-33%. Discriminative validity for both gender and fall status were also demonstrated.

Conclusions: The Arabic version of the LLFDI is a highly reliable and valid instrument for assessing function and disability in community dwelling, Arab older adults. The translated instrument has a discriminative ability between genders and between fallers and non-fallers. The translated instrument may be used in clinical settings and for research purposes.