Measurement properties of the Frenchay Activities Index among individuals with a lower limb amputation.

OBJECTIVE: To assess the reliability and validity of the original and a modified version of the Frenchay Activities Index (FAI) among individuals with a lower limb amputation.
DESIGN: Two week test-retest design.
SETTING: South Western Ontario Amputee Program, London, Ontario, Canada.
SUBJECTS: Consecutive sample of 84 individuals, primarily men (78.6%), mean age 56.5 years with a unilateral transtibial (71.4%) or transfemoral amputation related to traumatic (59.5%) or vascular causes.
INTERVENTIONS: All subjects completed a questionnaire containing the FAI and other scales, the 2-minute walk and timed up and go tests during a regularly scheduled clinic visit. Fifty-five subjects completed a second FAI which was mailed to them two weeks later. Twenty-nine others completed the second FAI upon return for testing related to another project. MAIN MEASURES: FAI, Activity-specific Balance Confidence Scale, Prosthetic Evaluation Questionnaire-Mobility Scale, 2-minute walk, timed up and go and walking device aid use.
RESULTS: Relative reliability for the FAI (intraclass correlation coefficient (ICC) = 0.79) and FAI-18 (ICC = 0.78) was acceptable, however bias between measurements was detected. Hypothesized relationships (p < 0.001) between both FAI versions and the Activity-specific Balance Confidence Scale, Prosthetic Evaluation Questionnaire-Mobility Scale, 2-minute walk and timed up and go test were observed. Significant group differences were observed for amputation cause, mobility device use, age and years as an amputee. Neither version distinguished between amputee level or gender groups.
CONCLUSIONS: The original and modified FAI are valid and reliable tools for unilateral amputees. Reliability is adequate to detect group but not individual level differences. Additional FAI-18 items did not substantially improve the ability to detect between-amputation-group differences.