A Rasch analysis of the Frenchay Activities Index in patients with spinal cord injury.

Abstract

A prospective interview study. To determine whether items of the Frenchay Activities Index (FAI) measure Instrumental Activities of Daily Living (IADL), as a unidimensional construct, in patients with spinal cord injury (SCI). To examine whether the response categories of the FAI are useful in discerning the various ability levels of IADL. No known IADL scale has been designed for SCI patients. The FAI, to our knowledge, has never been validated in patients with SCI. A total of 233 persons with SCI participated in this study. The FAI was administered to the patients by interview at locations convenient for the participants. A Rasch analysis was used to examine the unidimensionality and appropriateness of the response categories of the FAI. All but 2 items ("going outside" and "reading books") of the FAI fitted the model's expectations. The results of Rasch analysis indicated that the response categories for the remaining 13 items of the FAI should be collapsed to create more suitable response categories (4 items, into dichotomies, and the remaining 9 items, into trichotomies). Thus, a revised 13-item FAI was formed by deleting the 2 misfitting items and collapsing the response categories of the items. This study demonstrated that the revised 13-item FAI assesses a single, unidimensional IADL for SCI patients living in the community. The revised FAI shows potential for assessment of IADL in SCI patients.