Does the functional assessment measure (FAM) extend the functional independence measure (FIM) instrument? A rasch analysis of stroke inpatients.

Adding the items of the Functional Assessment Measure (FAM) to the Functional Independence Measure (FIM instrument) has been proposed as a method to extend the range of the FIM, particularly when assessing functional status in rehabilitation patients with brain injury, including stroke. It has been proposed that this approach is especially helpful in ameliorating ceiling effects when brain-injured patients have reached the end of their inpatient rehabilitation stay or are being seen in outpatient settings. In the present study, 376 consecutive stroke patients on a Canadian inpatient rehabilitation unit were concurrently administered the FIM and the FAM. Rasch analysis was used to evaluate how well the FAM items extended the difficulty range of the FIM for both the Motor and Cognitive domains. Within the Motor domain, only the FAM item assessing Community Access was found to be more difficult than extant FIM items, and this item showed some tendency to misfit with the other motor items. In the Cognitive domain, the only FAM item with a higher difficulty level than the FIM items was that assessing Employability. Notably, strict adherence to scoring guidelines for these two FAM items requires taking patients out into the community to evaluate their actual performances, a practice unlikely in the typical inpatient stroke rehabilitation unit. Results indicate that use of the entire FAM as an adjunct to the FIM reduces test efficiency while providing only minimal additional protection against ceiling effects.