Monitoring recovery by physical therapists using the FIM scale during rehabilitation programs: An inter-rater and intra-rater reproducibility study

Our aim was to evaluate the reproducibility of the Functional Independence Measure (FIM) scale when assessed by physical therapists in the routine setting of a Rehabilitation Hospital. We included a consecutive series of patients with spinal cord or cerebral lesions. Each of the 50 selected patients was evaluated by two of the 5 experienced physical therapists participating in the study. The degree of inter-rater and intra- rater agreement was measured by a weighted k statistic, k for perfect agreement, and k for the agreement with tolerance. The weighted k index for inter-rater agreement on the FIM score was in the almost perfect range (k 0.87; 95% CI = 0.79 - 0.95), but a 20-point tolerance was necessary to reach a k value of 0.81 (95% CI = 0.66 - 0.95). Agreement was substantial or almost perfect for most subscales, but the k index with 1-point tolerance reached the almost perfect rating for comprehension only. For intra-rater agreement, weighted k index was in the almost perfect range for the FIM score and for all subscales; kappa index reached the almost perfect range with a 4-point tolerance for FIM score and with 1- point of tolerance for all subscales except in- terpersonal relations. FIM is useful to monitor patient improvement during rehabilitation treat- ment, mostly when assessed by the same physical therapist.