Brain Injury Functional Outcome Measure (BI-FOM): A Single Instrument Capturing the Range of Recovery in Moderate-Severe Traumatic Brain Injury
John Whyte, Joseph T. Giacino, Allen W. Heinemann, Yelena G. Bodien, Tessa Hart, Mark Sherer, Gale G. Whiteneck, David Mellick, Flora M. Hammond, Patrick Semik, Amy Rosenbaum, Risa Richardson
Abstract
OBJECTIVE: To develop a measure of global functioning after moderate-severe TBI with similar measurement precision but a longer measurement range than the FIM. DESIGN: Phase 1: retrospective analysis of 5 data sets containing FIM, Disability Rating Scale, and other assessment items to identify candidate items for extending the measurement range of the FIM; Phase 2: prospective administration of 49 candidate items from phase 1, with Rasch analysis to identify a unidimensional scale with an extended range. SETTING: Six TBI Model System rehabilitation hospitals. PARTICIPANTS: Individuals (N=184) with moderate-severe injury recruited during inpatient rehabilitation or at 1-year telephone follow-up. INTERVENTIONS: Participants were administered the 49 assessment items in person or via telephone. MAIN OUTCOME MEASURES: Item response theory parameters: item monotonicity, infit/outfit statistics, and Factor 1 variance. RESULTS: After collapsing misordered rating categories and removing misfitting items, we derived the Brain Injury Functional Outcome Measure (BI-FOM), a 31-item assessment instrument with high reliability, greatly extended measurement range, and improved unidimensionality compared with the FIM. CONCLUSIONS: The BI-FOM improves global measurement of function after moderate-severe brain injury. Its high precision, relative lack of floor and ceiling effects, and feasibility for telephone follow-up, if replicated in an independent sample, are substantial advantages.