Divergent Recovery Trajectories: The Influence of Injury Mechanism on Stair-Climbing Outcomes After Traumatic Brain Injury - a TBI Model Systems Study

Background/Objectives: Traumatic Brain Injuries (TBIs) often cause profound functional impairments, yet the influence of TBI mechanisms on stair-climbing functional independence over extended timelines remains poorly understood. This study assesses whether Rasch-transformed FIM Stairs scores varied by TBI mechanism over follow-ups spanning 10 years or more. Methods: Data from the TBI Model Systems database were analyzed. The original 30,768 data entries were reduced to 6,226, corresponding to individuals with at least 10 years of data. Functional Independence Measure Stairs data were transformed to logit units via Rasch analysis before being evaluated with a linear mixed-effects regression, incorporating TBI mechanisms, age, follow-up time, and their interactions, with random effects accounting for the participant ID and pre-injury residence location. Results: TBI mechanisms meaningfully shape very long-term stair-climbing. Gunshot wounds and pedestrian-related accidents are associated with poorer performances, whereas motorcycles, bicycles, unclassified vehicular accidents, winter sports, other sports, and fall-related TBIs demonstrated relatively better function. Age, follow-up time, and their interaction also reached significance. Conclusions: Stair-climbing recovery trajectories over extended time significantly vary by TBI mechanism, with individuals with TBIs from gunshots and pedestrian-related accidents showing the most unfavorable recoveries. These findings support the development of mechanism-specific prognostic guidance and individualized rehabilitation strategies, thereby encouraging tailored approaches to improve outcomes.