Role of agitation in prediction of outcomes after traumatic brain injury

OBJECTIVE: To determine the role of agitation in the prediction of traumatic brain injury rehabilitation outcomes. DESIGN: A longitudinal study of 340 consecutive patients admitted to an acute traumatic brain injury rehabilitation unit was conducted. Outcomes under study included rehabilitation length of stay, discharge destination, functional independence at discharge (FIM instrument), productivity at 1-yr follow-up, and life satisfaction at 1-yr follow-up (Satisfaction with Life Scale). RESULTS: Univariate analyses suggested that the presence of agitation in rehabilitation is predictive of a longer length of stay and decreased functional independence in the cognitive realm at discharge. In addition, individuals who exhibit agitation at any time during rehabilitation are less likely to be discharged to a private residence. However, multivariate analyses indicated that cognitive functioning at admission to rehabilitation (FIM cognitive) mediates the relationship between the presence of agitation and length of rehabilitation, as well as between agitation and FIM cognitive at discharge. Similar results were found when discharge residence was the dependent variable; however, agitation also contributed some unique variance to the prediction. Lower cognitive functioning at admission to rehabilitation was associated with the occurrence of agitation during rehabilitation, longer length of stay, lower cognitive functioning at discharge, and a decreased likelihood that an individual would be discharged to a private residence. CONCLUSIONS: The results of the multivariate analyses support the contention that agitation and cognition are intimately related, with the long-term effects of the former being at least partially driven by the latter. These findings support the importance of systematically monitoring both agitation and cognition when applying interventions to reduce agitation.