Early Measures of TBI Severity Poorly Predict Later Individual Impairment in a Rat Fluid Percussion Model

Abstract

Background: Multiple measures of injury severity are suggested as common data elements in preclinical traumatic brain injury (TBI) research. The robustness of these measures in characterizing injury severity is unclear. In particular, it is not known how reliably they predict individual outcomes after experimental TBI. Methods: We assessed several commonly used measures of initial injury severity for their ability to predict chronic cognitive outcomes in a rat lateral fluid percussion (LFPI) model of TBI. At the time of injury, we assessed reflex righting time, neurologic severity scores, and 24 h weight loss. Sixty days after LFPI, we evaluated working memory using a spontaneous alternation T-maze task. Results: We found that righting time and weight loss had no correlation to chronic T-maze performance, while neurologic severity score correlated weakly. Discussion: Taken together, our results indicate that commonly used early measures of injury severity do not robustly predict longer-term outcomes. This finding parallels the uncertainty in predicting individual outcomes in TBI clinical populations.

Keywords

• traumatic brain injury (TBI)
• rats
• early measures
• neurologic severity score
• fluid percussion injury