Moderate-Severe TBI as a Progressive Disorder: Cognitive declines in the Chronic Stages of Injury

Objective: Overarching aim: To examine extent of cognitive declines in the chronic stages of TBI and correlates of decline. Objective 1: To replicate our previous findings of post-recovery cognitive decline (Till et al, 2008) in a non-overlapping and larger sample. Objective 2: To examine prevalence of decline across multiple time windows. Objective 3: To examine correlates of decline. We previously found that tests of verbal retrieval showed the most decline; therefore, we examined whether hippocampal volume loss was associated with cognitive decline. We also examined variables that predicted decline in past research Background: Our group and others have shown that moderate-severe TBI is a progressive disorder, with losses to brain volume, white matter integrity and cognitive function in the chronic stages of injury. In 2008, our group found that 27% of n=33 moderate-severe TBI patients; here, we attempt to replicate and extend those findings. Design/Methods: In N=48 adults with moderate-severe TBI, we employed the reliable change index to examine decline from 2 to 5, 5 to 12 and 12 to 30+ months post-injury. We employed logistic regression to examine predictors of decline, including pre-injury related factors (age, years of education, sex) and injury and post-injury factors, including PTA, hours of therapy and hippocampal volume loss from 5 to 12 months post-injury. Results: The proportion of patients showing decline increased across time, with 12.5% from 2–5 months, 17% from 5–12 months, and 27% from 12–30+ post-injury. PTA and left hippocampal volume loss from 5–12 months post-injury accounted for significant cognitive decline from 12 to 30+ months post-injury. Conclusions: The current study replicated Till et al, 2008, with 27% of patients declining from 12 to 30+ months post-injury. We extended the findings by showing an increasing proportion of decline across the chronic stages of injury. Injury severity and left hippocampal volume loss predicted cognitive decline. Disclosure: Dr. Changoor has nothing to disclose. Dr. Colella has nothing to disclose. Dr. Monette has nothing to disclose. Dr. Green has nothing to disclose.