| Objective: To examine whether cognitive reserve (CR) attenuates the initial impact of TBI on cognitive performance (passive model) and results in faster cognitive recovery rates in the first year post-injury (active model), and whether the advantage of CR differs based on the severity of TBI.;Setting: Inpatient/outpatient clinics at academic medical center.;Participants: Adults with mild TBI (mTBI; n=28), complicated mild TBI (cmTBI; n=24), and moderate-to-severe TBI (msevTBI; n=57), and demographically-matched controls (n=66).;Design: Retrospective; longitudinal cohort assessed at 1-, 6-, and 12-months post-injury.;Main Measures: Outcomes were 3 cognitive domains: processing speed/executive function, verbal fluency, and memory. Premorbid IQ, estimated with the Wechsler Test of Adult Reading, served as CR proxy.;Results: Higher premorbid IQ was associated with better performance on cognitive domains at one-month post-injury, and the effect of IQ was similarly beneficial for all groups. Cognitive recovery rate was moderated only by TBI severity; those with more severe TBI had faster recovery in the first year.;Conclusion: Results provide evidence for the passive, but not active, model of CR during TBI recovery. Specifically, the mechanism for the passive model is preservation of the pre-injury relationship between CR and cognition. CR does not moderate the rate of recovery. |
