Education attenuates the negative impact of traumatic brain injury on cognitive status

Abstract

Objective: To investigate whether the cognitive reserve hypothesis helps to explain differential cognitive impairment among survivors of traumatic brain injury (TBI), whereby survivors with greater intellectual enrichment (estimated with education) are less vulnerable to cognitive impairment.

Design: Cross-sectional study.

Setting: Medical rehabilitation research center.

Participants: Survivors of moderate or severe TBI (n=44) and healthy controls (n=36).

Interventions: Not applicable.

Main outcome measures: Intellectual enrichment was estimated with educational attainment. Group was defined as TBI or healthy control. Current cognitive status (processing speed, working memory, episodic memory) was evaluated with neuropsychological tasks.

Results: TBI survivors exhibited worse cognitive status than healthy persons (P<.001), and education was positively correlated with cognitive status in TBI survivors (r=.54, P<.001). Most importantly, regression analysis revealed an interaction between group and education (R(2) change=.036, P=.004), whereas higher education attenuated the negative impact of TBI on cognitive status. TBI survivors with lower education performed much worse than matched healthy persons, but this TBI-related performance discrepancy was attenuated at higher levels of education.

Conclusions: Higher intellectual enrichment (estimated with education) reduces the negative effect of TBI on cognitive outcomes, thereby supporting the cognitive reserve hypothesis in persons with TBI. Future work is necessary to investigate whether intellectual enrichment can build cognitive reserve as a rehabilitative intervention in survivors of TBI.

Keywords: AD; Alzheimer disease; Brain injuries; Cognitive disorders; Cognitive reserve; Neuropsychology; Rehabilitation; TBI; traumatic brain injury.