Education attenuates the negative impact of traumatic brain injury on cognitive status
ABSTRACT To investigate the cognitive reserve hypothesis in survivors of traumatic brain injury (TBI). Cognitive impairment is prevalent among survivors of moderate and severe TBI, although some survivors fare better than others. The cognitive reserve hypothesis states that intellectual enrichment (estimated with education) protects against cognitive decline in neurologic populations (e.g., Alzheimer's disease).
Forty-four survivors of moderate or severe TBI and 36 healthy controls participated in this cross-sectional study at a medical rehabilitation research center.
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.
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 (R2Δ = .036, p = .004), whereby 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.
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.
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ABSTRACT: The expectation for moderate to severe traumatic brain injury (TBI) is permanent damage and lasting deficits. However, in a multicenter investigation, Schneider et al.(1) show that by 1 year postinjury, one-fourth of patients with TBI achieve disability-free recovery (DFR), defined as a score of zero on the Disability Rating Scale. Of importance, cognitive reserve (CR) in the form of educational attainment was related to DFR.Neurology 04/2014; 82(18). DOI:10.1212/WNL.0000000000000395 · 8.30 Impact Factor
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ABSTRACT: To evaluate the hypothesis that educational attainment, a marker of cognitive reserve, is a predictor of disability-free recovery (DFR) after moderate to severe traumatic brain injury (TBI). Retrospective study of the TBI Model Systems Database, a prospective multicenter cohort funded by the National Institute on Disability and Rehabilitation Research. Patients were included if they were admitted for rehabilitation after moderate to severe TBI, were aged 23 years or older, and had at least 1 year of follow-up. The main outcome measure was DFR 1 year postinjury, defined as a Disability Rating Scale score of zero. Of 769 patients included, 214 (27.8%) achieved DFR at 1 year. In total, 185 patients (24.1%) had <12 years of education, while 390 (50.7%) and 194 patients (25.2%) had 12 to 15 years and ≥16 years of education, respectively. DFR was achieved by 18 patients (9.7%) with <12 years, 120 (30.8%) with 12 to 15 years, and 76 (39.2%) with ≥16 years of education (p < 0.001). In a logistic regression model controlling for age, sex, and injury- and rehabilitation-specific factors, duration of education of ≥12 years was independently associated with DFR (odds ratio 4.74, 95% confidence interval 2.70-8.32 for 12-15 years; odds ratio 7.24, 95% confidence interval 3.96-13.23 for ≥16 years). Educational attainment was a robust independent predictor of 1-year DFR even when adjusting for other prognostic factors. A dose-response relationship was noted, with longer educational exposure associated with increased odds of DFR. This suggests that cognitive reserve could be a factor driving neural adaptation during recovery from TBI.Neurology 04/2014; 82(18). DOI:10.1212/WNL.0000000000000379 · 8.30 Impact Factor
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ABSTRACT: Cognitive reserve (CR) is defined as the ability to cope with brain damage due to pre-existing cognitive processes or to the development of new compensatory processes. Existing research on CR is mostly based on the study of neurodegenerative disorders, such as Alzheimer's disease. Recently, however, this construct has also been applied to other neurological conditions, including multiple sclerosis, Parkinson's disease, epilepsy, stroke, and traumatic brain injury. The present review provides an overview of the studies that have investigated the influence of CR on neuropsychological outcome in stroke and traumatic brain injury patients. We performed a selective search on MEDLINE, CINAHL, and Web of Science Core Collection, using specific keywords including "cognitive reserve", "stroke", and "traumatic brain injury". The review is organized as follows: the first section focuses on works investigating the effect of CR on neuropsychological outcomes in post-stroke patients; the second section discusses studies which support the CR theory in traumatic brain injury. This review suggests that the study of CR in adult brain injury is still insufficient. Future research should investigate the role of other variables, like cognitive and social activities, as markers of CR in patients with brain injury, functional brain correlates of CR in brain activity, and the effect of CR on brain injury rehabilitative outcomes.Neurological Sciences 07/2014; 35(10). DOI:10.1007/s10072-014-1897-z · 1.50 Impact Factor