What influence does self‐reported history of single or repeated mild TBI have on cognitive performance and brain volume at mid‐life?

Background: The long‐term consequences of mild traumatic brain injury (mTBI) are poorly understood. Prior studies have shown that a history of mTBI is associated with a 2 fold increase of dementia diagnosis. However, the precise mechanisms for increased dementia risk which could start in mid‐life remain unclear. TBI can cause varying degrees of damage to different regions of the brain, and as a result, may affect distinct subdomains of cognitive function in distinct ways. This study investigated cognitive performance and brain volume among individuals at risk of Alzheimer's Disease (AD) in mid‐life with a history of self‐reported mTBI. Method: 578 participants (118 no head injury, 116 single mTBI & 344 repeated mTBI) aged 40‐60 years participating in the PREVENT study, a large cohort study examining the risk of AD in mid‐life, underwent structural 3T MRI and neuropsychometric evaluation (ACE‐III and COGNITO) at baseline. Self‐reported, cross‐sectional data on head injury were collected through the Brain Injury Screening Questionnaire (BISQ). FSL (version 6.0.1) was used to calculate brain volume (correcting for head size). Comparisons between participants with no history of head injury and single or repeated mTBI were done using a one‐way ANOVA. Result: There was no statistically significant difference in total brain volume between participants with or without a history of mTBI (F(2,576) = 1.24, p = 0.29). There was also no significant difference between self‐reported mTBI and ACE‐III total scores F(2,579) = 0.0112, p = 0.99) or performance on memory (p = 0.87), language (p = 0.24), visuospatial abilities (p = 0.61) and attention (p = 0.14) in the COGNITO battery. Conclusion: We found no evidence that a history of mTBI (single or repeated) is associated with cognitive impairment in this cohort. Future longitudinal studies are necessary to further evaluate self‐reported mTBI and how the aging process might interact with cognitive outcome post‐injury. Future analysis of covariates such as lower socioeconomic status, gender, physical health and history of alcohol/drug use, that are known to impact cognitive performance and are related to greater rates of TBI, will be studied to determine the influence of a history of mTBI on dementia risk. [ABSTRACT FROM AUTHOR]