Mediating Effects of Cognitive Effort and Depression on Intelligence, Memory, and Executive Functions in Individuals with Mild Traumatic Brain Injury

OBJECTIVE: Mild traumatic brain injury (mTBI) is frequently associated with psychiatric symptoms and cognitive dysfunction, as well as with the receipt of workers' compensation, as many mTBIs occur due to work-related accidents. We hypothesized that depression and insufficient cognitive effort mediate the relationship between sociodemographic variables and cognitive dysfunction in mTBI. METHODS: A retrospective chart review study was conducted using 115 records of patients with mTBI. Cognitive effort was measured based on scores on the Rey 15-Item Test. Multivariate linear regression analysis was performed to examine factors predictive of cognitive functions. Path analysis was subsequently performed to investigate the mediating effects of depression and cognitive effort in relation to receipt of workers' compensation and demographic variables. RESULTS: Fifteen of the 115 participants (13.0%) received failing scores on the Rey 15-Item Test, which indicated insufficient cognitive effort. Path analysis indicated that cognitive effort mediated the effects of age and workers' compensation on cognitive functions. CONCLUSION: Given the significant mediating effects of cognitive effort on cognitive performance, it is important to address patient motivation and encourage mTBI patients covered by workers' compensation to perform tests with authentic effort.