Short Title:Journal of Neurology
Year, Volume, Issue, Page(s):15, 262, 1, 59-64
This translational study tested a theoretical model linking cognitive reserve (CR), working memory (WM) and long-term memory (LTM) and used mediation modeling to better understand the relationship between the three constructs in traumatic brain injury (TBI). There is variability among memory impairment resulting from TBI; some individuals exhibit long-term memory (LTM) impairment while others do not. This variability has been explained, at least in part, by the theory of CR, which suggests that individuals who have spent significant time engaged in intellectually enriching activities (higher CR) are less likely to experience LTM decline. Recent evidence suggests that WM capacity may be one mediating variable that can help explain how or why CR protects against LTM impairment. The study tested this hypothesis in 50 patients with moderate-to-severe TBI. Specific neuropsychological tests were administered to estimate CR, LTM, and WM. The results were congruent with a recent theoretical model that implicates WM capacity as a mediating variable in the relationship between CR and LTM. These data corroborate recent findings in an alternate neurological population and suggest that WM is an underlying mechanism of CR. Additional research is necessary to establish whether (1) WM is an important individual difference variable to include in memory rehabilitation trials and (2) to determine whether rehabilitation and treatment strategies that specifically target WM may also lead to complimentary improvements on diagnostic tests of delayed LTM in TBI and other memory impaired populations.