Research Reports - Working memory capacity links cognitive reserve with long-term memory in traumatic brain injury
J Neurol. 2014 Oct 7
Sandry J(1), DeLuca J, Chiaravalloti N
Traumatic brain injury (TBI) can have devastating negative consequences on an
individuals' ability to remember information; however, 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 cognitive reserve (CR). The theory suggests that
individuals who have spent significant time engaged in intellectually enriching
activities (higher CR) are better able to withstand LTM impairment despite
neurological injury. The cognitive mechanisms that underlie this relationship are
not well-specified. Recent evidence suggests that working memory (WM) capacity
may be one mediating variable that can help explain how/why cognitive reserve
(CR) protects against LTM impairment. The present research tested this hypothesis
in a sample of fifty moderate to severe TBI patients. 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 (Sobel's Z = 2.62, p = 0.009).
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.
