Traumatic brain injuries (TBI) may have a great impact on long-term memory, according to a recent study.

Memory impairment affects 54 to 84 percent of individuals with TBI. While the variable impact of TBI on long-term memory has been recognized, the underlying cognitive mechanisms have not been detailed in this population. This variability in impairment among individuals with comparable injuries has been explained, in part, by the theory of cognitive reserve, i.e., higher intellectual enrichment confers a protective effect on long-term memory.

To test the role of working memory in the protective effect of cognitive reserve on long-term memory, researchers from the Kessler Foundation evaluated 50 patients with moderate to severe TBI for working memory, long-term memory and cognitive reserve.

"Our results support working memory as a possible mediator in the relationship between cognitive reserve and long-term memory and this finding corroborates our related work in multiple sclerosis," Dr. Joshua Sandry, lead author of the study, said in a statement. "We need more research to determine the value of including working memory in cognitive rehabilitation trials."

It remains to be seen whether treatment strategies aimed at working memory will lead to improvement in long-term memory in individuals with TBI and those with memory impairments caused by other conditions, Sandry, a National MS Society postdoctor, added.

The findings are detailed in the journal Neurology.