Glucose enhances long-term declarative memory in mildly head-injured varsity rugby players

Abstract

In the present investigation, we sought to determine whether glucose could enhance declarative memory in head-injured individuals, as has been shown previously with elderly and Alzheimer's patients who had preexisting memory impairments. Varsity rugby players, both with and without a history of concussions, were given glucose- or saccharin-sweetened beverages and then tested on a series of neuropsychological tests of attention and memory; their blood-glucose levels were monitored. Beverages and tests were administered in a counterbalanced, crossover design, enabling within-subjects comparisons. Previously concussed participants were found to perform slightly worse than participants with no history of concussions (controls) on the preliminary screening interview tests and tests of memory and divided attention given in the saccharin (placebo) condition. Glucose was shown to enhance performance of the previously concussed participants and impair the performance of controls on tests of long-term declarative memory. The effects of glucose on memory appeared to be related to the participants' ability to clear glucose from the blood.