Characterizing Multiple Memory Systems in Moderate-Severe Traumatic Brain Injury

Abstract

Cognitive rehabilitation following brain injury rests on the ability of clinicians to support their patients’ (re)learning of knowledge, skills, and strategies. Learning and memory are therefore central to the success of behavioral rehabilitative interventions, and consideration of patterns of impaired and intact memory across multiple memory systems may help to improve treatment outcomes in individuals with moderate-severe traumatic brain injury. Here, I evaluate a battery of experimental tasks that purport to rely on declarative and/or procedural memory ability, with an eye towards the development of measures capable of assessing individual differences across these memory systems. Patients with TBI demonstrated significantly poorer performance on a spatial reconstruction task compared to healthy comparison participants, despite scoring within the normal range on a standardized declarative memory measure. As a group, patients with TBI did not significantly differ from healthy comparison participants on any of the experimental procedural memory measures. In addition, there were no significant correlations between individual difference measures across procedural memory tasks. Results suggest that the spatial reconstruction task may be a sensitive measure for characterization of subtle declarative memory impairment. Results from a battery of widely-used procedural memory tasks suggests that significant development of these measures will be required before they are suitable for use as individual differences measures. This study motivates the systematic development of declarative and procedural memory measures that are sensitive to group- and individual-differences that could be used across disorders to better characterize the influence of multiple memory systems on real-world outcomes. Use of such measures to better characterize patients with TBI promises to improve treatment decision-making and prediction of long-term clinical outcomes.