Deficits in both long and short-term memory are among the most common and treated consequence of moderate-severe traumatic brain injury (TBI). These deficits interfere with daily life and post-injury rehabilitation, as well as with the learning of new compensatory strategies. Short-term verbal memory, in particular, is the ability to store verbal information for brief periods of time, and is necessary to everyday life. However, little is known about the neural correlates of short-term deficits following TBI, and in particular about whether specific patterns of white matter damage tend to lead to worse verbal short-term memory outcomes. In the current study, we used Diffusion Tensor Imaging (DTI), and in particular fractional anisotropy (FA) to examine the association between white matter damage and short-term verbal memory performance on a sample of thirty-two individuals with chronic moderate-severe TBI and twenty healthy comparisons. To measure short-term verbal memory, we used the Immediate Recall subtest of the California Verbal Learning Test (CVLT-Immediate). Our analyses revealed that individuals with TBI’s performance was significantly lower on the CVLT-Immediate (p<.05), and that individuals with TBI displayed lower FA in widespread white matter tracts. An exploratory whole-brain analysis showed that within the TBI group performance on the CVLT-Immediate was significantly correlated with white matter integrity in the following tracts: the bilateral anterior thalamic radiation, inferior front-occipital fasciculus, and inferior longitudinal fasciculus, forceps minor, and uncinate fasciculus, as well as the left superior longitudinal fasciculus, cingulum, forceps major, and corticospinal tract. Further analysis revealed that 76% of the voxels whose white matter integrity correlated with CVLT-Immediate performance within the TBI group were located in the left hemisphere, with only 23% in the right hemisphere.
These findings provide preliminary evidence suggesting that white matter damage predominantly located in the left hemisphere might be associated with verbal short-term memory deficits in the chronic phase of a TBI.

LEFT HEMISPHERE WHITE-MATTER INTEGRITY IS ASSOCIATED WITH SHORT-TERM VERBAL MEMORY IMPAIRMENT FOLLOWING TBI