Diffusion tensor imaging (DTI) is commonly used in research after traumatic brain injury (TBI), with most focus on fractional anisotropy (FA). This study investigated how DTI relates to injury and cognition. Participants were 272 service members and veterans (44 non-injured controls (NIC), 56 injured controls (IC), 112 mild TBI (mTBI), 60 more severe TBI (sTBI)) with valid neuropsychological testing and DTI at least 11 months post-injury. The sTBI group had increased cerebral white matter (CWM) axial diffusivity (AD), MD, and radial diffusivity (RD), but not FA, compared to TC/mTBI (ps<.03). Additionally, the mTBI group had lower superior longitudinal fasciculus (SLF) AD/MD than NIC/sTBI. Hierarchical regressions revealed CWM AD/MD/RD and SLF AD/MD tended to be inversely related to Delayed Memory in sTBI and directly related to Delayed Memory in TC. Additionally, Processing Speed was related to bilateral SLF MD, right CWM AD/MD/RD in sTBI, left SLF AD in TC, and left SLF AD/MD in mTBI. Findings across our relatively large mTBI group were attenuated compared to prior research in mTBI samples. In contrast to prior research, FA was not significantly related to TBI. Other DTI metrics were related to cognition and should be considered in future larger studies of DTI/cognition.
|First Author||Sara Marie Lippa|
|Second Author||Ping Hong Yeh|
|Third Author||John Ollinger|
|Fourth Author||Tracey A Brickell|
|Fifth Author||Louis M French|
|Sixth Author||Rael T Lange|