Objective: We investigated using diffusion tensor imaging (DTI) and the association between white matter integrity and executive function (EF) performance in postacute mild traumatic brain injury (mTBI). In addition, we examined whether injury severity, as measured by loss of consciousness (LOC) versus alterations in consciousness (AOC), is related to white matter microstructural alterations and neuropsychological outcome.
Participants: Thirty Iraq and Afghanistan War era veterans with a history of mTBI and 15 healthy veteran control participants.
Results: There were no significant overall group differences between control and mTBI participants on DTI measures. However, a subgroup of mTBI participants with EF decrements (n = 13) demonstrated significantly decreased fractional anisotropy of prefrontal white matter, corpus callosum, and cingulum bundle structures compared with mTBI participants without EF decrements (n = 17) and control participants. Participants having mTBI with LOC were more likely to evidence reduced EF performances and disrupted ventral prefrontal white matter integrity when compared with either mTBI participants without LOC or control participants.
Conclusions: Findings suggest that altered white matter integrity contributes to reduced EF in subgroups of veterans with a history of mTBI and that LOC may be a risk factor for reduced EF as well as associated changes to ventral prefrontal white matter.
San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology (Mr Sorg); Veterans Affairs San Diego Healthcare System (VASDHS) (Drs Delano-Wood, Schiehser, Hanson, Nation, Jak, Meloy, Frank, Lohr, and Bondi and Mr Luc and Mss Lanni); Center of Excellence for Stress and Mental Health, VASDHS (Drs Delano-Wood, Schiehser, Hanson, Jak, Frank, Lohr, and Bondi); and Departments of Psychiatry (Drs Delano-Wood, Schiehser, Hanson, Jak, Meloy, Lohr, and Bondi) and Radiology (Drs Lu and Frank), School of Medicine, University of California, San Diego.
Corresponding Author: Lisa Delano-Wood, PhD, VA San Diego Healthcare System (151B), 3350, La Jolla Village Dr, San Diego, CA 92161 (email@example.com).
This work was supported by grants awarded by the Veterans Affairs (Career Development Awards [CDA]: L.D.-W., D.S.) as well as the Department of Defense (Investigator-Initiated Research Grant [IIRG]: L.D.-W.). This material is further supported with resources of the Veterans Affairs Center of Excellence for Stress and Mental Health (CESAMH: L.D.-W., A.J.J., K.L.H) and a National Institute of Health grant awarded to Dr Lawrence Frank (R01 MH096100-01). The coauthors report no conflicts of interest.
The authors sincerely thank the OEF/OIF (Operation Enduring Freedom/Operation Iraqi Freedom) veterans who volunteered to participate in this study, those who could not, and those who continue to serve at home and abroad. In addition, they are grateful to the Veterans Affairs CESAMH at the Veterans Affairs San Diego Healthcare System for their organizational assistance.
The authors declare no conflicts of interest.