title: White matter abnormalities are associated with overall cognitive status in blast-related mTBI.
abstract: Blast-related mild traumatic brain injury (mTBI) is a common injury of the Iraq and Afghanistan Wars. Research has suggested that blast-related mTBI is associated with chronic white matter abnormalities, which in turn are associated with impairment in neurocognitive function. However, findings are inconsistent as to which domains of cognition are affected by TBI-related white matter disruption. Recent evidence that white matter abnormalities associated with blast-related mTBI are spatially variable raises the possibility that the associated cognitive impairment is also heterogeneous. Thus, the goals of this study were to examine (1) whether mTBI-related white matter abnormalities are associated with overall cognitive status and (2) whether white matter abnormalities provide a mechanism by which mTBI influences cognition. Ninety-six Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OEF) veterans were assigned to one of three groups: no-TBI, mTBI without loss of consciousness (LOC) (mTBI-LOC), and mTBI with LOC (mTBI + LOC). Participants were given a battery of neuropsychological tests that were selected for their sensitivity to mTBI. Results showed that number of white matter abnormalities was associated with the odds of having clinically significant cognitive impairment. A mediation analysis revealed that mTBI + LOC was indirectly associated with cognitive impairment through its effect on white matter integrity. These results suggest that cognitive difficulties in blast-related mTBI can be linked to injury-induced neural changes when taking into account the variability of injury as well as the heterogeneity in cognitive deficits across individuals.
authors.affiliation: Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA. dmiller3@bu.edu.|Memory Disorders Research Center, VA Boston Healthcare System , Boston, MA, USA. dmiller3@bu.edu.
authors.forename: Danielle R
authors.initials: DR
authors.lastname: Miller
authors.affiliation: National Center for PTSD, VA Boston Healthcare System, Boston, MA, USA.|Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA.|Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, MA, USA.
authors.forename: Jasmeet P
authors.initials: JP
authors.lastname: Hayes
authors.affiliation: Memory Disorders Research Center, VA Boston Healthcare System , Boston, MA, USA.|Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Ginette
authors.initials: G
authors.lastname: Lafleche
authors.affiliation: Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, MA, USA.|Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.|Harvard Medical School, Harvard University, Boston, MA, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Salat
authors.affiliation: Memory Disorders Research Center, VA Boston Healthcare System , Boston, MA, USA.|Department of Psychiatry, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Mieke
authors.initials: M
authors.lastname: Verfaellie
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D001753:Blast Injuries / Q000150:complications / Q000000981:diagnostic imaging* / Q000523:psychology*; D001924:Brain Concussion / Q000000981:diagnostic imaging* / Q000209:etiology / Q000523:psychology*; D003071:Cognition; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D054542:Iraq War, 2003-2011; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D012189:Retrospective Studies; D013313:Stress Disorders, Post-Traumatic / Q000000981:diagnostic imaging / Q000209:etiology / Q000523:psychology; D014474:Unconsciousness / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology; D014728:Veterans; D000067398:War-Related Injuries / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology; D066127:White Matter / Q000000981:diagnostic imaging* / Q000293:injuries
keywords: Cognitive impairment; DTI; Loss of consciousness; White matter integrity; mTBI