White matter abnormalities are associated with chronic postconcussion symptoms in blast-related mild traumatic brain injury.
Blast-related mild traumatic brain injury (mTBI) is a common injury among Iraq and Afghanistan military veterans due to the frequent use of improvised explosive devices. A significant minority of individuals with mTBI report chronic postconcussion symptoms (PCS), which include physical, emotional, and cognitive complaints. However, chronic PCS are nonspecific and are also associated with mental health disorders such as posttraumatic stress disorder (PTSD). Identifying the mechanisms that contribute to chronic PCS is particularly challenging in blast-related mTBI, where the incidence of comorbid PTSD is high. In this study, we examined whether blast-related mTBI is associated with diffuse white matter changes, and whether these neural changes are associated with chronic PCS. Ninety Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans were assigned to one of three groups including a blast-exposed no--TBI group, a blast-related mTBI without loss of consciousness (LOC) group (mTBI--LOC), and a blast-related mTBI with LOC group (mTBI + LOC). PCS were measured with the Rivermead Postconcussion Questionnaire. Results showed that participants in the mTBI + LOC group had more spatially heterogeneous white matter abnormalities than those in the no--TBI group. These white matter abnormalities were significantly associated with physical PCS severity even after accounting for PTSD symptoms, but not with cognitive or emotional PCS severity. A mediation analysis revealed that mTBI + LOC significantly influenced physical PCS severity through its effect on white matter integrity. These results suggest that white matter abnormalities are associated with chronic PCS independent of PTSD symptom severity and that these abnormalities are an important mechanism explaining the relationship between mTBI and chronic physical PCS.
Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts.|Memory Disorders Research Center, VA Boston Healthcare System, Boston, Massachusetts.
Danielle R
DR
Miller
National Center for PTSD, VA Boston Healthcare System, Boston, Massachusetts.|Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts.|Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, Massachusetts.
Jasmeet P
JP
Hayes
Memory Disorders Research Center, VA Boston Healthcare System, Boston, Massachusetts.|Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts.
Ginette
G
Lafleche
Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, Massachusetts.|Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts.|Harvard Medical School, Harvard University, Boston, Massachusetts.
David H
DH
Salat
Memory Disorders Research Center, VA Boston Healthcare System, Boston, Massachusetts.|Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts.
Mieke
M
Verfaellie
D000328:Adult; D055826:Afghan Campaign 2001-; D001753:Blast Injuries / Q000150:complications*; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000150:complications* / Q000209:etiology* / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D054542:Iraq War, 2003-2011; D056784:Leukoencephalopathies / Q000209:etiology*; D008297:Male; D009483:Neuropsychological Tests; D038223:Post-Concussion Syndrome / Q000209:etiology*; D011569:Psychiatric Status Rating Scales; D015599:Trauma Severity Indices; D014728:Veterans; D055815:Young Adult
OEF/OIF; PTSD; diffusion tensor imaging; loss of consciousness