title: Assessing Quantitative Changes in Intrinsic Thalamic Networks in Blast and Nonblast Mild Traumatic Brain Injury: Implications for Mechanisms of Injury.
abstract: In the global war on terror, the increased use of improvised explosive devices has resulted in increased incidence of blast-related mild traumatic brain injury (mTBI). Diagnosing mTBI is both challenging and controversial due to heterogeneity of injury location, trauma intensity, transient symptoms, and absence of focal biomarkers on standard clinical imaging modalities. The goal of this study is to identify a brain biomarker that is sensitive to mTBI injury. Research suggests the thalamus may be sensitive to changes induced by mTBI. A significant number of connections to and from various brain regions converge at the thalamus. In addition, the thalamus is involved in information processing, integration, and regulation of specific behaviors and mood. In this study, changes in task-free thalamic networks as quantified by graph theory measures in mTBI blast (N = 186), mTBI nonblast (N = 80), and controls (N = 21) were compared. Results show that the blast mTBI group had significant hyper-connectivity compared with the controls and nonblast mTBI group. However, after controlling for post-traumatic stress symptoms (PTSS), the blast mTBI group was not different from the controls, but the nonblast mTBI group showed significant hypo-connectivity. The results suggest that there are differences in the mechanisms of injury related to mTBI as reflected in the architecture of the thalamic networks. However, the effect of PTSS and its relationship to mTBI is difficult to distinguish and warrants more research.
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|2 North Tide LLC , Dulles, Virginia.|3 Uniformed Services University of the Health Sciences , Bethesda, Maryland.
authors.forename: Dominic E
authors.initials: DE
authors.lastname: Nathan
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|2 North Tide LLC , Dulles, Virginia.
authors.forename: Julie F
authors.initials: JF
authors.lastname: Bellgowan
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.
authors.forename: Terrence R
authors.initials: TR
authors.lastname: Oakes
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|4 Center of Neuroscience and Regenerative Medicine (CNRM) , Bethesda, Maryland.
authors.forename: Louis M
authors.initials: LM
authors.lastname: French
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|5 Henry M. Jackson Foundation , Bethesda, Maryland.
authors.forename: Sreenivasan R
authors.initials: SR
authors.lastname: Nadar
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|2 North Tide LLC , Dulles, Virginia.
authors.forename: Elyssa B
authors.initials: EB
authors.lastname: Sham
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|2 North Tide LLC , Dulles, Virginia.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.|3 Uniformed Services University of the Health Sciences , Bethesda, Maryland.
authors.forename: Gerard
authors.initials: G
authors.lastname: Riedy
mesh_terms: D000328:Adult; D015415:Biomarkers; D001921:Brain / Q000473:pathology; D001924:Brain Concussion / Q000209:etiology / Q000503:physiopathology*; D001930:Brain Injuries / Q000175:diagnosis; D000070642:Brain Injuries, Traumatic / Q000175:diagnosis / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008889:Military Personnel; D009483:Neuropsychological Tests; D012146:Rest / Q000502:physiology; D013788:Thalamus / Q000293:injuries / Q000378:metabolism / Q000502:physiology*
chemical_list: D015415:Biomarkers
keywords: blast injury; graph theory; mild traumatic brain injury; resting state fMRI; thalamic connectivity