Journal of neurotrauma
-
Journal of neurotrauma · Jan 2014
Randomized Controlled Trial Comparative StudyNeural Activation during Response Inhibition Differentiates Blast from Mechanical Causes of Mild to Moderate Traumatic Brain Injury.
Military personnel involved in Operations Enduring Freedom and Iraqi Freedom (OEF/OIF) commonly experience blast-induced mild to moderate traumatic brain injury (TBI). In this study, we used task-activated functional MRI (fMRI) to determine if blast-related TBI has a differential impact on brain activation in comparison with TBI caused primarily by mechanical forces in civilian settings. Four groups participated: (1) blast-related military TBI (milTBI; n=21); (2) military controls (milCON; n=22); (3) non-blast civilian TBI (civTBI; n=21); and (4) civilian controls (civCON; n=23) with orthopedic injuries. ⋯ These results indicate that the chronic effects of TBI are associated with abnormal brain activation during successful response inhibition. During failed inhibition, the pattern of activation distinguished military from civilian TBI, suggesting that blast-related TBI has a unique effect on brain function that can be distinguished from TBI resulting from mechanical forces associated with sports or motor vehicle accidents. The implications of these findings for diagnosis and treatment of TBI are discussed.
-
Journal of neurotrauma · Jan 2014
Randomized Controlled TrialInvestigating the Properties of the Hemodynamic Response Function Following Mild Traumatic Brain Injury.
Abstract Although several functional magnetic resonance imaging (fMRI) studies have been conducted in human models of mild traumatic brain injury (mTBI), to date no studies have explicitly examined how injury may differentially affect both the positive phase of the hemodynamic response function (HRF) as well as the post-stimulus undershoot (PSU). Animal models suggest that the acute and semi-acute stages of mTBI are associated with significant disruptions in metabolism and to the microvasculature, both of which could impact on the HRF. Therefore, fMRI data were collected on a cohort of 30 semi-acute patients with mTBI (16 males; 27.83±9.97 years old; 13.00±2.18 years of education) and 30 carefully matched healthy controls (HC; 16 males; 27.17±10.08 years old; 13.37±2.31 years of education) during a simple sensory-motor task. ⋯ The interaction was the result of an earlier time-to-peak and positive magnitude shift throughout the estimated HRF in patients with mTBI relative to HC. This difference in HRF shape combined with the greater volume of activated tissue may be indicative of a potential compensatory mechanism to injury. The current study demonstrates that direct examination and modeling of HRF characteristics beyond magnitude may provide additional information about underlying neuropathology that is not available with more standard fMRI analyses.
-
Journal of neurotrauma · Sep 2013
Randomized Controlled Trial Multicenter StudyExposure of cyclosporin a in whole blood, cerebral spinal fluid, and brain extracellular fluid dialysate in adults with traumatic brain injury.
Cyclosporin A (CsA), an immunosuppressive medication traditionally used in the prevention of post-transplant rejection, is a promising neuroprotective agent for traumatic brain injury (TBI). Preliminary studies in animals and humans describe the efficacy and safety of CsA when administered following neurotrauma. The objective of this study is to describe CsA exposure in adults with severe TBI by assessing concentrations in whole blood, cerebrospinal fluid (CSF), and brain extracellular fluid (ECF) dialysate as measured by brain microdialysis. ⋯ CsA was detected in the blood, CSF, and brain ECF dialysate. CsA exposure characteristic differences exist for whole blood, CSF, and ECF dialysate in severe TBI patients when administered as a continuous intravenous infusion. These exposure characteristics should be used for safer CsA dose optimization to achieve target CsA concentrations for neuroprotection in future TBI studies.
-
Journal of neurotrauma · Sep 2013
Randomized Controlled Trial Multicenter StudyNeurological Outcome Scale for Traumatic Brain Injury: III. Criterion-Related Validity and Sensitivity to Change in the NABIS Hypothermia-II Clinical Trial.
The neurological outcome scale for traumatic brain injury (NOS-TBI) is a measure assessing neurological functioning in patients with TBI. We hypothesized that the NOS-TBI would exhibit adequate concurrent and predictive validity and demonstrate more sensitivity to change, compared with other well-established outcome measures. We analyzed data from the National Acute Brain Injury Study: Hypothermia-II clinical trial. ⋯ The NOS-TBI demonstrated higher sensitivity to change, compared with the GOS (p<0.038) and GOS-E (p<0.016). In summary, the NOS-TBI demonstrated adequate concurrent and predictive validity as well as sensitivity to change, compared with gold-standard outcome measures. The NOS-TBI may enhance prediction of outcome in clinical practice and measurement of outcome in TBI research.
-
Journal of neurotrauma · Aug 2013
Randomized Controlled TrialThe effect of varied test instructions on neuropsychological performance following mild traumatic brain injury: an investigation of "diagnosis threat".
Diagnosis threat is a psychosocial factor that has been proposed to contribute to poor outcomes following mild traumatic brain injury (mTBI). This threat is thought to impair the cognitive test performance of individuals with mTBI because of negative injury stereotypes. University students (N=45, 62.2% female) with a history of mTBI were randomly allocated to a diagnosis threat (DT; n=15), reduced threat (DT-reduced; n=15), or neutral (n=15) group. ⋯ The only significant result was for the 2 × 3 ANOVA on an objective test of attention/working memory, Digit Span (p<0.05), such that the DT-reduced group performed better than the other groups, which were not different from each other. Although not consistent with predictions or earlier DT studies, the absence of group differences on most tests fits with several recent DT findings. The results of this study suggest that it is timely to reconsider the role of DT as a unique contributor to poor mTBI outcome.