Browsing by Subject "Traumatic Brain Injury"
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Item Modeling of Human Brain Tissues and Head Injuries Induced by Blast and Ballistic Impact(2013-11-07) Kulkarni, Sahil GThe use of body armor and combat helmets has reduced fatalities from explosions and ballistic attacks. However, frequent use of improvised explosive devices and continuing efforts to reduce the weight of each combat helmet have increased the risk of ballistic-impact and blast-induced traumatic brain injuries among soldiers. The objective of this dissertation research project is to develop predictive constitutive and computational models to be used in head injury diagnosis and to aid in the development of new combat helmets that can mitigate non-penetrating head injuries. A transversely isotropic visco-hyperelastic constitutive model is provided for soft tissues, which accounts for large deformations, high strain rates, and short-memory effects. The presented model is tested for a range of strain rates and for multiple loading scenarios based on available experimental data for porcine and human brain tissues. Using this constitutive relation, a finite element model of a helmet/head assembly is developed to study non-penetrating TBI. The effects of constitutive models and blast directions on finite elements simulations of blast induced TBI are investigated. Further, the effectiveness of combat helmets against non-penetrating TBI induced by blast and ballistic impacts is studied. Two types of combat helmets are considered: the advanced combat helmet (ACH) and the enhanced combat helmet (ECH). Spatial distributions and temporal variations of the intracranial pressure and stress components obtained in the simulations reveal significant differences in brain tissue responses to different constitutive models and blast directions. It is found that these combat helmets provide some level of protection against non-penetrating TBI and that the level of protection is higher for the ECH than the ACH.Item Post-Traumatic Stress Disorder (PTSD) Symptoms as Predictors of Suicide Behavior Among Veterans with and without a History of Traumatic Brain Injury (TBI)(2012-10-19) Villarreal, Edgar JavierPrior research has established that a history of post-traumatic stress disorder (PTSD) and/or traumatic brain injury (TBI) increases the risk of suicide behavior. Few studies have examined the role of specific PTSD symptom clusters and suicide attempts. The current study is among a handful of studies that have examined the association between the presence of PTSD symptom clusters and suicide attempts among Veterans with PTSD and/or TBI. The study utilized archival data from a sample of 137 Veterans receiving mental health treatment at the Denver Veteran Affairs Medical Center. Results from logistic regression analyses indicated that PTSD symptom clusters were not associated with an increased risk for suicide behavior among individuals with and without a history of TBI. Results suggest that looking at the presence of PTSD symptoms is not sufficient to account for the risk of suicide behavior. Clinical and research implications on the need to examine the role of PTSD symptom severity and suicide behavior are discussed.Item Trajectories of Life Satisfaction During the First 10 Years Following Traumatic Brain Injury(2014-05-23) Williamson, MeredithTo examine the predictive relationships of functional ability, gender, and age on the longitudinal trajectories of life satisfaction across 10 years following onset of traumatic brain injury (TBI). Participants were part of the Traumatic Brain Injury Model Systems (TBIMS) longitudinal study of outcomes following TBI. Hierarchical linear modeling (HLM) was employed to assess changes in life satisfaction across 10 years post-injury as a function of functional ability, gender and age. The sample included 7,813 participants (2,170 women, 5,643 men) who were included in the TBIMS database. Satisfaction with life across 10 years post-injury was measured by the Satisfaction with Life Scale administered at 1, 2, 5, and 10 years post-injury. The Functional Independence Measure (FIM?) was administered to measure functional ability at 1, 2, 5, and 10 years post-injury. Additional predictor variables included gender and age. Participants? life satisfaction scores remained stable across 10 years post-injury. Greater functional ability as measured by the FIM? Total scale, FIM? Cognitive subscale, and FIM? Motor subscale was associated with greater life satisfaction across time. A significant interaction effect between age and functional ability was present. Gender was not a significant predictor of life satisfaction. Life satisfaction across 10 years post-injury is relatively stable. Greater functional ability was associated with greater life satisfaction. Older participants with greater functional impairments had higher life satisfaction scores across 10 years post-injury compared to their younger counterparts.