Falls among the elderly population continue to be a growing concern in the healthcare industry and are marked by staggeringly high social and economic costs. The incidence of falls is known to increase with age, and currently the elderly population is growing at an astounding rate as baby-boomers are now entering this age group. Also, recovery following fall-related injuries decreases with increased age. These confounding factors currently make falls a very important area of research. Of the injuries typically seen in falls among the elderly, head injuries are one of the most debilitating. Death due to head trauma among the elderly is gaining national attention; head trauma is now considered the number one cause of death among elders who fall1. Among other technologies, medical helmets are often employed to protect against such injuries, but patient compliance with these helmets remains an issue. Current helmets use foams and cotton as padding, contributing to clumsy designs. Dilatent and honeycomb materials may be the future of this industry as their low weight and high efficacy per thickness make them ideal materials for thinner, lighter, less cumbersome head protection devices. This study outlines various modes of head injury and then highlights several head protection measures. The newer materials are tested using various methods to determine the most promising candidates for prototype designs. Next, three prototypes are assembled from the newer materials and compared directly based on the protection measures established. Finally, the top-performing prototype is compared against two existing medical helmets in a similar fashion. The results show that the best prototype significantly outperforms one of the existing medical helmets, and shows slight improvement over the other. These results establish the promise of these newer materials in the application of head protection devices.

Traumatic brain and spinal cord injury continue to be substantial clinical problems with few available treatment strategies. Individuals who are at a greater risk for sustaining a central nervous system (CNS) injury, such as professional athletes and military personnel, may benefit from a prophylactic supplement that would intervene in the neurodegenerative pathways immediately following injury. The high demand for selenium within the central nervous system, as well as the synthesis of selenoproteins by neurons and astrocytes suggests a critical role of selenium within the brain and spinal cord. Studies were designed to test the efficacy of enriched dietary selenium status in providing neuroprotective benefits in rodent models of spinal cord and traumatic brain injury. Levels of selenium storage within the CNS are increased relative to the amount of selenium present in the diet, indicating that selenium compounds effectively cross the blood brain barrier. In a model of moderate severity spinal cord contusion injury, dietary selenium supplementation reduced the number of days until recovery of independent bladder function following injury. These benefits did not translate to improvements in locomotor function during open field testing or reduction in overall lesion volume in the injured animal groups. Examination of gene expression changes 24 hours after spinal cord injury revealed that dietary selenium enrichment increased expression of genes involved in DNA repair, mitochondrial respiration, and transcriptional regulation. By expanding the scope of these studies to include models of traumatic brain injury, these data show the importance of selenium in the cortex as well. In particular, when compared to diets deficient in selenium, higher levels of dietary selenium improve spatial memory performance and mitochondrial respiration. The results of this dietary study show modest improvements following both traumatic brain and spinal cord injury and suggest that while selenium enrichment may not have a profound effect on the secondary injury cascade immediately following injury, the presence of adequate dietary selenium is critical for mitochondrial respiration. Together the results of these studies suggest that dietary supplementation may play a subtle role in injury mechanisms within the CNS and warrant further investigation.

<p>Explosions are associated with more than 80% of the casualties in the Iraq and Afghanistan wars. Given the widespread use of thoracic protective armor, the most prevalent injury for combat personnel is blast-related traumatic brain injury (TBI). Almost 20% of veterans returning from duty had one or more clinically confirmed cases of TBI. In the decades of research prior to 2000, neurotrauma was under-recognized as a blast injury and the etiology and pathology of these injuries remains unclear.</p><p>This dissertation used the finite element (FE) method to address many of the biomechanics-based questions related to blast brain injuries. FE modeling is a powerful tool for studying the biomechanical response of a human or animal body to blast loading, particularly because of the many challenges related to experimental work in this field. In this dissertation, novel FE models of the human and ferret head were developed for blast and blunt impact simulation, and the ensuing response of the brain was investigated. The blast conditions simulated in this research were representative of peak overpressures and durations of real-world explosives. In general, intracranial pressures were dependent on the peak pressure of the impinging blast wave, but deviatoric responses in the brain were dependent on both peak pressure and duration. The biomechanical response of the ferret brain model was correlated with in vivo injury data from shock tube experiments. This accomplishment was the first of its kind in the blast neurotrauma field.</p><p>This dissertation made major contributions to the field of blast brain injury and to the understanding of blast neurotrauma. This research determined that blast brain injuries were brain size-dependent. For example, mouse-sized brains were predicted to have approximately 7 times larger brain tissue strains than the human-sized brains for the same blast exposure. This finding has important implications for in vivo injury model design, and a scaling model was developed to relate animal experimental models to humans via scaling blast duration by the fourth-root of the ratio of brain masses. </p><p>This research also determined that blast neurotrauma is correlated to deviatoric metrics of the brain tissue rather than dilatational metrics. In addition, strains in the blasted brain were an order-of-magnitude lower than expected to produce injury with traditional closed-head TBI, but an order-of-magnitude higher in strain rate. The 50th percentile peak principle strain metric of values of 0.6%, 1.8%, and 1.6% corresponded to the 50% risk of mild brain bleeding, moderate brain bleeding, and apnea respectively. These findings imply that the mechanical thresholds for brain tissue are strain-based for primary blast injury, and different from the thresholds associated with blunt impact or concussive brain injury because of strain rate effects.</p><p>The conclusions in this dissertation provide an important guide to the biomechanics community for studying neurotrauma using in vivo, in vitro, and in silico models. Additionally, the injury risk curves developed in this dissertation provide an injury risk metric for improving the effectiveness of personal protective equipment or evaluating neurotrauma from blast.</p> / Dissertation

Introduction-Physical activity can reduce the risk of contracting many of the 'diseases of the sedentary', such as coronary heart disease and cancer (Blair et al., 1996). Recognition of this protective effect has led to the development of many programmes designed to promote the benefit of participation in sport and physical exercise (Hillary Commission, 1993; Nicholl et aI., 1995). With participation in sport, especially contact sport, the risk for injuries increases, including injuries to the head and neck (Wilberger, 1993; Wekesa et al., 1996; Pettersen, 2002). Mild traumatic brain injuries (MTBI) or concussion as used interchangeably in the literature (Maroon et al., 2000; Wills & Leathem, 2001) are an important public health concern, due to the high incidence and frequently persisting symptomatology (Evans, 1992). Mild traumatic brain injury is defined as a complex patho-physiological process affecting the brain induced by traumatic biomechanical forces (Aubry et al., 2002; McCrory et al., 2004). A sub-concussive injury or very mild traumatic brain injury (vMTBI) may be defined as an apparent brain insult with insufficient force to cause hallmark symptoms of concussion (Jordan, 2000; Webbe & Bath, 2003). The high incidence of sport related head injuries in South Africa is alarming, although the prevalence thereof is unknown and difficult to assess, as the seemingly trivial injuries frequently remain unreported (Roux et al., 1987). This is especially applicable in sport where a milder form of head injury is common. This is cause for concern as cumulative head injuries traditionally regarded as trivial or 'minor' may result in players running the risk of increasingly negative consequences following repetitive 'minor' head injuries. In contact sport such as rugby, players are at great risk of sustaining repetitive mild traumatic brain injuries. The negative outcome following these repetitive minor head injuries has been demonstrated by numerous studies on boxers and other athletes exposed to repeated MTBI and vMTBI (McLatchie et aI., 1987). The incidence of vMTBI has not yet been researched in school rugby and this study is the first to report the incidence of vMTBI in a secondary school rugby team. Obiectives - The objectives of this study were to determine the incidence, the neuropsychological consequences and the effect on the academic performance of repeated mild (MTBI) and very mild traumatic brain injuries (vMTBI) in a secondary school rugby team during one playing season. Methods - A cohort of 35 secondary school male rugby players divided into a vMTBI (group 1) (n=26) and a MTBI (group 2) (n=9) from a local secondary school's first and second team, was followed for a full competitive season by a trained Biokineticist, who was present at all the games and contact sessions played. All vMTBI and MTBI and the severity of these injuries were documented. A control (group 3) that consisted of 10 secondary school non-rugby players were compared with the vMTBI and MTBI groups. The incidence of repeated MTBI and vMTBI in a secondary school rugby team were gathered by questionnaires and observation next to the field by a trained Biokineticist. Pre-season and post-season neuropsychological tests were conducted on the research groups and the control group. The neuropsychological tests that were conducted on the three groups were the Colour Trial Test 1 and 2 (CTT 1 + 2), the Symbol Digit Modalities Test (SDMT), the Wechsler Memory Scale-Revised (WMS-R) and the Standardised Assessment of Concussion (SAC). After each match played throughout the season the research group also completed a SAC test. The academic results of the final examination (year 1) of the year of the specific rugby season were obtained, as well as the academic results of the final examination of the preceding two years (year 2 and 3). The programme STATISTICA (version 7.0, Stat soft, Tulsa, OK) was used to analyse the data. Descriptive statistics, one-way ANOVA's, two-way repeated measures ANOVA's, Post-hoc Tuckey HSD analysis and Pearson's product moment correlation were used for all the statistical analyses. Results - This study of a secondary school rugby team has shown 726 vMTBI's and 18 MTBI's throughout one rugby season. This relates to 1951 vMTBI's per 1000 player hours and 48 MTBI's per 1000 player hours. Reductions in delayed memory (p=O.O1)from preseason to post-season in a group of players with repetitive vMTBI's during a single rugby season were found. This was the first evidence of possible neurocognitive deficits towards delayed memory in very mild traumatic brain injuries at secondary school level. Statistically significant (p<=0.05)results of the SAC test totals between both the vMTBI and MTBI groups were documented in the different games throughout the rugby season and compared with the baseline test. No statistically significant differences (p<=0.05) between the pre-season and post-season's scores of the SAC test totals were documented. A decrease in academic performance in the subject Afrikaans (year 1 compared with year 2) with a p-value of p=O.O17(group 1) and p=O.O16(group 2) respectively was found. Conclusion - The findings of this study indicate a high incidence of vMTBI in a cohort of secondary school rugby players in one season, a statistically significant reduction (p=O.O1 )in delayed memory of the vMTBI rugby players and a statistically significant decrease in academic performance p=O.O17 (group 1) and p=O.O16 (group 2) in the subject Afrikaans from year 1 to year 2 final examinations. / Thesis (Ph.D. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.

Children with traumatic brain injury (TBI) often experience difficulties with inhibitory control (IC), manifest in both neurocognitive function (poor performance on the stop signal task, SST) and behavior (emergence of de novo attention-deficit/hyperactivity disorder, or secondary ADHD, S-ADHD). IC allows for the regulation of thought and action, and interacts with reward to modify behaviour adaptively as environments change. Children with developmental or primary ADHD (P-ADHD) exhibit poor IC and abnormalities when responding to rewards, yet the extent to which S-ADHD is similar to and different from P-ADHD in terms of these behaviours is not well-characterized. The cancellation and restraint versions of the SST were used to examine the effects of rewards on 2 distinct forms of IC in children and adolescents divided into 4 groups (control, TBI, S-ADHD, and P-ADHD). The SST requires participants to respond to a “go signal” and inhibit their responses when encountering a “stop signal”. Rewards improved performance similarly across groups, ages, and cancellation and restraint IC tasks. Adolescents exhibited better IC and faster and less variable response execution relative to children. Significant IC deficits were found in both tasks in the P-ADHD group, with participants with S-ADHD exhibiting intermediate cancellation performance relative to the other groups. Participants with TBI without S-ADHD were not impaired on either task. The relationship between neurocognitive and behavioral IC was examined by comparing multi-informant ratings of IC across groups, and examining the relationship between ratings and IC performance on the SST. Participants in the control and TBI groups were rated within the typical range, and exhibited fewer problems than either of the ADHD groups, who differed from each other (the P-ADHD group was rated as more inattentive than the S-ADHD group). Moderate to high concordance was found between parent and teacher reports, each of which was poorly concordant with self-reports. The P-ADHD and S-ADHD groups were unaware of their own deficits. Poorer IC predicted parent and teacher classification of participants into ADHD subtypes, although IC did not predict rating concordance. Despite similar clinical presentations, S-ADHD and P-ADHD differ in the phenotypic expression of behaviour and manifestation of IC across contexts.

Background: There is currently no standard method of diagnosing the presence or severity of concussion in acute primary care settings. This pilot project is part of a larger study to develop a Computerized Concussion Assessment Tool (CCAT). Methods: A prospective observational clinical study was conducted to explore the validity of the CCAT among patients presenting to the Emergency Department at Kingston General Hospital and at Hotel Dieu Hospital (Kingston, Ontario) with minor head injury. Twenty-two patients with concussion and eighteen patients with head injury (but not diagnosed with concussion) were recruited to the study. All participants completed a background questionnaire, several neurocognitive tests and the CCAT assessment. Performance on the CCAT was compared between these two groups. Data collected during the development phase of the CCAT from a Normal Volunteers group (n=68) were used in an additional comparison. CCAT Scores for Selective Attention, Divided Attention and Memory were compared with standard neurocognitive tests through correlational analyses. In addition, the validity and clinical yield of the CCAT were investigated relative to gold standard measures. Results: After adjustment for covariates, no statistically significant differences were found between the three participant groups for any of the three primary CCAT Scores (Selective Attention, Divided Attention and Memory). Correlational analyses showed that the CCAT Selective Attention Score and the CCAT Memory Score are moderately correlated with standard neurocognitive tests. There was no correlation observed for the CCAT Divided Attention Score and its associated neurocognitive test. Conclusion: The CCAT was unable to discriminate between concussed patients and non-concussed individuals. However, moderate correlations observed between the CCAT Scores for Memory and Selective Attention and their respective neurocognitive tests support a view that there should be optimism for the future development of the CCAT. Issues related to the feasibility of the study and its administration in the emergency department setting are discussed. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2008-09-23 10:40:20.199

No description available.

Traumatic brain injury (TBI) is a relatively unknown disease considering the tens of millions of people affected around the world each year. Many TBI patients die from their injuries and survivors often suffer from life-long disabilities. The primary injury initiates a variety of cellular and molecular processes that are both beneficial and detrimental for the brain, but that are not fully understood. The focus of this thesis has been to study the role of astrocytes in clearance of dead cells after TBI and to identify injury specific proteins that may function as biomarkers, by using cell cultures, animal models and in cerebrospinal fluid (CSF) from TBI patients. The result demonstrates a new function in that astrocytes, the most numerous cell type in the brain, engulf dead cells after injury both in cell cultures and in adult mice and thereby save neurons from contact-induced apoptosis. Astrocytes are effective phagocytes, but degrade the ingested dead cells very slowly. Moreover, astrocytes express the lysosome-alkalizing proteins Rab27a and Nox2 as well as major histocompatibility complex class II, the receptors on which antigens are being presented. By lowering the pH of the lysosomes with acidic nanoparticles, the degradation increases, but the astrocytes still remained less effective than macrophages. Taken together, the data indicates that the low acidification in astrocytes can preserve antigens and that astrocytes may be able to activate T cells. The expression and secretion of injury-specific proteins was studied in a cell culture model of TBI by separate mass spectrometry analysis of cells and medium. Interestingly, close to 30 % of the injury-specific proteins in medium are linked to actin, for example ezrin of the ezrin/radixin/moesin (ERM) protein family. Ezrin, but none of the other ERM proteins or actin, is actively secreted after injury. Extracellular ezrin also increases in CSF in response to experimental TBI in rats and is present in CSF from TBI patients, indicating that ezrin is a potential biomarker for TBI.

No description available.

Functional magnetic resonance imaging (fMRI) is a relatively new tool that has been used to examine patterns of neural activation within those with traumatic brain injuries (TBI). A review of relevant literature is presented, including alterations in activity within the frontal and parietal regions that are thought to be compensatory in nature. In addition, possible explanations for discrepancies within this research are discussed. The current study expands upon previous work by incorporating a delayed-match-to-sample (DMS) task within an event-related paradigm and neuropsychological testing to compare 12 individuals with a history of TBI to 12 control participants with orthopedic injuries (OI). Participants in the TBI group were high functioning and in the chronic stage of recovery. Neuropsychological testing revealed statistically significant group differences in measures of working memory, processing speed, memory, and executive functioning. However, groups were comparable in accuracy on the DMS task. Percent signal changes in fMRI data revealed statistically significantly increased activation within the right dorsolateral prefrontal cortex (BA 46) for the TBI group compared to controls. Additional alterations in activation were found between groups within the inferior temporal (BA 37) and parietal (BA 7) regions. Regression analyses showed no relationship between neuropsychological testing and percent signal change within BA 46, but predictive relationships between testing and BA 37 and BA 7. Logistic regression analyses suggest that fMRI data did not add any incremental predictive value beyond neuropsychological testing alone when attempting to predict group (TBI vs. OI) membership.