The long-term consequences of repetitive mild traumatic brain injuries (mTBIs), or concussions, as well as the immediate acute dangers of head collisions in sport have become of growing concern in the field of medicine, research and athletics. An estimated 3.8 million sports-related concussions occur in the United States annually, with the highest incidence having been documented in football, hockey, soccer, basketball and rugby (Harmon et al., 2013). The incidence of concussion in the National Rugby League (NRL) corresponds to approximately 8.0-17.5 injuries per 1000 playing hours, with tackling having been identified as the most common cause (Gardner et al., 2014; King et al., 2014). The highest incidence of rugby concussive impacts is a result of shoulder-to-head collisions (35%) during tackles and game play (Gardner et al., 2014). Shoulder-to-head concussive events occur primarily on the ball carrier and secondarily on the tacklers (Hendricks et al., 2014; Quarrie & Hopkins, 2008). While some studies report that the ball carrier is at a greater risk of sustaining a concussion (Gardner et al., 2015; King et al., 2010, 2014), others have demonstrated a greater incidence of tacklers being removed from play for sideline concussion evaluation (Gardner et al., 2014). Given this discrepancy, the purpose of this study was to compare dynamic response and brain tissue deformation metrics for ball carriers and defensive tacklers in professional rugby during shoulder-to-head concussive impacts using in-laboratory reconstructions. Ten cases with an injured defensive tackler and ten cases with an injured ball carrier were reconstructed using a pneumatic linear impactor striking a 50th percentile Hybrid III headform to calculate dynamic response and maximum principal strain values. There was no significant difference between the two impact conditions for peak resultant linear and rotational accelerations, as well as brain tissue deformation. Differences between metrics in this research and past research where the impacting system was not reported were discussed. These differences reflect the importance of accounting for impact compliance when describing the risk associated with collisions in professional rugby.

Research into traumatic brain injury (TBI) mechanisms is essential for the development of methods to prevent its occurrence. One of the most common ways to incur a TBI is from falls, especially for the young and very old. The purpose of this thesis was to investigate how the acceleration loading curves influenced the occurrence of different types of TBI, namely: epidural hematoma, subdural hematoma, subarachnoid hemorrhage, and contusion. This investigation was conducted in three parts. The first study conducted reconstructions of 20 TBI cases with varying outcomes using MADYMO, Hybrid III, and finite element methodologies. This study provided a dataset of threshold values for each of the TBI injuries measured in parameters of strain and stress. The results of this study indicated that using a combined reconstructive approach produces results which are in keeping with the literature for TBI. The second study examined how the characteristics of the loading curves which were produced from each reconstruction influenced the outcome using a principal components analysis. It was found that the duration of the event accounted for much of the variance in the results, followed with the acceleration components. Different curve characteristics also accounted for differing amounts of variance in each of the lesion types. Study 3 examined how the dynamic response of the impact influenced where in the brain a subdural hematoma (SDH) could occur. It was found that the largest magnitudes of acceleration produced SDH in the parietal lobe, and the lowest in the occipital lobe. Overall this thesis examined the mechanism of injury for TBI using a large dataset with methodologies which complement each other’s limitations. As a result in depth information of the nature of TBI was attained and information provided which may be used to improve future protection and standard development.

Severe traumatic brain injury (sTBI) is a cause of death and disability worldwide and requires treatment at specialized neuro-intensive care units (NICU) with a multimodal monitoring approach. The CT scan imaging supports the monitoring and diagnostics. The level of S100B and neuron specific enolase (NSE) reflects the severity of the injury. The therapy resistant intracranial hypertension requires decompressive craniectomy (DC). After DC, the cranium must be reconstructed to recreate the normal intracranial physiology as well as to address cosmetic issues. The evolution of the pathological intracranial changes was analyzed in accordance with the three CT classifications: Marshall, Rotterdam and Morris-Marshall. The Rotterdam scale was best in describing the dynamics of the pathological evolution. Both the Rotterdam score and Morris- Marshall classification showed strong correlation with the clinical outcome, a finding that suggests that they could be used for prognostication. We demonstrated a clear correlation between the CT classifications and concentrations of S100B and NSE. The results revealed a concomitant correlation between NSE and S100B and clinical outcome. We found that the interaction between the ICP, Rotterdam CT classification, and concentrations of biochemical biomarkers are all associated with DC. We found a high percentage of complications following cranioplasty. Our results call into question whether custom-made allograft should be considered the best material for cranioplasty. It is concluded that both the Rotterdam and Morris-Marshall classification contribute to clinical evaluation of intracranial dynamics after sTBI, and might be used in combination with biochemical biomarkers for better assessment. The decision to perform DC should include a re-assesment of ICP evolution, CT scan images and concentration of the biochemical biomarkers. Furthermore, when determining whether DC treatment should be used, surgeon should also consider the risks of the following cranioplasty.

Magister Scientiae (Occupational Therapy) - MSc(OT) / Traumatic brain injury (TBI) is a major public health concern which mostly affects the economically viable population. In addition, the Code of Good Practice as described in South African Labour Law serves as a guide for employers to encourage equal and fair opportunities for employees with disabilities. However, despite the presence of this policy, as well as other legislation, research has shown that individuals with TBI are failing to return to work. The Model of Occupational Self-Efficacy (MoOSE) was developed as a client centered approach to return individuals with TBI to work. The aim of the current study was to explore, and describe the experiences and perceptions of occupational therapists who have used the MoOSE in the vocational rehabilitation and return to work process of clients with TBI. The participants in the study were selected by means of purposive sampling and semi-structured face-to-face interviews were conducted on a monthly basis for three months with 10 occupational therapists. The semi-structured interviews were used to gain insight into and explore the perceptions of the occupational therapists who have used the MoOSE in their vocational rehabilitation programmes with clients who have suffered TBI. The findings of the study were analyzed by means of thematic content analysis. The outcome of this study was aimed at finding ways to enhance / improve the model when it is used in the vocational rehabilitation process with people who have suffered TBI. Informed consent was obtained from the research participants and confidentiality of their information was maintained. Data was collected by means of semi-structured interviews which were audiotaped and transcribed. Transcriptions were analysed by using constant comparative methods of data analysis which resulted in categories, which reflected the purpose of the study being created. The analysis of transcripts was done using Microsoft Word. Results were then divided into themes and discussed holistically. Four themes emerged that answered the research question. Theme one described how client related factors impacted on the implementation of the MoOSE. Theme two explored the therapist related factors that impacted on the implementation of the MoOSE while theme three discussed how characteristic of the model impacted on the vocational rehabilitation and return to work process. The participants appreciated the clear four stages of the MoOSE and the dynamicity of the model. Theme four described how the job market and employer perceptions impacted on the return to work process. Recommendations were then discussed that could further improve the model and the implementation thereof. Recommendations included adding a motivation component to the MoOSE, involving family members in the rehabilitation process and therapist reflection as a means to foster client-centered practice. Other recommendations were aimed at addressing policy issues which interferes with the return to work process and encouraging interdisciplinary collaboration in the vocational rehabilitation of individuals with TBI.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-07-25T12:32:10Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Angelo-tese doutorado.pdf: 2038180 bytes, checksum: be401d99f221bbdf4a8d892feb579538 (MD5) / Made available in DSpace on 2017-07-25T12:32:10Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Angelo-tese doutorado.pdf: 2038180 bytes, checksum: be401d99f221bbdf4a8d892feb579538 (MD5) Previous issue date: 2016-11-24 / Introdução: A incidência de hidrocefalia pós craniectomia descompressiva(CD) em pacientes com traumatismo cranioencefálico(TCE) é entre 0-45% segundo a literatura. A hidrocefalia traz prejuízos ao prognóstico neurológico e demanda reconhecimento clínico precoce. Existem diversas variáveis radiológicas e clínicas descritas com associação ao risco de hidrocefalia. Para estudar a influência desses fatores conduzimos um estudo retrospectivo, observacional em um centro terciário de atendimento a pacientes com TCE com foco principal na análise do volume de herniação transcraniana (VHTC) após CD. Métodos: selecionamos 50 pacientes que realizaram CD para TCE entre janeiro de 2014 e janeiro de 2015. Hidrocefalia foi reconhecida e definida na presença de critérios radiológicos de Gudeman, indicação de derivação ventricular, e na mensuração do Índice de Evans modificado maior que 33%. Analisamos as seguintes variáveis: Idade, Sexo, Escala de Coma de Glasgow à admissão, reatividade pupilar, índice de Zunkeller, presença de higroma, VHCE, diâmetro da craniectomia e distância da craniectomia em relação à linha média. Regressão logística foi utilizada definindo o desfecho com ou sem hidrocefalia como medida de análise. Resultados: 17 pacientes desenvolveram hidrocefalia (34%). VHCE após CD (p<0.001), Higroma subdural (p<0.001) ), Escala de coma de Glasgow abaixo de 6( p=0.015), sinais de herniação uncal(p=0.042) e maior valor no índice de Zumkeller(p=0.04) foram associados com o desenvolvimento de hidrocefalia pós-CD. Regressão logística demonstrou que entre essas variáveis as que foram consideradas como fatores de risco independente são o VHTC (OR 11.08; 95%IC 2.10,58.4; p=0.004) e a presença de higroma (OR 49.59; 95%IC 4.1,459;p=0.002). Conclusões: Observamos uma forte associação entre a severidade do TCE, o volume de herniação cerebral transcraniana e presença de higroma subdural com o desenvolvimento de hidrocefalia. Pacientes com esses achados devem ser acompanhados rigorosamente visando evitar prejuízo clínico. / In patients undergoing decompressive craniectomy(DC) for traumatic brain injury(TBI) there has been reported an incidence of hydrocephalus between 0-45%. Hydrocephalus affects long term survival and needs a prompt and correct diagnosis. There are several radiological and clinical features described in association with development of hydrocephalus. For study the influence of these factors we conducted a retrospective observational single-center cohort study in a tertiary care center with special attention to the transcalvarial brain herniation volume(TCH) after DC. Methods: We selected 50 patients that underwent DC after closed head injury between january 2014 and January 2015. Hydrocephalus was defined as a modified frontal horn index greater than 33%, Gudeman CT scan criteria or insertion of ventriculoperitoneal Shunt. Variables we analyzed were: age, post-resuscitation Glasgow Coma Scale (GCS) score, pupil reactivity, Zunkeller index, presence of hygroma, TCH volume, craniectomy diameter and distance of craniectomy from midline. Logistic regression was used with hydrocephalus as the primary outcome measure. Results: 17 patients developed hydrocephalus(34%). TCH volume after decompression ( p<0.001), subdural hygroma ( p ), lower admission Glasgow Coma Scale score ( p=0.015), unilateral pupil reactivity(p=0.042) and higher Zumkeller index(p=0.044) were significant risk factors for hydrocephalus after decompressive craniectomy. Logistic regression analysis showed that factors independently associated with the development of hydrocephalus was the TCH volume (odds ratio 11.08; 95%CI 2.10, 58.4; p = 0.0046), and presence of hygroma (odds ratio 49.59; 95%IC 4.1, 459; p=0.002). Conclusions: There is a clear association between severity of TBI, TCH volume and subdural hygroma with the development of hydrocephalus. Clinicians should follow closely patients with those findings in order to avoid late deterioration.

Motion capture technology and Magnetic Resonance Imaging with Diffusion Tensor Imaging (MRI-DTI) were used in this work to detect subtle abnormalities in patients with mild traumatic brain injury (MTBI). A new concept, termed dynamic variability, is introduced in this work to quantify and localize gait variability. Three chronic MTBI patients were recruited from the Veterans Affair Medical Center in Iowa City, IA, and three healthy controls with height, weight, and gender matched to the patients were recruited from the Reserve Officers' Training Corps in Iowa City, IA. Kinematic and kinetic data of the subjects were collected during the performance of three gait testing scenarios. The first test involved single-task walking and was used as a baseline. The second and third tests were dual tasks that involved walking while performing a cognitive or motor task and were designed to magnify gait abnormalities. The results showed that MTBI patients had reduced gait velocity, shortened stride length, and larger step width; findings that are consistent with those published in the literature. The new dynamic variability factor found that, as compared to controls, MTBI patients had more variability in their hip and ankle joint moments. MRI-DTI has been used to detect dysfunction of the major white matter tracts in chronic MTBI patients; although, the sample size of this study was too small to detect a difference between the MTBI and control subjects. The imaging and gait abnormalities are suggestive of frontal lobe-white matter tracts dysfunction.

Conversation is a highly interactive and coordinated effort between interactants. For example, interactants often mimic the behaviors and speech of one another and coordinate the timing of behaviors, or interactional synchrony. Despite being affected in certain neurological and psychiatric disorders, the neural mechanisms underlying these processes are not understood. The goal of this study is to understand the role of the ventromedial prefrontal cortex (vmPFC), an area of the brain involved in social and emotional behavior, for interpersonal coordination, including mimicry and interactional synchrony. To test the role of the vmPFC for mimicry, normal comparison (NC), brain damaged comparison (BDC), and participants with vmPFC damage interacted in two sessions with a research assistant (RA) who was performing a target behavior (1st session: nodding, 2nd session: face touching). The amount of time the participants spent nodding or touching their face in each session was recorded. NC and BDC participants tended to mimic the partner and nodded slightly more in the session in which the RA was nodding, and touched their face slightly more in the session in which the RA was touching their face. In contrast, vmPFC patients showed no difference in their behaviors in either session, suggesting that they were not influenced by the partner's behaviors and did not mimic them. In a second experiment, all of the above participant groups had a naturalistic conversation with an unfamiliar interactional partner. The conversational data were analyzed for numerous aspects of interpersonal coordination, including convergence of number of words, words per turn and backchannels, reciprocity of self-disclosures, the use of questions, interactional synchrony, and a time series analysis of response latency and speech rate. The vmPFC participants performed consistently worse than NC participants on convergence of words and words per turn, self-disclosures and asking questions. All brain-damaged participants were impaired on aspects of interactional synchrony, and no conclusive results were found for the time series analysis of response latency and speech rate. This study provides support for the hypothesis that the vmPFC is important for interpersonal coordination as the vmPFC group differed significantly from the NC group on the majority of the analyses. The final goal of this study was to understand the effects of traumatic brain injury (TBI) on interpersonal coordination. TBI patients participated in all of the experiments described above and preliminary results showed that they also seemed to be impaired on the mimicry task, and they performed slightly worse than NC participants on many of the interpersonal coordination analyses of the conversational data. This suggests that TBI also does seem to affect certain aspects of interpersonal coordination.

Stroke increases neurogenesis (birth of new neurons) through upregulation of ciliary neurotrophic factor (CNTF), a potent neurogenic cytokine made almost exclusively in the central nervous system. Previous study found that CNTF is induced and needed to stimulate neurogenesis in the subventricular zone (SVZ) of mouse brain in a stroke model. CNTF also has a neuroprotective function. Focal adhesion kinase (FAK), protein tyrosine kinase 2, is ubiquitously expressed in various cell types and mediates cell adhesion and migration. We previously discovered that systemic inhibition of FAK upregulates CNTF expression in the SVZ, making FAK a pharmacological target to increase CNTF to promote neurogenesis and neuroprotection after stroke. This study examined whether systemic FAK inhibitor treatment after stroke regulates SVZ neurogenesis and neuroprotection using a middle cerebral artery occlusion (MCAO) to induce a stroke in adult male C57BL/6 mice. A filament was inserted in the external carotid artery and then fed through the carotid bifurcation into the internal carotid artery to the base of the middle cerebral artery. After 30 minutes of occlusion, the filament was removed to restore blood flow. Mice were randomly assigned to receive 3 daily doses of saline or FAK inhibitor (FAK14, i.p., 3 mg/kg) and treatment started at 6 hours, 12 days, or 58 days after MCAO. Because CNTF has a neuroprotective function, the amount of tissue damage was analyzed to compare treatment groups. The neuroprotective role of FAK14 was examined by measuring MCAO-induced infarction. The infarct size was measured using the absence of NeuN (neuronal cell marker) and GFAP (activated astrocytes) and presence of CD68 (activated microglia). FAK14 given at 6 hours post-stroke reduced the infarct size to 38% of the uninjured side of the brain compared to 46% with saline. Proliferating cells were labeled by injecting bromodeoxyuridine (BrdU, 50 mg/kg), the mice were processed 2 h after the last BrdU injection, and proliferated cells in the SVZ were counted with unbiased stereology. There were no significant differences in the total numbers of BrdU+ cells between saline and FAK14 at 3, 14 and 60 days. Future studies are needed to confirm the levels of CNTF at the various times of treatment. If there is no difference in CNTF expression or increased expression of counteracting cytokines, no difference in neurogenesis between groups would be expected. The neuroprotective effect of FAK14 during the acute phase following injury could provide novel pharmacological options to stroke patients extending the current therapeutic treatment window.

abstract: Mild TBI (mTBI) has been associated with subtle executive function (EF) and cognitive-communication deficits. In bilinguals, there are unique cognitive demands required to control and process two languages effectively. Surprisingly, little is known about the impact of mTBI on EF, communication, and language control in bilinguals. Therefore, the aim of this study was to examine the cognitive-communication abilities in bilinguals with a history of mTBI, identify any language control impairments, and explore the relationship between these language control impairments and domain-general cognitive control abilities. To this end, three-hundred and twenty-seven monolingual and bilingual college students with and without mTBI history participated in two experiments. In these experiments, EF, communication, and language control were examined using experimental and clinical tasks as well as self-rating scales. In Experiment 1, there was an interaction between mTBI history and language group (monolinguals vs. bilinguals) in how participants performed on a clinical measure of EF and a verbal fluency task. That is, only bilinguals with mTBI scored significantly lower on these tasks. In addition, there was a significant correlation between errors on a language switching task and performance on non-verbal EF tasks. In Experiment 2, a subgroup of bilinguals with persistent cognitive and behavioral symptoms reported greater everyday communication challenges in their first and second languages. Also, unbalanced bilinguals reported greater EF difficulties than monolinguals and balanced bilinguals regardless of mTBI history. In conclusion, bilinguals may face unique cognitive-communication challenges after mTBI. Factors related to the bilingual experience (e.g., language balance, daily language use) should be considered in clinical evaluation and future research. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2020

Traumatic brain injury (TBI) is considered the “signature injury” for United States Veterans who deployed in support of Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND) since 2001. Veterans with TBI may be at higher risk for subsequent intentional and unintentional injuries due to cognitive and executive function impairments from the injury and co-occurring psychiatric conditions. This dissertation evaluated the association between TBI and attempted suicide, motor vehicle accidents, and opioid overdose, in a large cohort of United States OEF/OIF/OND Veterans aged 18 to 40 who received care in the Veterans Health Administration (VHA). These studies utilized data from the VHA electronic medical records collected between April 2007 and September 2012. Study 1 evaluated the association between TBI and attempted suicide. Veterans with TBI had approximately a 4-fold increased risk of attempted suicide compared to those without, adjusting for demographics (adjusted hazard ratio (aHR): 3.73, 95% CI = 3.07, 4.53). The mediation analyses suggested that the psychiatric conditions substantially attenuated the impact of TBI on attempted suicide (aHR: 1.25 (95% CI = 1.05, 1.48). Study 2 evaluated the association between TBI and motor vehicle accidents. Veterans with TBI had a 56% increased risk of motor vehicle accident compared to those without, adjusting for demographics (aHR: 1.58, 95% CI = 1.27, 1.97). However, the mediation analyses attenuated this association (aHR: 1.17, 95% CI = 0.96, 1.43). Study 3 evaluated the association between TBI and opioid overdose among OEF/OIF/OND Veterans receiving long-term opioid treatment for non-cancer, chronic pain. Veterans with TBI had 2-fold increased risk for opioid overdose compared to those without, adjusting for demographics (aHR: 2.00, 95% CI = 1.26, 3.16). Nevertheless, the mediation analyses suggested that psychiatric conditions attenuated the impact of TBI on opioid overdose (aHR: 1.38, 95% CI = 0.94, 2.01). In conclusion, these studies add to the literature about risk of intentional and unintentional injuries among Veterans with TBI. Additionally, it highlights that Veterans with TBI and at least one co-morbid psychiatric condition are a particularly vulnerable group with the highest risk for injuries.