Rugby is a popular sport in South Africa, and has been played by young boys from as early as seven years old (South African Rugby Union [SARU], 2011). Despite various physical health benefits, it carries a high risk for injury, especially head injury, and consequently has a high incidence of concussion (Alexander, 2009; Laubscher, 2006; Shuttleworth-Edwards, Smith & Radloff, 2008). It is common for 12 to 13 per cent of adolescent rugby players to report mild traumatic brain injury or concussion per season (Laubscher, 2006; Shuttleworth-Edwards et al., 2008). The true incidence is however considered to be higher, even as high as 70.4% (Shuttleworth-Edwards et al., 2008). Concussion, otherwise known as mild traumatic brain injury (mTBI) is described as a traumatically induced alteration in mental status, or traumatically induced cerebral dysfunction (Kraus, McArthur, Silvermand & Jayaraman, 1996) which may, or may not involve loss of consciousness (Quality Standards Subcommittee, American Academy of Neurology [AAN], 1997). The nature of concussion has traditionally been considered to be transient, and symptoms are usually resolved within a few days or weeks (Kirkwood et al., 2008; Taylor et al., 2010). However, when concussions are not fully resolved prior to players returning to the game, they may be vulnerable to second impact syndrome. This syndrome causes herniation and brain oedema, which may result in death (Patel, 2005), as has been reported in South African press (Alexander, 2009; South African Press Association [SAPA], 2012). Even without second impact syndrome, repeated concussions may render the brain neurocognitively vulnerable, leading to an array of short- and long-term cognitive symptoms (Alexander, 2009; Shuttleworth-Edwards et al., 2008). Short-term problems include difficulties with attention, focus and concentration; following multi-step instruction, engaging in mental problem-solving; verbal expression, receiving and processing verbal and visual information; maintaining effective levels of mental and physical energy; controlling mood; suppressing impulsive behaviours; initiating and maintaining productive interpersonal relationships with peers; engaging in meaningful conversation and participating in group activities (Jantz & Coulter, 2007). Short-term cognitive impairments due to repeated concussion have also been found, and include amongst the former symptoms, also problems with delayed memory, learning, social functioning, and abstract thinking (Anderson, Brown, Newitt & Hoile, 2011; Laubscher, 2006). Long-term sequelae follow when children did not return to their baseline level of functioning after three months (Kirkwood et al., 2008; Taylor et al., 2010). Long-term sequelae include problems with memory, visuo-motor processing, executive functioning, learning and abstract thinking (Anderson, 2002; Anderson et al., 2010; Horton et al., 2010; Lezak et.al., 2004; Shuttleworth-Edwards & Radloff, 2008). As mTBI is traditionally thought to be of transient nature, researchers tend to investigate moderate to severe TBI, rather than mTBI (Alexander, 2009; Anderson et al., 2010; Patel, 2005). This could easily lead to important facts about mTBI being missed or not acknowledged. Nevertheless, recent investigations are uncovering facts about mTBI that could transform the way in which we understand mTBI, providing increasing evidence that mTBI is more serious than widely believed (Blakemore, 2012; Maxwell, 2011; Toleda et al., 2012). However, there remains a lack of research investigating mTBI from a single cause. Considering the above information, the current study provides unique information about mTBI. It specifically investigated the long-term effects of mTBI on adolescents from a homogenous cause, which makes results more comparable. The importance of this study is highlighted in the face of evidence for the long-term effects of multiple concussions, that were sustained during school rugby, on academic achievement (Alexander, 2009; Laubscher, 2006).In the light of grey areas in existing research, the aim of this current study was to investigate whether there is a significant difference in academic achievement within and between two groups of adolescents that had either played rugby and sustained multiple concussions, or had not played rugby nor sustained any concussions, when measured at four points in time over six years. A retrospective data-analysis was performed on matched, controlled, prospective longitudinal data, which was obtained from a study that evaluated the impact of repeated mTBI on the cognitive and academic functioning of early adolescent rugby players over time (Alexander, 2009). This study elaborates on a subset of the previous data, adding the gr. 12 results for academic aggregate scores, to the previously reported academic dataset. Participants were selected from Alexander‟s study (2009), and had either played rugby and obtained two or more concussions (Rugby/Concussed (RC- group); n=17), or did not play rugby nor sustained any concussions (Non-rugby/Non-concussed (NRC-group); n=13). Academic aggregate scores from baseline (gr. 7) through gr. 12 were analysed using quantitative statistical measures. A normal probability plot determined that the data was distributed normally. Descriptive statistics were reported, where after repeated measures ANOVA‟s were conducted to determine the statistical significance of differences in academic scores between and within the groups over time. These results indicated that the NRC-group displayed statistically significant increase in academic achievement over time (p = .000), whereas the RC-group did not display any significant differences, despite displaying a downwards trend in achievement. The difference between the two groups was measured at its highest in gr. 12 (p = .003), indicating that the NRC-group performed statistically significantly better than the RC-group over time. However, a Pearson‟s correlation test revealed that the estimated IQ (Vocabulary subscale of the WISC-III) (Wechsler, 1991) had a positive correlation on academic achievement [r(34) = .54, p < .05)]. To control for the effect that this correlation had on the academic results, an ANCOVA was conducted. This analysis indicated a statistically significant difference in academic achievement between the two groups in gr.12 (p = .004), with a large effect size (d = 1.41), implicating practical significance. Findings consequently confirmed our hypothesis. The significant increase in academic achievement observed within the NRC-group over time, is consistent with what could be expected if the brain is allowed to develop normally without disruption such as mTBI (Blakemore, 2012; Horton et al., 2010). The finding that the RC group did not display statistically significant intra-group differences in academic achievement when measured over time, but that academic achievement followed a downward trend, is difficult to substantiate in the literature. The few research studies on the effect of cumulative concussion on young athletes do not isolate academic achievement as a variable (Iverson et al., 2004; Shuttleworth-Edwards et al., 2008). Further research into intra-group differences in this specific area of enquiry and population group is therefore necessary. Normal cognitive and brain development, maintains that the brain develops in a posterior to anterior direction, and the prefrontal regions which are vulnerable to concussion, develop last (Anderson, 2010; Blakemore, 2012; Lezak, 2004). Whereas the primary motor and sensory areas and areas for receptive and expressive language are fully developed by the age of ten years, the prefrontal brain areas that are responsible for more complex and abstract thought repertoires only start maturing in early adolescence and this development continues up to the age of 24 and even into the early 30s (Toleda et al., 2012). Injury to the developing brain at this critical stage of maturation may adversely affect the development of cognitive skills, preventing the child from acquiring the effective cognitive strategies needed for normal academic functioning and adequate academic achievement after TBI (Horton et al., 2010). However, if there is no insult to the brain, cognitive functions are expected to develop normally as a result of synaptic pruning and increased white-matter volume in the prefrontal cortex (Blakemore, 2012), making it likely that the maturation of these abilities will lead to greater cognitive and academic ability (Blakemore & Choudhury, 2006), such as seen for the NRC-group in this study. Limitations for this study include a small sample size and the testing of only one variable. It is therefore recommended that future studies include more variables, and aim at creating a larger, randomized sample size, possibly providing a more representative pool of participants to study this phenomenon in South African context. It is also advised that future studies consider using neuropsychological measures to test cognitive functioning. As previous studies have indicated specific impairment in executive functioning after TBI, it may be worth researching the effect of concussion on executive functioning more thoroughly (Anderson, 2002; Anderson et al., 2010; Horton et al., 2010). Further it may be valuable to consider using functional MRI studies to broaden existing knowledge about the interaction between pathophysiology and cognitive functioning This study also highly recommends that schools and rugby clubs catering for child and adolescent players reconsider the importance of implementing proper return to play protocols after players obtain concussions. / Thesis (MA (Clinical Psychology))--North-West University, Potchefstroom Campus, 2013

No description available.

Mild traumatic brain injury (mTBI), often referred to as concussion, has become increasingly recognized as a serious health issue in the general population. The prevalence of mTBI in athletes, particularly repeated injuries in young athletes, is of great concern as injuries to the developing brain can have long-term detrimental effects. In this study we used a novel awake closed-head injury (ACHI) model in rodents to examine repeated mTBI (rmTBI), to determine if repeated injuries produced the neurological and molecular changes evident with human concussion. Animals were administered 4, 8, and 16 rmTBIs and acute neurological assessments were performed after the injuries. Changes in glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (Iba-1) levels were assessed using Western blot analysis at one day following rmTBI in the ipsilateral dentate gyrus (DG) and the cornu ammonis (CA) regions of the hippocampus and the cortex (CX) indicative of astrocyte and microglial cell reactivity. Results indicated that the ACHI model produces neurological deficits immediately after the injuries, with the most deficits arising in the rmTBI16 group. Despite deficits in all injury groups, histological staining with cresyl violet revealed no significant morphological tissue damage to the brain. Western blot analysis, however, showed a significant increase in DG and CX GFAP expression in the rmTBI16 group with no changes in Iba-1 levels. This suggests an acute activation of astrocytes in response to injury, with a delay or absence of microglial activation. Our findings show that with repetitive concussions, we are able to detect acute neurological and molecular changes in the juvenile female brain. However, further investigation is necessary to determine if these are transient changes. / Graduate

No description available.

Trauma de crânio leve (TCE leve) é definido como um déficit neurológico transitório que ocorre após um trauma incluindo história de náuseas, vômitos, cefaléia ou tontura acompanhada de alteração ou perda da consciência com duração inferior a 15 minutos, amnésia pós traumática e Escala de Coma de Glasgow entre 13 e 15. Apesar da alta taxa de sobrevida, pode cursar com alguma morbidade, principalmente nos três primeiros meses posteriores ao trauma e cerca de 18 % dos pacientes desenvolvem pelo menos uma síndrome psiquiátrica no primeiro ano após o acidente. O diagnóstico ainda é um desafio no sentido de minimizar-se gastos desnecessários com exames subsidiários entretanto, intervenções precoces podem evitar seqüelas. Nosso objetivo foi verificar o impacto do TCE leve na qualidade de vida de suas vítimas e diagnosticar as várias alterações neuropsicológicas que podem advir deste trauma. Esses alterações podem ser verificadas através de instrumentos de pesquisa. Inicialmente, foram avaliadas cinqüenta vítimas com TCE leve, atendidas no Hospital João XXIII, em Belo Horizonte - MG, as quais foram submetidas a dosagem de proteína S100B e tomografia de crânio (TCC) na admissão. Nessa fase, verificou-se que a proteína S100B tem valor preditivo negativo de 100%. Dezoito meses após o trauma, esses pacientes foram procurados em suas residências, quando foi lhes solicitado para que respondessem a quatro instrumentos de pesquisa [dois para diagnóstico de qualidade de vida (World Health Organization WHOQOL-100), e o Short Form-36 (SF-36), um para análise da presença de ansiedade e depressão (Escala Hospitalar de Ansiedade e Depressão (EHAD) e o Questionário de Sinais e Sintomas (QSS), baseado no Post Concussion Questionnaire] com o objetivo de pesquisar a presença de sinais e sintomas da síndrome pós-concussão. Também foram pesquisados aspectos sociodemográficos, como idade, escolaridade, estado civil, renda pessoal e origem desta renda. Os mesmos questionários foram preenchidos por um grupo de controle composto, necessariamente, por coabitantes dos pacientes, sem história de trauma craniano de qualquer gravidade e com idade a mais próxima possível da do paciente. Na avaliação pelo WHOQOL-100, pacientes apresentaram qualidade de vida inferior nos domínios nível de independência, ambiente e no total de domínios (p< 0,05). Na avaliação do SF-36, pacientes revelaram qualidade de vida inferior nos domínios capacidade funcional, vitalidade, saúde mental (p<0,001), dor, estado geral de saúde e aspectos mentais (p<0,05). Pacientes apresentaram mais ansiedade e estavam uma classe acima de seus controles pela EHAD. Pacientes referem ainda número maior de sinais e sintomas da síndrome pós-concussão do que seus respectivos controles. Não verificamos correlação entre a qualidade de vida, classificação na EHAD ou número de sinais e sintomas da SPC com as dosagens de proteína S100B ou com a presença de lesão na TCC realizadas na admissão / Mild head trauma (MHT) is defined as a transitory neurological deficit that happens after the trauma and includes a history of nausea, vomiting, headache or dizziness and loss or alteration of consciousness (less than 15 minutes), post-trauma amnesia, and Glasgow Coma Scale (GCS) at admission between 13 and 15. Despite the high survival rates, some morbidity has been observed in the three month period after this trauma. Approximately 18% of head trauma patients develop at least one psychiatric syndrome in the first year after the accident. The diagnostics difficulty and the risks of complications after the MHT continue to be a relevant problem at the emergency departments around the world. Limitations of active participation in daily life are alterations that influence life quality. Several of these alterations may be diagnosed through Interview Instruments. Our study was divided in two phases. In the first phase, 50 MHT patients admitted at Hospital João XXIII, Belo Horizonte-MG, Brazil, had protein S100B dosing and head CT taken at admission. Concentration values of S100B lower than 0.01 g/l were considered negative once this was the lowest value found in patients who did not show brain injuty signs in the CT scan. In that study it was found that protein S100B has 100% negative predictive value. In this second phase of the study, 18 months after the trauma, these patients were contacted at their homes and asked to answer four self- assessment questionnaires: two for quality of life diagnostic - World Health Organizations WHOQOL-100 and the Short Form-36 (SF36); one for the analysis of anxiety and depression - Hospital anxiety and depression scale-HADS; and one instrument developed by the author based on the Rivermead Post Concussion Questionnaire to evaluate the presence of post-concussion syndrome signs and symptoms. Several socio-demographic aspects were also analyzed, including income, source of income, means of transportation used, etc. The same questionnaires were filled by a control group formed necessarily by patients co-inhabitants, with no history of head trauma of any severity, and with closest age as possible to the patients. In the WHOQOL assessment patients showed a lower quality of life in the independence, environment, as well as in the total domains (p< 0,05). In the SF 36 assessment patients showed a lower quality of life in the functional capacity, vitality, and mental health domains (p<0,001); and also in pain, general health situation, and mental aspects (p<0,05). Patients showed more anxiety and, in the HADS Scale, showed at least a level higher, on average, than their controls. Patients also showed a higher number of post-concussion signs and symptoms than their respective controls. We did not find correlation between the later quality of life and protein S100B dosing at admission. We were not able to find correlation between the protein concentrations with the presence of brain lesions in the CCT scans taken at patients admission in the emergency department

La présente thèse porte sur les effets à long terme des traumatismes craniocérébraux légers (TCCL), incluant les commotions cérébrales, ainsi que sur certains facteurs influençant l’évolution post-blessure chez deux populations considérées vulnérables, soit les athlètes féminines ainsi que les adultes vieillissants. Dans une première étude, les capacités olfactives d’athlètes féminines commotionnées, mais asymptomatiques, ont été évaluées en moyenne deux ans après la dernière commotion. L’intérêt de cette étude réside principalement dans l’investigation du rôle potentiel du polymorphisme BDNF Val66Met (BDNFMet), associé à une sécrétion réduite de la protéine BDNF impliquée dans la neuroplasticité, pour expliquer les variations du fonctionnement olfactif post-commotion. Dans une deuxième étude, les effets cognitifs d’avoir subi un seul TCCL ont été caractérisés chez des individus âgés de 50 à 70 ans ayant subi leur blessure environ cinq ans plus tôt. Cette caractérisation est particulièrement pertinente alors que la majorité des études s’intéressant aux effets à long terme de cette blessure ont étudié des individus ayant subi de multiples TCCL. De plus, cette étude visait à évaluer si un programme d’entraînement physique aérobie de douze semaines permettrait d’améliorer les fonctions cognitives altérées chez les TCCL comparativement aux contrôles. Les résultats de la présente thèse permettent d’abord de mieux caractériser certains effets à long terme du TCCL. Plus précisément, la première étude suggère un patron de fonctionnement olfactif distinct selon le génotype BDNF chez les athlètes féminines commotionnées. Ainsi, les porteuses du BDNFMet ont significativement mieux performé que les BDNFval aux différentes tâches olfactives. Puisque cette relation génétique n’était pas présente chez les participantes contrôles, ces résultats suggèrent que le fonctionnement olfactif, suite à une commotion cérébrale, est, du moins en partie, médié par le polymorphisme BDNFMet. La deuxième étude suggère, pour sa part, des effets cognitifs à long terme d’avoir subi un seul TCCL chez des individus sédentaires, mais en santé, âgés de 50 à 70 ans. Ainsi, les participants TCCL ont moins bien performé que les participants contrôles, appariés pour l’âge et le sexe, aux tâches neuropsychologiques mesurant des aspects de la vitesse de traitement de l’information, du fonctionnement exécutif (planification, fluence verbale) et de la mémoire visuelle. Cette étude n’a toutefois pas relevé de différence sur le plan de l’attention, de l’inhibition, de la mémoire verbale et des habiletés visuoconstructives. Ces résultats cognitifs sont un ajout intéressant à la littérature, car ils surviennent chez des individus qui ne présentaient aucun des facteurs de risque (maladie chronique, problème de santé mentale) typiquement associés aux effets à long terme des TCCL. En ce qui a trait au deuxième volet de l’étude, l’exercice physique aérobie a permis d’améliorer les capacités cardiorespiratoires (VO2max) des patients TCCL davantage que les étirements (condition contrôle). Toutefois, dans ce petit échantillon de seize participants, l’exercice aérobie n’a pas permis d’améliorer les fonctions cognitives altérées des patients TCCL. Différentes explications possibles sont abordées afin de guider les futures études. / The following thesis investigates the long-term effects of mild traumatic brain injury (mTBI), including concussions, and factors influencing post-injury evolution in two vulnerable populations: female athletes and aging individuals. In a first study, olfactory capacities of asymptomatic concussed female athletes were evaluated an average of two years after their last concussion. The appeal of this study lies mainly in its investigation of the potential role of the BDNF Val66Met (BDNFMet) polymorphism, which is associated with reduced secretion of the BDNF neuroplasticity protein, on post-concussion olfactory variations. In a second study, cognitive effects of sustaining a single mTBI were assessed in individuals between 50 and 70 years old who sustained their injury on average five years earlier. This characterization is particularly relevant given that most studies focusing on long-term effects of this injury have studied individuals having sustained multiple mTBI. Furthermore, this study also aimed to evaluate if a twelve-week aerobic exercise program would allow improvements of altered cognitive functions in mTBI patients. Results from the following thesis first allow to better describe some long-term effects of mTBI. More precisely, the first study suggests different patterns of olfactory functioning according to BDNF genotype in female concussed athletes. Thus, BDNFmet carriers performed significantly better than BDNFval carriers at the different olfactory tasks. Given that this genetic relationship was not present in control participants, these results suggest that olfactory functioning following a concussion is, at least in part, mediated by the BDNFmet polymorphism. As for the second study, it suggests long-term cognitive effects of having sustained a single mTBI in sedentary, but healthy, individuals between the ages of 50 and 70. Indeed, mTBI participants showed lower performance when compared to age and sex-matched control participants on neuropsychological tasks measuring aspects of processing speed, executive functioning (planning, verbal fluency) and visual memory. This study did not find any difference regarding attention, inhibition, verbal memory and visuoconstructive abilities. These cognitive results are an interesting contribution to the literature as they occur in individuals presenting no risk factor (chronic disease, mental health disorders) typically associated with long-term effects of mTBI. Regarding the second phase of this study, aerobic exercise improved cardiorespiratory fitness (VO2max) more than stretching (control condition) in mTBI patients. However, in this small sample of sixteen participants, aerobic exercise did not allow to improve altered cognitive functions in mTBI participants. Different possible explanations are addressed to guide future studies.

<div>Adolescent collision-sport athletes may be exposed to repetitive head impacts over years of practices and competitions without immediately observable symptoms. Despite the growing concerns, these athletes often continue play while at risk. Concrete objective measurements are desired to inform prompt and effective preventative strategies for this vulnerable population. However, adolescent brains are rapidly developing and the accrual of brain injury is often subtle. Prospective screening with sensitive biomarkers is challenging and requires advanced technologies, rigorous data processing, and the interdisciplinary expertise of engineering, neurobiology, and cognitive sciences.</div><div><br></div><div>To address the challenge, we first developed population-specific brain atlases to facilitate reproducible and meaningful statistical analyses. The atlases better characterized the neuroanatomy of early-to-middle adolescent (ages 13-19) collision-sport athletes, reduced deformation introduced during spatial normalization, and exhibited higher sensitivity in image analysis compared to standardized adult or age-appropriate brain templates. The atlases can be further applied to monitor the neuroanatomical trajectory and can serve as a coordinate reference system to retrospectively harmonize data collected from different sites and imaging acquisition parameters, facilitating group analysis at large scale.</div><div><br></div><div>Next, to assess whether the changes of white matter microstructure can be attributed to repetitive head impacts and are reflected by cognitive performance, we analysed the diffusion tensor imaging (DTI) data of high school men’s football and women's soccer across a single season, with accompanying data from head impact sensors and neurocognitive assessments. Within multiple brain regions, we observed significantly altered DTI metrics, both transiently over a season and chronically with more years of high school experience. For the football players, hits with peak translational acceleration over 37 <i>g</i> were sufficient to alter the distributions of DTI changes, and deficits in white matter microstructure correlated with poorer performance of anti-saccade task at one month post-season, suggesting increased vulnerability for inhibitory control. Monitoring repetitive head impacts thus provides a temporal profile for identifying at-risk individuals during the competitive season, informing prompt interventional strategies, therefore protecting the brain and cognitive health of early-to-middle adolescent collision-sport athletes in the long run.</div>

Over the last two decades, several studies have revealed the presence of olfactory disorders (OD) following moderate and severe traumatic brain injuries (TBI). Specifically, previous authors have shown that, following a TBI, several patients had quantitative (hyposmia/anosmia) and qualitative (parosmia) loss of sense of smell in important proportions. For moderate and severe TBI, the presence of such disorders, following trauma, is usually due to a coup-contrecoup mechanism responsible for the shearing of olfactory nerves penetrating the cribriform plate or to contusions or secondary hemorrhages within the olfactory bulb and cortical olfactory areas. Since these types of TBI cause obvious lesions, it was relatively simple to understand the nature of such disorders as well as identify the patients at risk of developing olfactory losses. A close follow-up of these patients is necessary since different studies have demonstrated associations between OD following TBI and long-term development of mood (depression, anxiety). Patients developing OD following moderate to severe TBI exhibited more symptoms of anxiety and depression for several weeks following the trauma, when compared to patients without OD. On the other hand, there are only three studies that have investigated the presence of OD and their consequences in patients with mild traumatic brain injury (mTBI), even though they represent nearly 85% of TBI. Moreover, due to the presence of several methodological flaws (choice of invalid evaluation tools, omission of a control group) a great heterogeneity regarding the proportion of mTBI patients who develop OD after the trauma, is found within the literature. So, the studies included in this thesis aim to give, with the establishment of a valid and controlled methodology, the very first idea of the proportion of patients with mTBI who will develop quantitative and qualitative OD. In addition, the predictive value of OD following mTBI on the development of anxiety and depressive symptoms and general health, is also covered in the manuscript. The first study aimed to assess the presence of olfactory disorders within the first 24 hours and one year after the mTBI. The results of this cross-sectional study demonstrated that, in the acute phase, more than half of the patients with mTBI exhibited a partial loss of their sense of smell (hyposmia). In fact, when compared to an orthopedic control group, the proportion of mTBI patients with OD following their accident was significantly higher. When evaluated one year after their mTBI, the patients did not have OD and no significant difference was found between control and mTBI groups. However, when comparing mTBI patients with OD (OD+) to those who did not present OD (OD-) at baseline, we found that OD+ mTBI patients reported significantly more anxiety and post-concussion symptoms, when evaluated one year following their trauma. The second study of this thesis aimed to deepen the results of the previous one, with the help of a larger group of patients, a longitudinal design as well as the implementation of new tools in order to evaluate a broader spectrum of post-concussive symptoms. In this study, olfaction and mood of patients with mTBI were evaluated 1 and 6 months following the trauma. The results show that, when compared to a group of control participants, a significantly high proportion of mTBI patients report a distortion of their olfaction (parosmia), 1 and 6 months following the trauma. In addition, the hierarchical regression analyzes indicate that, within the mTBI group, the presence of baseline parosmia significantly increases the value of the predictive model for the development of depression and anxiety. In conclusion, these two studies provided a much more accurate picture of the actual proportion of mTBI patients at risk of developing post-traumatic OD. Indeed, due to the numerous methodological controls applied, these results paint a more realistic portrait of the short and long term presence of OD following mTBI. Thus, these two projects have revealed alarming proportions, going far beyond what is recorded in the restricted literature available to date. In addition, it appears that baseline presence of qualitative OD following mTBI is a significant predictor of the development of symptoms of anxiety and depression. / Au cours des deux dernières décennies, plusieurs études ont révélé la présence de troubles olfactifs suite à des traumatismes crâniens (TCC) modérés et sévères. Spécifiquement, les précédents auteurs ont montré que, suite à leur TCC, plusieurs patients présentaient des pertes quantitative (hyposmie, anosmie) et qualitative (parosmie) de leur odorat. Dans le cas des TCC de types modérés et sévères, la présence de tels troubles est généralement causée par l’effet de coupcontre coup provoquant des lésions du nerf olfactif pénétrant dans la lame criblée de l’ethmoïde ainsi que par des contusions et des hémorragies au niveau du bulbe olfactif et des régions corticales traitant les stimuli olfactifs. En effet, puisque ces types de TCC provoquent des lésions assez apparentes, il a été facile de comprendre la nature de tels troubles ainsi que d’identifier les patients à risque de développer des pertes olfactives. Un suivi de ces patients est d’autant plus nécessaire puisque différentes études ont démontré des associations entre les pertes olfactives suite au TCC et la chronicisation de troubles de l’humeur (dépression, anxiété) et cognitifs. En effet, il a été démontré que, les patients développant des troubles olfactifs suite à un TCC modéré/sévère, présentaient davantage de symptômes d’anxiété et de dépression plusieurs semaines suite au trauma, lorsque comparés à des patients n’ayant pas de troubles olfactifs. En revanche, il n’y a que trois études qui ont, jusqu’à aujourd’hui, étudié la présence de troubles olfactifs et leurs conséquences auprès de patients ayant subi un traumatisme craniocérébral léger (TCCL), malgré le fait qu’ils représentent près de 85% des patients TCC. De plus, dû à la présence de plusieurs faiblesses méthodologiques dans les précédentes études (choix d’outils d’évaluation non valides, omission de groupe contrôle) une grande hétérogénéité, en ce qui a trait à la proportions de patient TCCL vivant avec un trouble olfactif, est retrouvée dans la littérature. Ainsi, les études composant le présent ouvrage visent globalement à évaluer, à l’aide d’une méthodologie valide et contrôlée, la réelle proportion de patients ayant subi un TCCL qui développeront un trouble olfactif. De plus, un regard sera posé sur les capacités prédictives de la présence de troubles olfactifs suite au TCCL sur le développement, à long terme, de symptômes anxieux et dépressifs. La première étude visait à évaluer la présence de troubles olfactifs dans les premières 24 heures et un an suite au TCCL. Les résultats de cette étude transversale, à caractère exploratoire, ont démontré que, en phase aiguë, plus de la moitié des patients ayant subi un TCCL présentaient une perte partielle de leur odorat (hyposmie). En effet, lorsque comparée à un groupe de patients contrôle, ayant subi une blessure orthopédique, la proportion de patients TCCL ayant un trouble olfactif suite à leur accident s’est révélée significativement plus élevée. Lorsqu’évalués un an suite à leur TCCL, les patients ne présentaient plus de troubles olfactifs et aucune différence significative ne fut retrouvée entre les patients TCCL et orthopédique. Cependant, lorsque nous avons comparé les patients TCCL qui, à l’évaluation initiale, présentaient un trouble olfactif (OD+) à ceux qui n’en présentaient pas (OD-) à l’évaluation initiale, nous avons trouvé que les patients TCCL OD+ rapportaient significativement plus de symptômes anxieux et post-commotionnels, lorsqu’évalués un an suite à leur trauma. La deuxième étude de cet ouvrage visait à approfondir les résultats de la précédente, à l’aide d’un plus grand groupe de patients, d’un devis longitudinal ainsi que l’implantation de nouveaux outils d’évaluation permettant d’évaluer un plus large spectre de symptômes post-commotionnels. Dans cette étude, l’olfaction et l’humeur des patients ayant subi un TCCL furent évaluées 1 et 6 mois suite au trauma. Les résultats montrent que, lorsque comparé à un groupe de participants contrôles, une proportion significativement élevée de patients TCCL rapporte avoir remarqué une distorsion de leur olfaction (parosmie), 1 et 6 mois suite au trauma. De plus, les analyses de régression hiérarchique indiquent qu’au sein du groupe de patients TCCL, la présence de parosmie au premier temps de mesure (court-terme) augmente significativement la valeur du modèle de prédiction de la présence de symptômes dépressifs et anxieux à long terme. En somme, ces deux études ont permis de dresser un portrait beaucoup plus précis de la réelle proportion de patients TCCL qui risquent de développer un trouble olfactif. En effet, grâce aux divers contrôles méthodologiques que nous avons appliqués, les présents résultats permettent de peindre un portrait plus réaliste de la présence, à court et long-terme, de troubles olfactifs suite à un TCCL. Ainsi, ces deux projets ont mis en lumière des proportions allant bien au-delà de ce qui est recensé dans le peu de littérature disponible à ce jour. De plus, il semble que la présence initiale de troubles olfactifs suite au TCCL soit un prédicteur significatif du développement des symptômes d’anxiété et de dépression des patients.

Le traumatisme craniocérébral léger (TCCL) s'accompagne d'une constellation de symptômes de nature variée, appelés symptômes post-commotionnels (SPC). La majorité des patients se rétablissent complètement et rapidement, à savoir dans le mois qui suit l'accident. Cependant, 10 à 20 % d'entre eux présentent un rétablissement prolongé avec des SPC persistants (SPCP), lesquels entravent la qualité de vie, l'intégration à la communauté et le retour aux activités. Pour la minorité de patients présentant des SPCP, il est donc nécessaire d'intervenir au-delà de la psychoéducation préventive aiguë recommandée par les guides de pratique. Or, il existe très peu d'interventions visant spécifiquement à outiller ces patients afin de diminuer les SPC et ainsi, accélérer le rétablissement. En effet, à l’heure actuelle, les interventions psychologiques et psychoéducatives développées spécifiquement pour la phase post-aiguë, qui prend place entre les phases aiguë (0-1 mois après le TCCL) et chronique (> 6 mois post-accident), sont particulièrement rares. Les quelques études existantes plaident en faveur d'une approche brève de quelques séances de psychoéducation et/ou de soutien. Cependant, il s'agit de données préliminaires et de nombreuses inconnues subsistent encore quant au format idéal (ex. : en personne vs par téléphone, individuel vs en groupe, nombre de séances, contenu précis). En outre, la pauvre qualité méthodologique des études complique significativement les interprétations possibles à ce sujet (ex. : absence de groupe contrôle, groupes non randomisés). L'objectif principal de cette thèse était donc de développer une nouvelle intervention de psychoéducation et de soutien destinée aux personnes en phase post-aiguë du rétablissement post-TCCL, et d’explorer sa faisabilité ainsi que son efficacité. L'objectif du premier article de la thèse (Chapitre 2) était de remédier à la pauvreté de la littérature en ce qui a trait, d'une part, à la description des protocoles d'intervention de psychoéducation et, d'autre part, relativement à leurs assises théoriques. Il avait donc pour objectif de présenter la démarche théorique et méthodologique associée au développement de l'intervention SAAM, un programme de quatre séances d'intervention individuelles d’une heure, données en personne, et visant chacune un type de SPC fréquent en phase post-aiguë : Sommeil/fatigue, Attention, Anxiété/humeur, Mémoire/organisation. Le programme offre de l'information au patient, le rassure sur son rétablissement et l'accompagne vers un retour graduel aux activités, en l'outillant à cet effet. Cette approche est ancrée dans un modèle théorique intégratif de persistance des symptômes (Hou et al., 2012), dont les composantes sont expliquées dans l'article. Celui-ci permet non seulement de mieux saisir les fondements théoriques associés à la création du nouvel outil d'intervention, mais en dévoile également son contenu. Il met donc en lumière une démarche qui s'inscrit parfaitement dans un effort de clarification et de transparence, essentiel au progrès de la recherche interventionnelle. Plus largement, ce travail permettra de faciliter la réplication scientifique et de soutenir le transfert de connaissances vers les milieux cliniques. Le deuxième article de la thèse (Chapitre 3) avait pour objectif d'estimer la faisabilité et d’explorer l'effet de l'intervention SAAM auprès de patients symptomatiques en phase post-aiguë de leur rétablissement. Une étude pilote d’essai contrôlé randomisé à deux groupes parallèles (expérimental, n = 13 et liste d'attente, n = 12) a permis de démontrer la faisabilité et la tolérance à l’intervention SAAM. Les données préliminaires suggèrent un effet de l’intervention sur la diminution des SPC en général. En ce qui a trait plus directement aux SPC visés par l'intervention SAAM, une amélioration des plaintes reliées aux symptômes dépressifs, à la fatigue et à la perception de la qualité du sommeil a été mise en évidence à la suite de l'intervention. Cependant, l’étude n'a pas montré d’effet bénéfique du programme SAAM en termes de plaintes somatiques ni de performance cognitive (attention, mémoire). De plus, aucun effet n'a été observé sur le plan de l'intégration à la communauté. Des analyses supplémentaires (Chapitre 4) suggèrent que l'intervention SAAM pourrait restaurer le besoin de compétence, un besoin psychologique fondamental intimement relié au bien-être des individus. Enfin, des analyses supplémentaires portant sur un questionnaire de satisfaction face à l'intervention confirment un haut taux de satisfaction des participants face à l'intervention, ce qui est de bon augure pour l'implémentation en milieux cliniques. Par son aspect novateur, son format standardisé bref et facilement accessible, ainsi que ses effets objectivés sur plusieurs SPCP particulièrement invalidants à la suite du TCCL, le programme d'intervention SAAM est prometteur. La portée clinique de cette thèse est donc particulièrement importante et est discutée, avec ses limites et les avenues de recherche futures, dans le dernier chapitre. Ces résultats soulignent l'importance de poursuivre la recherche dans le champ des interventions post-TCCL, afin d’outiller les cliniciens et d’offrir les meilleurs soins possibles aux patients ayant subi un TCCL. / Mild traumatic brain injury (mTBI) is accompanied by a constellation of manifestations known as post-concussive symptoms (PCS). The majority of patients recover completely and promptly, i.e. within one month of injury. However, 10-20 % experience prolonged recovery with persistent PCS (PPCS), which impact quality of life, community integration and resumption of activities. For the minority of patients who present PPCS, it is necessary to provide them with resources beyond the acute preventive psychoeducation recommended by practice guidelines. However, there are very few interventions available to reduce PCS and thus enhance recovery. To date, psychological and psychoeducational interventions developed specifically for the post-acute phase, which takes place between the acute (0-1 month after mTBI) and the chronic phase (> 6 months post-injury), are particularly rare. The scarce existing evidence suggests that the optimal intervention should be brief, including a few sessions of psychoeducation and/or counseling. Nevertheless, these are preliminary data and many open questions remain regarding the optimal format (e.g., in person vs. on the phone, individual vs. group, number of sessions, specific content). Moreover, the poor methodological quality of previous intervention studies significantly complicate interpretations (e.g., absence of control groups, non-randomized groups). The main objective of this thesis was therefore to develop and explore the feasibility and treatment effect of a novel psychoeducational and counseling intervention program for the post-acute phase after mTBI. The objective of the first article of the thesis (Chapter 2) was to overcome the paucity of work describing psychoeducational intervention protocols and their theoretical underpinnings. The article therefore aimed to present the theoretical and methodological approach associated with the development of the SAAM intervention. SAAM is a program including four 1-hour individual intervention sessions given in person, each targeting a type of common PCS in the post-acute phase: Sleep/fatigue, Attention, Anxiety/mood, Memory/organization. It informs the patient, provides reassurance about recovery, and supports the gradual resumption of activities by giving the patient the tools to do so. This approach is anchored in an integrative theoretical model of symptom persistence (Hou et al., 2012), the components of which are explained in the article. The latter provides a better understanding of the theoretical rationale behind the development of the SAAM intervention, and includes a detailed description of the protocol. The article is meant to align with efforts to clarify the theoretical underpinnings of the intervention program and enhance transparency in scientific reporting, an essential step in the advancement of interventional research. More broadly, this work will facilitate scientific replication and knowledge transfer in clinical settings. The second article (Chapter 3) aimed to estimate feasibility and explore the treatment effect of the SAAM intervention in symptomatic patients during the post-acute phase. A pilot randomized controlled trial with two parallel groups (experimental, n = 13 and wait list, n = 12) demonstrated the feasibility and tolerability of the intervention. Preliminary data suggest an effect of the intervention in reducing overall PCS. More specifically, regarding the PCS targeted by the SAAM intervention, an improvement in complaints related to depressive symptoms, fatigue, and sleep quality perception was observed post-intervention. However, the intervention failed to show a positive effect in addressing anxiety or somatic complaints, nor was it significantly impactful in improving cognitive performance (attention, memory). No effect was observed in terms of community integration either. Nonetheless, additional analyses (Chapter 4) suggest that SAAM intervention might restore the need for competence, a basic psychological need closely related to the individual's well-being. Finally, additional analyses pertaining to an intervention satisfaction questionnaire confirm that participants report a high level of satisfaction with the intervention, which bodes well for clinical implementation. The SAAM intervention holds promise because of its innovative aspect, its brief and easily accessible standardized format, and its demonstrated effects on several disabling PCS. The clinical significance of this thesis is notable and is discussed, along with study limitations and future avenues of research, in the final chapter. This work emphasizes the importance of pursuing research efforts in the field of post-mTBI interventions, in order to provide clinicians with the tools they need to offer the best possible care to patients who have sustained mTBI.

Le traumatisme crânio-cérébral léger (TCCL) est reconnu comme un sérieux problème de santé publique et a fait l’objet de nombreuses études scientifiques étant donné sa prévalence élevée. Les enfants d’âge préscolaire, définis ci-après comme les enfants âgés de cinq ans et moins, constituent un groupe hautement à risque de subir une telle blessure, mais demeurent pourtant sous représentés dans la littérature. Or, une blessure à un si jeune âge peut être particulièrement redoutable en raison de la vulnérabilité du cerveau immature et du mince registre d’acquis. La présente thèse a pour objectif d’accroître les connaissances scientifiques sur les conséquences du TCCL chez l’enfant d’âge préscolaire. Plus spécifiquement, elle vise à évaluer l’impact d’une telle blessure sur le sommeil et le fonctionnement exécutif. La thèse est composée de deux articles empiriques. L’objectif du premier article était d’évaluer le sommeil de l’enfant d’âge préscolaire six mois après un TCCL, et d'identifier les facteurs contribuant au sommeil post-TCCL. L'échantillon comprenait 225 enfants âgés entre 18 et 60 mois, répartis en trois groupes : enfants ayant subi un TCCL (n = 85), enfants ayant subi une blessure orthopédique (n = 58) et enfants au développement typique (n = 82). Six mois après la blessure, les parents ont complété l’échelle des problèmes de sommeil du Child Behavior Checklist, et un sous-groupe d’enfants a porté un actigraphe pendant cinq jours. Les résultats n’indiquent aucune différence entre les trois groupes d’enfants ni au questionnaire complété par les parents, ni aux paramètres de sommeil mesurés par l’actigraphe, soit la durée et l’efficacité du sommeil nocturne. Toutefois, la présence de difficultés de sommeil pré-morbides et une blessure caractérisée par une altération de la conscience nuisent au sommeil mesuré six mois post-TCCL. Le deuxième article visait à évaluer le fonctionnement exécutif six mois après un TCCL, et le rôle du sommeil dans le fonctionnement exécutif post-TCCL auprès de la même cohorte d’enfants. Les enfants ayant subi un TCCL (n = 84) et les enfants au développement typique (n = 83) ont été inclus dans les analyses. Les résultats n’indiquent aucune différence de groupe aux épreuves d’inhibition et de flexibilité cognitive administrées six mois après la blessure. Par ailleurs, les enfants ayant subi un TCCL qui présentent plus de problèmes de sommeil ou un sommeil nocturne de plus courte durée ont des performances inférieures aux tâches exécutives comparativement aux enfants au développement typique. Les résultats de cette thèse permettent une meilleure compréhension du sommeil après un TCCL en bas âge et des facteurs y contribuant. De plus, la thèse démontre l’importance de surveiller le sommeil post-TCCL étant donné que des perturbations de sommeil peuvent avoir des répercussions sur le fonctionnement de l’enfant, notamment sur ses habiletés exécutives. / Mild traumatic brain injury (mTBI) is a highly prevalent and serious public health concern. Epidemiological data indicate that preschoolers (i.e., children under 5 years of age) are at especially high risk of sustaining TBI, yet few studies targeted this age group. This is of concern given that the brain is still immature in the early years of life, and children are at the beginning of their development, with few consolidated skills. The overall objective of this thesis is to expand our understanding of the impact of preschool mTBI, specifically on sleep and executive functioning. The thesis includes two empirical articles. The first article aimed to investigate sleep and its predictors in preschoolers with mTBI. The sample included 225 children, aged 18 to 60 months, divided into three groups: children with mTBI (n = 85), children with orthopedic injury (n = 58) and typically developing children (n = 82). Six months post-injury, parents were asked to fill out the Sleep scale from the Child Behavior Checklist, and children wore an actigraph for five days. No group differences were found in parental ratings of sleep problems or for nighttime sleep duration and sleep efficiency, as measured by actigraphy. However, preexisting sleep disturbances and brain injury resulting in alteration of consciousness were identified as predictors of poorer sleep six months post-injury in the mTBI group. The aim of the second article was to investigate executive functions six months post-injury in the same cohort of preschoolers, and to determine the role of sleep in the links between mTBI and executive functioning. Children with mTBI (n = 84) and typically developing children (n = 83) were included in the analyses. There were no significant group differences on measures of inhibition and cognitive flexibility six months post-injury. However, relative to controls, children with mTBI and shorter nighttime sleep duration or increased sleep problems exhibited poorer executive functions. This thesis allows a better understanding of the factors associated with sleep disturbance after preschool mTBI. In addition, the results highlight the importance of documenting sleep in preschoolers with mTBI, as sleep difficulties place children at risk for later executive dysfunction, which may subsequently impact other spheres of functioning.