Les commotions cérébrales d’origine sportive sont fréquentes chez les athlètes professionnels et semblent l’être tout autant chez les jeunes sportifs. Chez l’adulte, les symptômes se résorbent dans la majorité des cas assez rapidement (7-10 jours), mais la récupération peut s’avérer différente chez les jeunes. Plusieurs études utilisant les potentiels évoqués cognitifs ont découvert des anomalies cérébrales en l’absence de symptômes cliniques observables chez l'adulte. Toutefois, peu de données scientifiques sont disponibles sur les répercussions d’un tel impact sur le cerveau en développement. Le but de l’étude était de déterminer s’il existe une relation entre l’âge de survenue au moment de la commotion et la gravité des déficits. Cette étude transversale a évalué le fonctionnement cognitif de sportifs par des tests neuropsychologiques ainsi que les mécanismes neuronaux de l’orientation de l’attention (P3a) et de mise à jour de l’information en mémoire de travail (P3b) à l’aide de potentiels évoqués cognitifs. Les athlètes étaient répartis selon trois groupes d’âge [9-12 ans (n=32); 13-16 ans (n=34); adultes (n=30)], la moitié ayant subi une commotion dans la dernière année. Les comparaisons entre les groupes ont été effectuées par une série d’ANOVAs. Comparativement au groupe contrôle, les adolescents commotionnés présentaient des déficits de mémoire de travail. Les athlètes commotionnés démontraient une réduction de l’amplitude de la P3b comparativement aux non-commotionnés. Les résultats illustrent la présence de déficits neurophysiologiques persistants et ce, au moins six mois suivant l’impact. Les enfants semblent aussi sensibles que les adultes aux effets délétères d’une commotion cérébrale et les conséquences s’avèrent plus sévères chez l’adolescent. / Sport-related concussions are common injuries among professional athletes as well in adolescents and children participating in organized sports. Although the majority of concussions resolve rapidly in adults (7-10 days), recovery could be different in younger athletes. Several studies using event-related potentials show that adult athletes have cerebral anomalies in the absence of clinical symptoms. However, the consequences of a sport-related concussion on the developing brain are less known. The purpose of this study was to determine whether age differences exist with respect to cognitive functioning following a sport-related concussion. This cross-sectionnal study assessed cognitive functioning using standardized neuropsychological tests as well the neuronal mechanisms associated with the re-orienting attention (P3a) and with the update of information in working memory (P3b), using event-related potentials. Athletes were divided into three age groups [9-12 yrs (n=32); 13-16 yrs (n=34); and adults (n=30)] half of whom suffered from a sport-related concussion. Group comparisons were investigated with a series of ANOVAs. Specifically, concussed adolescents showed persistent deficits in working memory compare with their non injured counterparts. Concussed athletes from all age groups had significantly lower amplitude for the P3b component of their ERPs compared to their non injured teammates. No age-related differences for ERP’s were found among the concussed groups. These data suggest persistent neurophysiological deficits that are present at least 6 months following a concussion. Children appear to be as sensitive as adults to the consequences of a concussion and adolescents seem experience the most severe outcomes.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

<div>Recent advances in Magnetic Resonance Imaging (MRI), a noninvasive imaging technique, have spurred the exploration of poorly understood physiological phenomena <i>in vivo</i>. Applications of MRI vary greatly, from anatomical evaluation to complex functional analysis. The body of this dissertation presents four applications of MRI: 1) investigation of a novel traumatic brain injury (TBI) biomarker, 2) analysis of position-specific head acceleration events on neurometabolic profiles in high school football athletes, 3) the first reporting of neurometabolic changes in middle school football athletes, and 4) a novel application of diffusion-weighted imaging (DWI) to characterize implantable drug-delivery depots (Appendix A).</div><div> </div><div>Magnetic resonance spectroscopy (MRS) is an MRI method used to evaluate the metabolic profiles of tissues. Certain brain metabolites (N-acetyl aspartate, <i>myo</i>-inositol, choline, creatine, and glutamate/glutamine) offer unique information regarding brain homeostasis following TBI. When coupled with additional metrics, such as head acceleration events recorded during collision-sport participation, the mechanisms of neurophysiological changes can be further elucidated. Here, player position-specific neurometabolic changes were evaluated in high school and middle school football athletes. Striking differences were noted between linemen and non-linemen as well as high school and middle school athletes.</div><div> </div><div>However, in most clinical cases of TBI, information regarding head acceleration events is unknown and baseline scans are not available.Therefore, it is critical to evaluate candidate biomarkers which increase solely in response to injury. Acrolein, a toxic reactive oxygen species, has been shown to increase following injury to the central nervous system in animal models. Hence, acrolein is a prime TBI biomarker candidate and has been investigated using nuclear magnetic resonance and MRS at 7 Tesla.</div><div> </div><div>Applications of MRI are not limited to the brain, or even tissues. Studies have reported that up to 50% of patients fail to take their medications correctly - resulting in disease progression and medication waste. <i>In situ</i> forming implants (ISFIs) offer an alternative to oral dosage regimens but have not been validated <i>in vivo. </i>Using DWI, ISFIs can be characterized noninvasively and their design can be refined, ultimately improving patient outcomes.</div><div> </div><div>Taken together, MRI is powerful tool that can be used to investigate a wide range of physiological questions. Chapters 2-4 will emphasize efforts to improve TBI diagnostics and better understand neurometabolic changes in youth football athletes. Appendix A offers insights into the DWI-guided characterization of <i>in situ</i> forming implants.</div>

The aim of this study was to examine the depiction of mental illness with elite athletes. Mental illness has long been a sensitive object in the public's eye, but in recent years that has started to shift and the subject has destigmatized. More and more people are open and talk about their inner problems. But in one group in society the development has not been up to pace, and that is elite athletes. The study has also looked at the difference between tabloid and daily press. The theoretical framework was constructed by using the agenda setting theory, the framing theory, theories of media logic and the thoughts of news evaluation. The method used in the study was critical discourse analysis, and used in the way through out by Norman Fairclough and his three dimensional modell. A total of 38 articles from the newspapers Dagens Nyheter, Svenska dagbladet, Aftonbladet and Expressen was analyzed. The analysis found that the papers tend to portray mental illness as a negative major problem of today's society. A majority of the articles analyzed tended put the athlete aspect of the person in limelight, rather than letting the athlete just be a suffering person. They way the papers achieved to sustain the image of being a unbeatable hero by reminding the audience about the athletic achievements won, when the athlete was presented in the article. Keywords: Johan Franzén, Jenny Rissveds, mental illness, depression, concussions, concussion, eating disorder and eating disorders.

The NeuroTracker (NT), a computerized three-dimensional multiple object tracking (3D-MOT) training device, has potential benefits for concussion assessment and management, as well as maintenance of cognitive function. Accessing 3D technology is a limiting factor for 3D-MOT, so we assessed the performance of MOT training in 2D and 3D environments in both healthy and concussed individuals (8-91 years of age). The participants (n=86) who completed all ten training sessions over the three-month period, were assigned to one of three different studies: (1) an environment comparison (2D versus 3D), (2) an age comparison (youth, young adult, and older adult), or (3) a concussed population comparison (non-concussed, recently concussed, and prolonged concussed). In all studies, performance increased with training, indicating all individuals could increase perceptual cognitive function in all environments. Significant differences were apparent when 2D and 3D environments were compared, with participants in the 3D environment out performing participants in the 2D environment. Furthermore, switching from the 3D to the 2D environment was detrimental to learning performance. When comparing learning performance between different aged individuals, a linear regression demonstrated learning performance increased at a lesser rate with age(p<0.05). Concussed populations also demonstrated correlative trends when comparing learning performance, as well as initial NT scores. The longer an individual was suffering from concussion symptoms, the lower the initial NT score was, but the higher the rate of learning performance was through out training. Further investigation into attention, memory, and visual processing speeds in each population may help to better resolve the relationship between these domains and clarify if NT can serve as a means for concussion assessment and rehabilitation for individuals at any age in the future. / Graduate

The purpose of this qualitative study was to indicate the experiences of collegiate student-athletes in meeting academic demands when experiencing prolonged recovery from concussion and if they perceive a need for academic accommodations. There is a gap in present concussion and an absence of studies that examine if academic accommodations are helpful during concussion recovery. The study was guided by 3 research questions focused on the return to learn during the recovery process. The study was limited to 9 student-athletes currently enrolled at three postsecondary institutions: Christian Brothers University, Rhodes College, and the University of Memphis. The study participants met pre-established criteria for the study, were recruited by their athletic trainer at their respective institution, and voluntarily participated in individual interviews with the researcher or co-interviewer. Through a phenomenological approach, individual interviews were conducted with the participants. Four themes were identified in the data: negative impact on academic performance, academic pressures, inequity of student-athlete treatment, and impact on concentration ability. Each study participant’s story was shared through the data analysis process, and significant statements from the interviews as related to the research questions were included in the data analysis section. Ultimately, the data suggested that future research continue to focus on how student-athletes' recovery from concussion impacts their return to learn process.

Graduation date: 2004

Background: Research suggests that musculoskeletal injury (MSI) influences cognitive functioning. Cognitive functioning following MSI in athletes is not evaluated currently. Purpose and Method: To examine cognitive deficit in athletes following musculoskeletal injuries, the Automated Neuropsychological Assessment Metric (ANAM) was administered to 22 varsity athletes prior to competition and following MSI. A healthy comparison group of 22 athletes was also tested at time intervals matched with the injured group. Results: A 2 (Group) X 2 (Time) repeated measures ANOVA revealed significant main effects for time on ANAM subtests of Delayed Code Substitution and Simple Reaction Time. Post-hoc Paired t-Tests revealed significant improvements in both groups for Simple Reaction Time, and a significant improvement for the comparison group on Match-to-Sample. Implications: Athletes with musculoskeletal injuries did not show cognitive deficit post-injury; however, the apparent absence of practice effects on a test of spatial processing and working memory requires further examination.

Background: Research suggests that musculoskeletal injury (MSI) influences cognitive functioning. Cognitive functioning following MSI in athletes is not evaluated currently. Purpose and Method: To examine cognitive deficit in athletes following musculoskeletal injuries, the Automated Neuropsychological Assessment Metric (ANAM) was administered to 22 varsity athletes prior to competition and following MSI. A healthy comparison group of 22 athletes was also tested at time intervals matched with the injured group. Results: A 2 (Group) X 2 (Time) repeated measures ANOVA revealed significant main effects for time on ANAM subtests of Delayed Code Substitution and Simple Reaction Time. Post-hoc Paired t-Tests revealed significant improvements in both groups for Simple Reaction Time, and a significant improvement for the comparison group on Match-to-Sample. Implications: Athletes with musculoskeletal injuries did not show cognitive deficit post-injury; however, the apparent absence of practice effects on a test of spatial processing and working memory requires further examination.

Les commotions cérébrales subies en contexte sportif constituent un sujet préoccupant. Il est estimé qu’aux États-Unis, environ cinq pourcent de l’ensemble des athlètes subiront une commotion cérébrale. Celle-ci est considérée comme une blessure transitoire dans la majorité des cas. Dans le domaine de la commotion cérébrale sportive, le phénomène de risque accru chez des athlètes ayant subi préalablement des commotions cérébrales est bien documenté. Cet aspect remet en question l’aspect transitoire de la blessure. Les techniques d’imagerie fonctionnelle offrent un grand potentiel dans la compréhension de cette pathologie en montrant notamment les différences fonctionnelles chez des participants ayant subi un traumatisme crânio-cérébral léger en l’absence de résultats comportementaux. Il est probable que des altérations fonctionnelles persistent au-delà de la phase de récupération postsymptômes. L’électrophysiologie, en particulier les potentiels évoqués cognitifs sont un outil de choix pour étudier la question en raison de leur sensibilité et de la mesure fonctionnelle qu’ils permettent d’obtenir. Les potentiels évoqués cognitifs consistent en une réponse électrique cérébrale moyenne générée lors de l’accomplissement d’une tâche. Il est possible d’identifier différentes composantes dans le tracé d’un potentiel évoqué; ces composantes sont associées à différents aspects de l’activité électrique cérébrale durant le traitement perceptuel et cognitif.Les articles scientifiques inclus dans cette thèse se penchent sur les effets de commotions cérébrales multiples chez des athlètes plusieurs mois après la dernière commotion. Dans un premier temps, l’aspect temporel est évalué par le biais de la mesure de la P3a et la P3b dans différents groupes d’athlètes. Ces composantes sont liées aux processus de mémoire et d’attention. Les résultats suggèrent que, malgré un fonctionnement normal, les athlètes ayant subi des commotions cérébrales éprouveraient de probables changements cognitifs sous-cliniques persistants se traduisant par une atténuation des P3a et P3b. Des altérations seraient aussi présentes quelques années après la dernière commotion, mais de façon plus subtile. La deuxième étude soumise s’intéresse aux processus électrophysiologiques liés au maintien de l’information en mémoire de travail visuel chez des athlètes ayant subi plusieurs commotions cérébrales. La mesure utilisée est la SPCN (sustained posterior controlateral negativity), une composante ERP spécifique au processus cognitif étudié. Les résultats montrent non seulement une composante atténuée chez les athlètes ayant subi trois commotions cérébrales ou plus, mais aussi une modulation de la composante en fonction du nombre de commotions cérébrales subies. Ces résultats pourraient contribuer à expliquer le risque accru de subir des commotions cérébrales subséquentes observées chez ces athlètes. En lien avec la littérature, ces données pourraient s’expliquer par la présence de déficits cognitifs sous-cliniques ou encore par la mise en place de mécanismes compensatoires. Enfin, ces résultats invitent à une grande prudence dans la gestion des cas de commotions cérébrales ainsi qu’à un effort d’éducation plus poussé chez les jeunes athlètes afin qu’ils puissent prendre les meilleures décisions concernant leur avenir. / Concussions sustained in sporting contexts are a major concern. In United States only, it has been estimated that among all athletes in college teams, 5% will be concussed. According to an agreement following an international symposium on concussion in sport, in most cases, this is a transient injury. Within the field, it is known that the likelihood of sustaining a concussion increased as a function of the number of past concussions. This aspect challenges the transient conception of the injury. Functional imaging techniques such as functional magnetic resonance imaging (fMRI) or eventrelated potentials (ERP) showed functional alterations in absence of any behavioral changes within concussed athlete groups. ERP consist in the averaged cerebral electrical signal recorded on the scalp during a given stimulation or task. Many components may be identified within the signal, each associated to specific perceptual and cognitive functioning. In concussed athletes, it is possible that functional alterations persist well beyond the acute period. ERP have been chosen to study this topic because of their sensitivity. Scientific papers included in this thesis discuss the effects of multiple concussions among young adult athletes months after the last concussion. The first study investigates two groups of athletes with multiple concussions at different time points. P3a and P3b were used as electrophysiological markers. These components are known to be related to attention and memory functions. Results demonstrate that, despite normal neuropsychological evaluation, attenuation is present on both P3. Those changes were still present years after, but in a more subtle manner. The second study describes the effect of multiple concussions on sustained posterior contralateral negativity (SPCN), an ERP component specifically related to information maintenance in visual working memory. Results showed that athletes who sustained three concussions or more display an attenuated SPCN. Also, a modulation of the SPCN as a function of the number of concussions was point out. Overall, these results might help to explain the increased risk of further concussions among concussed athletes. It is possible that results are explained by subclinical cognitive deficits and/or compensatory mechanisms. Finally, such data invites extra precaution in the management of concussions. Also, it seems important to give young athletes plenty of information to allow them to make more enlightened decisions about their future.