Introduction: Despite the unique act of actively using the head as part of the game in soccer, insufficient attention is paid to its potential harmful effects. There is an increased concern regarding head trauma in soccer and its impact both in the short- and long-term. Only a few studies have examined the ability of head protection to mitigate head trauma, and opinions differ regarding its effectiveness. Objective: The purpose of this project was to investigate the injury mechanisms behind concussions in soccer and its short- and long-term effect. Furthermore, the project aimed to evaluate the ability of head protection to protect against head impacts in soccer. Methods: Two finite element models of THUMS version 4.02 pedestrians were used to simulate head collisions between two players, with the aim of mimic an aerial duel in soccer. Different impact angles and impact points were simulated, after which worst case scenarios were selected for further evaluation with head protection. The kinematics of the head and the strains of the brain tissue were used to evaluate the head's response to impacts and to evaluate the effectiveness of head protection. Results: The study showed that the maximum strain of the brain tissue as well as the kinematics of the head were sensitive to the point of impact, while the angle of impact did not show any significant influence. Head protection showed a good ability to reduce the kinematics of the head and the strain of the brain tissue. A thicker head protector had an increased ability to reduce the max values and a low friction head protector had the capacity to further reduce the max values in certain types of impacts. Conclusion: Head protection showed promising ability to reduce head kinematics and the maximum strain of the brain tissue. / Introduktion: Trots den unika handlingen av att aktivt använda huvudet som en del av spelet i fotboll, ägnas otillräcklig uppmärksamhet åt dess potentiella skadliga effekter. Det finns en ökad oro kring huvudtrauman inom fotboll och dess påverkan både på kort och lång sikt. Endast ett fåtal studier har undersökt huvudskydds förmåga att mildra huvudtrauman och olika åsikter råder angående dess effektivitet. Syfte: Syftet med detta projekt var att undersöka skademekanismerna bakom hjärnskakningar inom fotboll samt dess kort- och långsiktiga påverkan. Vidare ämnade projektet till att utvärdera ett huvudskydds förmåga att skydda vid huvudislag inom fotboll.  Metoder: Två finita element modeller av THUMS version 4.02 fotgängarmodell användes för att simulera huvudkollisioner mellan två spelare, i syfte att imitera en luftduell i fotboll. Olika islagsvinklar och islagspunkter simulerades varpå värsta scenarier valdes för vidare utvärdering med huvudskydd. Huvudets kinematik samt töjningar av hjärnvävnaden användes för utvärdering av huvudets respons på islag samt för att undersöka huvudskydds effektivitet.  Resultat: Studien visade att den maximala töjningen av hjärnvävnaden samt kinematiken av huvudet var känslig för islagspunkt medan islagsvinkeln inte visade på någon signifikant inverkan. Huvudskydd visade på god förmåga att reducera huvudets kinematik och töjningen av hjärnvävnaden. Ett tjockare huvudskydd hade en ökad förmåga att reducera maxvärdenaoch ett huvudskydd med låg friktion hade kapaciteten att reducera maxvärdena ytterligare vid vissa typer av islag.. Slutsats: Huvudskydd visade på lovande förmåga att reducera huvudets kinematik och den maximala töjningen av hjärnvävnaden.

Le syndrome post-commotionnel (SPC) a été proposé comme un ensemble de symptômes qui peuvent apparaître après un traumatisme crânien léger (TCL) et perdurer des semaines, des mois, parfois jusqu’à un an, engendrant des conséquences importantes sur la vie quotidienne. Des débats entourent la définition et même l’existence du SPC. Ils portent notamment sur la spécificité des symptômes (qui peuvent apparaître dans d’autres conditions, ou chez des personnes non traumatisées), et sur la validité des outils diagnostiques qui restent très hétérogènes. La relation entre le SPC et le stress post-traumatique (SSPT) est également au cœur de ces questionnements. La cohorte PERICLES permet d’apporter un éclairage sur ces questions. Elle porte sur un groupe de patients TCL ainsi qu’un groupe de patients avec un traumatisme léger dont le siège n’est pas la tête. Dans un premier temps, nous avons étudié la spécificité des symptômes en comparant leur prévalence et évolution entre ces deux groupes de patients. Nous avons ensuite tenté de définir un critère diagnostique à partir des symptômes spécifiques à l’aide de tests de corrélations et analyse factorielle. Les facteurs prédictifs du SPC ont été évalués à partir de ce critère, à l’aide d’une régression logistique. Dans un deuxième temps, les facteurs prédictifs des SPC et SSPT ont été évalués et comparés, tout comme la proximité des symptômes des deux syndromes, à l’aide d’une analyse des correspondances multiples. Huit symptômes ont été sélectionnés comme spécifiques au TCL. Un critère diagnostique a pu être défini à partir de ces huit symptômes. Le TCL a été observé facteur prédictif du SSPT (OR = 4,47 [2,38 - 8,40]) mais pas du SPC. Enfin, les symptômes du SPC présentaient une forte proximité avec les variables de la dimension « hypervigilance » du SSPT. Ainsi, le SSPT apparaît être plus spécifique du TCL que le SPC. Les variables du SPC semblent être proches de celles du SSPT. Il semblerait que le stress lié au traumatisme joue un rôle plus important dans la persistance de symptômes à long terme que le mécanisme subi par le cerveau. / Postconcussion syndrome (PCS) has been proposed as a set of symptoms that may occur after mild traumatic brain injury (MTBI) and continue for weeks, months, sometimes up to a year, causing a significant impact on daily life. Debates surround the definition and even the existence of the PCS. They relate in particular to the specific symptoms (which may occur in other conditions or in people not traumatized), and the validity of diagnostical tools that are very heterogeneous. The relationship between the SPCS and post-traumatic stress disorder (PTSD) is also at the heart of these questions. The Pericles cohort can shed light on these issues. It focuses on a group of MTBI patients and a group of patients with mild trauma not related to the head (controls). At first we studied the specificity of symptoms by comparing their prevalence and evolution between these two groups of patients. We then attempted to define a diagnostical test based on specific symptoms using test correlations and factor analysis. Predictors of PCS were evaluated from this test, using logistic regression. In a second step, predictors of PCS and PTSD were assessed and compared, as well as the proximity between symptoms of both syndromes using a multiple correspondence analysis.Eight symptoms were selected as specific to MTBI. A diagnostic criterion has been defined from the eight symptoms. TCL was observed as a predictor of PTSD (OR = 4.47 [2.38 to 8.40]) but not of PCS. Finally PCS symptoms showed strong proximity with variables from "hypervigilance" PTSD dimension. Thus, PTSD appears to be more specific to MTBI than PCS. PCS variables appear to be similar to those of PTSD. It seems that the stress linked to the trauma plays a more important role in the persistence of long-term symptoms than the mechanism of the brain.

Sammanfattning Bakgrund: Studier tyder på bristande kunskaper angående hanteringen av idrottsrelaterad hjärnskakning samt i rehabilitering efteråt. Ryttares återgång till fysisk aktivitet kopplat med en jargong som främjar en för snabb återgång, där saknas studier.  Syfte: Att undersöka och beskriva en grupp tävlingsryttares upplevelser och erfarenheter av att ha fått en idrottsrelaterad hjärnskakning samt återgången till sin idrott, vardagsliv samt fysisk aktivitet. Metod: Data från fem informanter insamlades via semistrukturerade intervjuer och har analyserats med en innehållsanalys. Resultat: I studien framgick det två teman; “Hur IH yttrade sig och påverkade vardagen” samt “Vägen tillbaka” med totalt tio kategorier samt 16 subkategorier. Utifrån resultatet framgick det brister i adekvat information vid vårdtillfället rörande återgång till fysisk aktivitet efter idrottsrelaterad hjärnskakning. Omgivningens reaktioner påverkade ryttarna initialt till en något långsammare återgång till fysisk aktivitet, samtidigt som de egna kraven på skötsel av hästen fanns ständigt närvarande. Konklusion: Studien tyder på att återgången fortfarande går för snabbt men att omgivningens påverkan, i kombination med egen förståelse samt att den tidigare jargongen börjat avta har lett till en långsammare återgång. Dock finns kvarvarande brister angående information kring hur återgången bör ske efter en idrottsrelaterad hjärnskakning inom vården. / Abstract Background: Studies indicate a lack of knowledge regarding the handling of the acute state of sport related concussion and during the rehabilitation afterwards. Equestrians return to physical activity associated with a jargon that promotes an over-rapid return, where studies are lacking. Purpose: To investigate and describe a group of competing equestrians experiences of receiving a suspected or diagnosed sport related concussion and also their return to sport, everyday life and physical activity. Method: Data from five informants were collected through semi structured interviews and analysed with a content analysis. Results: The study showed two themes; “How SRC expressed and influenced everyday life” and “The way back” with a total of ten categories and 16 subcategories. Based on the result, there were shortcomings in adequate information from the time of health care treatment regarding the return to physical activity after a sport related concussion. The society's reaction initially affected the riders to a slower return to physical activity, while the own requirements for taking care of the horse were constantly present. Conclusion: The study indicates that their return still goes on too quick, but the surroundings effects, in combination with their own understanding and that the previous jargon has begun to decline has led to a slower return. However, there are remaining deficiencies regarding the information about how the return should take place after a sport related concussion within the healthcare system.

Bakgrund: Hjärnskakning är en vanlig skada inom ishockey. Efter skada ses även påverkan på cervikala strukturer och nackutredning föreslås som en del i undersökningen efter hjärnskakning.  Neck Flexor Endurance Test är ett test som använts för att mäta nackflexorernas uthållighet. Syftet med den här studien var att fastställa normalvärde för junior-senior ishockeyspelares uthållighet i stabiliserande cervikal muskulatur.  Design:Deskriptiv pilotstudie Metod: Totalt 40 friska ishockeyspelare (33 herrjuniorer och 7 damspelare) testades i ryggliggande. Testpersonen höll huvudet statiskt i given position och testledaren observerade att testen utfördes rätt och klockade tiden med tidtagarur. Inga andra hjälpmedel användes. Varje deltagare hade två försök och tiden mellan försök ett och två var två minuter Resultat: Medelvärde för hela gruppens båda försök var 55,5 sekunder. Medelvärde för försök ett var för hela gruppen 62,3 sekunder +22,8, försök två 48,5 sekunder +18,1. Skillnaden mellan försök ett och försök två var statistiskt säkerställd (p<0,05). Konklusion: 40 friska ishockeyspelare har i den här studien uthållighet i nackens flexorer på i medelvärde 62,3 sekunder i ett försök. Spridningen var för stor för att man ska kunna ge råd om generell baseline. Skillnaden mellan gruppens försök ett och försök två tyder på att längre tid än två minuter behövs för full återhämtning av testade muskler.

The primary aim of the present study was to evaluate the effectiveness of the intervention provided by Massey University Concussion Clinic for individuals following Mild Traumatic Brain Injury (MTBI). Concussion Clinics were set up across New Zealand to provide early intervention and assessment for individuals with MTBI to prevent long term complaints. Treatment outcomes at these clinics have not been empirically examined before. The current study compared the levels of post concussion symptoms, anxiety, depression, and psychosocial functioning between an intervention and a control group using a quasi-experimental design. In addition, reasons for nonattendance to the clinic, and participants’ perceptions of their recovery were also explored. The main outcome measures used were the Rivermead Postconcussion Symptoms Questionnaire, the Hospital Anxiety and Depression Scale, and the Sydney Psychosocial Reintegration Scale-2. Outcomes were initially assessed soon after injury or referral to the clinic and then three months later. Participants were recruited from the Palmerston North Hospital Emergency Department and the Massey University Concussion Clinic. With 20 participants in the intervention group and 15 in the control group, the main results showed that the Concussion Clinic intervention significantly decreased the level of anxiety and depression reported by participants in the intervention group over the control group. Greater improvements in post concussion symptoms and psychosocial functioning were also indicated in the intervention group. Additional findings suggest difficulty with transportation as a reason for nonattendance, which could be a potential barrier to recovery. Furthermore, participants highlighted the benefits of attending the service and its role in their recovery. Important issues relating to the referral processes were also identified. Findings of the current study suggest that the Concussion Clinic intervention is effective in improving recovery for those accessing the service. Nevertheless, these results must be interpreted with caution due to the small sample size. Further research is warranted to examine the effectiveness of the Concussion Clinics with larger samples, and the current study may serve as a valuable pilot for these future investigations.

Neurocognitive and symptom profiles of concussed and nonconcussed adult provincial rugby union players were investigated over one rugby season, including early season (baseline), intermittent postconcussion, and end of season testing. In a non-equivalent quasi-experimental design, nonconcussed (n = 54) and concussed (n = 17) rugby groups were compared with demographically equivalent noncontact sport controls (n = 37, and n = 17, respectively). Measures included the ImPACT cognitive and symptom composites, and the WMS-III Visual Reproduction and Verbal Paired Associates subtests. The independent and dependent comparative analyses in respect of both nonconcussed and concussed groups, provided cross-validation of poorer acute and/or chronic neuropsychological outcomes for the rugby groups on the ImPACT Reaction Time, Visual Motor Speed, Impulse Control and Symptom composites, and the WMS-III Verbal Paired Associates. The finding of significantly poorer scores on Verbal Paired Associates up to 24 days post concussion for the rugby players versus controls, was longer than the 7 – 10 day recovery period frequently cited in the literature. The overall implication of the study is that even in a group with high cognitive reserve such as these provincial level athletes, there may be prolonged acute recovery, as well as permanent deleterious neuropsychological consequences of cumulative concussive injury in association with a sport such as rugby. Accordingly, the move towards careful individualised postconcussion monitoring of neurocognitive functioning is endorsed, including early identification of any significant permanent reductions in cognitive reserve. Sensitivity of the ImPACT test might be enhanced via inclusion of a verbal associate learning task.

Mild traumatic brain injury (MTBI) has gained increasing attention over recent years with much research directed at the nature of persisting symptoms experienced by individuals with MTBI. Owing to the subtle nature of cognitive-communicative difficulties after MTBI, as well as the lack of sensitivity of traditional assessment tools in identifying these difficulties, individuals with MTBI are seldom referred for speech-language therapy services. The need has therefore arisen for the communicative abilities of individuals with MTBI to be assessed in ways other than through the implementation of traditional assessment tools. This preliminary study, for which a qualitative approach with a multiple case study design was adopted, aimed to investigate communication following MTBI from the perspective of a spouse. The spouses of three individuals with MTBI were selected to participate in this study. Semi-structured interviews consisting of two open-ended questions were held with each spouse. The content obtained from the interviews was subjected to a discourse analysis (DA) and the themes that were identified were interpreted within the Model of Social Communication (Hartley, 1995). The results of this study revealed that each of the participants perceived changes in the communication of their spouses since the MTBI. When interpreted within the Model of Social Communication (Hartley, 1995), these communication difficulties were considered to be either the result of impaired internal processes (including impairments in executive control, stored knowledge, subcortical and limbic input or cognition) or the interaction between these impaired internal processes and the environment. The implications of these results regarding the role of the speech-language therapist in MTBI are highlighted. The potential value of the spouse, and the use of DA as both a methodological and clinical tool in the field of speech-language therapy are discussed. Recommendations for future research are made. / Dissertation (M (Communication Pathology))--University of Pretoria, 2007. / Speech-Language Pathology and Audiology / M (Communication Pathology) / unrestricted

La fatigue est l’un des symptômes les plus fréquents et persistants chez les victimes de commotion cérébrale. Au cours des dernières années, des signes d’altérations cognitives post-commotionnelles à la suite d’un effort aérobie, soit une forme de fatigue dont la cause est physique plus que cognitive, ont été trouvés à court et à long terme chez des athlètes étudiants. Or, puisque ces athlètes évoluent dans un contexte où ils doivent non seulement performer dans leur discipline sportive, mais aussi à l’école ou au travail, il convient de se demander si un effort mental soutenu n’aurait pas le même effet chez cette population. L’objectif de cette étude était donc de déterminer si des athlètes étudiants ayant subi une commotion cérébrale (groupe HC) se sentent plus fatigués ou ont davantage tendance à se fatiguer mentalement que ceux n’ayant jamais subi de commotion cérébrale (groupe ST). Les sujets devaient répondre à une série de questionnaires auto-rapportés. Ils devaient aussi compléter une tâche informatisée recrutant les fonctions exécutives avant et après avoir répondu à une épreuve de raisonnement, d’une durée d’une heure, visant à simuler un examen scolaire. Leur réaction physiologique à la tâche était mesurée via un appareil d’électroencéphalographie et un cardiofréquencemètre. Si dans l’ensemble les résultats n’appuient pas l’hypothèse initiale, les deux groupes ont montré des différences notables dans leur façon de répondre à la tâche. Nous avons notamment constaté l’absence d’un effet de pratique à la condition la plus facile ainsi qu’une variabilité de la performance généralement plus élevée chez les sujets avec un historique de commotion cérébrale. De plus, contrairement au groupe témoin, ceux qui rapportaient des symptômes plus importants de fatigue cognitive quotidienne, de somnolence et de dépression montraient également une moins bonne précision à la tâche après un effort cognitif soutenu. Ces résultats suggèrent que les commotions cérébrales pourraient avoir pour effet d’accroître la sensibilité de certains individus à l’effort cognitif. De futures études devraient se pencher sur cette relation afin de la confirmer et d’en comprendre les causes. / Fatigue is one of the most common and persistent symptoms in concussion victims. In recent years, signs of post-concussive cognitive impairment following aerobic exertion, a form of fatigue whose cause is more physical than cognitive, have been found in both shortand long-term in student athletes. However, since these athletes evolve in a context where they must not only perform in their sport, but also at school or at work, it is worth asking whether sustained mental effort would have the same effect in this population. The objective of this study was therefore to determine whether student athletes who have suffered a concussion (HC group) feel more tired or are more likely to become mentally fatigued than those who have never suffered a concussion (ST group). Subjects were asked to complete a series of self-report questionnaires. They were also required to complete a computerized task recruiting executive functions before and after completing a one-hour reasoning test meant to simulate a school examination. Their physiological response to the task was measured using electroencephalography and a heart rate monitor. While the results do not support the original hypothesis, the groups showed significant differences in the way they responded to the task. Particularly, we found the absence of a practice effect at the easiest condition as well as a generally higher performance variability in subjects with a history of concussion. In addition, unlike the control group, those who reported greater symptoms of daily cognitive fatigue, drowsiness and depression also showed poorer task accuracy after sustained cognitive effort. These results suggest that concussions may have the effect of increasing the sensitivity of some individuals to cognitive effort. Future studies should investigate this relationship in order to confirm it and understand its causes.

The process of controlling executive and motor behaviours is central to one’s ability to self-regulate and accomplish day-to-day goals across the lifespan. Executive and motor control share a set of underlying neural substrates that support a common set of processes, including planning, sequencing and monitoring of behaviour. They share a bidirectional relationship, such that gains or deficits in one area can have profound effects on the other. This doctoral dissertation examines the interplay between executive and motor control at three distinct stages of life and in the context of neurological conditions whose clinical manifestations shed additional light on the nature of the constructs. Central to each investigation is the methodological theme of intraindividual variability, as a means of leveraging valuable data within-persons. Chapter 2 examines executive and motor control in typically developing children and children with attention-deficit/hyperactivity disorder (ADHD). Findings suggest that dysregulation of motor processes accounts for hyperactive symptoms in ADHD and detracts from higher-order executive control. Chapter 3 examines the impact of mild traumatic brain injury (mTBI) in young adult varsity athletes, who routinely practice executive motor control by virtue of their level of play. Findings suggest that the impacts of mTBI are discernible through a dampened electrophysiological response during computerized tests of higher order executive functioning, and may not outweigh the otherwise myriad health benefits of athletic engagement. Chapter 4 examines the impact of dementia on executive motor control during gait dual-tasking in older adults. Findings suggest that the consistency of performance across multiple indicators of gait is sensitive to dementia, and that engagement in cognitive and social lifestyle behaviours is protective against likelihood of both dementia and mild cognitive impairment (MCI) classification. On mass, these findings highlight the importance of assessing executive motor control to understand the pathophysiology of neurological conditions. The potential benefits that may generalize from one area to the other offer unique opportunities for preventative and rehabilitative efforts. / Graduate

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