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Ice hockey has been identified as a sport with a high risk for concussions due to it being highly physical. Improvements have been made over the years to improve the protective gear for the players effectively eliminating more severe traumatic brain injuries (TBIs) however mild concussions (mTBI) are still prevalent to this day. One way of predicting these injuries in the recent years is the usage of finite element (FE) analysis to recreate impacts to study the effects of said head kinematics and strain parameters using validated FE models of the brain. In this thesis, video analysis was done on five cases resulting in a concussion and five cases not resulting in concussion from both the Swedish Hockey League (SHL) and the National Hockey League (NHL) to extract the initial velocities and positioning. The average velocity for the injured player and attacking player was 5.12 m/s and 5.08 m/s respectively for the impacts resulting in a concussion. Additionally, the average velocity for the injured player and attacking player was 4.80 m/s and 5.51 respectively for the impacts not resulting in a concussion. The video analysis methodology was also validated using a dataset from a football game and resulted in an average error of 25.4%. The impacts were recreated using the extracted velocities and initial positions in LS-PrePost with the full body FE model THUMS v.4.02 representing a 50th percentile adult male fitted with a helmet previously developed by master thesis students at KTH. The simulations were ran using LS-DYNA. The head kinematics from the head’s center of gravity and brain strain measured called Maximum Principal Strain (MPS) were extracted. Using the MPS values, the 95th percentile was calculated to then determine the likelihood of concussion. The MPS95 ranged from 0.18 to 0.63 for the cases resulting in a likelihood of concussion of 7.48 to 100%. For the cases not resulting in a concussion, the MPS95 values ranged from 0.20 to 0.45 resulting in likelihood of concussion 11.1 to 80.5%. The head kinematics extracted reported similar outcome in terms of risk of suffering concussions. The varying results can be pointed to the drawbacks in the methodology such as the error of the video analysis and the positioning of FE models. / Ishockey har fastställts som en sport med höga risker för hjärnskakning på grund av dess fysiska natur. Med åren har förbättringar gjorts på skyddsutrustningen vilket har avlägsnat allvarligare hjärnskador (TBI) från sporten, men dessvärre förekommer mildare hjärnskakningar än idag. På senare år har användning av finita element (FE) metoder använts för att återskapa kollisionerna för att förutspå dessa skador. Detta görs genom att använda validerade FE modeller av hjärnan för att analysera kinematiken samt töjningarna. I detta arbete gjordes en videoanalys av fem fall som resulterade i hjärnskakning samt fem fall där kollisionen inte resulterade i en hjärnskakning från både den Svenska Hockey Ligan (SHL) och "National Hockey League" (NHL). Från videoanalysen togs de initiala hastigheterna samt positionerna fram. Den genomsnittliga hastigheten för den skadade spelaren respektive attackerande spelaren var 5.12 m/s och 5.02 m/s för fallen där hjärnskakning hade skett. För fallen där hjärnskakning inte hade skett var hastigheten för den skadade respektive attackerande spelaren var 4.80 m/s samt 5.51 m/s. Videoanalysmetoden validerades genom att utföra videoanalysis på en databas från en fotbollsmatch. Valideringen resulterade i ett genomsnittligt fel på 25.4%. Kollisionerna återskapades genom att använda de extraherade initiala hastigheterna och positionerna i LS-PrePost med FE helkroppsdockan THUMS v.4.02 som representerade en 50:e percentil vuxen man utrustad med en ishockeyhjälm som utvecklats av tidigare masterexamensstudenter på KTH. Simuleringarna gjordes genom LS-DYNA. Huvudkinematiken från huvudets tyngdpunkt samt de maximala principiella töjningarna (MPS) i hjärnan extraherades. Från de extraherade MPS värdena kunde den 95:e percentilen uträknas för att bestämma sannolikheten att hjärnskakning sker. För fallen där hjärnskakning skett, varierade MPS95 värdet mellan 0.18 till 0.63 vilket motsvarar en risk för hjärnskakning på 7.48% respektive 100%. För fallen där hjärnskakning inte hade skett varierade MPS95 värdet från 0.20 till 0.45 vilket motsvarar 11.1% respektive 80% risk för hjärnskakning. Den extraherade huvudkinematikens risk för hjärnskakning överensstämde för det mesta med MPS95 sannolikheterna. De varierande resultaten kan hänvisas till de brister i metoden som exempelvis felet i videoanalysen samt positioneringen av FE modeller.

Recently there has been considerable attention directed towards the increased risk for head injuries that athletes face while participating in high impact sports. Furthermore, there is also heightened interest in the asymptomatic sport related sub-concussive blows, commonly experienced during play, that possibly lead to long term neurological deficits. Purpose: The goal of this study was to investigate retired professional athletes of the Canadian Football League with a history of sport-related concussions, using several advanced MRI methods. The ultimate goal being the identification of any potential synergistic effects between a history of sport-related concussions, and exacerbated cognitive decline later on in life. Materials and Methods: Twenty former professional athletes of the Canadian Football League were scanned using a GE Discovery MR750 3T MRI with a 32-channel RF-coil. Axial FSPGR-3D images were used to define rs-BOLD and DTI scans. Seed based network analysis of the DMN was performed on rs-BOLD data. Voxel-wise tensor fitting of DTI data provided the means for estimating several tensor metrics. Results were normalized through comparison with a database of healthy controls. Potential associations between functional connectivity, white matter integrity, and cortical thickness measures were correlated with retired athlete position and years of professional play. Results: We found widespread cortical thinning in retired CFL subjects, alongside significant increases in axial and mean diffusivity in the corona radiata and splenium and genu of the corpus callosum compared to controls. Seed based correlation analysis of the DMN network revealed interrupted connectivity in retired athletes. Athlete age, po- sition, and number of years played appear to be factors in overall core white matter microstructural integrity. Conclusions: When compared to an age and sex matched control population, differences were observed both in functional and structural con- nectivity, suggesting that even years after retiring the brains of these former athletes still exhibit signs of damage. / Thesis / Master of Applied Science (MASc) / Sport-related concussions affect millions of athletes on a yearly basis in the United States alone. Concussions are often accompanied by short-lived neurological impairments, such as confusion, headaches, dizziness, nausea and memory loss. In addition, there is the potential for development of long term mental health and cognitive impairment. The goal of this work was to identify any neurological changes present in retired athletes of the Canadian Football League, through the use of advanced magnetic resonance imaging techniques evaluating thickness of brain structures, changes in brain activity, and alterations in core microstructure of the brain. Analyzing the results of these techniques revealed changes in a number of brain regions within the retired professional athlete population. These results suggest that a career of high impact sports may lead to short term, in addition to long-term neurological consequences.

Concussions, attention-deficit disorder (ADHD), and learning disabilities can adversely impact learning and academic achievement, particularly with respect to attention, memory, and executive functioning; fortunately, cognitive training can be beneficial and remediating these weaknesses. One such program, strategic memory advanced reasoning training (SMART), utilizes a top-down approach to train individuals in executive, higher-ordered thinking strategies including strategic attention, integration, and innovation to facilitate information synthesis and enhance cognitive efficiency. Thus, the purpose of the study is to examine whether SMART improved performances on various neuropsychological measures tapping into attention, processing speed, memory, and executive functioning for college student-athletes with neurological conditions (e.g., concussions, ADHD, LD). Student-athletes were randomly assigned to the SMART program or a "wait-list" control group and were administered a neuropsychological battery at baseline, immediately following the intervention, and after a four-month delay. Results showed that participants benefited from SMART with respect to working memory immediately following the intervention after controlling for baseline scores. The benefits of working memory also persisted after four months. Additionally, SMART was beneficial for improving attention, but only after four months after the intervention. The findings of the current study were consistent with previous studies which showed positive effects of SMART on working memory with a variety of populations (e.g., children, adolescents, older adults, Veterans, brain-injured patients); however, the current study did not see improved performance on other aspects of executive functioning which contradict prior research. Statistical differences between the present study and prior research regarding SMART may be explained in methodology, participant characteristics, research setting, and/or limitations. Future studies may include combining cognitive training as the intervention and utilizing neuroimaging alongside cognitive training to examine the relationship between structural/functional change with neuropsychological performance.

Ce projet de recherche avait pour but d’évaluer les conséquences à long terme des commotions cérébrales d’origine sportive (CCOS) subies durant le développement sur la fonction cardio-autonomique. Nous avons comparé la variabilité de la fréquence cardiaque (VFC) de joueurs de hockey adolescents avec un historique d’une ou deux CCOS (commotion ; n = 39) à la VFC de joueurs de hockey adolescents n’en ayant jamais subi (contrôle ; n = 52). Les athlètes du groupe commotion ont été testés 26 mois (20) après leur dernière CCOS. L’électrocardiogramme des participants était mesuré durant, pendant et après un exercice sur ergocycle. La séance d’exercice consistait en un échauffement incrémenté de 6 minutes suivi de 20 minutes entre 60 et 70 % de la fréquence cardiaque maximale et finalement 2 minutes de retour au calme actif. Par la suite, un repos de 10 minutes était complété. Le logarithme naturel de l’écart-type des intervalles NN (lnETNN) et le logarithme naturel des basses fréquences (lnBF) étaient tous les deux plus élevés pour le groupe commotion que pour le groupe contrôle dans les trois conditions (repos, exercice et post-exercice) ( < 0,05). Cette différence était similaire pour toutes les conditions. Ces résultats suggèrent qu’une CCOS affecte la fonction cardio-autonomique différemment durant le développement qu’à l’âge adulte, renforçant la nécessité d’interventions post-commotion spécifiques durant développement. / This research project sought to evaluate long-term consequences of sport-related concussions (SRC) sustained during development on cardio-autonomic function. To do so, we compared the heart rate variability (HRV) of adolescents hockey players with a history of one or two sport-related concussion (HOC; n = 39) to the HRV of adolescents hockey players who never incurred a SRC (WHOC; n = 52). Athletes from the HOC group were 26 months (20) away from their last injury. Participants’ electrocardiogram was measured at rest, during and after an exercise session on ergocycle. The exercise session consisted of a 6 minutes incremental warm-up followed by 20 minutes between 60 and 70 % of maximal heart rate and finally a 2 minutes active cooldown. Then, a post-exercise rest of 10 minutes was completed. HRV linear and non-linear measures were calculated before, during and after the exercise session. Natural log of standard deviation of NN intervals (lnSDNN) and natural log of low frequencies (lnLF) were both higher for HOC group in the three conditions (rest, exercise, post-exercise) ( < 0.05). This difference was similar across all conditions. These results suggest that SRC might affect cardio-autonomic function differently during development than during adulthood thus reinforcing the need for specific post-concussion interventions for the developing population.

<p>Uvod: Traumatsko o&scaron;tećenje mozga (TOM) nastaje usled dejstva spolja&scaron;nje mehničke sile na kranijum i endokranijalni sadržaj, koje se karakteri&scaron;e privremenim ili trajnim neurolo&scaron;kim o&scaron;tećenjem, funkcionalnom onesposobljeno&scaron;ću ili psihosocijalnom neprilagođeno&scaron;ću. Blago TOM je najče&scaron;će i čini između 70% i 90% svih povređenih sa TOM. Postoji veliki broj definicija ovog kliničkog entiteta, ali gotovo sve sadrže Glazgov koma skor 13-15, poremećaj stanja svesti u različitom trajanju, te posttraumatsku amneziju kao odrednice koje defini&scaron;u blago TOM. Najveći broj povređenih sa blagim TOM ima dobru prognozu i potpunu rezoluciju tegoba u kratkom vremenskom periodu nakon povređivanja, bez medicinski relevantnih posledica. Međutim, jedna grupa povređenih koja navodi nagla&scaron;enije i dugotrajnije tegobe koje mogu imati uticaja na ukupno zdravstveno stanje i kvalitet života. U savremenom naučnoistraživačkom radu aktuelni su poku&scaron;aji da se primenom novih dijagnostičkih metoda, detaljnim praćenjem povređenih i primenom neuropsiholo&scaron;kih testova objektivizuju ove tvrdnje, kako bi se pacijenti sa povi&scaron;enim rizikom od nastanka dugotrajnih tegoba pravovremeno identifikovali i kako bi se mogao sprovesti adekvatan tretman. Cilj: Cilj ove studije je da se utvrditi da li postoji korelacija između kliničkih i radiolo&scaron;kih simptoma i znakova i rezultata neuropsiholo&scaron;kog testiranja kod povređenih sa blagim traumatskim o&scaron;tećenjem mozga, kao i da se utvrdi da li neki od od kliničkih simptoma i znakova mogu biti pouzdan prediktor pojave perzistentnih neuropsiholo&scaron;kih posledica, i koja je priroda moždanih o&scaron;tećenja koja mogu biti u njihovoj osnovi. Materijal i metode: Sprovedeno istraživanje je u celosti bilo kliničko, prospektivno, i obuhvatilo je 64 povređena sa blagim TOM koji su u periodu od 2012. do 2015. godine hospitalizovani na Klinici za neurohirurgiju Kliničkog centra Vojvodine u Novom Sadu. Pre prijema je svim ispitanicima načinjen pregled endokranijuma kompjuterizovanom tomografijom (CT) koji nije prikazivao znakove traumatskih o&scaron;tećenja kranijuma niti endokranijalnog sadržaja. U toku hospitalizacije kod povređenih su praćeni i beleženi relevantni klinički parametri. U prvih 72 sata od povređivanja je kod 37 ispitanika načinjen pregled endokranijuma magnetnom rezonancom (MRI). Kod 25 ispitanika je načinjeno neuropsiholo&scaron;ko ispitivanje baterijom neuropsiholo&scaron;kih testova mesec dana nakon povređivanja i 6-9 meseci nakon povređivanja. Rezultati su uno&scaron;eni u bazu podataka i nakon toga statistički analizirani. Rezultati: U analiziranoj grupi od 64 povređena sa blagim TOM kod 37 ispitanika (58%) je načinjen MRI pregled endokranijuma, a pozitivan nalaz u smislu postojanja traumom izazvanih o&scaron;tećenja moždanog parenhima pronađen je kod 17 ispitanika (46%). Najsenzitivnije MRI sekvence su SWI i T2* kojima se otkrivaju veoma diskretni depoziti razgradnih produkata krvi. Povređeni sa pozitivnim MRI nalazom imaju lo&scaron;ije postignuće na rekogniciji liste B Rejovog testa verbalnog učenja u odnosu na povređene iz grupe bez intrakranijalne traumatske lezije. Rezultati neuropsiholo&scaron;kih testova ukazuju na pobolj&scaron;anje rezultata između prvog i drugog testiranja u pogledu egzekutivnih i govornih funkcija u ispitivanoj grupi. U ostalim ispitivanim kognitivnim aspektima nije pronađena značajna razlika među navedenim grupama Zaključak: TOM predstavlja jedan od najvećih savremenih medicinskih izazova koji se nameće zbog svoje visoke incidence, dijagnostičkih i terapijskih problema, ali i potencijalno lo&scaron;eg ishoda i visokih tro&scaron;kova rehabilitacije i resocijalizacije povređenih. Rezultati studije se mogu iskoristiti za bolje razumevanje blagog TOM u smislu lak&scaron;eg re&scaron;avanja dijagnostičkih dilema, kreiranje efikasnijih dijagnostičkih protokola i preciznije procene ishoda nakon povređivanja ove vrste.</p> / <p>Introduction: Traumatic brain injury (TBI) is a result of the influence of external mechanical forces on scull and endocranial structures which can produce temporarily or permanent neurological impairment, functional disability or psychosocial unconformity. Mild TBI is the most frequent form of TBI and represent between 70% and 90% of all TBI cases. There are several different definitions of mild TBI, but almost all of them contain Glasgow Coma Scale score 13-15, altered state of consciousness and different forms of amnesia as criteria for mild TBI diagnosis. Largest number of patients suffered mild TBI have good prognosis and complete resolution of symptoms in short period of time after injury, with out of any kind of sequeles. However, small group of patients report various symptoms and complaints which can last longer than is usual and seriously affect quality of life of this patients. Numerous researches has been conducted applying novel imaging technologies, long follow-up periods and neuropsychological testing in order to make these non-specific self-reported complaints as much objective as possible. The other reason is necessity of timely identification of patients in risk of developing long term complaints so they can be treated in a proper manner. Objective: The aim of this study was to determine is there correlation between clinical and radiological signs and symptoms and results of neuropsychological testing in patients with mild TBI. The aim also was to determine are there some clinical signs which can be reliable predictor of appearance of neuropsychological consequences and what is the nature of cerebral lesion suspected to be a cause of this consequences. Materials and methods: The research was clinical, completely prospective and included total of 64 patients with mild TBI who were hospitalized between 2012 and 2015 at Clinic for neurosurgery, Clinical Centre of Vojvodina in Novi Sad. All patients had computed tomography scan (CT) at the admission which failed to show any signs of trauma of cranial bones or endocranial content. During the first 72 hours after injury the magnetic resonance imaging (MRI) has been performed in 37 patients. 25 patients had neuropsychological testing one month and 6-9 months after injury. We entered results in database and after completion we performed statistical analysis. Results: In 37 of 64 patients (58%) MRI examination has been performed and in 46% of patients we found trauma induced small haemorrhagic and oedematous brain lesions. The most sensitive sequences in our protocol were SWI and T2* confirmed superb sensitivity in detection of small foci of blood. Patients with detected MRI abnormalities showed poorer accomplishment at recognition of list B of Ray Auditory Verbal Learning Test in comparison with group with no intracranial lesions. The results of neuropsychological testing showed significant improvement of executive and speech functions between two periods in time when tests have been administered. We found no other significant differences between analysed cognitive functions in this period in our group of patients. Conclusion: TBI is one of the most important contemporary medical problems due to his high incidence, diagnostics and therapy related issues, but also potentially poor outcome and high costs of rehabilitation. Results of this study can be used for better understanding of mild TBI in order to solve some diagnostic dilemma, create more efficient diagnostic protocols and facilitate more precise outcome assessment after mild TBI.</p>

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

The purpose of this article is to review relevant literature on the effect of mild traumatic brain injury (mTBI) and blast injury on the vestibular system. Dizziness and imbalance are common sequelae associated with mTBI, and in some individuals, these symptoms may last for six months or longer. In war-related injuries, mTBI is often associated with blast exposure. The causes of dizziness or imbalance following mTBI and blast injuries have been linked to white matter abnormalities, diffuse axonal injury in the brain, and central and peripheral vestibular system damage. There is some evidence that the otolith organs may be more vulnerable to damage from blast exposure or mTBI than the horizontal semicircular canals. In addition, benign paroxysmal positional vertigo (BPPV) is a common vestibular disorder following head injury that is treated effectively with canalith repositioning therapy. Treatment for (non-BPPV) mTBI-related vestibular dysfunction has focused on the use of vestibular rehabilitation (VR) augmented with additional rehabilitation methods and medication. New treatment approaches may be necessary for effective otolith organ pathway recovery in addition to traditional VR for horizontal semicircular canal (vestibulo-ocular reflex) recovery.

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