The present study comprises part of an ongoing research study investigating the effects 0 f cumulative mild head injuries 0 n Rugby Union p layers. The aim 0 f t he study was to ascertain whether there are neuropsychological effects of cumulative mild head injuries sustained during the rugby-playing careers of senior schoolboy rugby players. Participants were top-level rugby players from high schools in Grahamstown and Cape Town (n = 79) and non-contact sport controls of top-level field hockey players from the same schools (n = 58). Group mean comparisons across a battery of neuropsychological tests were carried out between the Total Rugby versus the Total Field Hockey group, and the Rugby Forwards versus the Rugby Backs group. Comparisons between Total Rugby versus Total Field Hockey revealed impaired performance by the rugby players on two tests of visuoperceptual tracking, namely Digit Symbol Substitution and Trail Making Test (Part A). For Rugby Forwards versus Rugby Backs, there were no consistent differences to support the expectation that forwards would perform worse than backs. Forwards performed more poorly than backs on WMS Associate Learning Subtest - Hard (Delayed Recall), whereas backs performed more poorly than forwards on Digits Backwards. This suggests that some individuals in the cohort were starting to exhibit verbal memory deficit, albeit not clearly in association with forward positional play. Overall, results of the present study provide tentative support for the hypothesis that school level rugby players are more susceptible to the effects of cumulative concussive and sub-concussive head injuries than are non-contact sport controls. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Objectives: The majority of individuals who sustain a mild traumatic brain injury (mTBI) will experience a full recovery within the first weeks or months post-injury. However, some individuals will experience ongoing difficulties, or persistent post-concussion symptoms (PCS), for years following the injury. To date, most researchers have attributed PCS to either neuropathological factors or to psychogenic factors. Lacking exploration has been the role of psychosocial variables and the consideration of PCS from a more holistic, or 'whole person', perspective. As such, the goal of the current study was to undertake an investigation of persistent PCS using a broad, neuropsychosocial framework. Specifically, this was done by investigating how (a) cognitive functioning, (b) susceptibility to anxiety while in the context of a stressful situation (i.e., anxiety susceptibility), and (c) multiple components of identity (including self-perception, TBI- related self-concept, and TBI-related social identity) influence the severity of persistent PCS. The main underlying assertion to this research is that there are multiple factors that underlie the experience of persistent PCS; a purely neuropathological or psychogenic perspective is not sufficient to understand the complex processes inherent in recovery after mTBI. Method: The sample consisted of 21 adults, between 20 and 65 years of age, who had sustained an mTBI at least one year earlier. Following a telephone interview to determine eligibility (and a separate telephone interview with a source of collateral information) the participants completed a number of standardized neuropsychological measures and self- report questionnaires during an in-person, one-on-one data collection session. Results: The only injury-related or demographic variable that had an influence on PCS was injury etiology, whereby individuals with sports related injuries reported significantly less PCS than did those who sustained non-sports related injuries (e.g., motor vehicle accidents). Cognitive functioning had no influence on PCS severity, nor did anxiety susceptibility. However, one's general propensity to experience anxiety (i.e., trait anxiety) was a significant predictor of PCS. Further, multiple aspects of identity influenced PCS with both current self-perception and TBI-related social identity being significant predictors of self-reported PCS severity. Conclusions: Despite the failure to find any impact of neuropsychological factors on PCS in the current study, other lines of research have demonstrated neuropathological changes associated with mTBI – some of which may be chronic. Therefore, cognitive functioning may not be a sufficiently sensitive indicator of possible neuropathology at more than one year post-injury. On the other hand, the current study demonstrates that psychological and psychosocial factors are highly relevant to recovery and outcome following mTBI, and are significant predictors of PCS severity. Overall, the results support the assertion that recovery after mTBI is complex and that there are multiple factors that underlie persistent PCS. Further, the study demonstrates the importance of conceptualizing the process of recovery from a broad, neuropsychosocial perspective. Implications for treatment interventions and future research are discussed. / Graduate

Mild traumatic brain injury (mTBI) is a common and often inconspicuous wound that is frequently associated with chronic low-grade symptoms and cognitive dysfunction. Previous evidence suggests that daily blue wavelength light therapy may be effective at reducing fatigue and improving sleep in patients recovering from mTBI. However, the effects of light therapy on recovering brain structure remain unexplored. In this study, we analyzed white matter diffusion properties, including generalized fractional anisotropy, and the quantity of water diffusion in isotropic (i.e., isotropic diffusion) and anisotropic fashion (i.e., quantitative anisotropy, QA) for fibers crossing 11 brain areas known to be significantly affected following mTBI. Specifically, we investigated how 6 weeks of daily morning blue light exposure therapy (compared to an amber-light placebo condition) impacted changes in white matter diffusion in individuals with mTBI. We observed a significant impact of the blue light treatment (relative to the placebo) on the amount of water diffusion (QA) for multiple brain areas, including the corpus callosum, anterior corona radiata, and thalamus. Moreover, many of these changes were associated with improvements in sleep latency and delayed memory. These findings suggest that blue wavelength light exposure may serve as one of the potential non-pharmacological treatments for facilitating structural and functional recovery following mTBI; they also support the use of QA as a reliable neuro-biomarker for mTBI therapies.

The corpus callosum provides a physical and functional connection between the two hemispheres of the brain allowing interactions between homologous cognitive, sensory and motor areas. In humans, the integrity of transcallosal connections between motor cortices can be evaluated quickly and non-invasively using transcranial magnetic stimulation (TMS) via the ipsilateral silent period (iSP). While the technique has been known for 20 years, many issues remain unsolved regarding which methods are best to elicit the iSP as an index of transcallosal inhibition. In addition, there is still limited information regarding the influence of individualized factors such as age on iSP measurements. This thesis investigates how common physiological and methodological factors influence the iSP in order to establish this method as a reliable index to assess the integrity of the transcallosal pathway linking primary motor cortices. In the first series of experiments, we used a previously described TMS protocol to elicit iSPs [1] to investigate changes in motor transcallosal inhibition in relation to individual factors linked to age, hand preference and history of concussions. A second series of methodological experiments examined the effects of stimulation intensity on the iSP and to determine its inter-session reliability. Our first series of experiments provided evidence that advancing age and history of concussions in young athletes were each independently associated with alterations in transcallosal inhibition. This was evidenced by changes in the duration of transcallosal inhibition (DTI) and in the latency of transcallosal inhibition (LTI) derived from iSP measurements. These experiments also revealed that the degree of hand preference in young adults was reflected in measures of transcallosal inhibition, so that mixed-handed individuals (i.e., ambidextrous) exhibited evidence of more efficient transcallosal transmission than either strong right or left handed individuals. The second series of experiments focusing on methodological aspects showed that the iSP duration (though not its onset) was influenced by stimulation intensity, increasing linearly with intensity up to 140% of the resting motor threshold (RMT). Our analysis further revealed that the probability of eliciting detectable iSP also increased with increasing intensity up to 130% RMT before reaching a plateau. A stimulation intensity of 130% of RMT appears to be optimal to elicit iSPs in healthy participants. In a subsequent study, we showed that iSP elicited at this stimulation intensity (i.e., 130% RMT) had good inter-session reliability. In light of these investigations, we recommend for future studies that, in addition to contraction of the homologous muscles of the opposite hand as proposed by Giovannelli et al 2009, that an intensity of 130% RMT should be used to elicit the iSP when assessing transcallosal inhibition between motor cortices.

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

No description available.

Bakgrund: Hjärnskakningar är ett stort problem inom amerikansk fotboll på alla nivåer och mörkertalet hjärnskakningar som inte rapporteras och behandlas anses stort. Obehandlade hjärnskakningar kan få stora konsekvenser för den aktive både på och utanför planen. Hjärntrappan används som ett rehabiliteringsverktyg för idrottsutövare drabbade av hjärnskakning inom svensk idrott, men det saknas studier i vilken utsträckning den används inom amerikansk fotboll. Syfte: Syftet med studien var att kartlägga strategier gällande rehabilitering för säker återgång till idrott efter hjärnskakning hos amerikansk fotbollslag på seniornivå i Sverige. Metod: En enkätundersökning genomfördes via telefon. Populationen var 36 amerikansk fotbollslag som var i seriespel i Sverige under säsongen 2020 och 16 lag deltog i studien. Resultatet av enkäten analyserades sedan med deskriptiv och jämförande statistik. Resultat: Majoriteten av de deltagande lagen använde Hjärntrappan som strategi för rehabilitering av hjärnskakning. En signifikant skillnad mellan dam- och herrlag och användningen av Hjärntrappan påvisades. Det påvisades inte någon signifikant skillnad mellan varken tillgång till medicinsk personal i laget eller storleken på orten som laget utgick ifrån och användningen av Hjärntrappan. Slutsats: Hjärntrappan är den mest använda rehabiliteringsstrategin vid hjärnskakning inom amerikansk fotbollslag i seriespel på seniornivå i Sverige. Det finns skillnader mellan dam- respektive herrlag och användningen av Hjärntrappan. Fler och större studier behövs för att generalisera resultaten till samtliga amerikansk fotbollslag i Sverige. / Background: Concussions are a big problem in American football and the number of concussions that goes untreated is considered large. Untreated concussions can have serious consequences for the athlete both on and off the field. Hjärntrappan is used in Sweden to rehabilitate concussions, but there is no studies to what extent it is used in American football in Sweden. Aim: The aim of the study was to investigate what rehabilitation strategies senior American football teams in Sweden used when a player had a concussion. Method: A survey was conducted via telephone. The population was 36 Swedish American football teams that were playing in the Swedish league system during the 2020 season and 16 teams participated in the study. The results of the survey were then analyzed with descriptive and comparative statistics. Results: The majority of the participated teams used Hjärntrappan as rehabilitation strategy when a player had a concussion. A significant difference between the woman’s and men’s teams and the use of Hjärntrappan was found. No significant difference was found between either the access to medical staff in the team or the size of the city where the team was based and the use of Hjärntrappan. Conclusion: Hjärntrappan is the most common rehabilitation strategy among senior American football teams in the Swedish league system after concussion. There is a difference between men’s and woman’s teams and the use of Hjärntrappan. More and extended reseach is needed to generalize the results to all American football teams in Sweden.

Sport-related injuries (SRI) can be foreseen and averted when mechanisms and risk factors are completely understood. An appreciation of the relationship between sport-related concussion (SRC) and lower extremity musculoskeletal injuries (LEMI) is emerging amid professional and collegiate athletes. However, findings of such a relationship in adults may not be generalizable to younger populations, and the literature has not addressed this relationship in adolescents. The purpose of this cross-sectional quantitative study was to examine the relationship between SRC and LEMI in high school athletes. The dynamic model of etiology in sport injury provided the study's conceptual framework. A de-identified secondary dataset of high school athletic injuries was obtained from the Athletic Training Practice Based Rehab Network and analyzed with descriptive and inferential statistics. Concussions, knee sprains, and ankle sprains represented about 12%, 17%, and 70%, respectively, of the 1,613 cases in the dataset. Chi-square tests revealed that SRCs, and the number of SRCs, were associated with knee sprains [(p < .001), Cramer's V = .148] and ankle sprains [(p < .001), Cramer's V = .545]. This study may promote positive social change by prompting further retrospective and prospective studies to clarify whether a relationship exists between SRC and LEMI in high school athletes, and if so, whether this relationship is causal in nature. New knowledge may be used to guide practices and policies to reduce sports injuries in high school athletes, which may lead to fewer SRIs among adolescents, fewer school absences, more physical activity, and better health and well-being throughout the lifespan, thereby promoting a more active, productive, and healthy society.

No description available.

No description available.