Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009. / Härtill 4 uppsatser.

Thesis (M.S.)--University of Michigan, 1995.

This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.

Submitted in partial compliance with the requirements for a Master’s Degree in Technology, Durban University of Technology, Durban, South Africa, 2018. / Background: Chiropractors are a unique group of health care professionals who are at risk for developing work-related musculoskeletal injuries. Diversity of daily practice imposes different physical demands on the chiropractor. The present study aims to determine the prevalence of work-related musculoskeletal injuries in chiropractors in eThekwini municipality and selected risk factors associated with work-related musculoskeletal injuries. There are very few studies available that look at the chiropractor holistically in terms of work-related musculoskeletal injuries. However, these existing studies suggest that chiropractors are at a greater risk for the development of work-related musculoskeletal injuries. Method: The study design was a quantitative, cross-sectional, descriptive study utilising a self- administered questionnaire, developed specifically for this research, using an expert group and pilot study. The questionnaire contained sections on personal as well as practice demographics, with questions pertaining to the single most severe work-related musculoskeletal injury, as well as the second and third most severe work-related musculoskeletal injury. Risk factors for work- related musculoskeletal injury were tested by using chi square in the case of categorical variables. In the event of violation of the expected frequencies, the Fisher’s exact test was used to obtain the p-value. Logistical regression was used to obtain odds rations in the presence of more than one explanatory variable. A p-value of <0.05 was used to indicate statistical significance. Results: Sixty-two chiropractors responded, giving a response rate of 64%. The life-time prevalence of work-related musculoskeletal injuries was 69%. A predominance of injuries to the upper extremity (50%) and lower back (28.3%) were recorded. The hand/wrist was the most common anatomical site of injury (31.5%) followed by the lower back. Number of years in practice was considered a risk factor for injury as most injuries occurred within the first five years of practice (41.6%). The likelihood of injury decreases with an increase in the number of years in practice. The majority of injuries affected the soft tissue, including ligament sprains (27.5%) and muscle strains (26.6%) and occurred while the practitioner was performing manipulation (38.2%) of the lumbosacral (80.77%) area with the patient in the side posture (61.53%). Conclusion: The results concur with other studies on work-related musculoskeletal injuries in chiropractors and add insight into risk factors predisposing this population to injury. Chiropractors need to understand the risk factors for occupational injury to implement strategies to avoid risk of injury. / M

This study investigates the cumulative effects of concussive and subconcussive mild head injury on the cognitive functioning of schoolboy rugby players. A comprehensive battery of neuropsychological tests and a self-report postconcussive questionnaire were administered to top level schoolboy rugby players (n=47), and a non-contact sport control group of top level schoolboy hockey players (n=34). Group comparisons of the percentage of individuals with cognitive deficit were carried out between i) the schoolboy rugby and the schoolboy hockey players, ii) the rugby forward and the rugby backline players; iii) the rugby forward and the schoolboy hockey players and, iv) the rugby backline and the schoolboy hockey players. Results on the neuropsychological test battery did not provide any substantial evidence of a higher level of neuropsychological impairment in the rugby players relative to the control group, or in the rugby forward players relative to the rugby backline players. Results obtained on the postconcussive symptom questionnaire provided tentative indications that the rugby players do report a greater frequency of postconcussive symptomatology. The symptoms most frequently reported were being easily angered, memory problems, clumsy speech and sleep difficulties. It was hypothesized that the absence of cognitive impairment in the schoolboy rugby players compared with that noted for professional players was due to their younger age, relatively high IQ and education level and a less intensive level of physical participation in the sport, and hence less accumulated exposure to the game, thereby decreasing their exposure to mild head injuries. From a theoretical perspective, these pre-existing conditions were considered to act as protective factors against reductions in brain reserve capacity and concomitant susceptibility to the onset of neuropsychological dysfunction.

This study aims to explore, and to a certain extent to clarify, what it means psychologically to experience Traumatic spinal cord injury (TSCI) in a South African spinal unit. The target time chosen for analysis is the acute medical period. The study presents a review of the literature on psychological adjustment to TSCI and then proceeds to introduce and extensively articulate the hermeneutic approach and methodology. Subsequently, an interpretive research strategy is presented for the purpose of studying the acute phase of TSCI. The data for the study was obtained by means of three dialogical interviews which were tape recorded, transcribed and analyzed with~n a cyclical framework consisting of three interdependent levels. The interpretive procedure is modeled upon the 'reading guide' developed by Brown, Tappan, Gilligan, Miller and Argyris (1989). The analysis follows a course from the individual psychological descriptions of the experience to the generation of a general, nomothetic narrative account of the acute phase. The findings are then discussed in relation to the existing literature and evaluated on the basis of the goals of the study. The study highlights the value of some of the 'stage' ways of thinking about SCI adjustment, while simultaneously stressing the need for placing adjustment within a more personalized, and individually meaningful context. Significant differences between the psycho-physical experiences of patients in the categories of complete and -incomplete SCI were found, which suggests that a sharper distinction be made in the literature between these two groups, in order to account for the marked variations in their experiences.-- The study also contains a number of shortcomings, such as a lack of understanding about certain historical and contextual factors which may have mediated the experiences of the trauma for the individuals concerned. These shortcomings and some suggestions fro their resolution are then discussed. The study concludes with an evaluation of the research strategy and methodology and also offers some suggestions for future research.

A dissertation submitted in partial compliance with the requirements for the Masters Degree in Technology: Chiropractic, 2002. / The purpose of this study was to determine the effectiveness and relative effectiveness of a topical Capsaicin cream and knee joint mobilization in the treatment of Osteoarthritis (OA) of the knee. / M

This study investigated the cumulative effect of mild head injuries on rugby players. A comprehensive battery of neuropsychological tests was administered and subjects completed a self-report postconcussive symptom questionnaire. Data were collected for the two rugby groups, Springbok rugby players (n = 26) and Under 21 rugby players (n = 19), and for the control group, national hockey players (n = 21). Group comparisons of the percentage of individuals with deficit or self-reported symptomatology were made between: (i) the contact sport groups and the control group; (ii) the forwards and the backs within each rugby group and the rugby forwards and the control group; and (iii) the Springbok and Under 21 rugby players. Broadly speaking, comparative results on the neuropsychological tests and the self-reported postconcussive symptoms clearly distinguished between contact sport players and non-contact sport players and indicated the presence of diffuse brain damage in the contact sport players. There was also clear evidence of positional variation within the rugby groups, with the forwards (more full contact positions) most susceptible to impairment. Neuropsychological test results revealed deficit in information processing speed, attention and concentration, mental flexibility, visual memory and verbal new learning. The most significant neuropsychiatric complaints were reported in the areas of memory, social contact, sensitivity to noise, lowered frustration tolerance, anxiety and worry, and depression. The most sensitive neuropsychological test used in the present study was the Digit Symbol Substitution test. This test clearly distinguished contact sport players from non-contact sport players, and forwards from backs.

The objective of the study was to investigate the cumulative neurocognitive effects of repetitive concussive and subconcussive events in club level Rugby Union (hereafter rugby) during the course of one rugby season, in a combined group and individualized case-based approach. Amateur adult club level rugby players (n = 20) were compared with a non-contact control group (n = 22) of equivalent age, years of education and estimated IQ (p = > .05, in all instances), although the two groups were clearly differentiated on the basis of a history of reported concussions (p = < .05). Video analyses documented the tackling maneuvers observed amongst the players during all matches across the rugby season revealing a sobering average of more than a thousand tackles per player, excluding any contact practice sessions. Five rugby players (n = 5) who were observed to have a head jarring event were also isolated for individualized postconcussive follow-up analysis of their neurocognitive profiles. Measures included the ImPACT Verbal and Visual Memory, Visual Motor Speed and Reaction Time composites and the Purdue Pegboard. Independent and dependent statistical analyses were employed to compare the rugby versus control group neurocognitive test profiles at and between the three test intervals. Correlational analyses explored the association between concussion, tackling and neurocognitive test outcomes. Descriptive comparisons of individual neurocognitive test scores with normative data were employed for the case analyses. Taken together, the results implicated vulnerability amongst club rugby players on the motor and speeded tasks, with less robust indications on the memory tasks. While limited in terms of its small sample size, it is considered that the outcome of the study was rendered more robust by virtue of being methodologically multifaceted with heuristic implications for future research studies in the area. The novel inclusion of tackling data as well as fine-tuned case analyses, were of particular relevance in that regard. The results add to a growing body of literature that implicates deleterious neurocognitive effects in participants of a sport such as rugby due to repetitive head jarring incidents that are intrinsic to the game.

Ligament tears are more prevalent than all other knee injury pathologies, and contribute significantly to musculoskeletal joint pain and disability reported worldwide. Despite current soft tissue reconstruction techniques, the injured ligament fails to regenerate due to dysregulated cell-extracellular matrix (ECM) interactions that culminate in scar formation. Hallmarks of scar formation, or fibrotic healing include disorganized ECM, pathological stiffness or tissue rigidity, and the accumulation and persistence of myofibroblasts. A primary driver of fibrosis, myofibroblasts are characterized by high contractility, excessive deposition of collagen type I, coupled with inflammatory and fibrotic signaling. Notably these cells are critical early on in the response to injury, by aiding in the contracture of the wound bed and depositing collagen to repair the injury site. However, myofibroblasts are not capable of fully regenerating the native ligamentous matrix, and resolution of the phenotype is necessary in order to cue surrounding cells, prevent chronic inflammation and aberrant tissue remodeling. Persistence of the myofibroblast phenotype thus leads to a ligament scar that is functionally weaker than the healthy tissue matrix, characterized by significantly different histological, biochemical, and biomechanical properties. The consequential instability of this scar disrupts load distribution within the knee joint and increases the risk of subsequent injury, osteochondral degeneration, and ultimately, the development of post-traumatic osteoarthritis. Therefore, there is a critical need for strategies that target the inflammatory and fibrotic myofibroblast phenotypes for soft tissue healing. It follows that the overarching goal of this thesis is to engineer an immunomodulatory matrix to regulate myofibroblast activation and downstream fibrogenic signaling. To this end, models of soft tissue fibrotic repair are explored in order to test the central hypothesis that cues from the repairing ECM play an important role in regulating myofibroblast activation and persistence. Specifically, this thesis will compare myofibroblast differentiation and signaling in three in vitro models of tissue repair: 1) 2D on tissue culture polystyrene (TCPS), and two 3D models namely 2) collagen hydrogel and 3) electrospun collagen fiber matrices. As expected, on the 2D model, a persistent myofibroblast phenotype could be generated over time with an optimized transforming growth factor beta 1 (TGF-β1) stimulation protocol. To create repair-relevant 3D matrix models, we engineered collagen hydrogels with controlled mechanical properties, as well as electrospun fiber platforms that isolate key matrix factors including, collagen content, stiffness, fiber diameter, and alignment. These models emulate the connective tissue repair process via recapitulating the increasing matrix stiffness and fiber assembly of the early (granulation tissue), proliferative, and remodeling stages of the repair. Myofibroblast differentiation potential, parallel inflammatory and fibrotic cytokine secretion, as well as matrix remodeling potential were observed to be dependent on matrix model parameters. Moreover, single-cell resolution RNA sequencing revealed heterogenous myofibroblast populations within the context of response to engineered collagenous substrates. Specifically, myofibroblast accumulation was observed on hydrogel substrates that recapitulate the pathologically stiff mechanics and disorganization of fibrotic scar tissue while architectural cues of engineered fiber substrates prevented myofibroblast differentiation in a diameter and alignment-dependent manner. Moreover, nanoscale fibers elicited the greatest anti-fibrotic and anti-inflammatory properties compared to microscale fibers and stiff collagen-based hydrogels. Throughout, this thesis also explores the contribution of NF-κB signaling to myofibroblast plasticity and persistence using engineered collagen-based platforms, highlighting the dynamic role of myofibroblasts as critical immunoregulating cells. The NF-κB signaling pathway is implicated in a broad array of fibrotic and chronic inflammatory conditions, and more recently has been associated with survival of persistent myofibroblast populations in soft-tissue fibrosis and tendon degeneration models. In this thesis, NF-κB activation was seen to be related to the persistent myofibroblast phenotype and increase over time in both 2D TCPS and 3D collagenous hydrogel matrices that mimic pathologically stiff scar tissue, while a temporally dependent activation pattern was observed in electrospun collagen fiber-based models. At the transcriptional level, NF-κB survival signaling was significantly enriched in myofibroblast populations supported by TCPS and stiff collagen-based hydrogels but downregulated on soft hydrogels and fibers with decreasing fiber diameter that prevented robust myofibroblast differentiation at single cell resolution. Building upon these new insights regarding matrix cues that drive myofibroblast activation, we designed an immunomodulatory matrix that mediates small molecule release targeting NF-κB inhibition. The immunomodulatory matrix achieved robust amelioration of the myofibroblast phenotype as well as reduced the secretion of key inflammatory and fibrotic cytokines by these cells. Moreover, a similar anti-fibrotic response was seen for human ligament fibroblasts treated with these matrices. Collectively, this thesis work presents a systematic evaluation of myofibroblast plasticity and persistence within the context of 2D (TCPS), 3D (collagen-based hydrogels), and finally 3D with defined microarchitectural cues (electrospun collagen-based fibers) that recapitulate the progressive stages of scar-mediated healing, and reveals NF-κB as a promising target for reducing myofibroblast persistence. Moreover, the immunomodulatory control of myofibroblast plasticity and persistence via matrix cues coupled with NF-κB inhibition informs future strategies for true ligament healing.