The influence of injury cause, contact-sport participation, and personal knowledge on expectation of outcome from mild traumatic brain injury

Objective: This study investigated the influence of injury cause, contact-sport participation, and prior knowledge of mild traumatic brain injury (mTBI) on injury beliefs and chronic symptom expectations of mTBI. Method: A total of 185 non-contact-sport players (non-CSPs) and 59 contact-sport players (CSPs) with no history of mTBI were randomly allocated to one of two conditions in which they read either a vignette depicting a sport-related mTBI (mTBIsport) or a motor-vehicle-accident-related mTBI (mTBIMVA). The vignettes were otherwise standardized to convey the same injury parameters (e.g., duration of loss of consciousness). After reading a vignette, participants reported their injury beliefs (i.e., perceptions of injury undesirability, chronicity, and consequences) and their expectations of chronic postconcussion syndrome (PCS) and posttraumatic stress disorder (PTSD) symptoms. Results: Non-CSPs held significantly more negative beliefs and expected greater PTSD symptomatology and greater PCS affective symptomatology from an mTBIMVA vignette thann mTBIsport vignette, but this difference was not found for CSPs. Unlike CSPs, non-CSPs who personally knew someone who had sustained an mTBI expected significantly less PCS symptomatology than those who did not. Despite these different results for non-CSPs and CSPs, overall, contact-sport participation did not significantly affect injury beliefs and symptom expectations from an mTBIsport. Conclusions: Expectations of persistent problems after an mTBI are influenced by factors such as injury cause even when injury parameters are held constant. Personal knowledge of mTBI, but not contact sport participation, may account for some variability in mTBI beliefs and expectations. These factors require consideration when assessing mTBI outcome.

Demographics and discharge outcomes of dysvascular and non-vascular lower limb amputees at a subacute rehabilitation unit: A 7-year series

Objective To examine personal and social demographics, and rehabilitation discharge outcomes of dysvascular and non-vascular lower limb amputees. Methods In total, 425 lower limb amputation inpatient rehabilitation admissions (335 individuals) from 2005 to 2011 were examined. Admission and discharge descriptive statistics (frequency, percentages) were calculated and compared by aetiology. Results Participants were male (74%), aged 65 years (s.d. 14), born in Australia (72%), had predominantly dysvascular aetiology (80%) and a median length of stay 48 days (interquartile range (IQR): 25–76). Following amputation, 56% received prostheses for mobility, 21% (n = 89) changed residence and 28% (n = 116) required community services. Dysvascular amputees were older (mean 67 years, s.d. 12 vs 54 years, s.d. 16; P < 0.001) and recorded lower functional independence measure – motor scores at admission (z = 3.61, P < 0.001) and discharge (z = 4.52, P < 0.001). More nonvascular amputees worked before amputation (43% vs 11%; P < 0.001), were prescribed a prosthesis by discharge (73% vs 52%; P < 0.001) and had a shorter length of stay (7 days, 95% confidence interval: –3 to 17), although this was not statistically significant. Conclusions Differences exist in social and demographic outcomes between dysvascular and non-vascular lower limb amputees.

Single voxel Magnetic Resonance Spectroscopic (1H-MRS) analysis of deep brain structures after traumatic prefrontal brain injury (TBI) in rat

Chronic difficulties arising from mild brain injury (TBI) are difficult to predict because the processes underlying changes after TBI are poorly understood. In mild brain injury the extent of neuropsychiatric and cognitive symptoms correspond poorly to overt tissue loss (Barth 1983; Liu 2010). Cellular, immune and hormonal cascades occurring after injury and continuing during the healing process may impact uninjured brain regions sensitive to the effects of physiological and emotional stress, which receive projections from the injury site. Changes in these most basic properties due to injury or disease have profound implications for virtually every aspect of brain function through disruption of neurotransmitter, neuroendocrine and metabolic systems. In order to screen for changes in transmitter and metabolic activity, in this study we developed Single voxel proton Magnetic Resonance Spectroscopy (1H-MRS) for use in both injured and control animals. We first evaluated if 1H-MRS could be used to evaluate in vivo, alterations in brain metabolism and catabolism of the prefrontal cortex, amygdala and ventral hippocampus in both control and injured animals after controlled cortical impact injury to the rat prefrontal cortex. We found that metabolite measurements for Myo-Inositol, Choline, creatine, Glutamate+Glutamine, and N-acetyl-acetate are attainable in deep brain structures in vivo in injured and controls rats. We next seek to evaluate longitudinally, in vivo, alterations in brain metabolism and catabolism of the prefrontal cortex, amygdala and ventral hippocampus during the first month after controlled cortical impact injury to the rat prefrontal cortex. These ongoing studies will provide data on the changes in transmitters and metabolites over time in injured and non-injured subjects. These studies address some of the fundamental questions about how mild brain injury has such diverse effects on overall brain health and function.

Correcting for bias when estimating the cost of hospital-acquired infection : an analysis of lower respiratory tract infections in non-surgical patients

Hospital acquired infections (HAI) are costly but many are avoidable. Evaluating prevention programmes requires data on their costs and benefits. Estimating the actual costs of HAI (a measure of the cost savings due to prevention) is difficult as HAI changes cost by extending patient length of stay, yet, length of stay is a major risk factor for HAI. This endogeneity bias can confound attempts to measure accurately the cost of HAI. We propose a two-stage instrumental variables estimation strategy that explicitly controls for the endogeneity between risk of HAI and length of stay. We find that a 10% reduction in ex ante risk of HAI results in an expected savings of £693 ($US 984).

A Petrov-Galerkin method for a singularly perturbed ordinary differential equation with non-smooth data

In this paper, a singularly perturbed ordinary differential equation with non-smooth data is considered. The numerical method is generated by means of a Petrov-Galerkin finite element method with the piecewise-exponential test function and the piecewise-linear trial function. At the discontinuous point of the coefficient, a special technique is used. The method is shown to be first-order accurate and singular perturbation parameter uniform convergence. Finally, numerical results are presented, which are in agreement with theoretical results.