Medicine (RMH) - Research Publications
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ItemSACCADE ADAPTATION IN AUTISM AND ASPERGER'S DISORDER(PERGAMON-ELSEVIER SCIENCE LTD, 2013-07-23)Autism and Asperger's disorder (AD) are neurodevelopmental disorders primarily characterized by deficits in social interaction and communication, however motor coordination deficits are increasingly recognized as a prevalent feature of these conditions. Although it has been proposed that children with autism and AD may have difficulty utilizing visual feedback during motor learning tasks, this has not been directly examined. Significantly, changes within the cerebellum, which is implicated in motor learning, are known to be more pronounced in autism compared to AD. We used the classic double-step saccade adaptation paradigm, known to depend on cerebellar integrity, to investigate differences in motor learning and the use of visual feedback in children aged 9-14 years with high-functioning autism (HFA; IQ>80; n=10) and AD (n=13). Performance was compared to age and IQ matched typically developing children (n=12). Both HFA and AD groups successfully adapted the gain of their saccades in response to perceived visual error, however the time course for adaptation was prolonged in the HFA group. While a shift in saccade dynamics typically occurs during adaptation, we revealed aberrant changes in both HFA and AD groups. This study contributes to a growing body of evidence centrally implicating the cerebellum in ocular motor dysfunction in autism. Specifically, these findings collectively imply functional impairment of the cerebellar network and its inflow and outflow tracts that underpin saccade adaptation, with greater disturbance in HFA compared to AD.
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ItemCost-Effectiveness of Optimizing Use of Statins in Australia: Using Outpatient Data From the REACH Registry(ELSEVIER, 2011-10)BACKGROUND: Although few cardiovascular registries report the costs of illness or cost-effectiveness of health interventions, such information is critical to inform the effective and cost-effective management of cardiovascular disease, particularly if drawn from population-based registries, which more accurately reflect clinical practice and follow up patients for much longer than clinical trials. OBJECTIVE: The goal of this study was to estimate the cost-effectiveness of closing the statin "treatment gap" in the secondary prevention of coronary artery disease (CAD) in Australia. METHODS: A decision analysis Markov model was developed with yearly cycles and the health states of alive or dead. Using data from the Australian Reduction of Atherothrombosis for Continued Health Registry, the model compared current statin coverage (82%) in the secondary prevention of CAD (the current group) with a hypothetical situation of 100% coverage (the improved group). The 18% gap was filled with use of generic statins. Data from a recent meta-analysis were used to estimate the benefits of statin use in terms of reducing recurrent cardiovascular events and death. Government reimbursement data from 2011 were used to calculate direct health care costs. The cost of the intervention to improve statin coverage was assumed to be $250 per person. Years of life lived and costs were discounted at 5% annually. All values are given in Australian dollars. RESULTS: Among the 2058 subjects in the current group, the model estimated that there would be 106 nonfatal myocardial infractions, 68 nonfatal strokes, and 275 deaths over 5 years. In the improved group, all of whom took statins, the corresponding numbers were 101, 65, and 259, equating to numbers needed to treat of 426, 639, and 127, respectively. Over the 5 years, there would be 0.018 life-years gained (discounted) at a net cost of $546 (discounted) per person. These equated to an incremental cost-effectiveness ratio of $29,717 per life-year gained. CONCLUSION: The results suggest that for patients with CAD, maximizing coverage with statins, in line with evidence-based recommendations, represents a cost-effective means of secondary prevention.
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ItemTime to treatment with intravenous alteplase and outcome in stroke: an updated pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials(ELSEVIER SCIENCE INC, 2010-05-15)BACKGROUND: Early administration of intravenous recombinant tissue plasminogen activator (rt-PA) after ischaemic stroke improves outcome. Previous analysis of combined data from individual patients suggested potential benefit beyond 3 h from stroke onset. We re-examined the effect of time to treatment with intravenous rt-PA (alteplase) on therapeutic benefit and clinical risk by adding recent trial data to the analysis. METHODS: We added data from ECASS III (821 patients) and EPITHET (100 patients) to a pool of common data elements from six other trials of alteplase for acute stroke (2775 patients). We used multivariate logistic regression to assess the relation of stroke onset to start of treatment (OTT) with treatment on favourable 3-month outcome (defined as modified Rankin score 0-1), mortality, and occurrence and outcome of clinically relevant parenchymal haemorrhage. The presence of an arterial occlusion was inferred from the patient's symptoms and absence of haemorrhage or other causes of ischaemic stroke. Vascular imaging was not a requirement in the trials. All patients with confirmed OTT within 360 min were included in the analysis. FINDINGS: Treatment was started within 360 min of stroke onset in 3670 patients randomly allocated to alteplase (n=1850) or to placebo (n=1820). Odds of a favourable 3-month outcome increased as OTT decreased (p=0.0269) and no benefit of alteplase treatment was seen after around 270 min. Adjusted odds of a favourable 3-month outcome were 2.55 (95% CI 1.44-4.52) for 0-90 min, 1.64 (1.12-2.40) for 91-180 min, 1.34 (1.06-1.68) for 181-270 min, and 1.22 (0.92-1.61) for 271-360 min in favour of the alteplase group. Large parenchymal haemorrhage was seen in 96 (5.2%) of 1850 patients assigned to alteplase and 18 (1.0%) of 1820 controls, with no clear relation to OTT (p=0.4140). Adjusted odds of mortality increased with OTT (p=0.0444) and were 0.78 (0.41-1.48) for 0-90 min, 1.13 (0.70-1.82) for 91-180 min, 1.22 (0.87-1.71) for 181-270 min, and 1.49 (1.00-2.21) for 271-360 min. INTERPRETATION: Patients with ischaemic stroke selected by clinical symptoms and CT benefit from intravenous alteplase when treated up to 4.5 h. To increase benefit to a maximum, every effort should be taken to shorten delay in initiation of treatment. Beyond 4.5 h, risk might outweigh benefit. FUNDING: None.