While those with congenital bicuspid aortic valve make up 30-40% of those presenting during adulthood and typically presenting earlier (ages 40+ to 50+) than those with tricuspid aortic valves (65+).Acute rheumatic fever post-inflammatory is the cause of less than 10% of cases. Rare causes of aortic stenosis include Fabry disease, systemic lupus erythematosus, Paget disease, high blood uric acid levels, and infection. Pathophysiology
The human aortic valve normally consists of three cusps or leaflets and has an opening of 3.0-4.0 square centimeters. When the left ventricle contracts, it forces blood through the valve into the aorta and subsequently to the rest of the body. When the left ventricle expands again, the aortic valve closes and prevents the blood in the aorta from flowing backward (regurgitation) into the left ventricle. In aortic stenosis, the opening of the aortic valve becomes narrowed or constricted (stenotic) (e.g., due to calcification). Degenerative (the most common variety), and bicuspid aortic stenosis both begin with damage to endothelial cells from increased mechanical stress. Inflammation is thought to be involved in the earlier stages of the pathogenesis of AS and its associated risk factors are known to promote the deposition of LDL cholesterol and lipoprotein(a), a highly damaging substance, into the aortic valve, causing significant damage and stenosis over time. Infiltration of inflammatory cells (macrophages, T lymphocytes), followed by the release of inflammatory mediators such as interleukin-1-beta and transforming growth factor beta-1 occurs.
As with one-to-one interventions, several digital interventions have also proven successful in children with generalized math learning difficulties. Räsänen and colleagues have found that games such as The Number Race and Graphogame-math can improve performance on number comparison tasks in children with generalized math learning difficulties.Several digital interventions have been developed for dyscalculics specifically. Each attempts to target basic processes that are associated with maths difficulties. Rescue Calcularis was one early computerized intervention that sought to improve the integrity of and access to the mental number line. Other digital interventions for dyscalculia adapt games, flash cards, and manipulables to function through technology.While each intervention claims to improve basic numerosity skills, the authors of these interventions do admit that repetition and practice effects may be a factor involved in reported performance gains. An additional criticism is that these digital interventions lack the option to manipulate numerical quantities. While the previous two games provide the correct answer, the individual using the intervention cannot actively determine, through manipulation, what the correct answer should be. Butterworth and colleagues argued that games like The Number Bonds, which allows an individual to compare different sized rods, should be the direction that digital interventions move toward. Such games use manipulation activities to provide intrinsic motivation toward content guided by dyscalculia research. One of these serious games is Meister Cody – Talasia, an online training that includes the CODY Assessment – a diagnostic test for detecting dyscalculia.