with fact retrieval, children with math disabilities may rely on immature computational strategies. specifically, children with mathematical disabilities showed poor command of counting strategies unrelated to their ability to retrieve numeric facts. this research notes that it is difficult to discern whether poor conceptual knowledge is indicative of a qualitative deficit in number processing or simply a delay in typical mathematical development. working memory: studies have found that children with dyscalculia showed impaired performance on working memory tasks compared to neurotypical children. furthermore, research has shown that children with dyscalculia have weaker activation of the intraparietal sulcus during visuospatial working memory tasks. brain activity in this region during such tasks has been linked to overall arithmetic performance, indicating that numerical and working memory functions may converge in the intraparietal sulcus. however, working memory problems are confounded with domain-general learning difficulties, thus these deficits may not be specific to dyscalculia but rather may reflect a greater learning deficit. dysfunction in prefrontal regions may also lead to deficits in working memory and other executive function, accounting for comorbidity with adhd. studies have also shown indications of causes due to congenital or hereditary disorders, but evidence of this is not yet concrete. treatment to date, very few interventions have been developed specifically for individuals with dyscalculia. concrete manipulation activities have been used for decades to train basic number concepts for remediation purposes. this method facilitates the intrinsic relationship between a goal, the learner's action, and the informational feedback on the action. a one-to-one tutoring paradigm designed by lynn fuchs and colleagues which teaches concepts in arithmetic, number concepts, counting, and number families using games, flash cards, and manipulables has proven successful in children with generalized math learning difficulties, but intervention has yet to be tested specifically on children with dyscalculia. these methods require specially trained teachers working directly with small groups or individual students. as such, instruction time in the classroom is necessarily limited. for this reason, several research groups have developed computer adaptive training programs designed to target deficits unique to dyscalculic individuals. software intended to remediate dyscalculia has been developed. while computer adaptive training programs are modeled after one-to-one type interventions, they provide several advantages. most notably, individuals are able to practice more with a digital intervention than is typically possible with a class or teacher. 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. based on these findings, dybuster calcularis was extended by adaptation algorithms and game forms allowing manipulation by the learners. it was found to improve addition, subtraction and number line tasks, and was made available as dybuster calcularis. a study used transcranial direct current stimulation (tdcs) to the parietal lobe during numerical learning and demonstrated selective improvement of numerical abilities that was still present six months later in typically developing individuals. improvement were achieved by applying anodal current to the right parietal lobe and cathodal current to the left parietal lobe and contrasting it with the reverse setup. when the same research group used tdcs in a training study with two dyscalculic individuals, the reverse setup (left anodal, right cathodal) demonstrated improvement of numerical abilities. epidemiology dyscalculia is thought to be present in 3–6% of the general population, but estimates by country and sample vary somewhat. many studies have found prevalence rates by gender to be equivalent. those that find gender difference in prevalence rates often find dyscalculia higher in females, but some few studies have found prevalence rates higher in males. history the term dyscalculia was coined in the 1940s, but it was not completely recognized until 1974 by the work of czechoslovakian researcher ladislav kosc. kosc defined dyscalculia as "a structural disorder of mathematical abilities." his research proved that the learning disability was caused by impairments to certain parts of the brain that control mathematical calculations and not because symptomatic individuals were 'mentally handicapped'. researchers now sometimes use the terms "math dyslexia" or "math learning disability" when they mention the condition. cognitive disabilities specific to mathematics were originally identified in case studies with patients who experienced specific arithmetic disabilities as a result of damage to specific regions of the brain. more commonly, dyscalculia occurs developmentally as a genetically linked learning disability which affects a person's ability to understand, remember, or manipulate numbers or number facts (e.g., the multiplication tables). the term is often used to refer specifically to the inability to perform arithmetic operations, but is also defined by some educational professionals and cognitive psychologists such as stanislas dehaene and brian butterworth as a more fundamental inability to conceptualize numbers as abstract concepts of comparative quantities (a deficit in "number sense"), which these researchers consider to be a foundational skill upon which other mathematics abilities build. symptoms of dyscalculia include the delay of simple counting, inability to memorize simple arithmetic facts such as adding, subtracting, etc. there are few known symptoms because little research has been done on the topic. etymology the term dyscalculia dates back to at least 1949. dyscalculia comes from greek and latin and means 'counting badly'. the prefix dys- comes from greek and means 'badly'. the root calculia comes from the latin calculare, which means 'to count'; it is also a cognate of calculation and calculus.