dyscalculia dyscalculia dyscalculia (/ˌdɪskælˈkjuːliə/) is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. it is sometimes colloquially referred to as "math dyslexia", though this analogy is misleading as they are distinct syndromes. dyscalculiapronunciation/ˌdɪskælˈkjuːliə/ specialtypsychiatrycomplicationsdifficulty with daily tasksdurationlifetime dyscalculia is associated with dysfunction in the region around the intraparietal sulcus and potentially also the frontal lobe. dyscalculia does not reflect a general deficit in cognitive abilities or difficulties with time, measurement, and spatial reasoning. estimates of the prevalence of dyscalculia range between 3 and 6% of the population. in 2015 it was established that 11% of children with dyscalculia also have adhd. dyscalculia has also been associated with turner syndrome and people who have spina bifida. mathematical disabilities can occur as the result of some types of brain injury, in which case the term acalculia is used instead of dyscalculia, which is of innate, genetic or developmental origin. signs and symptoms the earliest appearance of dyscalculia is typically a deficit in subitizing, the ability to know, from a brief glance and without counting, how many objects there are in a small group. children as young as five can subitize six objects, especially looking at a die. however, children with dyscalculia can subitize fewer objects and even when correct take longer to identify the number than their age-matched peers. dyscalculia often looks different at different ages. it tends to become more apparent as children get older; however, symptoms can appear as early as preschool. common symptoms of dyscalculia are having difficulty with mental math, trouble analyzing time and reading an analog clock, struggle with motor sequencing that involves numbers, and often counting on fingers when adding numbers. common symptoms dyscalculia is characterized by difficulties with common arithmetic tasks. these difficulties may include visualizing numbers as meaningless or nonsensical symbols, rather than as characters indicating a numerical value (hence the misnomer "math dyslexia") seemingly "careless" mistakes in arithmetic operations (addition, subtraction, multiplication, etc.) ability to grasp math on a conceptual level, but an inability to put those concepts into practice difficulty recalling the names of numbers, or thinking that different numbers "feel" the same (e.g. interchanging the same two numbers for each other when reading or recalling them) a "warped" sense of spatial awareness, and/or trouble understanding shapes, distance, or volume difficulty with time, directions, recalling schedules, sequences of events, and/or financial planning inability to grasp and remember mathematical concepts, rules, and formulae inability to concentrate on mentally intensive tasks poor name/face retrieval; may substitute names beginning with same letter. anxiety when faced with tasks dealing with mathematics persistence in children although many researchers believe dyscalculia to be a persistent disorder, evidence on the persistence of dyscalculia remains mixed. for instance, in a study done by mazzocco and myers (2003), researchers evaluated children on a slew of measures and selected their most consistent measure as their best diagnostic criterion: a stringent 10th-percentile cut-off on the tema-2. even with their best criterion, they found dyscalculia diagnoses for children longitudinally did not persist; only 65% of students who were ever diagnosed over the course of four years were diagnosed for at least two years. the percentage of children who were diagnosed in two consecutive years was further reduced. it is unclear whether this was the result of misdiagnosed children improving in mathematics and spatial awareness as they progressed as normal, or that the subjects who showed improvement were accurately diagnosed, but exhibited signs of a non-persistent learning disability. persistence in adults there are very few studies of adults with dyscalculia who have had a history of it growing up, but such studies have shown that it can persist into adulthood. it can affect major parts of an adult's life. most adults with dyscalculia have a hard time processing math at a 4th-grade level. for 1st–4th grade level, many adults will know what to do for the math problem, but they will often get them wrong because of "careless errors", although they are not careless when it comes to the problem. the adults cannot process their errors on the math problems or may not even recognize that they have made these errors. visual-spatial input, auditory input, and touch input will be affected due to these processing errors. dyscalculics may have a difficult time adding numbers in a column format because their mind can mix up the numbers, and it is possible that they may get the same (wrong) answer twice due to their mind processing the problem incorrectly. dyscalculics can have problems determining differences in different coins and their size or giving the correct amount of change and if numbers are grouped together, it is possible that they cannot determine which has less or more. if a dyscalculic is asked to choose the greater of two numbers, with the lesser number in a larger font than the greater number, they may take the question literally and pick the number with the bigger font. adults with dyscalculia may struggle with directions while driving and with controlling their finances, leading to difficulties on a day-to-day basis. college students or other adult learners college students particularly may have a difficult time due to the fast pace and change in difficulty of the work they are given. as a result of this, students may develop much anxiety and frustration. after dealing with their anxiety for a long time, students can become averse to math and try to avoid it as much as possible, which may result in lower grades in math courses. students with dyscalculia, however, can also do exceptionally well in writing, reading, and speaking. causes both domain-general and domain-specific causes have been put forth. with respect to pure developmental dyscalculia, domain-general causes are unlikely as they should not impair one's ability in the numerical domain without also affecting other domains such as reading. two competing domain-specific hypotheses about the causes of developmental dyscalculia have been proposed – the magnitude representation (or number module deficit hypothesis) and the access deficit hypothesis. magnitude representation deficit dehaene's "number sense" theory suggests that approximate numerosities are automatically ordered in an ascending manner on a mental number line. the mechanism to represent and process non-symbolic magnitude (e.g., number of dots) is often known as the "approximate number system" (ans), and a core deficit in the precision of the ans, known as the "magnitude representation hypothesis" or "number module deficit hypothesis", has been proposed as an underlying cause of developmental dyscalculia. in particular, the structural features of the ans are theoretically supported by a phenomenon called the "numerical distance effect", which has been robustly observed in numerical comparison tasks. typically developing individuals are less accurate and slower in comparing pairs of numbers closer together (e.g., 7 and 8) than further apart (e.g., 2 and 9). a related "numerical ratio effect" (in which the ratio between two numbers varies but the distance is kept constant, e.g., 2 vs. 5 and 4 vs. 7) based on weber's law has also been used to further support the structure of the ans. the numerical ratio effect is observed when individuals are less accurate and slower in comparing pairs of numbers that have a larger ratio (e.g., 8 and 9, ratio = 8/9) than a smaller ratio (2 and 3; ratio = 2/3). a larger numerical distance or ratio effect with comparison of sets of objects (i.e., non-symbolic) is thought to reflect a less precise ans, and the ans acuity has been found to correlate with math achievement in typically developing children and also in adults. more importantly, several behavioral studies have found that children with developmental dyscalculia show an attenuated distance/ratio effect than typically developing children. moreover, neuroimaging studies have also provided additional insights even when behavioral difference in distance/ratio effect might not be clearly evident. for example, gavin r. price and colleagues found that children with developmental dyscalculia showed no differential distance effect on reaction time relative to typically developing children, but they did show a greater effect of distance on response accuracy. they also found that the right intraparietal sulcus in children with developmental dyscalculia was not modulated to the same extent in response to non-symbolic numerical processing as in typically developing children. with the robust implication of the intraparietal sulcus in magnitude representation, it is possible that children with developmental dyscalculia have a weak magnitude representation in the parietal region. yet, it does not rule out an impaired ability to access and manipulate numerical quantities from their symbolic representations (e.g., arabic digits). this shows the part of the brain where the sulcus is located in the parietal lobe. moreover, findings from a cross-sectional study suggest that children with developmental dyscalculia might have a delayed development in their numerical magnitude representation by as much as five years. however, the lack of longitudinal studies still leaves the question open as to whether the deficient numerical magnitude representation is a delayed development or impairment. access deficit hypothesis rousselle & noël propose that dyscalculia is caused by the inability to map preexisting representations of numerical magnitude onto symbolic arabic digits. evidence for this hypothesis is based on research studies that have found that individuals with dyscalculia are proficient on tasks that measure knowledge of non-symbolic numerical magnitude (i.e., non-symbolic comparison tasks) but show an impaired ability to process symbolic representations of number (i.e., symbolic comparison tasks). neuroimaging studies also report increased activation in the right intraparietal sulcus during tasks that measure symbolic but not non-symbolic processing of numerical magnitude. however, support for the access deficit hypothesis is not consistent across research studies. diagnosis at its most basic level, dyscalculia is a learning disability affecting the normal development of arithmetic skills. a consensus has not yet been reached on appropriate diagnostic criteria for dyscalculia. mathematics is a specific domain that is complex (i.e. includes many different processes, such as arithmetic, algebra, word problems, geometry, etc.) and cumulative (i.e. the processes build on each other such that mastery of an advanced skill requires mastery of many basic skills). thus dyscalculia can be diagnosed using different criteria, and frequently is; this variety in diagnostic criteria leads to variability in identified samples, and thus variability in research findings regarding dyscalculia. the example of each condition in the numerical stroop effect task other than using achievement tests as diagnostic criteria, researchers often rely on domain-specific tests (i.e. tests of working memory, executive function, inhibition, intelligence, etc.) and teacher evaluations to create a more comprehensive diagnosis. alternatively, fmri research has shown that the brains of the neurotypical children can be reliably distinguished from the brains of the dyscalculic children based on the activation in the prefrontal cortex. however, due to the cost and time limitations associated with brain and neural research, these methods will likely not be incorporated into diagnostic criteria despite their effectiveness. types research on subtypes of dyscalculia has begun without consensus; preliminary research has focused on comorbid learning disorders as subtyping candidates. the most common comorbidity in individuals with dyscalculia is dyslexia. most studies done with comorbid samples versus dyscalculic-only samples have shown different mechanisms at work and additive effects of comorbidity, indicating that such subtyping may not be helpful in diagnosing dyscalculia. but there is variability in results at present. due to high comorbidity with other disabilities such as dyslexia and adhd, some researchers have suggested the possibility of subtypes of mathematical disabilities with different underlying profiles and causes. whether a particular subtype is specifically termed "dyscalculia" as opposed to a more general mathematical learning disability is somewhat under debate in the scientific literature. semantic memory: this subtype often coexists with reading disabilities such as dyslexia and is characterized by poor representation and retrieval from long-term memory. these processes share a common neural pathway in the left angular gyrus, which has been shown to be selective in arithmetic fact retrieval strategies and symbolic magnitude judgments. this region also shows low functional connectivity with language-related areas during phonological processing in adults with dyslexia. thus, disruption to the left angular gyrus can cause both reading impairments and difficulties in calculation. this has been observed in individuals with gerstmann syndrome, of which dyscalculia is one of constellation of symptoms. procedural concepts: research by geary has shown that in addition to increased problems