frequently interchanging the same two numbers for each other when reading or recalling them)
Problems with differentiating between left and right
A "warped" sense of spatial awareness, or an understanding of shapes, distance, or volume that seems more like guesswork than actual comprehension
Difficulty with time, directions, recalling schedules, sequences of events, keeping track of time, frequently late or early
Difficulty reading maps
Difficulty working backwards in time (e.g. What time to leave if needing to be somewhere at X time)
Difficulty reading musical notation
Difficulty with choreographed dance steps
Having particular difficulty mentally estimating the measurement of an object or distance (e.g., whether something is 3 or 6 meters (10 or 20 feet) away)
Inability to grasp and remember mathematical concepts, rules, formulae, and sequences
Inability to concentrate on mentally intensive tasks
Mistaken recollection of names, poor name/face retrieval; may substitute names beginning with same letter. Some people with dyscalculia also have aphantasia that affects how they can "see" in their minds eye. However, people without dyscalculia also report having this – but it is more prevalent in those with dyslexia and other learning disabilities. 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.
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. 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.