May 31, 2011 at 9:28 AM ET
Described as the mathematical equivalent of dyslexia, dyscalculia is a little-known disorder that makes it extremely difficult to learn math. While dyslexics struggle with reading and interpreting words and letters, dyscalculics have a hard time with basic arithmetic and understanding the meaning and concepts of numbers.
Although often a forgotten stepchild to its well-known relative dyslexia, dyscalculia affects the same number of people -- an estimated 5 to 7 percent of the population, suggests new research in the May 27 issue of Science.
Often first discovered by low scores on math achievement tests, both children and adults who suffer from dyscalculia have trouble grasping the size of a number and its relative value.
Unlike dyslexics, however, they don't reverse the order of numbers when reading them. "Typically, dyscalculics don't have problems with the order of symbols, but anything with numbers could cause anxiety or even panic," says Brian Butterworth, an emeritus professor of cognitive neuroscience at University College London, and lead author of the Science review article.
While many people think they're bad at math or don't have a head for numbers, dyscalculics are slower and less accurate at estimating the number of sets of objects and selecting the larger of two numbers, explains Butterworth.
For example, if dyscalculics were shown two playing cards -- a 5 and an 8 -- and asked to say which card was larger, they would count all the symbols on each card. If asked to count down from 10, they would count up from 1 to 10, then 1 to 9, then 1 to 8, etc.
They might use their fingers to count and do simple addition, far beyond the age when it's normally done. And they are challenged by making change and handling money, and estimating the height of a room (they may say 200 feet). They also have trouble with concepts of time, like approximating how long a car trip will take.
Dyscalculia appears to be inherited, and scientists have begun to identify abnormalities in the brain that make learning math such a grind.
Even so, it's important for those affected to realize that "having a serious problem learning arithmetic does not mean you are stupid," says Butterworth.
In fact, the disability can affect people with normal intelligence and normal working memory, or be seen in those with other developmental difficulties, such as dyslexia and ADHD. Some adults with severe dyscalculia can even be very good at geometry and using statistical packages, and capable of doing college-level computer programming. So it doesn't affect all mathematical abilities or skills.
But it can be a lifelong liability if it's misdiagnosed, unrecognized by teachers or not properly treated.
The paper calls for greater attention and funding for the problem, and specialized teaching that strengthens the processing of numbers using concrete materials, such as beads and counters, supported by game-like software for learners.
The important thing is to not go on to more advanced concepts until the basics have been mastered, says Butterworth.