Part 2: Numbers vs. Letters: Dyslexia, Dysgraphia & Dyscalculia

For information on the ways the brain understands symbols, read Part 1 of this blog: Numbers vs. Letters: How We Interpret Symbols

Neuroscientists are still studying how the brain interprets letters and numbers, but what they have found so far is certainly interesting. For example, we know that the brain interprets letters and numbers differently. Letters and numbers each have their own unique system they get filtered through in order for the brain to identify and attach a meaning to them. That is why some people can read perfectly fine, but struggle keeping numbers straight in math and vice versa. So what are dyslexia, dysgraphia and dyscalculia? Dyslexia is a visual processing disorder that affects a person's ability to read. There are four types of dyslexia. They are phonological dyslexia, surface dyslexia, rapid naming deficit and double deficit dyslexia. Phonological dyslexia, also called auditory dyslexia, involves difficulty processing the sounds of the individual letters and syllables and matching them with their written forms. Surface dyslexia, also called visual dyslexia, involves difficulty recognizing whole words, resulting in difficulty learning and memorizing words. Rapid naming deficit dyslexia involves difficulty connecting words to objects, making naming a letter, number, color, or object quickly and automatically difficult. Double deficit dyslexia involves a difficulty with both phonological dyslexia and rapid naming deficit. 

Dysgraphia involves an inability to write coherently and can be a symptom of a neurological condition or as an aspect of a learning disability. There are five types of dysgraphia. They are dyslexic, motor, spatial, phonological and lexical. Dyslexic dysgraphia involves difficulty recalling letter formations and shapes, resulting in poor spelling and writing when not copying. Motor dysgraphia involves difficulty writing due to a deficiency in fine motor skills, however this does not affect their spelling. Spatial dysgraphia involves a deficiency in spatial processing skills, affecting both spontaneous and copied writing. Spatial dysgraphia does not affect spelling. Phonological dysgraphia involves difficulty connecting a sound to a specific letter, affecting both spelling and writing, often making it hard to remember and correctly use phonemes. Lastly, lexical dysgraphia affects spelling due to an extreme reliance on standard sound to letter patterns. 

Dyscalculia involves difficulty in performing arithmetical calculations resulting from irregularities in the brain. There are six types of dyscalculia. verbal, practonostic, lexical, graphical and ideognostical. Verbal dyscalculia involves difficulty naming and understanding the mathematical concepts presented verbally, due to issues with auditory processing. Practognostic dyscalculia involves understanding an abstract mathematical concept but having difficulty translating that concept into practice. Lexical dyscalculia does not affect understanding of mathematical concepts, instead it involves a deficit in visual processing, causing difficulty reading and interpreting mathematical symbols, numbers, expressions or equations. Graphical dyscalculia involves difficulty writing mathematical symbols, and does not affect the ability to understand the information. Ideognostical dyscalculia involves difficulty carrying out mental operations as well as understanding and remembering mathematical concepts. Operational dyscalculia involves difficulty manipulating numbers and mathematical symbols in the calculation process, and does not affect the ability to understand the numbers and the relationships between them.

While some of these do affect someone’s ability to understand information, the truth is, the majority of them don’t. Which brings us back to the concept that processing information and the ability to do so, is not inherently connected to a person's capacity to learn. The brain has a separate system for interpreting letters, numbers, symbols, shapes and colors. The brain also interprets each of those bits of information differently depending on how it is being presented, such as visually or verbally. On top of that, no two people think the same. So whether it is numbers or letters, you interpret them in your own unique way. Pretty cool if you ask us!