|An example of OpenDyslexic typeface, which is used to mitigate common reading errors due to dyslexia.|
|Classification and external resources|
|ICD–10||F81.0 (developmental), R48.0|
Dyslexia, also known as reading disorder, is characterized by trouble with reading despite normal intelligence. Different people are affected to varying degrees. Problems may include difficulties in spelling words, reading quickly, writing words, “sounding out” words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. When someone who previously could read loses their ability, it is known as alexia. The difficulties are involuntary and people with this disorder have a normal desire to learn.
Dyslexia is believed to be caused by both genetic and environmental factors. Some cases run in families. It often occurs in people with attention deficit hyperactivity disorder (ADHD) and is associated with similar difficulties with numbers. It may begin in adulthood as the result of a traumatic brain injury, stroke, or dementia. The underlying mechanisms of dyslexia are problems within the brain‘s language processing. Dyslexia is diagnosed through a series of tests of memory, spelling, vision, and reading skills. Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching.
Treatment involves adjusting teaching methods to meet the person’s needs. While not curing the underlying problem, it may decrease the degree of symptoms. Treatments targeting vision are not effective. Dyslexia is the most common learning disability and occurs in all areas of the world. It affects 3–7% of the population; however, up to 20% may have some degree of symptoms. While dyslexia is more often diagnosed in men, it has been suggested that it affects men and women equally. Some believe that dyslexia should be best considered as a different way of learning, with both benefits and downsides.