Template:Extract abstract

Dyslexia is a neurodevelopmental disorder characterized by difficulty learning to read and spell. Underlying deficits typically include impaired phonological awareness (an awareness of the sound structure of words) and processing; difficulty with verbal working memory; and slow verbal processing speed. Observable problems include frequent spelling errors that same-age children do not exhibit; difficulty learning how to decode individual words, including "sounding out" words; and struggling to pronounce words correctly and fluently when reading aloud. Deficits in reading comprehension often occur as a secondary consequence.

Dyslexia is a heterogeneous disorder, which means that not all people with dyslexia have the same signs, symptoms, underlying deficits, or functional impairment. Children and adults with dyslexia exhibit higher rates of comorbid conditions such as developmental language disorders; attention-deficit/hyperactivity disorder (ADHD); and difficulties with motor coordination, mental calculation, concentration, and personal organization, but these are not, by themselves, markers of dyslexia. Dyslexia manifests on a continuum of severity—it is a dimensional disorder. People with this disorder have a normal desire to learn.

Dyslexia is believed to be caused by both genetic and environmental factors, and their interaction. Dyslexia often runs in families. Dyslexia that develops subsequent to a traumatic brain injury, stroke, or dementia is usually called acquired dyslexia. The underlying mechanisms of dyslexia are problems within the brain's language processing. Dyslexia is diagnosed through a series of tests of memory, spelling, and reading skills. Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching or opportunity to learn.

Treatment involves adjusting teaching methods to meet the person's needs. While not curing the underlying problem, it may decrease the degree or impact 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% of the general population may have some degree of symptoms.