Dyslexia | |
---|---|
Other names | Reading disorder, alexia |
Difficulties in processing letters and words | |
Specialty | Neurology, pediatrics |
Symptoms | Trouble reading[1] |
Usual onset | School age[2] |
Types | Surface dyslexia |
Causes | Genetic and environmental factors[2] |
Risk factors | Family history, attention deficit hyperactivity disorder[3] |
Diagnostic method | Series memory, spelling, vision, and reading test[4] |
Differential diagnosis | Hearing or vision problems, insufficient teaching[2] |
Treatment | Adjusting teaching methods[1] |
Frequency | 3–7%[2][5] |
Dyslexia, previously known as word blindness, is a learning disability that affects either reading or writing.[1][6] Different people are affected to different degrees.[3] 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.[3][7] Often these difficulties are first noticed at school.[2] The difficulties are involuntary, and people with this disorder have a normal desire to learn.[3] People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers.[2][8]
Dyslexia is believed to be caused by the interaction of genetic and environmental factors.[2] Some cases run in families.[3] Dyslexia that develops due to a traumatic brain injury, stroke, or dementia is sometimes called "acquired dyslexia"[1] or alexia.[3] The underlying mechanisms of dyslexia result from differences within the brain's language processing.[3] Dyslexia is diagnosed through a series of tests of memory, vision, spelling, and reading skills.[4] Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching or opportunity to learn.[2]
Treatment involves adjusting teaching methods to meet the person's needs.[1] While not curing the underlying problem, it may decrease the degree or impact of symptoms.[9] Treatments targeting vision are not effective.[10] Dyslexia is the most common learning disability and occurs in all areas of the world.[11] It affects 3–7% of the population;[2][5] however, up to 20% of the general population may have some degree of symptoms.[12] While dyslexia is more often diagnosed in boys, this is partly explained by a self-fulfilling referral bias among teachers and professionals.[2][13] It has even been suggested that the condition affects men and women equally.[11] Some believe that dyslexia is best considered as a different way of learning, with both benefits and downsides.[14][15]