Dyslexia is a learning disability that makes itself manifest primarily as a difficulty with reading and spelling. It is separate and distinct from reading difficulties resulting from other causes, such as a non-neurological deficiency with vision or hearing, or from poor or inadequate reading instruction. This suggests that dyslexia results from differences in how the brain processes written and spoken language.
Definition
There are many definitions of dyslexia but no consensus. Some definitions are purely descriptive, while others embody causal theories. It appears that ‘dyslexia’ is not one thing but many, in so far as it serves as a conceptual clearing-house for a number of reading skills deficits and difficulties, with a number of causes.
The majority of currently available dyslexia research relates to the alphabetic writing system, and especially languages of European origin.
Although dyslexia is thought to be the result of a neurological difference, it is not an intellectual disability. Dyslexia is diagnosed in people of all levels of intelligence.
Signs and symptoms include:
- Confusion with before/after, right/left, and so on
- Difficulty learning the alphabet
- Difficulty with word retrieval or naming problems
- Difficulty identifying or generating rhyming words, or counting syllables in words (phonological awareness)
- Difficulty with hearing and manipulating individual sounds in words (phonemic awareness)
- Difficulty distinguishing different sounds in words (auditory discrimination)
- Difficulty in learning the sounds of letters
- Difficulty associating individual words with their correct meanings
- Difficulty with time keeping and concept of time
- Confusion with combinations of words
- Due to fear of speaking incorrectly, some children become withdrawn and shy or become bullies out of their inability to understand the social cues in their environment
- Difficulty in organization skills
Diagnosis
Formal diagnosis of dyslexia is made by a qualified professional, such as a neurologist, neuropsychologist, developmental pediatrician, or educational psychologist. Evaluation generally includes testing of reading ability together with measures of underlying skills such as tests of rapid naming to evaluate short term memory and sequencing skills, and non word reading to evaluate phonological coding skills. Evaluation will usually also include an IQ test to establish a profile of learning strengths and weaknesses. While such "discrepancy" tests between full scale IQ and reading level have, on their own, been shown to be flawed,[10], the tests often include interdisciplinary testing to exclude other possible causes for reading difficulties, such as a more generalized cognitive impairment or physical causes such as problems with vision or hearing.
