dyslexia Flashcards
what proportion of population can be diagnosed as dyslexic?
10%
What are characteristics of dyslexia ?
–Reading substantially below average for their age
–Adequate teaching exposure
–Adequate socio-economic opportunity
–No other disturbances of an organic origin
(e.g., autism, retardation etc)
–Normal to above average IQ
no other obvious explanation for reading difficulty
what is dyslexia?
difficulty in phonics
problems in tasks that require phonological decoding
what is phonics/ phonemic awareness
–Phonemic awareness is the awareness that language is made up of individual and unique sounds.
associating sound with letters on page
what are some examples of dyslexics showing problem in phonological decoding tasks?
–Spoonerisms
- rhyme
- reading non-words
- discriminating between similar phonemes
describe the process of reading in dyslexics
Eye fixation patterns:
–Dyslexic readers fixate longer on words and demonstrate more regressive eye movements
–Fixations are less stable in dyslexic readers
–Poor binocular convergence
what do models of reading predict in terms of those who are dyslexic?
what does this suggest?
that dyslexic readers can have difficulties in using the different reading routes defined in the dual route model
–This has resulted in the **identification of different subtypes of dyslexia **
- phonological dyslexia
- surface dyslexia
Features of phonological dyslexics
Many dyslexic readers have difficulties using the Phonological
Route.
i.e., They have difficulties sounding out and may over-rely on the lexical route
–Difficulties in reading non-words
(because non-words can only be read using the phonological route)
–Over reliance on the lexical route for reading and spelling
•E.g., spelling errors tend to look like a known word (“think” for “thorn” for example) Over reliance on context (“carrot” for “coconut”
what is surface dyslexia
•difficulty in using the lexical route
–Over reliance on the phonological route
features of surface dyslexia
reading and spelling errors include:
- difficulties reading irregular words (e.g., yacht)
(as these words cannot be sounded out, and must be read using the lexical route)
- Spelling tends to be phonological (e.g., “meringoo” for meringue)
- Reading tends to remain slow and laborious
Dyslexia and visual processing?
what was the previous assumption?
–Dyslexia was originally considered to be a difficulty in visual processing. However this belief was abandoned when dyslexic readers were consistently shown to have normal vision.
how does visual processing influence dyslexics?
many dyslexic readers show a deficit in processing visual information carried by the dorsal stream of the visual system.
difficulty processing information need to be transmitted to dorsal stream
what does the dorsal stream do?
guide saccades across page
what are features of pre-readers?
•Pre-readers at risk for dyslexia show dorsal deficits •Dorsal deficits predict later reading difficulty
is dyslexia visual discomfort? what is visual discomfort. what do those with visual discomfort experience?
- Visual Discomfort is a disorder of visual processing, that makes it very difficult to read.
- those with visual discomfort experience sensations such as;
–Words “moving”, “shimmering” and “shaking”
–Words “floating on the page”, or “carved into the page”
–Text looking like “rivers”
–May suffer migraine, and/or severe motion sickness
–Hyper-sensitivity to light
How does visual discomfort come about?
•Visual discomfort comes about because text looks like the type of visual stimuli that upsets the visual system i.e., high contrast black and white lines
similarities and Differences between dyslexics and those who have visual discomfort syndrome
Similarities:
- lower reading than average as they tend to avoid reading
Visual discomfort syndrome
- do not have problems with phonological decoding tasks
- a change to a more accomodating visual environment can assist reading
What conditions will ease the visual discomfort? Will dyslexics find it easier to read when visual environment is more accomodating?
Those experiencing visual discomfort may find it easier to read when there are changes in the visual environment
–Low lights
–Not fluorescent lights
–Low contrast, larger text
–Coloured text, glasses and/or overlays
No, dyslexics will not find it easier to read when visual environment is more accomodating
What is specific language impairment (SPI)?
it is a language disorder
where they have delayed receptive ( comprehending sentences) and expressive language (generating language)
50% comorbidity with dyslexia (existing at the same time)
What is difference between Specific language impariment and dyslexia?
Dyslexia concerns with reading while SPI concerns with difficulty in receptive and expressive language
what is SPI normally influenced by?
normally influenced by genetics
what percent of population have SPI?
7%
more males than females
what may be the cause of SPI?
one theory is the auditory Auditory Temporal Sampling Hypothesis
Other type of language disorders
-stuttering
what are characteristics of stuttering?
repeated movements and fixed postures of the speech mechanisms
