Reading, writing and aquried deficits and alternative communication forms Flashcards
What is developmental dyslexia and dysgraphia?
- Dyslexia: developmental learning disability (struggle to learn how to read)
- Dysgraphia: developmental learning disability (struggle to learn how to spell/write)
What is alexia and agraphia?
- Alexia: a reading disorder that is caused by injury to the brain in previously literate people
- Agraphia: a disorder of writing/spelling caused by injury to the brain in previously literate people
What are some examples of acquired reading disorders.
- Surface alexia
- Phonological alexia
- Deep alexia
- Pure alexia
Describe Surface alexia.
The first route in the dual route model (the semantic route) is lost and the semantics cannot be accessed and so the
patients have to rely on the Grapheme-phoneme route. They therefore make errors when a word appears that is not actually pronounced how it would be pronounced if using strict Grapheme-phoneme conversions.
Seen following stroke and dementia.
Describe Phonological alexia.
The second route in the dual route model (the grapheme-phoneme route) is lost and so the patients have to rely on the semantic/lexical route. Words they know will therefore be unaffected, but unfamiliar and nonwords will cause problems as the Grapheme-phoneme conversion is impaired.
Describe Deep alexia.
In large left hemisphere lesions both route can be affected. Not only will the person not be able to read novel- and non-words but they will make sematic errors
Describe Pure alexia.
Selective deficit in reading:
- Patients lose the ability to read letters and words (fast and fluently).
- Also called alexia without agraphia.
- Writing, and other language functions, are spared, although if asked to read back what
they have written they cannot
- Patients with pure alexia can typically identify (some) letters but not read whole wordswithout spelling through them: Letter-by-letter reading / word length effect
- typically have lesions in a specific region called “the visual word form area”(VWFA): Visual input to the cortex arrives bilaterally but regardless of the hemisphere in which they first arrive, the words are processed in the VWFA in the left hemisphere, from here is it sent on to the language networks of the temporal lobe
Desscribe the two routes in the Dual Route model.
1) the semantic/lexical route: letter units activate the word lexicon (containing details regarding the meaning and the correct phonological output)
2) the grapheme-phoneme route: converting each letter to a phoneme and combining the phonemes to pronounce the word
Describe the levels in the Interactive Activation model.
3 levels with (bottom-up processingfor unfamiliar/non-words, top-down processing for familiar words, aka. word superioty effect):
- feature: cells activated in the visual cortex by lines at specific angles
- letter: units in this layer is activated by the feature layer, and if all the appropriate features are activated, the letter unit is activated
- word: if the letter is part of a string of letters making up a word, this layer is activated
What is the word superiority effect (WSE)?
When you show someone a letter in isolation they are slower to
respond than if you show them the same later in the context of a real word (but not in a random
letter string
How is the WSE explained by the Interactive activation model?
Say, for example, I show you a letter “A” If you only see the letter A alone then the units in the feature layer (representing the 3 lines making up the A) will be activated which in turn will
activate the unit in the letter layer signaling “A”.
Now let’s say we present the “A” but now surrounded by two other letters to give the word “CAT”. Now, you still activate the unit layer and then the letter layer for “A” but now also the word layer for the word “CAT” is also activated (in a bottom up way so far). But, the activation at the word layer level is now passed back down to the letter layer again (in a top down manner) and so the “A” letter unit is now more highly activated leading to a faster identification of the
letter “A”
Identify the neural correlates of sign language
The classical language networks
- Broca’s area are activated when producing signs
- Wernicke’s area is activated during perception of sign language
Identify the neural correlates of reading braille
Visual areas of both hemispheres irregardless of which finger is used
Identify the nature and neural correlates of vocalization in animals.
Songbirds: use song to define territory and attract mates - critical periods in early life for learning (only use songs learned in this period). Species specific
Monkeys: different food related vocalizations and alarm calls. Normally only use in the company of others (not purely emotional response)
Can agraphia be similarly classified as alexia into surface, phonological and deep?
Yes
