Written Language Disorders Flashcards
Language disorders are primarily based on a theoretical framework of language processing routes.
There is much debate about which model is most fitting.
Which model does this chapter use?
Three-route model: Holds that reading incorporates 3 computational routes: two lexical routes and a non-lexical route when processing written language.
What does the nonlexical route compute?
Computes pronunciation of a word on the basis of sub-lexical grapheme-phoneme correspondences (letter-sound association).
What does the lexical-semantic route entail?
The route between visual analysis and semantic memory of words. Through this path we access a word’s meaning.
What is the purpose of the direct-lexical route?
This route is a direct connection between the visual analysis elements and the corresponding representation in a phonological lexicon. (Reading aloud).
What is Pure Alexia? (Alexia without Agraphia)
Complete inability to read despite maintained auditory language comprehension, language production and intact visual modality.
What are the anatomical issues of Pure Alexia?
Debate over which lesions can cause these symptoms.
Dejerine(1892) argues that a left hemisphere lesion produces a right-sided hemianopia, which means visual information cannot be processed.
Geschwind argues that lesions in corpus callosum prevents visual information the left visual field from crossing to the right hemisphere.
It is argued that there is a rudimentary reading system in the right hemisphere.
What are the hopes of remediation for patients suffering from pure alexia?
Unfortunately there is not much hope for betterment in these cases. In some cases it was possible to teach patients letter naming to such a degree that they could do letter-by-letter reading. (Letter-naming tasks)
How can pure alexia be assessed?
Specific tests in Psycholinguistic Assessment of Language Processing in Aphasia. nr. 22/29
Letter-by-letter reading is characterized by?
Reading each individual letter in order to read a word.
Is speed of reading words related to word length?
Yes. The longer the word is the slower recognition is. Can only recognise words by naming each of its component letters.
What is argued to be the core impairment in LBL-readers?
Processing letters in parallel to each other.
There can also additionally be deficits in word level processing.
Much debated issue.
Which regions are implicated in LBL-reading deficits?
Lesions to posterior parts of the left hemisphere frequently associated with LBL-reading
Damage to left occipito-temporal junction probable cause of word recognition deficits.
Lesions affecting left V1 or its geniculostraite afferents can cause similar but treatable impairments. (Hemianopic Alexia)
It is debated whether deficits reflect damage to a left system leads to right side inhibition, or if deficits reflects damage to a single shared system.
What are the options of remediation for LBL-reading?
´Following treatments yielded significant increased
Multiple Oral re-reading (MOR) read same passages several time
Cross-case matching decisions about pairs of letters in different sized fonts.
Identify letters at the end of a word before reading them loud.
How is it assessed?
Measure of reading speed on a word list which manipulates letter length (PALPA #29)
What is Neglect dyslexia?
Reminiscent of visual neglect except only when reading words. Neglect in side contra-lateral to lesion. Usually associated with other features of neglect, but patients without other features have been observed.
Which type of reading does it affect?
Both word reading and sentence reading.
What is the theory behind neglect dyslexia?
Damage to any three distinct levels of representation, Retina-centered, Stimulus-centered, word-centered, might be affected in neglect dyslexia.
Lesions to which areas can cause neglect dyslexia?
Left or right Occipito-parietal lesions.
Which kind of words are effective when assessing neglect dyslexia?
Words that becomes different words when starting or ending letter is omitted. (cage, lever, peach, etc.)
What is deep dyslexia?
Almost complete inability to read nonwords and novel words aloud.
Which words are deep dyslexics most likely to read aloud?
Words with a high concreteness/imageability rating.
What are the three different theoretical accounts of the imageability effect in deep dyslexia?
Plaut & Shallice (1993): Computational model of deep dyslexic. Postulates that abastract words contain fewer semantic features, and are less resistant to semantic feature loss than concrete words.
Newton & Barry (1997): Abstract words tend to be more ambiguous than concrete words. Ambiguity makes lexicalisation more difficult for abstract words.
Crutch & Warrington (2005): Abstract words tend to be represented in semantic memory in terms of their associations with related concepts. Concrete words are represented in tersms of similarity to other members of the same category. Qualitatively different representational systems.
Which errors are common in deep dyslexia patients?
Semantic errors: The hallmark; reading uncle -> cousin; hurt -> injure.
Visual errors: Confusing words which share similar letters. Crown -> Crowd
Both of the above: Stream -> train
Derivational errors: Confusing words with similar morphological elements. Heat -> Hot.
What damages are believed to cause deep dyslexia?
Anatomically there is evidence that lesions or infarcts to the left fronto-temporo-parietal region cause deficits.
Usually there is severe damage to the nonlexical route and the direct-lexical route that connects words to the phonological lexicon when reading aloud.
It is argued that three types of deep dyslexia exists:
Input deep dyslexia: Deficits in access to word representations
Central deep dyslexia: Deficits in the representations themselves
Output deep dyslexia: Problems accessing speech output from semantic representations.
How can possible remediation happen?
Teaching phoneme blending
Re-teaching grapheme-phoneme correspondences.