Ways of reading
why is it important to know the type of written language system for the language(s) of your patients?
there are different types of language systems which will affect the reading disorder and the types of errors made
non lexical route/grapheme to phoneme conversion
used for non words and unfamiliar words
match graphemes onto sound patterns we know to pronounce the word properly
abstract letter ID->grapheme phoneme conversion->phonological assembly
phonological dyslexia
impaired reading of non words and unfamiliar real words
word reading>>non word reading
forced to read via meaning so semantic variables will influence performance concrete>abstract, imageability effect, word class effect
errors: real word errors, visual, morphological, non words are lexicalizations
what is the difference between a peripheral alexia and a central alexia?
peripheral alexia->may not have language impairment depending on brain area-usually RH lesions
central alexia->phonological or deep and most will also have some form of aphasia
visual dyslexia characteristics and damage
similar to neglect but not selective to one side
letter omissions, additions, impairment at letter analysis or orthographic input lexicon
can perceive and decode some but not all letters in a word
lexical route to reading
uses visual analysis system- focus is on abstract letter identification what are the letters and what is their positioning
ignores font and letter case
dual route model of reading
uses both lexical route and and non lexical route/grapheme phoneme analysis to by pass meaning to get right to speech production
where is the damage in phonological dyslexia?
grapheme phoneme conversion module
not associated with any kind of aphasia
what is the difference between a central dyslexia and a peripheral dyslexia?
central dyslexia the damage is to lexical or non lexical routes
peripheral dyslexia damage is in functional area difficulties with early analysis of letters and words
attentional dyslexia
errors based on influence of other letters in the word
difficulty with spatial sequencing/ordering of the letters
impairment in visual orthographic analysis
lesion in brain often more posterior
what is the orthographic input lexicon? and what type of reading would this fall under?
store of all written words you recognize by sight may not know the meanings of these words -> then sent to the semantic system where meanings of words are stored
involved in the lexical route to reading
what strategies of reading are used at different ages?
when learning to read as children grapheme to phoneme as we gain experience with words as we age mostly lexical and only grapheme phoneme for new words or non words
characteristics of deep dyslexia
more severe, also trouble with non words
errors: semantic, visual errors, poor function word reading and substitutions, can't read non words,preservation of concrete content words, derivational errors, verbs harder than nouns, imageability effects
letter by letter reading /pure alexia characteristics
word identified only after each letter is named aloud or subvocally, very slow, word length effect on speed and accuracy, may have difficulty with letter identification
associated with other deficits
AX of visual analysis system
letter identification (contrast upper and lower case)
letter sound correspondences
letters vs numbers
what is the pathway used for silent reading?
written word->visual analysis letter ID->orthographic input lexicon->semantics
BONUS what is a visual phonological error in reading?
thread ->tread
where is the damage in deep dyslexia?
suspected damage in semantic module and grapheme phoneme module
where is the damage in pure alexia?
visual analysis module
AX grapheme phoneme conversion
oral reading look at effect of non words and imageability
what other steps are involved in oral reading?
phonological output lexicon->store of spoken word forms
phonological assembly->generates specified phoneme string for speech
semantics->phon output lexicon->phon assembly
BONUS what is a morphological error in reading?
called-> calling
surface dyslexia
able to read regularly spelled words, errors on exception words, non word reading preserved,
errors- regularization, regularity effect regular words read more accurately, interaction with frequency regularity effect greatest on low frequency words
damage:lexical semantic route/semantic module
characteristics of neglect dyslexia
visual errors, length of error similar to word length, often associated with hemispatial neglect, errors on one side of word
AX orthographic input lexicon
lexical decision task is this a word or non word