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Language

Language. Ref: Banich pp. 286-298. Classical Model of Language. Predicted Patterns Never "Absolute“ Symptoms can dissociate. BUT:. Multi-component view. All of these can become selectively impaired:. Anterior (around Broca’s area) : Articulation of speech

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Language

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  1. Language Ref: Banich pp. 286-298

  2. Classical Model of Language • Predicted Patterns Never "Absolute“ • Symptoms can dissociate BUT:

  3. Multi-component view All of these can become selectively impaired: • Anterior (around Broca’s area): • Articulation of speech • Understanding syntactic relationships • Posterior (around Wernicke’s area): • Retrieval of phonemes for production • Selection of words for production • Access to semantic info about words

  4. Examples of Components • Articulatory Planning: • Anterior (overlaps Broca’s area) • Damage: halting, effortful, distorted speech • Retrieval of Phonemes: • Posterior (nr. Wernicke’s area) • Damage: good articulation, but can’t recall word sounds, make phonemic paraphasias • e.g. Turtle: um.. tornet, no that's not right.... (etc)... turking.. that's wrong what's the end part?…

  5. Examples of Components • Access to Semantic Info. • Posterior (overlaps Wernicke’s area) • Damage: P can’t understand word meanings, produces semantic paraphasias: • e.g. Turtle: That’s some kind of animal, isn’t it. A seal, is it?

  6. Anterior vs. posterior areas Anterior regions are involved in: Generation of new combinations e.g. sentences (novel combinations of words) articulation (must be done afresh each time) • Posterior language regions (LH) are involved in: • Storage/retrieval of familiar, well-learned relationships • e.g. phoneme sequences of common words • meanings of common words

  7. Reading Ref: Banich: Visual language, pp. 295-299 (up to writing)

  8. Coltheart’s Two Route Model Grapheme-phoneme (or phonological) route Lexical (or direct) route Print Lexicon: word sounds and meanings Grapheme-phoneme Conversion e.g. sh -> /s/ Pronunciation

  9. Coltheart’s Two Route Model Lexical route: • Recognise whole word • Look up in lexicon • Good for known words (not unfamiliar words) Grapheme-phoneme route: • Identify graphemes(e.g. b, k th, sh) • Convert each grapheme to a phoneme • Good for regular words (e.g. cat) but not irregular words (e.g. yacht)

  10. Dyslexia Two major types of acquired dyslexia: Phonological dyslexia = Damage to grapheme-phoneme route Surface dyslexia = Damage to lexical route Acquired Dyslexia = reading impairment resulting from damage to brain (cf. Developmental dyslexia = reading impairment present throughout development)

  11. Phonological dyslexia Grapheme-phoneme route damaged: • can’t read nonwords, unfamiliar words • lexicalisation errors e.g. heef -> beef • OK on familiar words: prob. may go undetected • regularity not important (yacht = yet) Print Grapheme- phoneme conversion Lexicon Pronunciation

  12. Phonological dyslexia Tests: PALPA (Psycholinguistic Assessment of Language Processing in Aphasia) -> Nonword reading subtest ked bem nar cug fon lat shid boak doop birl dusp soaf

  13. Phonological dyslexia Localisation:

  14. Surface dyslexia Lexical route damaged: - can’t read irregular words e.g. yacht, pint. - regularization errors e.g. pint -> /pInt/, busy -> buzzy One patient, when given the word "listen" to read, pronounced it "Liston", then exclaimed "Liston, the boxer!“ - OK on regular words, even unfamiliar ones Print Grapheme- phoneme conversion Lexicon Pronunciation

  15. Surface dyslexia Tests: PALPA spelling-sound regularity subtest effort (R) pretty (E) middle (R) barge (R) break (E) envy (R) blood (E) bowl (E) plank (R) navy (R) ceiling (E) iron (E) cough (E) context (R) rub (R) routine (E) bury (E) yacht (E) flannel (R) tail (R) wolf (E) island (E) wedding (R) chicken (R) colonel (E) luck (R) smog (R) nerve (R)

  16. Surface dyslexia Localisation:

  17. Double Dissociation Good Poor Poor Good

  18. Other types of dyslexia • Surface and Phonological are examples of Central dyslexias (a third subtype to come) • Peripheral dyslexias: visual analysis of word e.g. letter-by-letter reading: can't perceive whole word

  19. Deep Dyslexia • Another kind of “central dyslexia” • Can't read unfamiliar words (like in phonological dyslexia) • BUT also have problems with known words (esp. function words, abstract words) • Complex errors: semantic e.g. affection -> love visual e.g. science -> scene

  20. Deep Dyslexia sour: bad thirst: thirsty lamp: lap clothing: clothes insult: imbecile? no... decent: I know what it is, but I can't say it capacity: absence applause: its clapping Reading by Patient BM

  21. Deep Dyslexia • Both "routes" seem affected: - can't use grapheme-phoneme route - also unable to reliably access lexicon directly • Sometimes partial access: Patient AR: Ostrich: "I get the impression of an animal“ Localisation: Extensive damage to LH

  22. Explanations for Deep Dyslexia 1. Imperfect Lexicon: • P can't use grapheme-phoneme route at all • therefore, must rely on what's left of lexical route • errors occur when word not available in lexicon • evidence : similar errors in other language tasks

  23. Explanations for Deep Dyslexia 2. “Right Hemisphere Reading": • LH so damaged, P relies entirely on RH • RH word knowledge limited • Evidence : increased RH activity in dyslexics (fMRI) Anterior production areas RH lexicon (intact but limited) LH lexicon (damaged) CAT CAT

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