LanguageLanguageRef: Banich pp. 286-298Ref: Banich pp. 286-298

Classical Model of LanguageClassical Model of Language

1.1. Predicted Patterns Never "Absolute“Predicted Patterns Never "Absolute“

2.2. Symptoms can dissociateSymptoms can dissociate

BUT:BUT:

Multi-component viewMulti-component view

Anterior (around Broca’s area)Anterior (around Broca’s area)::

• Articulation of speechArticulation of speech

• Understanding syntactic relationshipsUnderstanding syntactic relationships

Posterior (around Wernicke’s area):Posterior (around Wernicke’s area):

• Retrieval of phonemes for productionRetrieval of phonemes for production

• Selection of words for productionSelection of words for production

• Access to semantic info about wordsAccess to semantic info about words

All of these can become selectively impaired:All of these can become selectively impaired:

Examples of ComponentsExamples of Components

Articulatory PlanningArticulatory Planning::

• Anterior (overlaps Broca’s area)Anterior (overlaps Broca’s area)

• Damage: halting, effortful, distorted Damage: halting, effortful, distorted speechspeech

Retrieval of PhonemesRetrieval of Phonemes::

• Posterior (nr. Wernicke’s area)Posterior (nr. Wernicke’s area)

• Damage: good articulation, but can’t recall Damage: good articulation, but can’t recall word sounds, make word sounds, make phonemic paraphasiasphonemic paraphasias

e.g. Turtle: e.g. Turtle: um.. tornet, no that's not right.... um.. tornet, no that's not right.... (etc)... turking.. that's wrong what's the end (etc)... turking.. that's wrong what's the end part?…part?…

Examples of ComponentsExamples of Components

Access to Semantic Info.Access to Semantic Info.

• Posterior (overlaps Wernicke’s area)Posterior (overlaps Wernicke’s area)

• Damage: P can’t understand word Damage: P can’t understand word meanings, produces meanings, produces semantic semantic paraphasias:paraphasias:

e.g. Turtle: e.g. Turtle: That’s some kind of animal, That’s some kind of animal, isn’t it. A seal, is it?isn’t it. A seal, is it?

Anterior vs. posterior areasAnterior vs. posterior areas

AnteriorAnterior regions are involved in: regions are involved in:

Generation of new combinationsGeneration of new combinationse.g.e.g. sentences (novel combinations of words)sentences (novel combinations of words)

articulation (must be done afresh each time)articulation (must be done afresh each time)

PosteriorPosterior language regions (LH) are involved in: language regions (LH) are involved in:

Storage/retrieval of familiar, well-learned relationshipsStorage/retrieval of familiar, well-learned relationships

e.g.e.g. phoneme sequences of common wordsphoneme sequences of common words

meanings of common wordsmeanings of common words

ReadingReadingRef: Banich: Visual language, Ref: Banich: Visual language,

pp. 295-299 (up to writing)pp. 295-299 (up to writing)

Coltheart’s Two Route ModelColtheart’s Two Route Model

Lexicon:Lexicon:word soundsword soundsand meaningsand meanings

Grapheme-phonemeGrapheme-phonemeConversionConversione.g. sh -> /s/e.g. sh -> /s/

PrintPrint

PronunciationPronunciation

Grapheme-phoneme Grapheme-phoneme (or phonological) (or phonological)

routeroute

Lexical (or direct) Lexical (or direct) routeroute

Coltheart’s Two Route ModelColtheart’s Two Route Model

Lexical routeLexical route::• Recognise Recognise wholewhole word word• Look up in lexiconLook up in lexicon• Good for Good for knownknown words (not words (not unfamiliarunfamiliar words) words)

Grapheme-phoneme routeGrapheme-phoneme route::

• Identify Identify graphemesgraphemes (e.g. b, k th, sh)(e.g. b, k th, sh)

• Convert each grapheme to a phonemeConvert each grapheme to a phoneme

• Good for Good for regularregular words ( words (e.g. cate.g. cat) but not ) but not irregularirregular words (words (e.g. yachte.g. yacht))

DyslexiaDyslexia

Two major types of acquired dyslexia:Two major types of acquired dyslexia:

Phonological dyslexiaPhonological dyslexia = Damage to grapheme-phoneme route = Damage to grapheme-phoneme route

Surface dyslexiaSurface dyslexia = Damage to lexical route = Damage to lexical route

Acquired DyslexiaAcquired Dyslexia = reading impairment resulting from damage = reading impairment resulting from damage

to brainto brain

(cf. Developmental dyslexia = reading impairment present (cf. Developmental dyslexia = reading impairment present

throughout development)throughout development)

Phonological dyslexiaPhonological dyslexia

Grapheme-phoneme route damagedGrapheme-phoneme route damaged::

• can’t read nonwords, unfamiliar can’t read nonwords, unfamiliar wordswords

• lexicalisationlexicalisation errors errorse.g. e.g. heef -> beefheef -> beef

• OK on familiar words: prob. may go OK on familiar words: prob. may go undetectedundetected

• regularity not importantregularity not important((yachtyacht = = yetyet))

LexiconLexiconGrapheme-Grapheme-

phonemephonemeconversionconversion

PrintPrint

PronunciationPronunciation

Phonological dyslexiaPhonological dyslexia

kedked bembem

narnar cugcug

fonfon latlat

shidshid boakboak

doopdoop birlbirl

duspdusp soafsoaf

Tests: PALPA (Tests: PALPA (Psycholinguistic Assessment of Language Processing in AphasiaPsycholinguistic Assessment of Language Processing in Aphasia))

-> Nonword reading subtest-> Nonword reading subtest

Phonological dyslexiaPhonological dyslexia

Localisation:Localisation:

Surface dyslexiaSurface dyslexia

Lexical route damagedLexical route damaged::

- can’t read irregular words- can’t read irregular wordse.g. yacht, pint.e.g. yacht, pint.

- regularization errors - regularization errors e.g. e.g. pint -> /pInt/, busy -> buzzypint -> /pInt/, busy -> buzzy

One patient, when given the word One patient, when given the word "listen" to read, pronounced it "listen" to read, pronounced it "Liston", then exclaimed "Liston, the "Liston", then exclaimed "Liston, the boxer!“boxer!“

- OK on regular words, even unfamiliar - OK on regular words, even unfamiliar onesones

LexiconLexiconGrapheme-Grapheme-

phonemephonemeconversionconversion

PrintPrint

PronunciationPronunciation

Surface dyslexiaSurface dyslexia

Tests: PALPA spelling-sound regularity subtestTests: PALPA spelling-sound regularity subtest

effort (R)effort (R) pretty (E)pretty (E) middle (R)middle (R) barge (R)barge (R)

break (E)break (E) envy (R)envy (R) blood (E)blood (E) bowl (E)bowl (E)

plank (R)plank (R) navy (R)navy (R) ceiling (E)ceiling (E) iron (E)iron (E)

cough (E)cough (E) context (R)context (R) rub (R)rub (R) routine (E)routine (E)

bury (E)bury (E) yacht (E)yacht (E) flannel (R)flannel (R) tail (R)tail (R)

wolf (E)wolf (E) island (E)island (E) wedding (R)wedding (R) chicken (R)chicken (R)

colonel (E)colonel (E) luck (R)luck (R) smog (R)smog (R) nerve (R)nerve (R)

Surface dyslexiaSurface dyslexia

Localisation:Localisation:

Double DissociationDouble Dissociation

Irregular words

Unfamiliar words

Phonological dyslexics

Surface dyslexics

Good Poor

Poor Good

Other types of dyslexia

• Surface and Phonological are examples of Surface and Phonological are examples of Central Central

dyslexiasdyslexias (a third subtype to come) (a third subtype to come)

• Peripheral dyslexiasPeripheral dyslexias: visual analysis of word: visual analysis of word

e.g. letter-by-letter reading: can't perceive whole worde.g. letter-by-letter reading: can't perceive whole word

Deep Dyslexia

• Another kind of “central dyslexia”Another kind of “central dyslexia”

• Can't read unfamiliar words (like in phonological dyslexia)Can't read unfamiliar words (like in phonological dyslexia)

• BUT also have problems with BUT also have problems with knownknown words words (esp. function words, abstract words)(esp. function words, abstract words)

• Complex errors:Complex errors: semantic semantic e.g. affection -> lovee.g. affection -> lovevisual visual e.g. science -> scenee.g. science -> scene

Deep Dyslexia

sour:sour: badbad

thirst:thirst: thirstythirsty

lamp:lamp: laplap

clothing:clothing: clothesclothes

insult:insult: imbecile? no... imbecile? no...

decent:decent: I know what it is, but I can't say itI know what it is, but I can't say it

capacity:capacity: absenceabsence

applause:applause: its clappingits clapping

Reading by Patient BMReading by Patient BM

Deep Dyslexia

• Both "routes" seem affected:Both "routes" seem affected:

- can't use grapheme-phoneme route- can't use grapheme-phoneme route

- also unable to reliably access lexicon directly- also unable to reliably access lexicon directly

• Sometimes partial access: Sometimes partial access:

Patient AR: Patient AR:

Ostrich: "I get the impression of an animal“Ostrich: "I get the impression of an animal“

Localisation: Extensive damage to LHLocalisation: Extensive damage to LH

Explanations for Deep Dyslexia

1. Imperfect Lexicon1. Imperfect Lexicon::

• P can't use grapheme-phoneme route at allP can't use grapheme-phoneme route at all

• therefore, must rely on what's left of lexical routetherefore, must rely on what's left of lexical route

• errors occur when word not available in lexiconerrors occur when word not available in lexicon

• evidence : similar errors in other language tasksevidence : similar errors in other language tasks

Explanations for Deep Dyslexia

• LH so damaged, P LH so damaged, P relies entirely on RHrelies entirely on RH

• RH word knowledge RH word knowledge limitedlimited

• Evidence : increased Evidence : increased RH activity in RH activity in dyslexics (fMRI)dyslexics (fMRI)

Anterior production areas

RH lexicon (intact but limited)

LH lexicon (damaged)

CAT CAT

2. “Right Hemisphere Reading":2. “Right Hemisphere Reading":