Disorders of Lexical Disorders of Lexical SelectionSelection

Garret 1992bGarret 1992b

Brian NisongerBrian Nisonger

4 types of Linguistic errors4 types of Linguistic errors

Message to Lemma RepresentationMessage to Lemma RepresentationLemma to Word Form RepresentationLemma to Word Form RepresentationWord Forms to phonetic Word Forms to phonetic

representation for connected speechrepresentation for connected speechSpeech representation to motor Speech representation to motor

representationrepresentationThis paper deals with the first twoThis paper deals with the first two

Lexical DisordersLexical Disorders

AphasiasAphasias Loss of usage or comprehension of wordsLoss of usage or comprehension of words Broca’s AphasiaBroca’s Aphasia

Characterized by the inability to produce complete Characterized by the inability to produce complete grammatical sentencesgrammatical sentences

May be missing function words, pronouns or other May be missing function words, pronouns or other categoriescategories

Comprehension may or may not be impairedComprehension may or may not be impaired Wernicke’s AphasiaWernicke’s Aphasia

Can produce “fluent” sentencesCan produce “fluent” sentencesUsually semantically nonsensicalUsually semantically nonsensicalComprehension is impairedComprehension is impaired

Lexical Disorders-IILexical Disorders-II

DyslexiasDyslexiasA reading based learning disability that A reading based learning disability that

impairs the ability to readimpairs the ability to readDeep DyslexiaDeep Dyslexia

A reading disorder where semantic errors A reading disorder where semantic errors occuroccur

Bush=>TreeBush=>TreeAntique=>VaseAntique=>VaseUncle=>NephewUncle=>Nephew

Alzheimer's diseaseAlzheimer's diseaseMore on this laterMore on this later

Semantic Deficits of Lexical Semantic Deficits of Lexical SelectionSelection

Normal Errors vs Lexical DisordersNormal Errors vs Lexical DisordersSimilaritiesSimilarities

Word Substitution ErrorsWord Substitution ErrorsSynonymicSynonymicAntonymicAntonymicAssociativeAssociative

TOT statesTOT statesDifferencesDifferences

Grammatical CategoriesGrammatical CategoriesHypernymsHypernyms

Hypernym ProblemsHypernym Problems

Object Oriented ProgrammingObject Oriented ProgrammingInheritanceInheritance

Animal=>HorseAnimal=>HorsePlant=>FlowerPlant=>FlowerSupertypeSupertype

Generally if W1 entails W2 then W2 is a Generally if W1 entails W2 then W2 is a hypernym of W1hypernym of W1

Substitution rare in normal speech Substitution rare in normal speech errors, common in lexical disorderserrors, common in lexical disorders

Categorical OrganizationCategorical Organization

Alzheimer’s PatientsAlzheimer’s PatientsVisual Naming TaskVisual Naming Task

Hypernym substitutionHypernym substitutionGeneral substituted for SpecificGeneral substituted for Specific

Errors may be related to normal speech Errors may be related to normal speech when a word is unavaliablewhen a word is unavaliableI bought a plantI bought a plantI bought a flowerI bought a flower

So what does it mean so far?So what does it mean so far?

Lexical Representations in the brainLexical Representations in the brain Message=>LemmaMessage=>Lemma Lemma=>Word FormLemma=>Word Form Word Form=>Phonetic/Orthographic Word Form=>Phonetic/Orthographic

representationrepresentationSpecifically divided Phonetic from OrthographicSpecifically divided Phonetic from Orthographic

Deep Dyslexia only orthographicDeep Dyslexia only orthographic Other aphasias can be both phonetic and orthographicOther aphasias can be both phonetic and orthographic More on this laterMore on this later

Concepts SpaceConcepts Space Hierarchical in natureHierarchical in nature Semantic FieldsSemantic Fields

More on this laterMore on this laterGarret 1992aGarret 1992a

Lexical Retrieval SystemLexical Retrieval System

Parallel Featural TestsParallel Featural TestsLinked Decision TablesLinked Decision TablesTable internal test parallelTable internal test parallelTable -> Table serialTable -> Table serialMight account for loss within categoriesMight account for loss within categories

But ability to categorize within fieldsBut ability to categorize within fields

Semantic Field EffectsSemantic Field Effects

Selective ImpairmentsSelective Impairments Loss of ability to generate words from specific domainsLoss of ability to generate words from specific domains

MajorMajor Concrete/AbstractConcrete/Abstract Living/non-livingLiving/non-living Animate/Non AnimateAnimate/Non Animate

Interesting cross phenomena with Worlds Languages?Interesting cross phenomena with Worlds Languages? MinorMinor

Color ItemsColor Items Food ItemsFood Items NumbersNumbers Baseball PlayersBaseball Players

Still possible to recognize words are of a certain Still possible to recognize words are of a certain category for some aphasia and other disorders but not category for some aphasia and other disorders but not produce themproduce them

More Field EffectsMore Field Effects

Affected categoriesAffected categories As low as 10% generationAs low as 10% generation

Non-affected categoriesNon-affected categories Near normal performanceNear normal performance

Field Effects stable across timeField Effects stable across time Rare or common words had no affect on Rare or common words had no affect on

Field effects Field effects For exampleFor example

Animal->BearAnimal->BearFruit->Prickly PearFruit->Prickly Pear

How does it fit in with the How does it fit in with the model?model?

Semantic Fields are a set of Lemmas Semantic Fields are a set of Lemmas Grouped by specified functional Grouped by specified functional

similarity of conceptssimilarity of conceptsPossibly used for rapid evaluation of Possibly used for rapid evaluation of

alternatives in productionalternatives in productionLexical AmbiguitiesLexical AmbiguitiesIn normal errors we see this affect as wellIn normal errors we see this affect as well

Garret 1992aGarret 1992aAphasic LossAphasic Loss

Major vs Minor categoriesMajor vs Minor categories

Some Distinctions and Cross Some Distinctions and Cross ClassificationClassification

ExamplesExamples Possible to have losses in Concrete Inanimate categoryPossible to have losses in Concrete Inanimate category No loss in Concrete Animate categoryNo loss in Concrete Animate category

Living vs NonLivingLiving vs NonLiving Seems to have less cross classificationsSeems to have less cross classifications

Sensory descriptionSensory description May not be relevant for inanimate non-concreteMay not be relevant for inanimate non-concrete

FunctionalFunctional Not relevant for living things but very relevant for Not relevant for living things but very relevant for

inanimate inanimate May be explained by other factors, but interestingMay be explained by other factors, but interesting

Higher Level Feature ErrorsHigher Level Feature Errors

Wheel->FootWheel->FootAnalogical relation between target and Analogical relation between target and

intrusionintrusionFunctionFunction

Mode of motionMode of motionLimbsLimbs

FootFootMode of motionMode of motion

Drive Train systemDrive Train systemWheelWheel

Where are we atWhere are we at

Clear field effects in aphasic errorsClear field effects in aphasic errorsSimilar to effects noted in normal Similar to effects noted in normal

speechspeechEvidence for difference betweenEvidence for difference between

concept representation=>lemma concept representation=>lemma representationrepresentation

concept representation=>perceptional concept representation=>perceptional representionrepresention

Causes of Semantic ErrorCauses of Semantic Error

Need to categorize errors Need to categorize errors Components of lexical system Components of lexical system

Production Production Comprehension Comprehension

Most accounts don’t separate Most accounts don’t separate ConceptConceptLemmaLemma

Two major categories of errorsTwo major categories of errorsConceptual impairmentConceptual impairmentLemma processingLemma processing

Concept=>LemmaConcept=>Lemma Lemma Replacement FailureLemma Replacement Failure Lemma=>Word FormLemma=>Word Form Word Form Output System Error (Possible 4Word Form Output System Error (Possible 4thth category) category)

Possible Reasons for Multiple Possible Reasons for Multiple Semantic ActivationSemantic Activation

Semantic SpreadingSemantic SpreadingMultiple words are activated Multiple words are activated

Message=>LemmaMessage=>LemmaMessage fragments can activate Message fragments can activate

multiple lemmas which then are filtered multiple lemmas which then are filtered through by more completed message through by more completed message fragmentsfragments

Failure of the Output SystemFailure of the Output System

GenerationGenerationFailure to filter alternative lexical Failure to filter alternative lexical

candidatescandidatesFailure to produce lexical candidatesFailure to produce lexical candidates

Possible correlation to normal speech Possible correlation to normal speech errorserrors

No real evidence besides intuitionNo real evidence besides intuition

Auditory vs OrthographicAuditory vs Orthographic

Loss of category can be specific to Loss of category can be specific to either auditory or orthographic formseither auditory or orthographic formsLoss of abstract for example may be Loss of abstract for example may be

present in auditory experiments but present in auditory experiments but absent in orthographic experimentsabsent in orthographic experiments

Modality-Specific FailuresModality-Specific Failures

ModalityModalityVerbalVerbalNon-verbal systemsNon-verbal systems

Semantics may be independent of Semantics may be independent of the verbal systemthe verbal system

Semantic ModalitySemantic Modality

Tactile naming experimentsTactile naming experimentsAbility to mime usage of objectAbility to mime usage of objectInability to name the objectInability to name the object

No knowledge of nameNo knowledge of nameNot TOTNot TOT

May cross classify with semantic field May cross classify with semantic field effectseffectsLoss of specific categories in non-verbal Loss of specific categories in non-verbal

naming tasks such as tactile namingnaming tasks such as tactile naming

What is semantics?What is semantics?

Possible that semantics may not be Possible that semantics may not be just limited to “ lexical meaning”just limited to “ lexical meaning”UsageUsageVisual recognitionVisual recognitionRelative SizeRelative SizeRelative LocationRelative LocationVisual problem solving intersectionsVisual problem solving intersections

Syntactic Category EffectsSyntactic Category Effects

Open ClassOpen ClassNouns, verbs, adjective, adverbsNouns, verbs, adjective, adverbs

Closed ClassClosed ClassDeterminers, Prepositions, modals, Determiners, Prepositions, modals,

negation, predicate markersnegation, predicate markers

Closed Class Retrieval Closed Class Retrieval FailuresFailures

ComprehensionComprehensionMay or may not have inability to May or may not have inability to

comprehend grammatical function wordscomprehend grammatical function wordsProductionProduction

““Telegraphic”Telegraphic”““Doctor office Monday teeth”Doctor office Monday teeth”

No link between inability to produce No link between inability to produce grammatical words and comprehension grammatical words and comprehension of grammatical wordsof grammatical words

Types of closed class failuresTypes of closed class failures

AgrammaticalAgrammatical Inability to produce grammatical categoriesInability to produce grammatical categories

ParagrammaticalParagrammatical Producing the wrong grammatical categoriesProducing the wrong grammatical categories Usually comprehension problemsUsually comprehension problems

OverlapOverlap In Hebrew grammatical category cannot be In Hebrew grammatical category cannot be

omittedomitted Broca’s aphasia patients often pick incorrect Broca’s aphasia patients often pick incorrect

endingsendingsBroca’s aphasia = AgrammaticalBroca’s aphasia = Agrammatical

Closed Classes Failures of Deep Closed Classes Failures of Deep DyslexiaDyslexia

Fewest errors with concrete nounsFewest errors with concrete nounsHighest errors for closed classesHighest errors for closed classes Inability to read closed class words in Inability to read closed class words in

isolationisolationLonger passages may provide Longer passages may provide

context for guessingcontext for guessingPossible failure of lemma=>word Possible failure of lemma=>word

processingprocessing

Alternate Retrieval System for Alternate Retrieval System for Closed ClassesClosed Classes

Failures in open class not found in closed Failures in open class not found in closed classclass Phonemic paraphasiasPhonemic paraphasias

Substitutions of non-correct soundsSubstitutions of non-correct sounds NeologismsNeologisms

Non-words being introduced as wordsNon-words being introduced as words

Possibility that grammatical structure selects Possibility that grammatical structure selects for specific words within specific domains for specific words within specific domains within the closed classes instead of as a wholewithin the closed classes instead of as a whole Activation of multiple meanings may be different in Activation of multiple meanings may be different in

closed classes and open classesclosed classes and open classes

Major Category ContrastsMajor Category Contrasts

Normal speech substitutions do not Normal speech substitutions do not cross grammatical categoriescross grammatical categoriesNouns substitute for Nouns, etc.Nouns substitute for Nouns, etc.

Wernicke’s Aphasia’s patients Wernicke’s Aphasia’s patients Substitutions do not cross grammatical Substitutions do not cross grammatical

categorycategory

Nouns and VerbsNouns and Verbs

Categories can be lost in modality specific Categories can be lost in modality specific taskstasks Ex: Two patients showed loss of verbs in oral Ex: Two patients showed loss of verbs in oral

output, but not in writtenoutput, but not in written AgrammaticsAgrammatics

More Loss of verbs in tasks across all modalitiesMore Loss of verbs in tasks across all modalities AnomicsAnomics

Disorder associated with dysfunction in “word Disorder associated with dysfunction in “word finding”finding”

No other disorder-frequent circumlocutionNo other disorder-frequent circumlocution More loss of nouns across all modalitiesMore loss of nouns across all modalities

Nouns and Verbs-IINouns and Verbs-IIWhat does it mean?What does it mean?

Anomics the failure may be at the Anomics the failure may be at the word-form retrieval levelword-form retrieval level

Agrammatics the failure may be at Agrammatics the failure may be at the phrasal construction or lemma the phrasal construction or lemma levellevel

Frequency and Grammatical Frequency and Grammatical Category EffectsCategory Effects

Be/Bee wood/would Be/Bee wood/would Show opposite effects for Broca’s vs. Show opposite effects for Broca’s vs.

Wernicke’s aphasia regardless of Wernicke’s aphasia regardless of frequencyfrequency

Case study of Wernicke’s aphasia Case study of Wernicke’s aphasia patient with no difference between high patient with no difference between high frequency and low frequency wordsfrequency and low frequency words

Possibly only affects open class words Possibly only affects open class words and not closed class wordsand not closed class words

SummarySummary

The effects of aphasia illustrate some The effects of aphasia illustrate some of the mechanisms of the lexical of the mechanisms of the lexical retrieval systemretrieval system

SpecificallySpecificallyConcept=>Lemma=>Phonological/Concept=>Lemma=>Phonological/

Orthographic formOrthographic formBy studying aphasias we can By studying aphasias we can

understand how lexical retrieval understand how lexical retrieval works and what that means for works and what that means for lexical ambiguitylexical ambiguity