disorders of lexical selection garret 1992b l.
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Disorders of Lexical Selection Garret 1992b. Brian Nisonger. 4 types of Linguistic errors. Message to Lemma Representation Lemma to Word Form Representation Word Forms to phonetic representation for connected speech Speech representation to motor representation

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4 types of linguistic errors
4 types of Linguistic errors
  • Message to Lemma Representation
  • Lemma to Word Form Representation
  • Word Forms to phonetic representation for connected speech
  • Speech representation to motor representation
  • This paper deals with the first two
lexical disorders
Lexical Disorders
  • Aphasias
    • Loss of usage or comprehension of words
    • Broca’s Aphasia
      • Characterized by the inability to produce complete grammatical sentences
      • May be missing function words, pronouns or other categories
      • Comprehension may or may not be impaired
    • Wernicke’s Aphasia
      • Can produce “fluent” sentences
      • Usually semantically nonsensical
      • Comprehension is impaired
lexical disorders ii
Lexical Disorders-II
  • Dyslexias
    • A reading based learning disability that impairs the ability to read
    • Deep Dyslexia
      • A reading disorder where semantic errors occur
        • Bush=>Tree
        • Antique=>Vase
        • Uncle=>Nephew
  • Alzheimer's disease
    • More on this later
semantic deficits of lexical selection
Semantic Deficits of Lexical Selection
  • Normal Errors vs Lexical Disorders
    • Similarities
      • Word Substitution Errors
        • Synonymic
        • Antonymic
        • Associative
      • TOT states
    • Differences
      • Grammatical Categories
      • Hypernyms
hypernym problems
Hypernym Problems
  • Object Oriented Programming
    • Inheritance
  • Animal=>Horse
  • Plant=>Flower
  • Supertype
    • Generally if W1 entails W2 then W2 is a hypernym of W1
  • Substitution rare in normal speech errors, common in lexical disorders
categorical organization
Categorical Organization
  • Alzheimer’s Patients
    • Visual Naming Task
      • Hypernym substitution
      • General substituted for Specific
  • Errors may be related to normal speech when a word is unavaliable
    • I bought a plant
    • I bought a flower
so what does it mean so far
So what does it mean so far?
  • Lexical Representations in the brain
    • Message=>Lemma
    • Lemma=>Word Form
    • Word Form=>Phonetic/Orthographic representation
      • Specifically divided Phonetic from Orthographic
        • Deep Dyslexia only orthographic
        • Other aphasias can be both phonetic and orthographic
        • More on this later
  • Concepts Space
    • Hierarchical in nature
    • Semantic Fields
      • More on this later
      • Garret 1992a
lexical retrieval system
Lexical Retrieval System
  • Parallel Featural Tests
    • Linked Decision Tables
    • Table internal test parallel
    • Table -> Table serial
    • Might account for loss within categories
      • But ability to categorize within fields
semantic field effects
Semantic Field Effects
  • Selective Impairments
    • Loss of ability to generate words from specific domains
      • Major
        • Concrete/Abstract
        • Living/non-living
        • Animate/Non Animate
          • Interesting cross phenomena with Worlds Languages?
      • Minor
        • Color Items
        • Food Items
        • Numbers
        • Baseball Players
    • Still possible to recognize words are of a certain category for some aphasia and other disorders but not produce them
more field effects
More Field Effects
  • Affected categories
    • As low as 10% generation
  • Non-affected categories
    • Near normal performance
  • Field Effects stable across time
  • Rare or common words had no affect on Field effects
    • For example
      • Animal->Bear
      • Fruit->Prickly Pear
how does it fit in with the model
How does it fit in with the model?
  • Semantic Fields are a set of Lemmas
    • Grouped by specified functional similarity of concepts
    • Possibly used for rapid evaluation of alternatives in production
      • Lexical Ambiguities
      • In normal errors we see this affect as well
        • Garret 1992a
      • Aphasic Loss
        • Major vs Minor categories
some distinctions and cross classification
Some Distinctions and Cross Classification
  • Examples
    • Possible to have losses in Concrete Inanimate category
    • No loss in Concrete Animate category
  • Living vs NonLiving
    • Seems to have less cross classifications
  • Sensory description
    • May not be relevant for inanimate non-concrete
  • Functional
      • Not relevant for living things but very relevant for inanimate
  • May be explained by other factors, but interesting
higher level feature errors
Higher Level Feature Errors
  • Wheel->Foot
    • Analogical relation between target and intrusion
    • Function
      • Mode of motion
        • Limbs
          • Foot
      • Mode of motion
        • Drive Train system
          • Wheel
where are we at
Where are we at
  • Clear field effects in aphasic errors
  • Similar to effects noted in normal speech
  • Evidence for difference between
    • concept representation=>lemma representation
    • concept representation=>perceptional represention
causes of semantic error
Causes of Semantic Error
  • Need to categorize errors
    • Components of lexical system
      • Production
      • Comprehension
    • Most accounts don’t separate
      • Concept
      • Lemma
    • Two major categories of errors
      • Conceptual impairment
      • Lemma processing
        • Concept=>Lemma
        • Lemma Replacement Failure
        • Lemma=>Word Form
        • Word Form Output System Error (Possible 4th category)
possible reasons for multiple semantic activation
Possible Reasons for Multiple Semantic Activation
  • Semantic Spreading
    • Multiple words are activated
  • Message=>Lemma
    • Message fragments can activate multiple lemmas which then are filtered through by more completed message fragments
failure of the output system
Failure of the Output System
  • Generation
    • Failure to filter alternative lexical candidates
    • Failure to produce lexical candidates
  • Possible correlation to normal speech errors
  • No real evidence besides intuition
auditory vs orthographic
Auditory vs Orthographic
  • Loss of category can be specific to either auditory or orthographic forms
    • Loss of abstract for example may be present in auditory experiments but absent in orthographic experiments
modality specific failures
Modality-Specific Failures
  • Modality
    • Verbal
    • Non-verbal systems
  • Semantics may be independent of the verbal system
semantic modality
Semantic Modality
  • Tactile naming experiments
    • Ability to mime usage of object
    • Inability to name the object
      • No knowledge of name
      • Not TOT
    • May cross classify with semantic field effects
      • Loss of specific categories in non-verbal naming tasks such as tactile naming
what is semantics
What is semantics?
  • Possible that semantics may not be just limited to “ lexical meaning”
    • Usage
    • Visual recognition
    • Relative Size
    • Relative Location
    • Visual problem solving intersections
syntactic category effects
Syntactic Category Effects
  • Open Class
    • Nouns, verbs, adjective, adverbs
  • Closed Class
    • Determiners, Prepositions, modals, negation, predicate markers
closed class retrieval failures
Closed Class Retrieval Failures
  • Comprehension
    • May or may not have inability to comprehend grammatical function words
  • Production
    • “Telegraphic”
      • “Doctor office Monday teeth”
  • No link between inability to produce grammatical words and comprehension of grammatical words
types of closed class failures
Types of closed class failures
  • Agrammatical
    • Inability to produce grammatical categories
  • Paragrammatical
    • Producing the wrong grammatical categories
    • Usually comprehension problems
  • Overlap
    • In Hebrew grammatical category cannot be omitted
    • Broca’s aphasia patients often pick incorrect endings
      • Broca’s aphasia = Agrammatical
closed classes failures of deep dyslexia
Closed Classes Failures of Deep Dyslexia
  • Fewest errors with concrete nouns
  • Highest errors for closed classes
  • Inability to read closed class words in isolation
  • Longer passages may provide context for guessing
  • Possible failure of lemma=>word processing
alternate retrieval system for closed classes
Alternate Retrieval System for Closed Classes
  • Failures in open class not found in closed class
    • Phonemic paraphasias
      • Substitutions of non-correct sounds
    • Neologisms
      • Non-words being introduced as words
  • Possibility that grammatical structure selects for specific words within specific domains within the closed classes instead of as a whole
    • Activation of multiple meanings may be different in closed classes and open classes
major category contrasts
Major Category Contrasts
  • Normal speech substitutions do not cross grammatical categories
    • Nouns substitute for Nouns, etc.
  • Wernicke’s Aphasia’s patients
    • Substitutions do not cross grammatical category
nouns and verbs
Nouns and Verbs
  • Categories can be lost in modality specific tasks
    • Ex: Two patients showed loss of verbs in oral output, but not in written
  • Agrammatics
    • More Loss of verbs in tasks across all modalities
  • Anomics
    • Disorder associated with dysfunction in “word finding”
    • No other disorder-frequent circumlocution
    • More loss of nouns across all modalities
nouns and verbs ii what does it mean
Nouns and Verbs-IIWhat does it mean?
  • Anomics the failure may be at the word-form retrieval level
  • Agrammatics the failure may be at the phrasal construction or lemma level
frequency and grammatical category effects
Frequency and Grammatical Category Effects
  • Be/Bee wood/would
    • Show opposite effects for Broca’s vs. Wernicke’s aphasia regardless of frequency
  • Case study of Wernicke’s aphasia patient with no difference between high frequency and low frequency words
  • Possibly only affects open class words and not closed class words
summary
Summary
  • The effects of aphasia illustrate some of the mechanisms of the lexical retrieval system
  • Specifically
    • Concept=>Lemma=>Phonological/Orthographic form
  • By studying aphasias we can understand how lexical retrieval works and what that means for lexical ambiguity