Language Disorders

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Language Disorders

• Medical and Psychosocial Aspects of Disability
• 11/2/04

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Communication

• There are 3 elements in this exchange, and all
  must be present
• Message
• Message must be expressed
• Message must be understood

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Speech and Language

• Speech is the motor act of communicating by
  articulating verbal expression
• Language is the knowledge of a symbol system used
  for interpersonal communication.

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Four domains of language

• Phonology
• Grammar
• Semantics
• Pragmatics

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Phonology

• The ability to produce and discriminate the
  specific sounds of a given language.
• Its unit, the phoneme, is characterized by
  distinctive features.
• Babies start discriminating phonemes during the
  first few months of life, and they produce them
  soon after.

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Phonology

• Phonological receptivity is pluripotential at
  birth
• Starts to decay at around 10 months
• Reaches a rather general inability to acquire
  native phonology by preadolescence

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Grammar

• The underlying rules that organize any specific
  language.
• The combinatorial rules that most native speakers
  of a language recognize as acceptable for that
  language and that allow a native speaker an
  infinite array of generative possibilities.

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Grammar

• Composed of both morphology and syntax.

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Morphology

• The within-word structure, syntax on the
  between-word structure.
• Morphology studies the smallest word unit that
  impacts on meaning, the morpheme.

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Syntax

• The set of rules that governs
• the types of words
• their order
• the rigidity of this order
• the way to formulate a question or a negation

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Semantics

• The study of meaning
• Includes the study of vocabulary (lexicon).

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Lexicon

• Lexical entries are organized in the mental
  dictionary according to well-defined rules
• Allows the young child to acquire a peak average
  of 10 new words per day.
• By 24 months the average child knows 50 words.

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Lexicon Growth

• The subsequent exponential growth makes it
  difficult to determine vocabulary size with
  exactitude.

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Environmental factors predicting large
vocabularies

• Reading and discussing children's stories
• The quality of dinner table conversations
• Large mother-produced number of words
• Higher socioeconomic status (SES)
• Being the firstborn ( Hoff-Ginsberg, 1998 )
• Quantity and sophistication of mother's
  vocabulary ( Snow, 1998 ).

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Pragmatics

• A number of sub-domains reflecting communicative
  competence.

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Sub domains of Pragmatics

• Rules of conversation (turn-taking, topic
  maintenance, conversational repair)
• Politeness
• Narrative and extended discourse
• The implementation of communicative intents

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Pragmatic disorders

• Little variety in language use
• May say inappropriate or unrelated things during
  conversations
• May tell stories in a disorganized way
• Can often make demands, ask questions, and greet
  people
• Has trouble organizing language to talk about
  what happened in the past.

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Pragmatic disorders

• Appear to pull topics out of the air
• May not use statements that signal a change in
  topic, such as "That reminds me."
• Peers may avoid having conversations with such a
  child.
• Can lower social acceptance.

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Language Developmental Trajectory
Telegraphic speech
Word combinations
Word production
Word comprehension
Canonical Babbling
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• By age 3, most normal children have mastered the
  basic structures of their native language

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Language acquisition

• Occurs with uniformity and rapidity
• Supports the hypothesized existence of innate,
  genetically determined Universal Grammars
• Recently proposed a combination of traditional
  learning and innate language modules.

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Disfluencies in Children

• Almost all children go through a stage of
  frequent disfluency
• usually between the ages of 2 and 5.
• Speech is produced easily in spite of the
  disfluencies.

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Etiology of Speech Language Disorders

• Mental retardation
• Hearing loss
• Maturation delay (developmental language delay)
• Expressive language disorder (developmental
  expressive aphasia)

• Bilingualism
• Psychosocial deprivation
• Autism
• Elective mutism
• Receptive aphasia
• Cerebral palsy

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Overview of major types of speech disorders

• Definitions vary, but generally agree that speech
  disorders involve deviations of sufficient
  magnitude to interfere with communication.
• They draw attention to the speaking act and away
  from the message

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1. Fluency Disorders

• Speech is characterized by repeated
  interruptions, hesitations, or repetitions
• Stuttering is by far the most well-known fluency
  disorder

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1. Fluency disorders - Stuttering

• Flow of speech is abnormally interrupted by
  repetitions, blocking, or prolongations of
  sounds, syllables, words, or phrases
• Very familiar, but actually quite rare only
  1-5 of the population.
• Articulation disorders actually occur much more
  frequently than stuttering

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Stuttering -- Causes

• Still a mystery
• Three perspectives
• Symptom of emotional disturbance
• Result of biological makeup
• Learned response

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Stuttering

• Disorder of speech fluency that interrupts the
  forward flow of speech.
• All individuals are disfluent at times
• Differentiated by the kind and amount of the
  disfluencies

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Characteristics-Repetition

• Sounds
• b-b-b-ball
• Syllables
• mo-mo-mommy
• Parts of words
• basket-basket-basketball
• Whole words, and phrases

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Characteristics-Prolongation

• Stretching, of sounds or syllables
• r-----abbit

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Characteristics

• Tense pauses, hesitations, and/or no sound
  between words
• Speech that occurs in spurts
• as the child tries to initiate or maintain voice
• Variability in stuttering behavior
• depending on the speaking situation

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Related behaviors

• tense muscles in the lips, jaw, and/or neck
• tremor of the lips, jaw, and/or tongue
• foot tapping
• eye blinks
• head turns

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2. Articulation disorders

• This is the largest category of all speech
  problems
• DSM-IV calls these phonological disorders.
• abnormal speech-sound production, characterized
  by inaccurate or otherwise inappropriate
  execution of speaking

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2. Articulation disorders

• Great majority are functional articulation
  disorders
• Might represent as much as 80 of the speech
  disorders diagnosed by speech clinicians
• Must be very careful to distinguish true problems
  from delay.
• E.g., r, s, th problems may largely disappear
  naturally after 5 years of age

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2. Articulation disorders

1. Omissions
2. Substitutions
3. Additions
4. Distortions

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3. Voice disorders

• Unusual or abnormal acoustical qualities in the
  sounds made when a person speaks
• Very little research here
• What is a normal sounding voice?
• Nasality, hoarseness, breathiness

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Normal Speech Development
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4. Delayed speech

• Failure to develop speech at the expected age
• Somewhat subjective
• Usually associated with other maturational delays
• May also be associated with a hearing impairment,
  mental retardation, emotional disturbance, or
  brain injury
• Often the result of environmental deprivation

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Epidemiology of Speech Delay

• Common childhood problem
• Affects 3 to 10 percent of children.
• 3-4X more common in boys than in girls.

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Most common causes of speech delay

• Mental retardation
• Hearing loss
• Maturation delay

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Overview of major types of language disorders

• Need to understand normal language and
  prelanguage development
• See Table 10.1 on 320
• May involve comprehension (understanding) or
  expression in written or spoken language
• These are very complex to diagnose and treat

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Language and Brain
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Language disorders

1. Expressive language disorders
2. Receptive language disorders
3. Aphasia loss of the ability to speak or
   comprehend language because of an injury or
   developmental abnormality in the brain

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EXPRESSIVE LANGUAGE DISORDER (developmental
expressive aphasia)

• Fail to develop the use of speech at the usual
  age.

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EXPRESSIVE LANGUAGE DISORDER

• Normal intelligence
• Normal hearing
• Good emotional relationships
• Normal articulation skills.
• Comprehension of speech is appropriate to the age
  of the child

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EXPRESSIVE LANGUAGE DISORDER

• Brain dysfunction that results in an inability to
  translate ideas into speech.

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EXPRESSIVE LANGUAGE DISORDER

• The child is at risk for language-based learning
  disabilities (dyslexia).
• May use gestures to supplement their limited
  verbal expression .

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Maturation Delay vs. Expressive Language Disorder?

• The late bloomer will eventually develop normal
  speech
• The child with an expressive language disorder
  will not do so without intervention.

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Maturation Delay vs. Expressive Language Disorder?

• It is sometimes difficult, if not impossible, to
  distinguish at an early age a late bloomer from a
  child with an expressive language disorder.

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BILINGUALISM

• A bilingual home environment may cause an
  apparent temporary delay in the onset of both
  languages.

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BILINGUALISM

• The bilingual child's comprehension of the two
  languages is normal for a child of the same age.
• Usually becomes proficient in both languages
  before the age of five years.

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Interference or transfer

• An English error due to the direct influence of
  the primary language structure.
• This is a normal phenomenon

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Silent period

• Common second-language acquisition phenomenon
• Often very quiet, speaking little
• Focus on understanding the new language
• The younger the child, the longer the silent
  period tends to last.

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Code switching

• Changing languages over phrases or sentences.
• Normal phenomenon

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Benefits of Bilingualism

• Children who are fluent bilinguals actually
  outperform monolingual speakers on tests of
  metalinguistic skill.

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Benefits of Bilingualism

• Our world is shrinking and business becomes
  increasingly international
• Children who are fluent bilingual speakers are
  potentially a tremendously valuable resource for
  the U.S. economy.

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Language Disorders

• Egyptians reported speech loss after blow to head
  3000 years ago
• Broca (1861) finds damage to left inferior
  frontal region (Brocas area) of a language
  impaired patient, in postmortem analysis

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Language Disorders (2)

• In language disorders
• 90-95 of cases, damage is to the left hemisphere
• 5-10 of cases, to the right hemisphere
• Wada test is used to determine the hemispheric
  dominance
• Sodium amydal is injected to the carotid artery
• First to the left and then to the right

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Language Disorders (3)

• Paraphasia
• Substitution of a word by a sound, an incorrect
  word, or an unintended word
• Neologism
• Paraphasia with a completely novel word
• Nonfluent speech
• Talking with considerable effort
• Agraphia
• Impairment in writing
• Alexia
• Disturbances in reading

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Three major types of AphasiaRosenzweig Table
19.1, p. 615

• Borcas aphasia
• Nonfluent speech
• Wernickes aphasia
• Fluent speech but unintelligible
• Global aphasia
• Total loss of language
• Others Conduction, Subcortical, Transcortical
  Motor/Sensory (see also Kandel, Table 59-1)

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Brain areas involved in Language
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Brocas AphasiaBrodmann 44, 45

• Lesions in the left inferior frontal region
  (Brocas area)
• Nonfluent, labored, and hesitant speech
• Most also lost the ability to name persons or
  subjects (anomia)
• Can utter automatic speech (hello)
• Comprehension relatively intact
• Most also have partial paralysis of one side of
  the body (hemiplegia)
• If extensive, not much recovery over time

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Wernickes AphasiaBrodmann 22, 30

• Lesions in posterior of the left superior
  temporal gyrus, extending to adjacent parietal
  cortex
• Fluent speech
• But contains many paraphasias
• girl-curl, bread-cake
• Syntactical but empty sentences
• Cannot repeat words or sentences
• Unable to understand what they read or hear
• Usually no partial paralysis

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Wernicke-Geschwind Model1. Repeating a spoken
word

• Arcuate fasciculus is the bridge from the
  Wernickes area to the Brocas area

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Wernicke-Geschwind Model2. Repeating a written
word

• Angular gyrus is the gateway from visual cortex
  to Wernickes area
• This is an oversimplification of the issue
• not all patients show such predicted behavior
  (Howard, 1997)

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Sign Languages

• Full-fledged languages, created by hearing-
  impaired people (not by Linguists)
• Dialects, jokes, poems, etc.
• Do not resemble the spoken language of the same
  area (ASL resembles Bantu and Navaho)
• Pinker Nicaraguan Sign Language
• Another evidence of the origins of language
  (gestures)
• Most gestures in ASL are with right-hand, or else
  both hands (left hemisphere dominance)
• Signers with brain damage to similar regions show
  aphasia as well

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Signer Aphasia

• Young man, both spoken and sign language
• Accident and damage to brain
• Both spoken and sign languages are affected
• Deaf-mute person, sign language
• Stroke and damage to left-side of the brain
• Impairment in sign language
• 3 deaf signers
• Different damages to the brain with different
  impairments to grammar and word production

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Spoken and Sign Languages

• Neural mechanisms are similar
• fMRI studies show similar activations for both
  hearing and deaf
• But in signers, homologous activation on the
  right hemisphere is unanswered yet

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Dyslexia

• Problem in learning to read
• Common in boys and left-handed
• High IQ, so related with language only
• Postmortem observation revealed anomalies in the
  arrangement of cortical cells
• Micropolygyria excessive cortical folding
• Ectopias nests of extra cells in unusual
  location
• Might have occurred in mid-gestation, during cell
  migration period

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Acquired Dyslexia Alexia

• Disorder in adulthood as a result of disease or
  injury
• Deep dyslexia (pays attn. to wholes)
• cow -gt horse, cannot read abstract words
• Fails to see small differences (do not read each
  letter)
• Problems with nonsense words
• Surface dyslexia (pays attn. to details)
• Nonsense words are fine
• Suggests 2 different systems
• One focused on the meanings of whole words
• The other on the sounds of words

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Electrical Stimulation

• Penfield and Roberts (1959) During epilepsy
  surgery under local anesthesia to locate cortical
  language areas, stimulation of
• Large anterior zone
• stops speech
• Both anterior and posterior temporoparietal
  cortex
• misnaming, impaired imitation of words
• Brocas area
• unable comprehend auditory and visual semantic
  material,
• inability to follow oral commands, point to
  objects, and understand written questions

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Studies by Ojemann et al.

• Stimulation of the brain of an English-Spanish
  bilingual shows different areas for each language
• Stim of inferior premotor frontal cortex
• Arrests speech, impairs all facial movements
• Stim of areas in inferior, frontal, temporal,
  parietal cortex
• Impairs sequential facial movements, phoneme
  identification
• Stim of other areas
• lead to memory errors and reading errors
• Stim of thalamus during verbal input
• increased accuracy of subsequent recall

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Williams Syndrome

• Caused by the deletion of a dozen genes from one
  of the two chromosomes numbered 7
• Shows dissociation between language and
  intelligence, patients are
• Fluent in language
• But cannot tie their shoe laces, draw images,
  etc.
• Developmental process is altered
• Number skills good at infancy, poor at adulthood
• Language skills poor at infancy, greatly improved
  in adulthood

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Lateralization of the Brain

• Human body is asymmetrical heart, liver, use of
  limbs, etc.
• Functions of the brain become lateralized
• Each hemisphere specialized for particular ways
  of working
• Split-brain patients are good examples of
  lateralization of language functions

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Lateralization of functions(approximate)

• Left-hemisphere
• Sequential analysis
• Analytical
• Problem solving
• Language

• Right-hemisphere
• Simultaneous analysis
• Synthetic
• Visual-Spatial skills
• Cognitive maps
• Personal space
• Facial recognition
• Drawing
• Emotional functions
• Recognizing emotions
• Expressing emotions
• Music

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Split-brain

• Epileptic activity spread from one hemisphere to
  the other thru corpus callosum
• Since 1930, such epileptic treated by severing
  the interhemispheric pathways
• At first no detectible changes (e.g. IQ)
• Animal research revealed deficits
• Cat with both corpus callosum and optic chiasm
  severed
• Left-hemisphere could be trained for
  symbolreward
• Right-hemisphere could be trained for inverted
  symbolreward

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Left vs. Right Brain

• Pre and post operation studies showed that
• Selective stimulation of the right and left
  hemisphere was possible by stimulating different
  parts of the body (e.g. right/left hand)
• Thus can test the capabilities of each hemisphere
• Left hemisphere could read and verbally
  communicate
• Right hemisphere had small linguistic capacity
  recognize single words
• Vocabulary and grammar capabilities of right is
  far less than left
• Only the processes taking place in the left
  hemisphere could be described verbally