Language Disorders
Medical and Psychosocial Aspects of Disability
11/2/04

Communication
 There are 3 elements in this exchange, and all must be present:
1.
Message
2.
Message must be expressed
3.
Message must be understood

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.

Four domains of language
 Phonology
 Grammar
 Semantics
 Pragmatics

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.

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

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.

Grammar
 Composed of both morphology and syntax.

Semantics
 The study of meaning
 Includes the study of vocabulary
(lexicon).

Lexicon
 Lexical entries are organized in the mental dictionary according to welldefined 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.

Lexicon Growth
 The subsequent exponential growth makes it difficult to determine vocabulary size with exactitude.

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 ).

Pragmatics
 A number of sub-domains reflecting communicative competence.

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

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.

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.

Language Developmental
Trajectory
Telegraphic speech
Word combinations
Word production
Word comprehension
Canonical Babbling

 By age 3, most normal children have mastered the basic structures of their native language

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.

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.

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

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

1. Fluency Disorders
 Speech is characterized by repeated interruptions, hesitations, or repetitions
 Stuttering is by far the most well-known fluency disorder

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

Stuttering -- Causes


1.
2.
3.
Still a mystery
Three perspectives:
Symptom of emotional disturbance
Result of biological makeup
Learned response

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

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

Characteristics-
Prolongation
 Stretching, of sounds or syllables
 r-----abbit

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

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

2. Articulation disorders



This is the largest category of all speech problems
DSMIV calls these “phonological disorders.”
“abnormal speech-sound production, characterized by inaccurate or otherwise inappropriate execution of speaking”

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

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

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

Normal Speech Development

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

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

Most common causes of speech delay
 Mental retardation
 Hearing loss
 Maturation delay

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

Language and Brain

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

EXPRESSIVE LANGUAGE
DISORDER
( developmental expressive aphasia)
 Fail to develop the use of speech at the usual age.

EXPRESSIVE LANGUAGE DISORDER
 Normal intelligence
 Normal hearing
 Good emotional relationships
 Normal articulation skills.
 Comprehension of speech is appropriate to the age of the child

EXPRESSIVE LANGUAGE DISORDER
 Brain dysfunction that results in an inability to translate ideas into speech.

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

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.

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.

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

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.

Interference or transfer
 An English error due to the direct influence of the primary language structure.
 This is a normal phenomenon

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.

Code switching
 Changing languages over phrases or sentences.
 Normal phenomenon

Benefits of Bilingualism
 Children who are fluent bilinguals actually outperform monolingual speakers on tests of metalinguistic skill.

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.

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

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

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

Three major types of Aphasia
Rosenzweig: Table 19.1, p. 615
 Borca’s aphasia
 Nonfluent speech
 Wernicke’s aphasia
 Fluent speech but unintelligible
 Global aphasia
 Total loss of language
Others: Conduction, Subcortical, Transcortical
Motor/Sensory (see also Kandel, Table 59-1)

Brain areas involved in Language

Broca’s Aphasia
Brodmann 44, 45
 Lesions in the left inferior frontal region
(Broca’s 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

Wernicke’s
Aphasia
Brodmann 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

Wernicke-Geschwind Model
1. Repeating a spoken word
 Arcuate fasciculus is the bridge from the
Wernicke’s area to the Broca’s area

Wernicke-Geschwind Model
2. Repeating a written word


Angular gyrus is the gateway from visual cortex to
Wernicke’s area
This is an oversimplification of the issue:
 not all patients show such predicted behavior (
1997)
Howard,

Sign Languages
 Full-fledged languages, created by hearingimpaired 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

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

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

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

Acquired Dyslexia = Alexia
 Disorder in adulthood as a result of disease or injury
 Deep dyslexia (pays attn. to wholes):
 “cow” -> “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

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
Broca’s area:
 unable comprehend auditory and visual semantic material,
 inability to follow oral commands, point to objects, and understand written questions

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


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

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

Lateralization of functions
(approximate)
 Left-hemisphere:
 Sequential analysis
 Analytical
 Problem solving
 Language
 Right-hemisphere:




Simultaneous analysis
 Synthetic
Visual-Spatial skills
 Cognitive maps

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Personal space
Facial recognition
Drawing
Emotional functions


Recognizing emotions
Expressing emotions
Music

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 symbol:reward
 Right-hemisphere could be trained for inverted symbol:reward

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