copyright © 2008 pearson allyn & bacon inc.1 chapter 13 human communication this multimedia...

Copyright © 2008 Pearson Allyn & Bacon Inc.1

Chapter 13

Human Communication

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• Chapter 13 Outline

• Speech Production and Comprehension: Brain Mechanisms

• Disorders of Reading and Writing



• Lateralization• Verbal behvaior is a lateralized function; most language

disturbances occur after damage to the _____ side of the brain, whether people are left-handed or right-handed.

• If the left hemisphere is malformed or damaged early in life, then language dominance is very likely to pass to the right hemisphere.

Left hemisphere is language dominant for 90% of all subjects: _______________________________________________________________________________________________________________________________

• Lateralization

• _______________________

• Impairs the ability to read ____________, and recognize complex _______________________.

• Damage impairs the ability of subjects from talking about or understanding statements _____________________________________________.

• Damage impairs the expression and recognition of ______________________________.




• Speech Production

• ___________________• Difficulty producing or comprehending speech not

produced by deafness or a simple motor deficit;

caused by brain damage.

• Broca’s aphasia• A form of aphasia characterized by

____________________________________________________________________________________.



• Speech production

• _______________ word (missing in Broca’s aphasia)• A preposition, article, or other word that conveys little

of the meaning of a sentence but is important in

specifying its grammatical structure.

(a, the, some, in, about)

• ______________ word (some can be produced with difficulty)

• A noun, verb, adjective, or adverb that conveys

meaning.

(apple, house, run) [telegraphic speech]




• Broca’s area• A region of frontal cortex, located just rostral to the

base of the left primary motor cortex, that is necessary

for speech production.

__________________________________________________________________________________________________________________________________.




• __________________• One of the usual symptoms of Broca’s aphasia; a

difficulty in comprehending or properly employing grammatical devices, such as verb endings (-ed) and

________________. If asked to point to the picture “The horse kicks the cow”, they perform poorly.

They omit grammatical markers, and do not understand them as well. They have motor and perceptual deficits involving grammar.


The only grammatical cue is word order




• ______________• Difficulty finding (remembering) the appropriate word

to describe an object, action, or attribute; one of the

symptoms of aphasia.

_________________, unable to access them.



• Speech comprehension

• _______________________• A region of auditory association cortex on the left

temporal lobe of humans, which is important in the

comprehension of words and the production of

meaningful speech.



• Speech comprehension• Recognizing words

____________________________________________.• Comprehending the meaning of words involves different

brain mechanisms. • After hearing a foreign word several times you learn to

_____________________________________.

• Wernicke’s aphasia• A form of aphasia characterized by poor speech

comprehension and fluent but _______________ speech.



• Recognition: pure word deafness

• Pure word deafness• The ability to hear, to speak and usually to read

and write without being able to comprehend the

meaning of speech; caused by damage to Wernicke’s

area or disruption of auditory input to this region.

(Fail a pointing task).

Patients may be able to read and write, recognize emotions expressed by the intonation of speech, and recognize non-speech sounds like a door bell, or barking dog.


MRI of temporal lobe damage associated with pure word deafness.

• Mirror Neurons

• Activated when performing and action, or seeing another subject perform it.

• Hearing words engages brain mechanisms that control __________________________________.

• Feedback from _____________________ may facilitate speech recognition. (Young children often move their lips when reading silently.)



The excitability of tongue muscles increased when subject heard words that involved tongue movements (beer).



• Comprehension: transcortical sensory aphasia

• _________________________ (posterior language area)• A speech disorder in which a person has difficulty

comprehending speech and producing meaningful

spontaneous speech but ______________; caused

by damage to the region of the brain posterior to

Wernicke’s area.


Posterior language area


Stimulation sites which when activated ‘mimic’ the loss of speech comprehension seen in transcortical aphasia.

Subjects can repeat what they hear, but they do not comprehend speech.


Red arrows represent the translation of ________into words.

Black arrows represent the _____________of words.



• Comprehension: transcortical sensory aphasia

• ________________ (poor understanding of topography)• Inability to name body parts or to identify body

parts that another person names.

Unable to point to their elbow, knee, or cheek.



• Repetition: conduction aphasia

• Arcuate fasciculus• A bundle of axons that connects Wernicke’s area

with Broca’s area; damage to these axons causes conduction aphasia.

Subjects have fluent meaningful speech with good comprehension.

They can only repeat speech sounds that have ____________. When they hear something meaningful it evokes ________________________________________________________________________.

They are unable to repeat a string of unrelated words, or ________________.


Lesions of arcuate fasiculus associated with conduction aphasia


Conduction aphasia: lesions disrupt the flow of auditory information (but not meaning) to the frontal lobe.


Computer generated model of arcuate fasciculus: damage to the red (deep & direct) pathway produces conduction aphasia.



• Memory of words: anomic aphasia

• _______________• A type of aphasia characterized by difficulty in finding

__________. The speech of patients with anomia is fluent and grammatical, and their comprehension is excellent.

• Partial amnesia for words. Damage to different areas may result in amnesia for verbs and nouns respectively.

• ____________________• A strategy by which people with anomic aphasia find

alternative ways to say something when they are

unable to think of the ________________________.



• Aphasia in deaf people

• Many deal people communicate via sign language.• Sign language qualifies as a language. ________

language may have preceded vocal speech.

• The grammar of sign language is on it visual and spatial nature.

• The spatial nature of sign language suggest aphasic disorders in deaf people who use sign language might be caused by lesions of the right hemisphere.

• The reverse is true, _________________________________________________________________________________________.


Seeing and imitating finger movements used in ASL activate the left hemisphere.


Linkage between speech and hand movements: subjects produce _______ lip openings and greater vocal amplitudes when trained to say a syllable associated with watching an actor ______________________.



• Prosody: rhythm, tone, and emphasis in speech

• ____________________________________• The use of changes in intonation and emphasis to

convey meaning in speech besides that specified by

the particular words; an important means of

communication of_____________.

Regulated by the _________hemisphere.


Prosodic elements activate the right hemisphere



• Stuttering• Stuttering is a speech disorder characterized by

frequent pauses, prolongations of sounds, or repetitions of sounds, syllables, or words that disrupt the normal flow of speech.

• Stuttering affects approximately 1 percent of he population and is three times more prevalent in ________________________________.

• Stutters have reduced auditory feedback produced by the ______________________. Delayed auditory feedback impairs the speech of normal subjects, but facilitates the speech of stutters.



• Stuttering

• Recent evidence suggests that stuttering is caused by abnormalities in regions of the brain that play a role in speech production.

• Stuttering is not a result of abnormalities in the neural circuits that contain the motor programs for speech.

• The problem appears to lie more in the neural mechanisms that are involved in the _________________________________________.


Over activation of areas associated with stuttering

The left temporal lobe appears to be the brain area that is over activated by stutters (Broca’s area and insula, regions involved articulation), and under-activation of auditory regions of the temporal lobe.

• Stuttering

• May be due to faulty auditory feedback from sounds of the stutter’s voice to the auditory areas in the temporal lobe.



After a successful course of therapy for stuttering the left temporal lobe shows increased activity.

Delayed auditory feedback disrupts speech for non-stutters, but assists stutters.



• Reading & speaking use some of the same brain areas.• Most subjects with Wernicke’s aphasia have difficulty reading and

writing, as well as understanding spoken speech.

• Pure alexia

• ______________(lesion in visual cortex in left hemisphere)• Loss of the ability to read without the loss of the

ability to_______; produced by brain damage.

• Also known as pure word blindness or alexia

without agraphia.


“… I still find it very odd to be able to write this letter, but not be able to read it back a few minutes later”…


Pure alexia: a disruption in the flow of information to the left hemisphere extrastriate cortex. These subjects can recognize ________.

Visual agnosia subjects can still ______, but not recognize objects.



• Toward an understanding of reading: two different reading processes

• A. ____________________• Reading by recognizing a word as a whole;

_______________.

• B. __________________• Reading by decoding the phonetic significance of

letter strings; ________________.


A. B.



• Toward an understanding of reading

• ____________________________________________• A reading disorder in which a person can read words

phonetically but has difficulty reading irregularly

spelled words by whole-word reading.

• ____________________________________________• A reading disorder in which a person can read familiar

words but has difficulty reading unfamiliar words or pronounceable nonwords.


Surface Dyslexia


Phonological Dyslexia


Phonological reading, we sound words out by “feeling ourselves _______________________” via Broca’s area activation.

Whole word readingLike reading a stop sign.



• Toward an understanding of reading

• ________________• A language disorder caused by brain damage in

which the person can read words aloud without

_____________________.

Unable to identify photos of the noun just read.



• Toward an understanding of writing

• _______________________• A writing disorder in which the person cannot sound

out words and write them phonologically.

Damage to superior temporal lobe.

• ______________________• A writing disorder in which the person can spell

regularly spelled words but not irregularly spelled

ones.

Damage to inferior parietal lobe.



• Developmental dyslexias

• ____________________________• A reading difficulty in a person of normal intelligence

and perceptual ability; of genetic origin or caused by

prenatal or perinatal factors.

Identical twins: 84-100%

Fraternal twins: 20-35%

Phonological impairments are common in many dyslexics.

Dyslexia is rare in _________, and high in ________.

In English __speech sounds can be spelled ____ different ways ( and __speech sounds can be spelled only __ different ways in Italian).

• Summary

• The brain is a parallel processor:

• Left hemisphere judges the timing of ______ changing sound elements that convey word identity.

• Right hemisphere judges longer duration, _______ changing components of the air stream that convey the emotional status of the speaker.

• Listeners use both channels to assess the speaker’s intention, how they feel about what they are saying, and the truthfulness of the utterance.


copyright © 2008 pearson allyn & bacon inc.1 chapter 13 human communication this multimedia...

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