Chapter 13
Human Communication
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• Chapter 13 Outline
• Speech Production and Comprehension: Brain Mechanisms
• Disorders of Reading and Writing
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• Speech Production and Comprehension: Brain
Mechanisms
• 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:
___________________________________________
___________________________________________
_________________________________________
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• 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
______________________________.
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• Speech Production and Comprehension: Brain Mechanisms
• 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
______________________________________________
______________________________________.
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• Speech Production and Comprehension: Brain Mechanisms
• 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]
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• Speech Production and Comprehension: Brain Mechanisms
• Speech production
• 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.
_______________________________________________
______________________________________________
_____________________________________.
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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The only grammatical
cue is word order
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• Speech Production and Comprehension: Brain Mechanisms
• Speech production
• ______________
• Difficulty finding (remembering) the appropriate word
to describe an object, action, or attribute; one of the
symptoms of aphasia.
_________________, unable to access them.
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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MRI of temporal
lobe damage
associated with
pure word
deafness.
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• 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.)
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The excitability of
tongue muscles
increased when subject
heard words that
involved tongue
movements (beer).
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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Posterior
language
area
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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.
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Red arrows
represent the
translation of
________into
words.
Black arrows
represent the
_____________
of words.
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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• Speech Production and Comprehension: Brain Mechanisms
• 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,
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or ________________.23
Lesions of arcuate fasiculus associated with conduction aphasia
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Conduction aphasia: lesions disrupt the flow of auditory
information (but not meaning) to the frontal lobe.
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Computer generated model of arcuate fasciculus: damage to
the red (deep & direct) pathway produces conduction aphasia.
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• Speech Production and Comprehension: Brain Mechanisms
• 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 ________________________.
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• Speech Production and Comprehension: Brain Mechanisms
• 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,
______________________________________________
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___________________________________________.
Seeing and imitating finger
movements used in ASL
activate the left hemisphere.
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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 ______________________.
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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Prosodic elements activate the right hemisphere
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• Speech Production and Comprehension: Brain Mechanisms
• 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.
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• Speech Production and Comprehension: Brain Mechanisms
• 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
_________________________________________.
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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.
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• Stuttering
• May be due to faulty auditory feedback from sounds of the
stutter’s voice to the auditory areas in the temporal lobe.
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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.
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• Disorders of Reading and Writing
• 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.
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“… 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”…
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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.
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• Disorders of Reading and Writing
• 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; ________________.
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B.
A.
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• Disorders of Reading and Writing
• 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.
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Surface Dyslexia
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Phonological Dyslexia
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Phonological
reading, we sound
words out by
“feeling ourselves
________________
_______” via
Broca’s area
activation.
Whole word reading
Like reading a stop
sign.
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• Disorders of Reading and Writing
• 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.
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• Disorders of Reading and Writing
• 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.
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• Disorders of Reading and Writing
• 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).
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• 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.
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