Transcript June 21_Language & Speech

Language & Speech
June 21, 2011
Review Quiz
Provide evidence for or against
the role of vaccines in autism.
2. Explain the formation of the
notochord and/or neural tube, and
why this stage of development is
important.
3. Describe the major regions (i.e.,
the structures you modeled with
clay yesterday) of the brain and
their formation.
1.
Discussion
What is Language?
 Why Do We Use Speech &
Language?
 Are Speech & Language Unique to
Humans?

Create Your Own Language
RadioLab Podcast
Words, Part 1
Wernicke’s & Broca’s Area
http://www.britannica.com/EBchecked/media/3601/Lateral-surface-of-left-hemisphere-of-brain
Language Lateralization

Areas important to language are primarily
located on the left side of the brain.
 This is determined using the Wada test.
– Anesthetic is injected into one carotid artery to
anesthetize one cerebral hemisphere.
– If language is located here, the person will lose
the ability to talk.

The left hemisphere is dominant for
speech in approximately 95% of all righthanded people!
So Then, the Right Hemisphere Has
No Role in Speech.

There is some involvement of the right
hemisphere, even though the left
hemisphere is dominant.
 For example, the right hemisphere is
important:
– Describing spatial information (maps, etc)
– Forming a story
– Prosody (melodical rhythm and stresses of
speech)
An Interesting Exception:
Case J.M.





16 y.o. white female
8th grade level in self-paced special
education classes
No movement on right side of body
Cranial deformities & extra bone in skull
Left hemisphere hypoplasia diagnosed at
age 8
– Left frontal lobe missing, area occupied by
fluid-filled cyst
– Decreased vasculature on left temporal,
parietal, and occipital lobes
From Lecture by Anthony Y. Stringer, Emory University , 2006
J.M.’s Brain Scan
From Lecture by Anthony Y. Stringer, Emory University , 2006
J.M.’s Angiograms
Normal Angiogram of
J.M.’s Right Hemisphere
From Lecture by Anthony Y. Stringer, Emory University , 2006
Angiogram
Showing Agenesis
of J.M.’s Left Middle
Cerebral Artery
J.M.’s Language Results
Boston Diagnostic Aphasia Exam
Repetition
Fluency
Word Discrimination
Complex Comprehension
Responsive Naming
Confrontation Naming
Reading
Kaplan Sentence Arrangement Test
%ile
70
96
87
85
87
100
90
60%
From Lecture by Anthony Y. Stringer, Emory University , 2006
Right Hemisphere and Language

May take on many
language functions in
response to severe left
hemisphere
developmental trauma
– Early intractable
epilepsy
– Hemisphere
agenesis/hypoplasia
– Early left
hemispherectomy

But, this comes at a
cost…
From Lecture by Anthony Y. Stringer, Emory University , 2006
Broca’s Aphasia

Results from
damage to Broca’s
area and
surrounding areas
in the left inferior
frontal lobe
 Slow, labored
speech with great
difficulty
producing words
http://faculty.washington.edu/chudler/functional.html
Role of Broca’s Area in Speech
May be responsible for memories of
the motor muscle sequences needed
for forming words
 Thus, deficits are of 3 types:

– Agrammatism: difficulty with grammar
– Anomia: difficulty finding a word
– Articulation: difficulty pronouncing
words
Difficulties in Broca’s Aphasia

Meaning of words is correct, but difficult to
pronounce
– Emphasis on content words, difficulty with function
words


Find it much easier to understand speech than to
produce it
“kid…kk…can…candy…cookie…candy…well I don’t
know but it’s writ…easy does
it…slam…early…fall…men…many no…girl.
Dishes…soap…soap…water…water…falling pah
that’s all…dish…that’s all.”
Physiology of Behavior. 7th edition.
Carlson, N.R.
Needham Heights (MA): Allyn and Bacon; 2001.
Other Regions in Broca's Aphasia

Left Precentral Gyrus of the Insula
– When damaged, see apraxia (impaired ability
to move tongue, lips, and throat)

Periaqueductal Gray of the midbrain
– When damaged, see disruptions in
vocalization, even to the extent of mutism

Neocortical damage in the frontal lobe
 Cerebellum
Wernicke’s Aphasia



Results from damage
to Wernicke's area in
the auditory
association cortex on
the left temporal lobe
Leads to difficulties in
comprehending words
and producing
meaningful speech
Speech fluidity is
maintained
http://faculty.washington.edu/chudler/functional.html
How Does Wernicke’s Aphasia
Sound?

“Never, no mista oyge I wann tell you this
happened when happened when he rent.
His—his kell come down here and is—he
got ren something. It happened. In thesse
ropiers were with him for hi—is friend—
like was. And it just happened so I don’t
know, he did not bring around anything.
And he did not pay it. And he roden all o
these arranjen from the pedis on from iss
pescid. In these floors now and so. He
hadn’t had em round here.”
Kertesz, 1981, p. 73
Physiology of Behavior. 7th edition.
Carlson, N.R.
Needham Heights (MA): Allyn and Bacon; 2001.
Wernicke’s Comprehension

When asked to use nonverbal cues to
respond to questions, responses of
patients reveal that they do not
comprehend the question.
 They are often unaware of their deficits.
 Receptive aphasia
– Wernicke’s area contains memories of
sequences of sounds that make up words
Difficulties in Wernicke’s Aphasia

Recognition:
– Pure word deafness, the inability to
understand a word even when it is heard

Comprehension:
– Transcortical sensory aphasia, damage to
posterior language areas affects the ability to
understand words even when recognized

Repetition:
– Conduction aphasia, poor repetition even
when speech is fluent and meaningful
Other Regions in Wernicke’s
Aphasia

Primary auditory cortex
– Interruption of delivery to Wernicke’s area
– Damage causes pure word blindness

Posterior Language Area
– Region located near the junction of the
temporal, occipital, and parietal lobes
– Damage causes transcortical sensory aphasia

Arcuate Fasciculus
– Axon passage between Wernicke’s area and
Broca’s area
– Damage causes conduction aphasia
Aphasia Subtypes
Subtype
Fluency
Repetition
Comprehension
Perisylvian: Broca’s
(Motor)
-
-
+
Transcortical: Motor
+
+
-
+
-
+
+
-
+
+
+
-
Perisylvian:
Wernicke’s (Sensory)
Transcortical: Sensory
Perisylvian: Conduction
Perisylvian: Global
Transcortical: Mixed
From Lecture by Anthony Y. Stringer, Emory University , 2006
Voices of Aphasia
Coloring Diagrams
RadioLab Podcast
Words, Part 2
Brainstorming

What other factors affect our use of
speech and language?
McGurk Effect Experiment
Is Language Human Specific?
Do Animals Have Language?

Talking with Kanzi
the Bonobo
 Introduction to the
Gorilla Foundation:
Koko’s Sign
Language
 Goodbye to Alex
the Parrot
Writing Assignment
What defines language?
 Is it unique to humans?


What experiments would you do to
identify language correlates in
animals?
Reading Neuroscience
Speech Similarities

The speech symptoms of people with
aphasia tend to be mimicked in their
reading symptoms.
– Agrammatical speech—Agrammatical
writing
– Patients with Broca’s aphasia
comprehend what they read, but have
difficulty reading it aloud.
Pure Alexia



Associated with
visual cortex and
posterior corpus
callosum lesions
Maintain the
ability to write,
but not read
Perceptual
disorder
Dear Dr. Warrington,
Thank you for your letter of
September 16th. I shall be
pleased to be at your office
between 10 & 10:30 am on
Friday 17th October. I still find it
very odd to be able to write this
letter but not to be able to read it
back a few minutes later. I much
appreciate the opportunity to
see you.
Yours sincerely,
Harry X
Pathways in Pure Alexia

Damage only to the left primary visual cortex
– Right visual field is blind; info from the left visual field
passes to the right visual cortex
– Information passes to the extrastriate cortex, crosses over
the corpus callosum
– Processed in left speech areas, making reading possible but
difficult

Damage to the left visual cortex and corpus
callosum
– Patient cannot read: right visual field is blind, and
information from the left visual field cannot pass over the
corpus callosum to the left speech areas

What about damage to the posterior corpus
callosum?
Hemialexia
Inability to read words that are
located only in the left visual field
 Words in the right visual field are
read normally

Dyslexia

Can be developmental or acquired
 Surface dyslexia
– Deficit in whole-word reading
– Associated with damage to left lateral temporal
lobe
– Errors are related to visual appearance, not
meaning

Phonological dyslexia
– Deficit in sounding out words phonetically
– Caused by damage to left frontal lobe
Other Dyslexias

Word-Form & Spelling Dyslexia
– Inability to recognize or sound out words, but
able to read slowly

Direct Dyslexia
– Cannot understand words that they are
reading aloud
– For example, may read a word aloud correctly,
but cannot match the appropriate picture for
the meaning of the word.
Writing Disorders

Phonological Dysgraphia
– Inability to write words phonetically
based on sounding them out

Orthographic dysgraphia
– Ability to write words only when
sounding them out
– Difficulty writing words that are not
spelled the way they sound
Decoding Phonemes Experiment
Concept Mapping

Reading Disorders
– Alexia
– Dyslexia
– Etc

How would you help people with
these disorders learn to read?
Improving Your Language Skills