Ling 411 – 06
I. Classifications of Aphasia
II. Laterality
III. Varieties of Anomia
IV. Reading and Writing
Problems of classification
 Different aphasics almost never share the
same set of symptoms (Benson&Ardila 111)
• Variations “are so plentiful as to be the rule”
(B&A 117)
• A single type of aphasia may have
distinctly
different loci of pathology (B&A 117)
 Conduction aphasia (117)
•
•
Parietal lobe
Arcuate fasciculus
 Transcortical motor aphasia (118)
 Differing interpretations of sets of
symptoms
 Different approaches to classification
Wide variation in classification schemes
 Influential ones in history of aphasiology:
• Wernicke-Lichtheim 1881, 1885
• Head 1926
• Goldstein 1948
• Luria 1966
• Benson 1979
• Benson & Ardila 1996
• Damasio 1998
 But ..
• All recognize just a small number of basic
•
syndromes
Most of the variation in classification schemes
is just terminological (Benson&Ardila 120)
Damasio’s Classification (1998:34ff)
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Wernicke’s aphasia
Broca’s aphasia
Conduction aphasia
Transcortical sensory aphasia
Transcortical motor aphasia
Global aphasia
Anomic aphasia
Alexia
Pure word deafness
Atypical aphasias
The 1996 Benson & Ardila Classification
(B&A: 119)
Pre-Rolandic
PeriSylvian
ExtraSylvian
Broca Aphasia
Post-Rolandic
Wernicke Aphasia
Conduction Aphasia
Extrasylvian
Motor Aphasia
Extrasylvian
Sensory Aphasia
Not included in above scheme:
(1) Problems with reading & writing
(2) Anomic aphasia
(3) Global aphasia
Features of the 1996 B&A Classification
(B&A: 119)
 Based on two anatomical dichotomies:
• Pre- vs post-Rolandic
• Perisylvian vs. extrasylvian
 For every type, two subtypes
• But the two subtypes can be just two ends of a
continuous scale, not distinct subtypes
 Alternatives to usual terms:
• “Extrasylvian” instead of “transcortical”
• “Broca” instead of “Broca’s”
• ‘Wernicke” instead of “Wernicke’s”
A major anatomical-functional dichotomy:
Front (anterior) vs. Back (posterior)
 Front
• Action and planning of action
• Process oriented
 Back
• Perception
• Perceptual integration
• Object oriented
Damasio vis-à-vis Benson & Ardila
Damasio
 Wernicke’s aphasia
 Broca’s aphasia
 Conduction aphasia
 Transcortical sensory
aph.
 Transcortical motor
aph.
 Global aphasia
 Anomic aphasia
 Alexia
Benson & Ardila
 Wernicke aphasia
 Broca aphasia
 Conduction aphasia
 Extrasylvian sensory
aph.
 Extrasylvian motor
aph.
 Global aphasia
 Anomic aphasia
 Wernicke II or
Posterior extrasylvian
Front-Back dichotomy and aphasia:
Alternative terms/emphases
 Fluent
 Non-fluent
 Receptive*
 Expressive*
 Sensory
 Motor
 Posterior
 Anterior
*But: (1) Very few aphasic patients are completely free
of receptive difficulties
(2) Virtually no aphasic is entirely without
expressive problems
(B&A 112)
Damasio’s Categories as
Anterior vs Posterior Aphasias
(Or: Pre-Rolandic vs Post-Rolandic)
Anterior
 Broca’s aphasia
 Transcortical motor
aphasia
Posterior
 Wernicke’s aphasia
 Conduction aphasia
 Transcortical sensory
aphasia
 Alexia
 Pure word deafness
Others:
Global Aphasia: Both anterior and posterior
Anomic aphasia: Can be either or both
Atypical aphasias
Cerebral dominance for language
 Linguistic abilities are subserved by
the left hemisphere in about 97% of
people
• 99% of right-handed people
 But this is just a first approximation
More refined look
 Some information is bilaterally
represented
• Highly entrenched items
• Initial consonants of high-frequency words (?)
• Some people have more bilateral
•
representation than others
Women and left-handers tend to have more
bilateral representation than men and righties
 Pitch, intonation, and other prosodic
features subserved by RH
 Semantic information is in both LH and RH
• But different aspects of semantic information
 Metaphor, irony, sarcasm, pragmatic
features, inferencing, subserved by RH
Left dominance for language in lefthanders
 Wada test (Milner 1975), on left-handers
• 69% aphasic after injection of left brain
• 18% aphasic after injection of right brain
• 13% aphasic after injection on each side
Goodglass 1993:57
Right dominance for language in right-handers
 Crossed aphasia: Term for right-handers
who suffer aphasia after RH injury
 Incidence of crossed aphasia is estimated
at 1%
Goodglass 1993:58
The genetics of laterality
 Matings of left-handed parents produce
no more than about 50% left-handed
offspring
 Annett’s theory (1985)
• A single right-shift gene (rs+)
• If rs++, right-handed (LH dominant)
• If rs+-, right handed (LH dominant)
• If rs-- (right-shift gene absent)..
 Can go either way
 Depends on environment, experience
 50% probability of becoming left-handed
Left hemisphere vs. right hemisphere
 Left hemisphere
• Analytical thinking
• Digital
• Heightened contrast
• Proof
 Right Hemisphere
• Holistic thinking
• Analog
• Fuzzy boundaries
• Hunches, intuition
Question:
What anatomical differences are responsible?
Separated right and left hemispheres
 Cutting corpus callosum separates them
 Isolated RH:
• Limited one-word reading comprehension
 Some grasp of meanings
 But unable to make judgments about sound
 Isolated LH:
• Awareness of both sound and meaning
Corpus Callosum
(revealed by excision of
top of right hemisphere)
Corpus
Callosum
Semantic categories:
Varieties of anomia
2 Cases of Rapp & Caramazza (1995)
 E.S.T. (901b) – Left temporal damage
• “Meaning spared, couldn’t say the word”: R&C
 J.G. (902a) – Left posterior temporal-parietal
• Meaning spared, couldn’t spell the word
correctly, but phonological recognition okay
Cf. Rapp & Caramazza,
Disorders of lexical processing
and the lexicon (1995)
Patient E.S.T.
(Rapp&Caramazza 1995:901b)
 Left temporal damage
 Shown picture of a snowman
• Unable to name it
• “It’s cold, it’s a ma… cold … frozen.”
 Shown picture of a stool
• “stop, step … seat, small seat, round seat, sit
on the…”
 Shown written form ‘steak’
• “I’m going to eat something … it’s beef … you
can have a [së] … different … costs more …”
 What can we conclude?
Assessment of E.S.T.
by Rapp & Caramazza
 Responses of E.S.T. indicate awareness of
the meanings (SNOWMAN, STOOL, STEAK)
 Therefore, “meaning is spared” (acc. To R&C)
Warning: Proceed with caution
 The assumption of Rapp&Caramazza is easy
to make
• I.e., that meaning (conceptual information) is
spared
 But there’s more to this than meets the eye!
 As we have seen, conceptual information is
widely distributed
 We only have evidence that some of the
conceptual information is spared
Patient E.S.T. – a closer look
 Left temporal damage
 Picture of a snowman
• “It’s cold, it’s a ma… cold … frozen.”
 Picture of a stool
• “stop, step … seat, small seat, round seat, sit
on the…”
 Written form ‘steak’
• “I’m going to eat something … it’s beef … you
can have a [së] … different … costs more …”
 These are not definitions
 This is connotative information
• Vague semantic notions about the meanings
Compare patient J.G. (902a)
 Damage: Left posterior temporal-parietal
 Meaning spared, couldn’t spell the word
correctly, but phonological recognition okay
• digit:
•
 D-I-D-G-E-T
 “A number”
thief:
 T-H-E-F-E
 “A person who takes things”
 These are actual definitions
The Role of RH in semantics
 Conceptual information, even for a
single item, is widely distributed
• A network
• Occupies both hemispheres
 RH information is more connotative
• LH information more exact
Connotative information in RH
 Tests on patients with isolated RH resulting from
callosotomy
 RH has information about (many) nouns and verbs
•
Not as many as in LH
 Semantic information differently organized in RH
 Zaidel (1990): “… the right hemisphere is
characteristically connotative rather than
denotative … . The arcs [of the semantic network]
connect more distant concepts … and the
organizing semantic relationships are more loosely
associative and dependent on experience” (125)
Baynes & Eliason, The visual lexicon: its access and
organization is commissurotomy patients (1998)
Semantic information: E.S.T. and J.G.
 Patient J.G. – real definitions
• digit: “A number”
• thief: “A person who takes things”
 Patient E.S.T. – connotative information
• snowman: “It’s cold, it’s a ma… cold … frozen.”
• stool: “ … seat, small seat, round seat, sit on
•
the…”
steak: “I’m going to eat something … it’s beef …
you can have a [së] … different … costs more …”
Conclusion about E.S.T.
 RH semantic information is intact
 LH semantic information is wiped out
 Phonological information is spared in both
hemispheres
 Question: Why can’t the RH semantic
information be conveyed to LH phonology?
Corpus Callosum
(revealed by excision of
top of right hemisphere)
Corpus
Callosum
Brain damage and nominal concepts
 Access to nominal concepts is impaired in
extra-sylvian sensory aphasia
 Type I – Damage to temporal-parietaloccipital junction area
• I.e., lower angular gyrus and upper area 37
• Poor comprehension
• Naming strongly impaired
• Semantic paraphasia
 Type II –Damage to upper angular gyrus
• Variable ability to comprehend speech
• Naming strongly impaired
• Few semantic paraphasias
• Many circumlocutions
Conceptual category dissociation I
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J.B.R. and S.B.Y. (905b-906a)
Herpes simplex encephalitis
Both temporal lobes affected
Could not define animate objects
• ostrich, snail, wasp, duck, holly
 Much better at defining inanimate
objects
• tent, briefcase, compass, wheelbarrow,
submarine, umbrella
 How to explain?
Conceptual category dissociation II
 J.J. and P.S. (Hillis & Caramazza 1991) (906-7)
• J.J. – left temporal, basal ganglia (CVA)
•
 Selective preservation of animal concepts
P.S. – mostly left temporal (injury)
 Selective impairment of animate category
P.S
J.J.
Reading and Writing
Alexia and Agraphia
 Alexia with agraphia
• Reading and writing both impaired
• A rare disorder
 Patients with both impairments usually also
have Wernicke’s aphasia or transcortical
sensory aphasia
 Alexia without agraphia, a.k.a. pure alexia
• Reading impaired, writing okay
• Can write spontaneously or to dictation
• Some can copy writing but with difficulty
Misprint in Antonio Damasio Reading
 Antonio Damasio, Signs of Aphasia
 P. 38: “As the designation implies, patients
presenting alexia with agraphia become
unable to read while they continue to be
able to write…”
 Should be “…alexia without agraphia…”
More on patient J.G.
 Damage: Left posterior temporal-parietal
 Meaning spared, phonological recognition
okay, but couldn’t spell the word correctly
• digit:
•
 D-I-D-G-E-T
 “A number”
thief:
 T-H-E-F-E
 “A person who takes things”
 These spellings are not correct, but..
Reading – relating writing to speech
Phonological
word image
Phonemes
The “Phonics” route
Letters
Reading – relating writing to speech
Phonological
word image
Graphic
word image
The “whole word” route
Letters
Two pathways for relating writing to speech
Phonological
word image
Graphic
word image
Phonemes
Letters
Redundancy?
Two pathways for relating writing to speech
 The “whole word” route is necessary for
•
•
•
caught
island
sign
•
•
•
commissurectomy
prosopagnosia
magnetoencephalography
 The “phonics” route is needed for long
unfamiliar words
The spelling attempts of J.G.
(one more look)
 digit:
• D-I-D-G-E-T
• “A number”
 thief:
• T-H-E-F-E
• “A person who takes things”
 J.G. has damaged “whole word” route
but intact “phonics” route
 Evidence that the two routes are
separately represented in the cortex
More evidence on phonological and
graphic forms
 Patient P.W.
(905)
• Damage: anterior parietal & posterior frontal
• Tested on identifying spoken words
•
 [skirt]: “S-O-C-K, skirt
• Verbal paraphasia in spelling but not in speech
 [brush]: “B-R-U-S-H, comb”
• Verbal paraphasia in speech but not in spelling
 [knife]: “S-P-O-O-N, fork”
• Verbal paraphasia in both modalities
Paraphasias are semantically related
Patient D.R.B.
(902b-903a)
 Left middle cerebral artery infarct
 Able to discriminate words and pseudo-words
• Either visual or auditory input
 Test: Two words – synonyms or not?
• For written input, 95% accurate
• For spoken input, only 61% accurate
 Evidence that representations of written
words can have direct connections to
semantic information
Graphic representation and meaning
 The traditional view: speech is primary,
writing secondary
• History
• Development
 Might suggest that writing has access to
meaning only via phonological representation
 But evidence from brain damage indicates
that (at least some) written forms have
direct access to meaning, independently of
phonology
Pathway to meaning
Conceptual
information
Phonological
word image
Graphic
word image
Phonemes
Letters
Pathways to meaning
Conceptual
information
Does this pathway
also exist?
Phonological
word image
Graphic
word image
Phonemes
Letters
Evidence for direct connections
between meaning and graphic form
 Patient D.R.B. (above)
• Judgments of synonymy better for pairs of
written words than pairs of spoken words
 Patient H.W.
(904)
• Damage: left parietal and occipital
• Tested on identifying written words
 Interest:
• “bank”
• “You go to the bank and put it in and you get
more money … not very much now”
More evidence for direct connections
between meaning and graphic form
 Patient R.G.B.
(904)
• Damage: left frontoparietal
• Tested on identifying written words
 Records:
• “radio”
• “You play ‘em on a phonograph … can
also mean notes you take and keep”
• Understands meaning from written
input, but has impaired phonological
information or impaired connection
to phonological information
Phonological-Graphic Connections:
The Angular Gyrus
The angular gyrus and the white matter below it
appear to be uniquely important for all aspects of
graphic language that involve its linkage to writing, to
spoken language, and to word meaning. Injury to this
area disrupts not only the ability to understand the
written word, but also disrupts related knowledge such
as oral spelling and letter-sound correspondence, and
therefore disrupts the ability to write.
Harold Goodglass
Understanding Aphasia 1993:51
The angular gyrus
Angular
gyrus
Connecting to output
Phonological
word image
Graphic
word image
Phonological
production
Phonemes
Letters
Broca’s area
Arcuate fasciculus
Angular gyrus
Connecting to Spoken and Written Output
Exner’s area
Graphic
production
Superior longitudinal fasciculus
Phonological
word image
Graphic
word image
Phoneme
images
Letter
images
Phonological
production
Broca’s area
Arcuate fasciculus
Angular gyrus
Exner’s Area
Broca’s
area
Wernicke’s area
Angular gyrus
Systems for Speech and Writing
Exner’s area
Graphic
production
Superior longitudinal fasciculus
Phonological
word image
Graphic
word image
Phoneme
images
Letter
images
Phonological
production
Broca’s area
Arcuate fasciculus
Angular gyrus
end