Ling 411 – 06
I. Classifications of Aphasia
II. Laterality
III. Varieties of Anomia
Classifications
“Classifications are a necessary evil”
Antonio Damasio (1998)
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
• Insula(?)
 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
Extra-Sylvian Aphasic Syndromes
According to Benson & Ardila
 “Extra-Sylvian” (a.k.a. “Transcortical”)
 Extrasylvian motor aphasia
• Type I
• Type II
 Extrasylvian sensory aphasia
 Sometimes just called ‘anomic aphasia’
• Type I
• Type II
Extra-Sylvian Aphasic Syndromes
 In all perisylvian syndromes, repetition is faulty
 In all extra-sylvian aphasic syndromes,
repetition is intact
(why?)
 “Aphasia without repetition disturbance almost
invariably indicates pathology outside the
perisylvian region” (B&A 1996:146)
Extrasylvian motor aphasia
 Nonfluent output
• Delayed initiation
• Terse, poorly elaborated utterances
• Incomplete sentences
• Verbal paraphasia
 Good comprehension
 Good repetition
Extrasylvian motor aphasia, Type I
 Left dorsolateral prefrontal damage
• Anterior and superior to Broca’s area
 Non-fluent output, but repetition good
 Articulation is normal
 Difficulty following commands
• Understand command but do not respond
 Damage anterior and superior to Broca’s area
(Brodmann areas 45, 46, and/or part of area 9)
(B&A 1996:152)
Extrasylvian motor aphasia, Type II
 Damage to supplementary motor area
• Occlusion of left anterior cerebral artery
 Non-fluent output, but good repetition
 Difficulty initiating speech
 Perhaps a purely motor disorder that does not
involve basic language functions
• (in which case it isn’t really a type of aphasia)
Supplementary motor area
Supplementary motor area
Important in
initiating
action (not
just speech)
Extrasylvian sensory aphasia
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Speech is fluent
Good repetition
Comprehension is impaired
Naming is impaired
Paraphasia is frequent, even verbose
• Semantic substitutions
• Neologisms
 Echolalia (patients repeat words of examiner)
 Pointing is impaired
 Two subtypes
Extrasylvian sensory aphasia, Type I
 Damage to temporal-parietal-occipital junction area
• I.e., lower angular gyrus and upper area 37
 Fluent spontaneous output
 Poor comprehension
 Naming strongly impaired
 Semantic paraphasia
Extrasylvian sensory aphasia, Type II
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Damage to upper angular gyrus
Fluent output
Variable ability to comprehend speech
Naming strongly impaired
Few semantic paraphasias
Repetition excellent
Many circumlocutions
Comparing Extra-Sensory Aphasia, Types 1 and 2
Type 1
 Damage to TPO junction
area
 Fluent spontaneous
output
 Poor comprehension
 Naming strongly impaired
 Semantic paraphasia
 Repetition good
Type 2
 Damage to upper angular
gyrus
 Fluent output
 Variable ability to
comprehend speech
 Naming strongly impaired
 Few semantic paraphasias
 Repetition excellent
 Many circumlocutions
Laterality
Cerebral dominance for language
 Linguistic abilities are subserved by the
left hemisphere in about 97% of people
• 99% of right-handed people
• A majority of left-handers
 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
The Role of RH in semantics
 Conceptual information, even for a
single item, is complex
• Therefore, widely distributed
• A network
• Occupies both hemispheres
 RH information is more connotative
• LH information more exact
Left dominance for language in left-handers
 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
 Right Hemisphere
• Analytical thinking
• Holistic thinking
• Digital
• Analog
• Heightened contrast
• Fuzzy boundaries
• Proof
• Hunches, intuition
Question:
What anatomical differences are responsible?
Corpus Callosum
(revealed by excision of top
of right hemisphere)
Corpus
Callosum
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
Varieties of anomia:
Semantic categories
Anomic aphasia
 Perhaps part of a continuum with extrasylvian
sensory aphasia
 Comprehension is good in many cases
• Unlike extrasylvian sensory aphasia
 Production and repetition are good
 Cannot be reliably localized
• Many different areas of damage can result in
naming difficulty
 But different semantic categories may be
impaired with different areas of damage
• Maybe not a true syndrome: Benson&Ardila
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, complex functions are not localized
• Only simple functions have locations
 Conceptual information, even for a single word
• Is complex, has many components
• Therefore, 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
Don’t forget this – (repeating)
 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
(Repeating:) 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.
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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
end