Aphasia

1
Aphasia

• Loss or impairment of language comprehension or
  production

2
Language Impairments
COMPREHENSION Auditory Single words Phrases
Commands (Token Test) Syntax Visual (Reading -
alexia) Single words Phrases

• PRODUCTION
• Spontaneous Speech
• Fluent versus nonfluent
• Unintended or off words (paraphasias)
• Word finding difficulties (anomia)
• Poor articulation
• Prosody (aprosodia)
• Repetition
• Single words
• Phrases
• Writing (agraphia)

3
Brocas Aphasia

• Bouillaud (1825) large series of speech loss
  with frontal lesions
• Marc Dax (1836) LH damage, right hemiplegia,
  aphasia linked
• Paul Broca (1861) convincing evidence of speech
  laterality Tan Nous parlons avez
  lhemispheregauche

Paul Broca (1824-1880)
4
(No Transcript)
5
Wernickes Aphasia

• Carl Wernicke (1874) reports that temporal lobe
  lesion disturbs comprehension.
• Developed connectionism model of language and
  predicated conduction aphasia

6
Aphasias

• Conduction
• Fluent speech
• Good comprehension
• Poor repetition
• Poor naming
• Possibly lesion in arcuate fasciculus or its
  connections in inferior parietal lobule

• Wernickes
• Fluent speech
• Poor comprehension
• Poor repetition
• Poor naming
• Posterior superior temporal lobe lesion (first
  temporal gyrus)

7
Aphasias

• Transcortical Sensory
• Fluent speech
• Poor comprehension
• Good repetition
• Poor naming
• Lesion in posterior temporo-parietooccipital
  junction while sparing Wernickes area

• Anomic
• Fluent speech
• Good comprehension
• Good repetition
• Poor naming
• Temporal or temporo-parietal lesion

8
Wernicke TCS Aphasia
9
Aphasias

• Brocas
• Non-fluent speech
• Good comprehension
• Poor repetition
• Poor naming
• Posterior inferior frontal lesion

• Global
• Non-fluent speech
• Poor comprehension
• Poor repetition
• Poor naming
• Lesion involves frontal, temporal and parietal
  lobes, Including Brocas and Wernickes area

10
Aphasias

• Mixed Transcortical
• Non-fluent speech
• Poor comprehension
• Good repetition
• Poor naming
• Anterior and posterior association cortex lesions
  while sparing perisylvian language region

• Transcortical Motor
• Non-fluent speech
• Good comprehension
• Good repetition
• Poor naming
• Lesion involves frontal lobe but spares Brocas
  area

11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Linguistic processes
15
Turn of the century models for Reading and
Speaking
16
(No Transcript)
17
(No Transcript)
18
Reading Aloud (Grapheme to Phoneme conversion
GPC)
19
Linguistic Competence of the Disconnected RH
Vocabulary vs syntactical competence
TOKEN TEST Point to the large yellow circle
20
Lexical Language in the disconnected RH
Token test assesses auditory comprehension but
more so syntactical competence
21
GPC but may index visual familiarity)
Auditory comprehension
Reading
GPC (via Rhyme)
22
Lexical Language in the disconnected RH
Token test assesses auditory comprehension but
more so syntactical competence
23
LH
RH
24
Syntactical incompetence of the RH (poor
prepositions) but competence for nouns and
adjectives, with control for word frequency
(i.e., visual familiarity)
25
Not all nouns are alikeRH competence for
concrete and imageable

• Concrete but not imageable
• Encephalon
• Matter
• Welt
• Imprint
• Morass
• plaza

• Not Concrete but imageable
• Alone
• Affectionate
• Wise
• Joy
• Fun
• blessing

26
Right Hemisphere Ability
27
Lexical Language in the disconnected RH
28
Isolation of grapho-motor module

• In VJ, writing dissociates from other language
  abilities.
• Writing in RH
• All others LH
• In JW VP all language abilities are localized
  in LH.

Unusual brain organization - dissociations
29
Gross functions across split brain series
30
Patient O.A.
31
Linguistic Competence that requires intact
interhemispheric language systems

• Alternative meanings
• Narrative processing, inference
• Metaphor
• Humor
• Indirect request

Technique suitable for fast, short presentations
only lt180 ms
32
inference
33
How to test sustained visual attention in one
visual field Z-lens
34
Ongoing inference in sentential readingsThe
pizza was too hot to cry
35
Hough (1990) - Narrative Integration
36
Polysemantic Processing

• Revising interpretations of non-humorous
  discourse
• Sally became too bored to finish the history
  book.
• She had already spent five years writing it.
  (or we saw her duck)
• Same initial inference generated by controls and
  RHD, but RHD failed to abandon dominant inference
  for alternative interpretation consistent with
  both sentences (Brownell 1996)
• RHD performance normals for integrating across
  sentence boundaries.
• Johnny missed the wild pitch.
• The windshield was shattered.
• Related Findings
• RH maintains activation over longer prime-target
  intervals.
• RH primed by weakly associated primes (foot, cry,
  glass for cut) as much as by direct prime
  (scissors for cut).
• LH shows only priming for direct prime
• Conclusions
• RH generates extensive (multiple)
  representational sets for meanings implied or
  novel
• LH inhibits alternatives and focuses on dominant
  reading.
• LH excels at selecting processing one
  (dominant) interpretation.

37
Priming for Polysemy

• Dominant context The dog played with the ball
• Subordinate context She bought a new dress for
  the ball
• Associated ROUND (dominant) or DANCE
  (subordinate)

38

• By 40 ms LH (RVF) has collapsed all subordinate
  (alternative) word meanings or never allowed them
  to emerge
• (I put my money in the bank)

39
Deep dyslexia
40
Deep dyslexia - Reliance on diffuse
representational system of RH
41
New word learning shifts childs attention from
thematic (RH) to categorical (LH)
42

• RH vocab 13y, syntax 5y

43
Aphasia with multiple languages

• Bilingual recovery
• Parallel recovery
• Differential or nonparallel recovery
• L1 recovers faster (Ribots lawold before new)
• L2 recovers faster (Pitres lawfrequent first)
• Due to different or overlapping brain areas, or
  what?
• Recovery implies that actual language centers
  werent destroyed, only cut off or inhibited.

44
Recovery from aphasia

• L1 and L2 may recover independently
• implies some differential representation in the
  brain.
• Case L1 recovery only Dimitrijevic (1940).
• Woman grew up speaking Bulgarian Yiddish (both
  L1), As adult, she learned Serbian (L2) which she
  spoke daily for 25y. She kept forgetting
  Bulgarian until brain injury at 60y resulted in
  loss of Serbian in speech (however, she still
  could understand L2)

45
Second language recovery

• 1/3rd of multilinguals do not recover L1, but L2
  or L3
• Case L2 recovery Minkowski (1928).
• Acquisition
• L1Swiss German
• L2 schooled in standard German
• L3 became fluent in French, then stroke after 19
  y
• Recovery
• spoke French (L3) for 3 weeks, then German (L2),
  but incapable of using Swiss German (L1) for 6
  months.
• Suddenly L1 returned, to detriment of French
  (L3).

46
Factors involved in L2 recovery

• Minkowski Languages are not spatially separated,
  but exert mutual inhibition in delicate balance
  (Great Powers of Europe metaphor 19-20th c).
• Lesion disrupts balance and can suppress any
  language (including L1).
• In support, lost languages can be recovered
  faster than usually required to learn from
  scratch
• Little evidence of right hemisphere involvement
  in L2
• But Brocas area in polyglots is no larger than
  monolinguals (e.g. Sauerwein spoke 54 languages
  with a normal-sized Brocas area, Fabbro 2001)

47
Experimental inhibition(Ojemann Whitaker 1978)

• Dutch inhibited
• English inhibited
• Both inhibited
• Neither inhibited

48
Recovery of dead languages

• Case Grasset (1884). Patient knew only French.
  After stroke, he could speak only single words in
  Latin that he learned from Mass.
• Case Pötzl (1925). Classics professor suffered a
  stroke and was only able to express himself in
  dead languages (Latin ancient Greek), which he
  acquired through reading alone.

49
Bilingual representation

• Sometimes only one language returns
• not always L1
• Production, comprehension and translation
  separable, even within a language.
• Comprehension often spared in all languages
• Inconsistent evidence for macroscopic
  localization differences for multiple languages
  (VHS Mind 26)

50
PET vs Lesion data Why is PET data so much more
focal?
51
Individual Differences in Language Lateralization
52
(No Transcript)
53
(No Transcript)
54
Agnosia

• Greek for lack of knowledge
• Coined by Sigmund Freud
• Inability to recognize people or objects even
  when basic sensory modalities, such as vision,
  are intact.
• Modality-specific impairment

55
What Where Ventral and Dorsal Visual
Pathways

• Established with electophysiology, lesion,
  neuropsychology and neuroimaging data

56
What-Where Distinction
Object task Same objects? Spatial Task Same
locations?
57
Three Types of Object in the World

• Words Objects Faces
• Alexia Agnosias Prosopagnosia
• Recognition involved three (or four) stages of
  processing
• Sensory input
• Perception (able to form percepts)
• Categorization (able to associate percept to
  meaning)
• Identification (able to identify specific example)

58
(No Transcript)
59
Agnosia

• Apperceptive
• Object recognition failure due to perceptual
  processing
• Associative
• Perceptual processing intact but subject cannot
  use information to recognize objects

60
(No Transcript)
61
Apperceptive Agnosia

• Impaired global structure (gestalt) extraction
• Diffuse brain injury (CO poisoning)
• Intact acuity, brightness discrimination, color
  vision and other elementary capabilities
• Real images recognized better than illustrations
  motion better than static (more cues)

62
Gestalt Principles
63
Example of connectedness
64
Gestalt principles
65
Case D.F. (Milner Goodale, 1995)

• Classic Apperceptive Agnosic
• Severly impaired FORM perception
• Damage to V2, V3, V4-- Ventral Stream
• Intact abilities should reflect operation of
  dorsal stream

66
(No Transcript)
67
Dissociating What from How

• Orientation reports IMPAIRED
• verbal
• matching
• Posting behavior SPARED
• Implication Orientation shape representations
  available for guiding action

68
Associative Agnosia

• Impaired matching percept to memory
• Occipitotemporal damage
• Draw accurately without recognizing
• Identify objects through other modalities (touch,
  verbal description)
• Not perceptual except copying is slow and
  sequential

69
(No Transcript)
70
(No Transcript)
71
(No Transcript)
72
(No Transcript)
73
Prosopagnosia or Face Blindness
74
Prosopagnosia

• Specific inability to recognize faces
• Are faces and other objects in the world
  represented in fundamentally different ways in
  memory?
• Does face-memory depend on fundamentally
  different brain systems?

75
Are Faces Special?
76
Are Faces Special?

• Objects represented in parts and holistically
• Faces represented holistically

77
(No Transcript)
78
Prosopagnosia

• Impairment of identity of familiar faces
• Posterior artery (medial OT, right sided usually)
• Perception and categorization is intact. Patient
  can still determine gender, ethnicity, age,
  emotions, everything but identity
• Conscious recognition impaired
• Nonconscious (implicit) recognition intact in
  some GSRs, EPs, forced decision
• Are faces a unique set of stimuli? Or difficult
  to discriminate highly similar exemplars from
  each other (e.g., prosopagnosic farmer who
  couldnt recognize faces but could recognize his
  cows)

ISSUE Are faces and other objects in the world
represented in fundamentally different ways in
memory?
79
(No Transcript)
80
(No Transcript)
81
Single cell recording in IT
82
Other agnosias

• Auditory Agnosia
• inability to recognize specific sounds in the
  context of intact hearing.
• pure word deafness
• sound agnosia
• receptive amusia (agnosia for music).
• Somatosensory Agnosia (Astereognosis)
• difficulty perceiving objects through tactile
  stimulation though basic tactile sensation
  intact.
• Simultanagnosia, Inability to recognize a whole
  image although individual details are recognized.
  
• Color anomia can discriminate colors on tasks but
  cannot name colors or point to colors named by
  examiner. (color recognition problem, not color
  perception which is Central Achromatosia)

83
Alexia (with or w/o agraphia

• Impairment in letter recognition and reading
• OP damage
• Word blindness inability to read

84
Patterns of dissociation support this idea