Transcript ling411-08-Grammar - OWL-Space

Ling 411 – 08
Disorders of Syntax and Morphology
Goodglass 1993: Chapter 6
REVIEW
Extra-Sylvian Aphasic Syndromes
and repetition
 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)
Major Language Areas
REVIEW
Supramarginal gyrus
(Goldstein’s area) Angular gyrus
Wernicke’s area
(Geschwind’s area)
Exner’s
area
Broca’s
area
Agrammatism
 Generally present in Broca’s aphasia
 Usually associated with Broca’s aphasia
 But other aphasics also have grammatical dysfunctions
• Paragrammatism – common in Wernicke aphasia
 A lot of variation among different patients
Agrammatism: an early observation (1819)
 Deleuze (1819), referring to a French-speaking
patient: The patient “used exclusively the
infinitive of verbs and used no pronouns. …
She produced absolutely no conjugated verb.”
Goodglass 1993: 104
Agrammatism vs. Paragrammatism
 Paragrammatism – too much speech
• Normal or excessive fluency
• Use of inappropriate words
• Neologisms
• No lack of function words and inflections
 But not always used appropriately
• Common in Wernicke’s aphasia
 Agrammatism – not enough speech
• Lack of fluency
• Omission (NOT deletion!*) of function
words and inflections
• Common in Broca’s aphasia
*Next slide
Omission vs. Deletion
 Goodglass (106):
• Sentences with a deleted main verb (“Joan and I
. . . Coffee”) may continue to appear.
• . . . misuse or deletions of morphology . . .
 Is he talking about deletion or omission?
 Deletion implies that it was first there, and then
removed
 Omission – it wasn’t put in at all
 Goodglass is following a practice that was common
among linguists at the time he wrote the book
Broca’s Aphasia
 Damage to frontal lobe
• Mainly, inferior frontal gyrus
 Largely intact comprehension
 Nonfluent, agrammatic speech
 “Telegraphic speech” –
• Abundance of content words (e.g., nouns)
• Lack of function words (e.g. prepositions)
 Impaired verb processing
• Bates, Chen, Tzeng, Li & Opie, 1991; Damasio
& Tranel, 1993; Daniele, Giustolisi, Silveri,
Colosimo & Gainotti, 1994; Lamb & Zhang,
2010; Shapiro & Caramazza, 2003
Subtypes of Broca aphasia
(acc. to Benson & Ardila)
REVIEW
 Type I
• A.k.a. little Broca aphasia
• Milder defects
• Less extensive damage
• Better prognosis
 Type II
• Symptoms worse
• More extensive damage
 These are not distinct, but variations
• Two spans along a scale
Example of agrammatic speech
Examiner: Can you tell me about why you came back to the
hospital?
Patient: yes … eh … Monday … eh … dad … Peter Hogan and
dad … hospital.
Er … two … er … doctors … and … er … thirty minutes …
and ... er … yes … hospital. And … er … Wednesday …
Wednesday. Nine o’clock. And … er … Thursday, ten o’clock
… doctors … two … two … doctors… and … er … teeth … fine.
E: Not exactly your teeth … your gP: Gum … gum …
E: What did they do to them?
P: And er … doctor and girl … and er … and er gum …
Goodglass 1993: 107
Some features of agrammatism
 Telegraphic speech
• Short utterances
• Omission of grammatical functors
 Relative abundance of substantives
 Verbs are uncommon, rare in some patients
• When present, uninflected or –ing form
 For French aphasics, infinitive form
 Use of word order is generally spared
 Comprehension is impaired for complex sentences
Verbal short-term memory deficit
(in Broca aphasia)
 Patients can readily point to individual objects
or body parts named by the examiner
 But when asked to point to the same items in a
specific sequence they often fail at the level of
only two or three items
Benson & Ardila 124
How to explain?
Problems in the study of agrammatism
 Must be distinguished from paragrammatism
 Grammatical aberrations – even among Broca
aphasics – vary from patient to patient
 Linguistics has not (yet) provided clear
answers to important basic questions:
• What normal grammatical functions are
• How they operate
Syntax
 First, we need to dispel the notion that syntax is
one capacity, that can be lost (or spared) as a unit
 Syntax can be understood as a set of
constructions
• Learned by children (and others) one by one
 Like vocabulary
• Some can be lost, others spared, in aphasia
 It is a label of the grammarian for multiple things
 Word order is often spared in Broca’s aphasia
while a lot of syntax is lost
Stability of word order in agrammatism
 Agrammatic patients can usually handle word
order in both production and comprehension
 Evidence (comprehension)
• Passive sentences misconstrued
• The horse was kicked by the dog
 Broca’s aphasic: horse as kicker
 Passive marker not apprehended
• Canonical word order guides the interpretation
 Possibly aided by conceptual knowledge
Reading and writing in agrammatism
 Agrammatic difficulties are also seen in
• Oral reading
• Writing to dictation
• Repetition
 But:
• Some patients are agrammatic in speech but not in
writing (Goodglass 1993: 110)
• Some can repeat correctly
• How to explain?
 Menn & Obler (1990) describe some patients who are less
agrammatic in oral reading than in spontaneous speech
(Goodglass 1993:111)
Variation among agrammatics
(Goodglass 1993:107)
 Syntax and morphology (study of agrammatic
French aphasics)
• Some patients have fairly good syntax but defective
morphology
• Some patients have fairly good morphology but
defective syntax
• Both types of patients fail to use inflected verb forms
 Gleason et al. observations (1975)
• Some patients use –s plural marker but not articles
• Other patients use articles but not –s plural marker
Loss of the use of relational markers
in receptive agrammatism (118)
 E.g. father’s sister
• Ex: Is “my father’s sister” a man or a woman?
• Patient answers randomly
 Unable to grasp the relational function of –’s
 Command given in testing:
• Ex: Touch the comb with the pencil
• Patient may touch the pencil with the comb
 Perhaps picks up comb because the word
comb comes first in the instruction
 Locative relations somewhat less fragile
• in back of/in front of, over/under, before/after
Linguistic structure in the cortex:
What we learn from agrammatism
 Agrammatism is generally associated with Broca’s aphasia
 Therefore, the grammatical skills lost in Broca’s aphasia
must be supported at least in part by either
• Broca’s area, or
• Area(s) adjacent to Broca’s area
 In other words: There must be something in or near Broca’s
area that is essential for correct grammatical production
• And grammatical comprehension –
 Receptive agrammatism
Receptive processing in Broca’s aphasia?
 Problem:
• Broca’s area is in frontal lobe
• Frontal lobe is supposed to be for motor production
 Motor production is top-down processing
• Receptive functions involve bottom-up processing
 Usually found in posterior cortical areas
• Comprehension involves receptive processing
 in frontal lobe?
• Bottom-up (receptive) processing in frontal lobe?
Receptive agrammatism in Broca’s aphasia
Two avenues to explanation
1. The role of short-term memory, and Broca’s area in
short-term memory
2. Maybe the frontal lobe can have receptive function
• To explore this possibility we must first examine the
phenomenon of imagery
For perspective,
A related problem: Imagery
 Types of sensory imagery
• Visual
• Auditory
• Somatosensory
 Cf. Motor imagery
Visual Imagery
 Visual images of people, buildings, etc.
• What is a visual image?
 What does it consist of?
• Is it a little picture in the brain?
 If so, where are the eyes to see it?
 What is it drawn on?
 Where is the visual perception
system to interpret it?
• If not, what?
Auditory Imagery
 Auditory images of words, music, etc.
• We can hear things in our heads
• What is an auditory image?
 What does it consist of?
• Sound?
 There is no air inside the head to vibrate
 What hears it?
• Little ears inside the head?
How Imagery Operates
 It’s unlikely that visual imagery uses some mechanism
independent of that for vision
 Therefore, it must use (some of) the same neural
connections used in perception
• For visual imagery, pathways in the occipital lobe
• For auditory imagery, pathways in the temporal lobe
• For tactile imagery, pathways in the parietal lobe
 Imagery is activation of some of the same neural pathways
that get activated upon receiving input from sense organs
Anatomical consequences
 Consequences of imaging explanation
• Top-down processing in perceptual areas
• Perceptual pathways must have parallel
pathways of opposite direction
 Why are imagined scenes less vivid than those
resulting from input to the eyes?
Bidirectional Processing
 Imagery requires top-down processing
• Using pathways that typically operate bottom-up
 Therefore, perceptual pathways must generally be
bidirectional
 Anatomical evidence supports the hypothesis
• Reciprocal pairs of cortico-cortical axons
Bidirectional Connections
 Most corticocortical connections are
bidirectional
 An established finding from neuroanatomy
 It’s not because the connecting nerve
fibers (axons) are themselves bidirectional
 It’s because we find different but roughly
parallel fibers going in opposite directions
Bidirectional Processing in Frontal Lobe?
 Frontal lobe processing: typically top-down
 But there is a large amount of uniformity in cortical
structure
 Hypothesis: Bottom-up processing also in frontal lobe
• From perceptual (i.e. posterior) areas to locations in
frontal lobe
• We already have seen evidence: the arcuate fasciculus
Bidirectional connections in frontal lobe
 Would explain how Broca’s area is involved in
receptive grammatical processing
 Would account for the finding that interpretation
of prepositions and verbs is a frontal lobe function
• Finding from the study of agrammatism
Attempts to explain agrammatism
 Many theories have been proposed
• Cf. Goodglass 1993:111ff
 Some intriguing ideas
• Loss of relational use of words (Jakobson, Luria)
 Difficulty with markers of such relationships
• Impairment of inner speech (Luria)
 Hence, impairment of auditory working memory
• Difficulty with unstressed words (Goodglass, Kean)
 Substantive words are commonly stressed
 Functors are generally unstressed
Caution in interpreting
 Agrammatism may not be just one phenomenon
• Syntax is not one structure but several
• All agrammatics and probably all Broca’s aphasics
are deficient in use of verbs
• Other phenomena of agrammatism show more
variability
 The problem (or part of the problem) may not be
grammar as such:
• Syntax revolves around verbs
 So maybe the problem is with the verbs
• Short-term memory – the inner speech loop
• Phonology: stressed vs. unstressed words
Phonological factors
 Function words are (in general) unstressed
 Maybe the difficulty is in production of unstressed words
 Intriguing finding of Goodglass et al.
• (See Goodglass 1993:114-115)
• Function words
 More likely to be produced after a stressed word
 But almost never produced initially
• Production starts with stressed word
• Even when the patient is asked to repeat:
 Open the door > Open the door
• Patient repeats correctly, including ‘the’
 The door is open > Door is open
• Same patient omits ‘the’ in repetition
More evidence on relational markers (119f)
 Grammatical particles that do not mark relations are
exempt from omission
• and
• Japanese clause-final particles
 Emphatic yo
 Question marker ka
 Confirmation-seeking particle ne
 Verbs always have a syntactic implication
• I.e. relationship to one or more nouns
 Menn & Obler: Impairment affecting grammatical
elements that mark relationships within the sentence
Nouns and Verbs:
Back Brain & Front Brain (?)
 “A Neurolinguistic Universal” –Eliz. Bates
• Verb deficit in Broca’s aphasia
• Noun deficit in Wernicke’s aphasia
 Suggests that
• Verbs are represented in frontal lobe
• Nouns are represented in or near temporal lobe –
angular gyrus and/or supramarginal gyrus) and/or
middle temporal gyrus
 Supported by semantic considerations
• Prototypical nouns represent perceivable objects
• Prototypical verbs represent activities of body
Proceed with Caution!
 We already know that a noun or a verb has a
complex cortical representation
 Therefore it is not in a single location
• The representation is complex, therefore is
distributed among multiple locations
 So what are we talking about when we talk
about nouns and verbs having a location?
 This problem will require further investigation
• Meanwhile, smthg to think about
Verb deficit and agrammatism: Why?
 Syntactic hypothesis
• Verbs are by their nature syntactically complex
• Nouns are not complex – they can stand alone
 Semantic hypothesis
• Verbs represent processes and processes are
managed by the frontal lobe
• Nouns represent things, and things are known
mainly through perception, which is managed
by the occipital, temporal, and parietal lobes
Subdivisions of Broca’s area
 Broca’s area includes two different (but
adjacent) Brodmann areas
• BA 44 – Pars Opercularis
• BA 45 – Pars Triangularis
 (Some people also include the Pars orbitalis,
just inferior to the pars triangularis)
Frontal Operculum
 Operculum: little cover
 The part of the frontal lobe that covers (part
of) the Sylvian fissure and anterior insula
 Adjacent to and inside the anterior portion
of Sylvian fissure
 Opposite it (across Sylvian fissure) in
temporal lobe is the temporal operculum
Subdivisions of Broca’s area
 Another view
Broca’s area and Broca’s aphasia
 Broca’s original patient
• Lesion was extensive
• Not just Broca’s area but also
 Adjacent areas
 Subjacent white matter
 A tradition has followed Broca
• Broca’s area held responsible for
symptoms of Broca’s aphasia
• Confounding factor:
 Broca’s area is usually only part of the
area of damage in Broca’s aphasia
Broca’s area and grammar
Conclusions
 Evidently, Broca’s area or an area adjacent to Broca’s area
is responsible for
• Not only phonological productions, but also
• Critical grammatical functions
 Both in production and in understanding
• Understanding of complex syntax
• At least some portion/aspect of verb processing
• Also, prepositions and other “function words”
 But not non-relational “function words” (‘and’)
 The situation is evidently very complicated and not well
explained
end