disorders of syntax and morphology ling 411 – 08 goodglass 1993: chapter 6
TRANSCRIPT
Disorders of Syntax and Morphology
Ling 411 – 08
Goodglass 1993: Chapter 6
Extra-Sylvian Aphasic Syndromesand 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)
REVIEW
Major Language Areas
Superior parietal lobule
Exner’s area
Broca’s area
Wernicke’s area Angular gyrus(Geschwind’s area)
Supramarginal gyrus (Goldstein’s area)
REVIEW
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)
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
REVIEW
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 g-P: 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 aphasiaTwo 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
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
Bidirectional connections in frontal lobe
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 grammarConclusions
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