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