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Disorders of Syntax and Morphology Ling 411 – 08 Goodglass 1993: Chapter 6.

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Presentation on theme: "Disorders of Syntax and Morphology Ling 411 – 08 Goodglass 1993: Chapter 6."— Presentation transcript:

1 Disorders of Syntax and Morphology Ling 411 – 08 Goodglass 1993: Chapter 6

2 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) REVIEW

3 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

4 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

5 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

6 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

7 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

8 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

9 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

10 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

11 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

12 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?

13 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

14 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

15 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

16 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)

17 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

18 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

19 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

20 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?

21 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

22 For perspective, A related problem: Imagery  Types of sensory imagery Visual Auditory Somatosensory  Cf. Motor imagery

23 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?

24 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?

25 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

26 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?

27 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

28 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

29 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

30  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

31 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

32 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

33 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

34 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

35 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

36 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

37 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

38 Subdivisions of Broca’s area  Broca’s area includes two different (but adjacent) Brodmann areasBrodmann areas BA 44 – Pars Opercularis BA 45 – Pars Triangularis  (Some people also include the Pars orbitalis, just inferior to the pars triangularis)

39 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

40 Subdivisions of Broca’s area  Another viewview

41 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

42 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

43 end


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