Speech/Language Speech/Language Production IProduction I
• Common Features of Models– extensive pre-planning– distinct stages of processing– general (intended meaning)-to-
specific (utterance) organization– most models use of speech errors as
data
Spreading Activation Theory (Dell)
• four levels of activity– Semantic (meaning)– Syntactic (grammatical structure of words in the
planned sentence)– Morphological (basic units of meaning or word
forms)– Phonological (sounds)
• representation formed at each level• processing occurs simultaneously at all
levels• uses speech errors as primary data
Spreading Activation (cont’d)
• Lexicon: connectionist network containing nodes for concepts, words, morphemes, and phonemes
• Insertion rules (which is highest activated?) determine items selected for insertion into sentences
• Errors predicted by model:– Errors more likely when speaker has not formed a coherent
speech plan– Errors should be from same category– Anticipation errors (because of multiple activations; “The sky is in
the sky”)– Exchange errors (because once selected, items’ activation turns
to zero (“I hit the bat with my ball”)
Speech Production IISpeech Production II
• Levelt/Bock approach– four stages: message, functional
processing, positional processing, and phonological encoding
– information about syntax (lemma) available before sound (lexeme)
– consistent with TOT phenomenon
Semantic substitution (“tennis bat”), blending (“sky is shining”), word-exchange errors (“let the bag out of the cat”)
Morpheme exchange errors (“trunked two packs”), spoonerisms (“hissed my mystery lectures”) within same clause
Bock & Levelt (1984)
ERRORS
Selection of word concepts, grammatical constructionOrdering parts of sentence, adding inflectionPhonological and prosodic elements worked out
Intended meaning
Neuropsychological evidence of staged selection
• Content-word retrieval vs. syntactic processing
• Distinction between anomia (e.g., word selection difficulties) vs. agrammatism (inability to construct grammatically correct sentences)
• Jargon aphasia: can construct grammatically correct sentences but not find correct words
Processes in Writing Processes in Writing (Hayes & Flower, 1980)(Hayes & Flower, 1980)
• Planning: generating info from LTM, organizing
• Translating: producing language conforming in meaning to that retrieved in the planning stage
• Reviewing: editing what is written
Types of Disorders
• Aphasia: acquired disorder of language due to brain damage
• Dysarthria: disorder of motor apparatus of speech
• Developmental language disturbances• Associated disorders
– Alexia– Apraxia– Agraphia
Major Historical Landmarks
• Broca (1861): Leborgne: loss of speech fluency with good comprehension
• Wernicke (1874): Patient with fluent speech but poor comprehension
• Lichtheim (1885): classic description of aphasic syndromes
Syndrome
Symptom Deficit Lesion
Broca’s Aphasia speech production;
sparse, halting speech, missing function words,
bound morphemes
Impaired speech planning and production
Posterior aspects of 3rd frontal convolution
Wernicke’s Aphasia
Auditory comprehension, fluent speech, paraphasia, poor repetion and naming
Impaired representation of sound structure of words
Posterior half of the first temporal gyrus
Pure motor speech disorder
Disturbance of articulation, apraxia of
speech, dysarthria, aphemia
Disturbance of articulation Outflow from motor cortex
Pure Word Deafness
Disturbance of spoken word comprehension,
repetition also impaired
Failure to access spoken words
Input tracks from auditory cortex to Wernicke’s area
Transcortical Motor Aphasia
Disturbed spontaneous speech similar to BA; relatively preserved
repetition, comprehension
Disconnection between conceptual word/sentence representations and motor
speech production
Deep white matter tracks connecting BA to parietal
lobe
Transcortical Sensory Aphasia
Disturbance in single word comprehension with
relatively intact repetition
Disturbed activation of word meanings despite normal recognition of
auditorily presented words
White matter tracks connecting parietal and
temporal lobe
Conduction Aphasia
Disturbance of repetition and spontaneous speech,
phonemic paraphasia
Disconnetion between sound patterns and speech production
mechanisms
Arcuate fasciculus; connection between BA
and WA
Contemporary anologues of Lichtheim’s (1885) Aphasic SyndromesContemporary anologues of Lichtheim’s (1885) Aphasic Syndromes
Additional Aphasia Additional Aphasia SyndromesSyndromes
Syndrome Symptom Deficit Lesion
Anomic Aphasia single-word production,
marked for common nouns; repetition and comprehension intact
Impaired storage or access to lexical entries
Inferior parietal lobe or connections within
perisylvian language areas
Global Aphasia Performance in all language functions
Disruption of all/most language components
Multiple perisylvian language components
Isolation of the language zone
Spontaneous speech, comprehension, some
preservation of repetition; echolalia
common
Disconnection between concepts and both
representations of word sounds and speech
production
Cortex outside perisylvian association
cortex
Broca’s Aphasia
• Telegraphic, effortful speech• Agrammatism• Some degree of comprehension deficit• Writing and reading deficits• Repetition abnormal – drops function
words• Buccofacial apraxia, right hemiparesis
M.E. Cinderella ... poor ... um 'dopted her ... scrubbed floor, um, tidy ... poor, um ... 'dopted ... Si-sisters and mother ... ball. Ball, prince um, shoe ...
Examiner. Keep going.M.E. Scrubbed and uh washed and un...tidy, uh, sisters and
mother, prince, no, prince, yes. Cinderella hooked prince. (Laughs.) Um, um, shoes, um, twelve o'clock ball, finished.
Examiner. So what happened in the end?M.E. Married.Examiner. How does he find her?M.E. Um, Prince, um, happen to, um ... Prince, and Cinderalla
meet, um met um met.Examiner. What happened at the ball? They didn't get married at the
ball.M.E. No, um, no ... I don't know. Shoe, um found shoe ...
Wernicke’s Aphasia
• Fluent, nonsensical speech• Impaired comprehension• Grammar better preserved than in
BA• Reading impairment often present• May be aware or unaware of deficit• Finger agnosia, acalculia, alexia
without agraphia
C.B. Uh, well this is the ... the /dødøü/ of this. This and this and this and this. These things going in there like that. This is /sen/ things here. This one here, these two things here. And the other one here, back in this one, this one /gø/ look at this one.Examiner. Yeah, what's happening there?C.B. I can't tell you what that is, but I know what it is, but I don't now where it is. But I don't know what's under. I know it's you couldn't say it's ... I couldn't say what it is. I couldn't say what that is. This shu-- that should be right in here. That's very bad in there. Anyway, this one here, and that, and that's it. This is the getting in here and that's the getting around here, and that, and that's it. This is getting in here and that's the getting around here, this one and one with this one. And this one, and that's it, isn't it? I don't know what else you'd want.
Wernicke description of “Cookie Theft Picture”
Conduction Aphasia
• Fluent language• Naming and repetition impaired• May be able to correct speech off-
line• Hesitations and word-finding
pauses• May have good reading skills
Global Aphasia
• Deficits in repetition, naming, fluency and comprehension
• Gradations of severity exist• May communicate prosodically• Involve (typically) large lesions• Outcome poorest; anomic
Transcortical Aphasias
Transcortical Motor• Good repetition• Impairment in
producing spontaneous speech
• Good comprehension
• Poor naming
Transcortical Sensory
• Good repetition• Fluent speech• Impaired
comprehension• Poor naming• Semantic
associations poor
Associated Deficits
• Alexia without Agraphia– Impairment in reading with spared
writing
• Apraxia– Loss of skilled movement not due to
weakness or paralysis
Fundamental Lessons
• Language processors are localized• Different language symptoms can
be due to an underlying deficit in a single language processor
• Language processors are regionally associated with different parts of the brain in proximity to sensory or motor functions
What Language Disorders RevealWhat Language Disorders Reveal about Underlying Processes about Underlying Processes
• Pure Word Deafness: selective processing of speech sounds implies a specific speech-relevant phonological processor
• Transcortical Sensory Aphasia: repetition is spared relative to comprehension; selective loss of word meaning; some cases suggest disproportionate loss of one or more categories
What Language Disorders RevealWhat Language Disorders Reveal about Underlying Processes about Underlying Processes
• Aphasic errors in word production: reveal complex nature of lexical access– Phonological vs. semantic errors: independent vs. interactive
relationship?– Grammatical class: nouns vs. verbs (category specificity)
• Broca’s aphasia: syntax comprehension and production– Central syntactic deficit; loss of grammatic knowledge– Problems in “closed-class” vocabulary (preposition, tense
markers)– Limited capacity account– Mapping account (inability to map from parsing to thematic
roles)• Jargon Aphasia: can construct gramatically “better” sentences
than agrammatics, but can’t find words, producing neologisms; reinforces distinction between content and grammatical struture
Prosody
• Linguistic vs. nonlinguistic prosody• Evidence for hemispheric differences• Clinical syndromes
– Disturbances of comprehension• Auditory affective agnosia• Phonagnosia
– Disturbances of prosodic output• Aprosodias
Aphasia and the Semantic System
• Meaning stored separately from form• Models of representation in
semantics– Feature-based models (see
categorization)– Nondecompositional meaning
• Modality-specific semantic deficits: optic aphasia as an example
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