Speech Production and Language Disorders: An Overview, Slides of Cognitive Psychology

Download Speech Production and Language Disorders: An Overview and more Slides Cognitive Psychology in PDF only on Docsity!

SPEECH

Speech/Language Production 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 (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 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

WEAVER++ (Word-Form

Encoding by Activation

and Verification)

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

Phonological

Dysgraphia

Deep

Dysgraphia

Language Disorders

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

C

M A

Lichtheim’s Model

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 Syndromes

Additional Aphasia Syndromes

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

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