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Language

Language. Ref: Banich pp. 361-364. Broca's Aphasia: Typical Features. Slowed, effortful speech, with many pauses Poor articulation Speech may be telegraphic Comprehension largely preserved. Wernicke's Aphasia: Typical Features. Fluent, well articulated speech, function words

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Language

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  1. Language Ref: Banich pp. 361-364

  2. Broca's Aphasia: Typical Features • Slowed, effortful speech, with many pauses • Poor articulation • Speech may be telegraphic • Comprehension largely preserved

  3. Wernicke's Aphasia: Typical Features • Fluent, well articulated speech, function words • May sound “empty” of content • Word substitution errors: • phonemic paraphasias e.g. castle -> "cacksel" • semantic paraphasias e.g. camel -> "horse" • neologisms e.g. queen -> "robbli” • Comprehension impaired

  4. Classical Model of Language • Broca's area = production ("articulatory images" of words) • Wernicke's area = comprehension ("auditory images") • Info is transmitted between the two:

  5. Two Problems with Classical Model • Predicted Patterns Never "Absolute“ • Symptoms can dissociate • e.g. Wernicke's aphasia: neologisms vs. semantic paraphasias

  6. Current View of Language • Linguistics and Cognitive Psychology: language seen as a complex hierarchical system. • Can describe language at a number of levels: • Phonological: what are the basic phonemes (sound units) used to build words? • Syntactic: what are the rules for combining words into sentences? • Semantic: what are the meanings of words, and how does meaning change when words are combined in sentences?

  7. Current View of Language • By this view, speech production and comprehension not unitary processes, but involve multiple components. For example: • Production = syntactic planning, word selection, retrieval of phonemes, articulatory programming • Comprehension = auditory processing, access to word meanings, syntactic processing.

  8. Current View of Language • For many individuals, syndromes don’t work • Therefore, some researchers now prefer the terms Fluent and NonfluentAphasia: Nonfluent aphasia: • Anterior damage (usually) • Covers Broca’s aphasia, as well as P’s with just one or two features Fluent aphasia: • Posterior damage (usually) • Covers Wernicke’s aphasia, as well as P’s with just one or two features

  9. Some Language Components All of these can become selectively impaired: • Anterior (around Broca’s area): • Articulation of speech • Understanding syntactic relationships • Posterior (around Wernicke’s area): • Retrieval of phonemes for production • Selection of words for production • Access to semantic info about words

  10. Some Language Components All of these can become selectively impaired: • Anterior (around Broca’s area): • Articulation of speech • Understanding syntactic relationships • Posterior (around Wernicke’s area): • Retrieval of phonemes for production • Selection of words for production • Access to semantic info about words

  11. i. Articulation of speech • Function of this Component: • Generation of motor programs or articulating words • Location: • Overlaps with Broca’s area • Effects of Damage: • Speech is halting, effortful • Words may sound distorted • P knows the sounds in words, but can't articulate

  12. ii. Retrieval of phonemes • Function of this Component: • Retrieval of stored info. about the sounds that make up words • Location: • Posterior: close to (partially overlapping?) Wernicke’s area • Effects of Damage: • P can articulate well • BUT don't know which sounds to articulate • Phonemic paraphasias in all speech situations…..

  13. ii. Retrieval of phonemes (cont.) Examples of phonemic paraphasias: um.. tornet, no that's not right.. t-.. turry-.. no.. turkey.. no... oh gosh.. tur-.. turk-... turking.. that's wrong what's the end part?.. um.. I can't remember... other examples: castle -> cacksel apron -> aben refrigerator -> redjerfredjer

  14. iii. Access to semantic info • Function of this Component: • Accessing word meanings • Involved in both production and comprehension • Location: • Posterior -> temporal lobe, some overlap with Wernicke’s area • Effects of Damage: • P can’t define words • Can’t match a word to its meaning • Semantic paraphasias in speech...

  15. iii. Access to semantic info (cont.) a. Poor word definition: bed: "Bed, bed, I don't know what that is" swan: "Swan, that sounds familiar, I'm sure I once knew it“ b. Failure at word-picture matching: Which is a picture of a newspaper?

  16. iii. Access to semantic info (cont.) c. Semantic paraphasias in speech and naming: That’s some kind of animal, isn’t it. A seal, is it? other examples: camel -> horse son -> daughter walking -> running

  17. Anterior vs. posterior language areas • This is broken here! e.g. phoneme retrieval - posterior region, but affects output more examples in later lectures… • How do we explain this? • The general rule: • Anterior = output • Posterior = input

  18. Anterior vs. posterior areas (cont.) Anterior regions are involved in: Generation of new combinations e.g. sentences (novel combinations of words) articulation (must be done afresh each time) • Posterior language regions (LH) are involved in: • Storage/retrieval of familiar, well-learned relationships • e.g. phoneme sequences of common words • meanings of common words More about anterior/posterior differences in upcoming lectures…

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