Language

1. Language Ref: Banich Ch 9 pp. 286-293

2. Language: Brain Regions

3. Aphasia Aphasia = language deficit resulting from brain damage • Two different “syndromes” result from damage to the two key areas: • Broca’s aphasia - damage to Broca’s area • Wernicke’s aphasia - damage to Wernicke’s area

4. Broca's Aphasia: Typical Features Production of speech: • In short fragments, with many pauses • Slowed, effortful • Poorly articulated • May be telegraphic: Jim Hurdle: "Ah... Monday... ah Dad and Jim Hurdle... and Dad... hospital. Two... ah... doctors... and ah... thirty minutes... and yes... ah... hospital. And er Wednesday... nine o'clock. And er Thursday, ten o'clock... doctors. Two doctors... and ah... teeth."

5. Broca's Aphasia: Typical Features Comprehension of speech: • Largely preserved When the doctor discussed what a relief the weather was compared with the cold, hard winter that they had been experiencing, Jim pulled his sweater tightly around himself and imitated a shiver.

6. Wernicke's Aphasia: Typical Features Production of speech: • Fluent, well articulated • Function words present • BUT often sounds “empty” of content • Word substitution errors: • phonemic paraphasias e.g. castle -> "cacksel" • semantic paraphasias e.g. camel -> "horse" • neologisms e.g. queen -> "robbli"

7. Wernicke's Aphasia: Typical Features Examples: You mean like this boy? I mean [noy], and this, uh [neoy]. This is a [kaynit], [kahken]. I don't say it, I'm not getting anything from it. I'm getting, I'm [dime] from it, but I'm getting from it. These were [eksprehsez], [ahgrashenz] and with the type of [mahnic] is standing like this... and then the... "Yes... well of course when they came there, I ... em... he came there, I didn't know... there and I didn't know anything for it, any... I suppose we were there, when I went 1 2 3 4 5 and looked there and said well so and so and so and so and so...”

8. Wernicke's Aphasia: Typical Features Comprehension of speech: • Impaired • Can't follow conversations • Can't obey simple commands • e.g. " Put the pencil on the card"

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

10. Two Problems with Classical Model • Problem 1: Predicted Patterns Never "Absolute“ • Broca's aphasics have some comprehension problems:e.g. Reversible sentence comprehension: “The boy is chasing the dog” "I have to pay attention more carefully to what people are saying now, because sometimes I miss things”

11. Two Problems with Classical Model Wernicke's aphasics have production problems: • Speech 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"

12. Two Problems with Classical Model Problem 2: Symptoms of each syndrome dissociate • Broca's aphasia: articulation problems vs. sentence comprehension impairment • Wernicke's aphasia: neologisms vs. semantic paraphasias

13. 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?

14. 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.

15. Current View of Language • Each of these components can become selectively impaired in aphasia • Some components located close together, so are more likely to be simultaneously affected • So, if you average across P’s, “syndromes” will emerge • BUT minor damage can affect just one component

16. 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

17. 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

18. 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

19. 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

20. 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…..

21. 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

22. 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...

23. 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?

24. 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

25. 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

26. 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…