26.4 - Communication: Producing and Understanding Language

Question 1

What are 3 important types of information found in language?

Answer 1

• Phonology = Sounds of words
• Semantics = Meaning of words
• Grammar = Combinatorial rules (syntax)

Question 2

What aspect of human language can animals not learn?

Answer 2

They can learn individual words, but they cannot learn syntax.

Question 3

What is recursion?

Answer 3

Embedding linguistic units within each other in a sentence.

Question 4

Is language unique to humans?

Answer 4

Yes, but it relies on other parts of cognition (e.g. memory) that are shared with other animals.

Question 5

Are there currently any animal models of language?

Answer 5

No

Question 6

What is lexicon?

Answer 6

Total set of all words in a language

Question 7

What is aphasia?

Answer 7

The inability to comprehend or formulate language because of damage to specific brain regions.

Question 8

What can cause aphasia?

Answer 8

Stroke/ Tumour/ TBI

Question 9

What are the classic aphasias?

Answer 9

• Broca’s aphasia (non-fluent/ productive)
• Wernicke’s aphasia (fluent/ receptive)
• Conduction aphasia

Question 10

What is non-fluent aphasia and what causes it?

Answer 10

• Lesions of Broca’s area - deficits in speech production
  
  • difficulty finding words/ grammar
• Features:
  
  • Disjointed speech
  • Uses mostly content words (nouns, names, etc.), not many function words
  • Poor articulation, but this is not consistent between patients so it is not a motor problem
  • Repetition of speech is impaired
  • Patients struggle to find words or name objects
  • Comprehension is spared, but have problems understanding syntax (i.e. may struggle with certain sentence structures)
  • Patient is aware of deficit

Question 11

Where is Broca’s area?

Answer 11

Left inferior frontal gyrus (Brodmann areas 44 and 45) of left cerebral hemisphere

Question 12

What is fluent aphasia and what causes it?

Answer 12

• Lesions of Wernicke’s area - deficits in comprehension
• Features:
  
  • Fluent speech
  • Impaired comprehension
  • Repetition of speech is impaired
  • Normal articulation
  • Grammatically correct sentences without meaning
  • Patient is unaware of deficit

Question 13

Where is Wernicke’s area?

Answer 13

Posterior part of superior temporal gyrus (Brodmann area 22) of left cerebral hemisphere

Question 14

What are some types of errors that patients with Wernicke’s aphasia may make?

Answer 14

• Semantic paraphasia -> When an entire word is substituted for the intended word (e.g. orange instead of apple)
• Phonemic paraphasia -> When part of a word is substituted with a non-word that preserves at least half of the segments and/or number of syllables of the intended word (e.g. wife instead of knife).
• Neologisms -> Making up a word.

Question 15

What aphasia is hemiplegia associated with?

[EXTRA]

Answer 15

• Hemiplegia is paralysis on one side of the body.
• It causes weakness, problems with muscle control, and muscle stiffness.
• It is more commonly associated with non-fluent (Broca’s) aphasia, because Broca’s area is much closer to the motor cortex, so it is more likely to be lesioned too.

Question 16

Describe how limits of comprehension in a patient with non-fluent (Broca’s) aphasia. Give some experimental evidence.

Answer 16

• Although patients with lesions in Broca’s area generally have relatively normal comprehension, they are impaired at syntactic processing due to their problems with grammar
• Much like with their use of mostly content words in speech, they also struggle to understand grammar (e.g. some tenses) when listening
• (Caramazza & Zurif, 1976):
  
  • Presented patients with three simple sentences like “the boy ate the apple”, “the boy kissed the girl” and “the boy was kissed by the girl”
  • The patients understood the first two sentences, since they can understand the subject words and can infer the meaning from the word order and logic
  • However, they struggle to understand the third sentence due to the passive voice
  • The two explanations are:
    
    • The object of the verb has moved (Trace-deletion hypothesis, Grodzinsky, 1990)
    • There is a lack of working memory to process this syntax

Question 17

Describe a model of the of the language systems in the brain (derived from observations of patients with aphasia).

Answer 17

Geschwind model (1960s) explains that when speaking a heard word:

• Auditory cortex passes auditory information to Wernicke’s cortex
• Wernicke’s cortex accesses the meaning of the word
• Wernicke’s area communicates with Broca’s area via the arcuate fasciculus
• Broca’s area stores motor information associated with that word and outputs to the motor cortex
• This leads to the speech of that word

Question 18

What is the dual stream model?

Answer 18

*Dorsal Stream - normally left lateralised.
- network for articulation + sensory motor
- auditory-motor integration
*Ventral Stream - weakly left lateralised
- maps sound to meaning of speech
- lexical interface.
*Bilateral processing links the two streams.

Question 19

How is semantic memory involved in language?

Answer 19

ability to connect words with their meaning.

Question 20

How is WM involved in language?

Answer 20

*understanding speech when there is a lot of background noise
*coherence of ideas and the following through of a thought pattern
*important aspect of comprehension, especially while reading as an internalised form of language generated by visual, rather than spatial, aspects in a convergence of the cortical areas.

Question 21

How is procedural memory involved in language?

Answer 21

enables speech with the correct phonology and grammar (pausing/ stresses)

Question 22

How is priming involved in language?

Answer 22

one word triggers access to words with similar semantic meaning

Question 23

Give some experimental evidence for the lesion that causes conduction aphasia.

[EXTRA]

Answer 23

(Buchsbaum, 2011):

• Mapped the areas of lesion in patients with conduction aphasia and found the most common areas of overlap
• Mapped the active areas in healthy patients performing a phonological working memory task
• The area that was most overlapping between the two groups was determined to be Area Spt (which is involved in phonological working memory)

Question 24

What is conduction aphasia?

Answer 24

Lesion of articulate fasciculus
*Impaired speech repetition
*Otherwise normal speech production and comprehension
*also impairments in self-monitoring of speech (Lose track/ tangents)

Question 25

What is primary progressive aphasia?

Answer 25

Neurodegeneration of the language network characterised by:

• Impaired usage, retrieval or comprehension of words (aphasia)
• Language disorder is the principal deficit (primary)
• Neurodegenerative (progressive)

Question 26

Are the aphasias static?

Answer 26

No, there can be a mix of different aphasias after a brain injury and symptoms can change.

Question 27

What are 3 variants of primary progressive aphasia?

Answer 27

• Progressive Non-Fluent/Agrammatic Aphasia (PNFA) -> Non-fluent
• Semantic Dementia (SD) (a.k.a. fluent) -> Fluent
• Logopenic Progressive Aphasia (LPA) -> Slow speech due to struggle to find words

Question 28

Compare the symptoms of PNFA (progressive non-fluent/agrammatic aphasia) and SD (senile dementia).

(i.e. compare non-fluent vs fluent primary progressive aphasia)

Answer 28

Question 29

What are the symptoms of the semantic variant of primary progressive aphasia?

Answer 29

*Progressive loss of ability to connect words to their meaning.
*Fluent speech and grammar normal

Question 30

What are the symptoms of Progressive, non-fluent aphasia?

Answer 30

*Problems w/ word finding (anomia)/ articulation (dyspraxia)/ grammar (dysarthria)
*Halting, non-fluent speech lacking grammar

Question 31

Describe the symptoms of LPA (logopenic progressive aphasia).

Answer 31

*Anomia (problems with word finding) –> long word-finsing pauses.
*Poor phonological STM (Struggle w/ word/ digit span tasks)
*Poor repetition (ok for short words)
*Normal articulation/ grammar.

Question 32

Summarise the patterns of atrophy in different types of primary progressive aphasia. Give some experimental evidence.

Answer 32

(Gorno-Tempini, 2004):

• Mapped the areas of the brain that were most commnoly atrophied in NFPA, SD and LPA
• NFPA featured atrophy of the left inferior frontal and insular cortex
• SD featured atrophy of the anterior temporal lobes
• LPA featured atrophy of the posterior temporal lobe and inferior parietal lobule

Question 33

Give some experimental evidence for syntax processing in different types of primary progressive aphasia.

[EXTRA?]

Answer 33

(Wilson, 2010):

• Tested the comprehension of different sentences in patients with NFPA and LPA
• Patients with NFPA showed the greatest inaccuracy when presented with sentences with a complex syntax (e.g. passive tense)
• Patients with LPA showed the greatest inaccuracy when presented with long sentences
• This suggests that NFPA features impairment of syntactic processing, while LPA features cognitive memory deficits

Question 34

Is it just grey matter that is affected in primary progressive aphasia?

Answer 34

No, it can also be the white matter, especially the dorsal pathways (arcuate fasciculus) between language areas.

Question 35

Summarise the main ways in which syntactic processing (i.e. understanding sentence structure) may be impaired in aphasias.

Answer 35

• Syntactic processing impaired in non-fluent (Broca’s) aphasia and non-fluent PPA
• Disconnection of arcuate fasciculus or damage to posterior STG (or both) impairs phonological working memory (conduction aphasia)
• Arcuate fasciculus function correlates with syntactic comprehension in PPA

Question 36

Summarise the role of Broca’s area and Wernicke’s area.

Answer 36

• Broca’s area is involved in speech production
• Wernicke’s area is involved in language comprehension

Question 37

How can you remember each of the PPA disorders?

Answer 37

• NFPA is essentially like Broca’s aphasia
• SD is essentially like Wernicke’s aphasia
• LPA is essentially like conduction aphasia

Question 38

What is a Specific Language Impairment (SLI)?

Answer 38

• AKA developmental language disorder, impairment, or dysphasia.
• Identified in children when there is an unexplained and language-specific impairment compared to other children the same age.
• A subset of SLI’s may also be associated with more general (non-language) perceptual impairments, specifically a disorder of rapid auditory temporal processing and/or magnocellular visual function. Some children show improved language function after training in these perceptual skills.
• Associated with reduced structural and functional left hemisphere asymmetry in frontal language brain regions.

Question 39

Who are the KE family?

Answer 39

• KE family in the UK (Watkins et al., 2002):
  
  • Approx. 50% of family affected w/ language comprehension + articulation problems
  • Reduced grey matter in Caudate Nucleus and increased in Putamen.
    *Genotyping –> single point mutation of FOXP2 gene on chromosome 7

Question 40

What is dyslexia?

[IMPORTANT]

Answer 40

• Dyslexia is trouble with reading despite normal intelligence
• The causes may be developmental or acquired
• Posterior parietal cortex lesions may be causes of acquired dyslexia. This is due to its role in the direction of attention, as is necessary for reading and speech in particular.

Question 41

What are the different theories of language development?

Answer 41

*Nativism - Humans are hard-wired to acquire
language from infancy. Universal Grammar (Chomsky): a
set of constraints for organizing language.
*Behaviourism - Language is largely acquired during
development through experience.

Question 42

How does language develop between 0 and 12 months?

Answer 42

*Auditory system reaches full maturation at 32 weeks gestation
*6 months - language specific perception of vowels
*9 months - start producing language specific speech
*12 months - language specific consonant perception
Decline in ability to perceive sounds not in native language –> why there are accents.

Question 43

What are the properties of language?

Answer 43

Question 44

Which hemisphere is commonly associated with language, how do we know?

Answer 44

Left
*Wada test –> common carotid on one side injected with sodium amytal which temporarily decreases activity in associated hemisphere –> deficits can be seen in language.

if LH, 50/50 between left and right hemisphere.

Question 45

What is verbal dyspraxia?

Answer 45

difficulty placing muscles in correct place to produce speech

Question 46

What is verbal dysarthria?

Answer 46

Weakening of muscles used to produce speech.

Question 47

What are deficits seen with language in autism?

Answer 47

Problems w/ language and comprehension (spectrum) but don’t struggle with grammar.

Question 48

What language deficits can be seen with dyslexia?

Answer 48

Children struggle to gain skills involved in accurate reading and spelling
Sometimes difficulty perceiving speech and chronology of sound.

Question 49

What are developmental language disorders?

Answer 49

Language difficulties that cause problems in everyday life.
*Affecting language production and comprehension
*Language is the primary deficit