Aphasia Flashcards
What is ‘Aphasia’?
An acquired disorder of language production (i.e., after language has been fully acquired). May affect all modalities of speech together, or just separate ones.
NOTE that in Developmental spoken language deficits would be considered a specific language impairment (SLI) and should reflect failures to fully acquire the same component a the adult spoken language system.
Describe the symptoms of Broca’s aphasia
Broca aphasia is a NON-FLUENT aphasia characterised by:
– speech with many hesitations, pauses, and short phrases. Slow and laboured speech.
– phonemic paraphasias (substitution, addition, omission, or rearrangement of speech sounds in words)
– disturbed grammar (agrammatism). Often have trouble with functor words (e.g., pronouns, articles, prepositions) both when speaking (production) and when listening to others (comprehension).
– Preference for using nouns (names) and common phrases (less often use adjectives)
– MAY also have apraxia of speech (disruption in motor speech programming) and dysarthria (disturbances in muscular control – weakness, slowness, or incoordination – of the speech mechanism). It can be difficult to differentiate which is which!
- Ability to ‘get their messages across’.
- Language comprehension and reading are typically less impaired than speech.
Describe the Wernicke-Lichtheim Schema model of aphasia.
What are the problems with this model?
A model of aphasia, based on early neural findings (Broca, Wernicke). The model has two primary modules which are joined by a connection (arcuate fascicules) one for speech production (Broca) with ouputs via articulatory mechanism; and another for comprehension (Wernicke), with input via the auditory nerve. Each area could also send information to ‘ideation’.
This is a very basic model which takes a ‘syndrome-approach’, thus it doesn’t tell us much about the specific ways in which things can ‘go wrong’.
What benefit does a cognitive model of aphasia have over Wernicke-Lichtheim’s schema model?
The cognitive modelling provides a in-depth understanding of the processes involving in speech. This can be used to aid interpretation of impaired speech and to inform treatment.
Outline the basic cognitive model of spoken language production (as discussed in class! spoken picture naming)
- Visual recognition - visual processing.
- Semantic system - storage of knowledge about the word, such as features (e.g., 4 legs, pet etc) which increases activation for the word ‘dog’.
a. conceptual semantics (Amodal)
b. lexical semantics (Word definition specific)
[3. Lemma (lexical-syntactic) level e.g., determiners of countable vs mass nouns- could be considered part of the lexical system]
- Lexical system/ phonological output lexical (same as in reading i.e., amodal) (Word forms) - knowledge of letter to sound rules.
- Segment level (phonemes) - sometimes called phonological output buffer (word broken into its sound parts (i.e., D.O.G).
- Speech
Think about how children SPEAK first and then learn to read - to understand how semantics and phonological (sound) rules’ might become amodal.
What might occur if the ‘visual recognition’ module of the spoken-word-production model is impaired?
(What is it [broadly] termed, what are the symptoms, what kind of errors are likely to occur when naming pictures)
Technically, this part of the model is not really in the ‘language system’ just yet.
Visual agnosia:
- difficulty perceiving visual information
- May not be able to distinguish real and made-up objects (e.g., body of tiger with a cow head)
Error types:
- No response
- Visual errors (e.g., snake instead of laces)
- Visual - semantic errors (e.g., lion instead of tiger, but due to a misperception!)
- sensitivity to quality of the picture i.e., less clear pictures –> greater errors (more redundant information is helpful!)
What might occur if the CONNECTION between ‘visual recognition’ module and the ‘Semantic system’ module of the spoken-word-production model is impaired?
(What is it [broadly] termed, what are the symptoms, what kind of errors are likely to occur when naming pictures)
‘Optic Aphasia’ is deficit in access to semantic via the visual modality (i.e., able to see what they are looking at, but not able to activate the features of what they are looking at)
Symptoms:
- Naming impairment only for visually presented objects
- No impairment when auditory or tactile presentation of stimuli
- Visual recognition unimpaired but….
- access to intact semantics works partially or not at all
- May be able to access route semantic information
Error types:
- No responses
- Semantic Errors
- Semantic circumlocutions (describing what they are seeing)
What might occur if the ‘Semantic system’ module of the spoken-word-production model is impaired?
(What is it [broadly] termed, what are the symptoms, what kind of errors are likely to occur when naming pictures)
‘Semantic Deficit’
- Semantic representations are damaged
- Affects all modalities (Reflect that semantics is shared between modalities)
- e.g., semantic dementia
Error types:
- No response
- Semantic errors (animal instead of tiger, may be some relation to the actual word e.g., cat for dog)
- Semantic circumlocution (trying to describe it)
What kind of ‘words’ already have higher innate ‘activation’?
- Common words
- Words recently used (relevant to perseveration)
Describe how semantic errors and semantic circumlocutions may arise (e.g dog -> cat)
(possible breakdowns)
[activation]
- LOSS OF SEMANTIC INFORMATION due to impaired ‘semantic module’: May lose specific semantic information about Dog, for example, ‘barks’ - while retaining ‘pet’ ‘furry’ ‘4-legs’ – this combination of information may instead activate ‘Cat’!
- Impairment in the CONNECTION between semantic information and words: may have faulty connections, such that even if all ‘dog’ - related features are activation may still lead to ‘cat’ (features no longer map onto dog and therefore dog doesn’t activate the most, cat does)
What errors might occur if the CONNECTION between the ‘Semantic system’ and the ‘Lexical system’ (phonological word form) module of the spoken-word-production model is impaired?
Errors:
- If no word information accessible
- No response
- Semantic circumlocutions
- Semantic errors (i.e., best you can do is related) - If partial word form information available:
- There may be evidence that the person is partially getting to the word (e.g., dog), but not easily or enough (e.g., short word starting with ‘d’).
- perhaps produce grammatical, gender, countability etc
Note that if NOTHING was active strong enough, or the system can’t decide than you would get ‘no response’.
What errors might occur if the ‘Lexical system’ (phonological word form) module of the spoken-word-production model is impaired?
Symptoms and errors
Phonological representation itself is impaired (can’t represent the activated words in terms of what it sounds like)
- non-lexical language tasks intact such as: repetition, reading of regular words and non-words. (also will be able to do semantic tasks! e.g., matching)
Errors:
- No response
- Semantic Circumlocutions
- Mixed errors (e.g., melon for lemon) [phonological and semantically]
Describe how a ‘mixed error’ might arise. e.g., Dog -> Frog
Lost the representation of ‘dog’ within the lexical system. Get some activation of frog because it is semantically related, and also some of the sounds are the same.
What errors might occur if the ‘segment level’ (phonological output buffer) module of the spoken-word-production model is impaired?
Symptoms and errors
A post-lexical impairment
- sequence of phonemes cannot be held correctly in working memory
- also referred to as ‘phonological output buffer’ impairment
- affects all tasks where a spoken response is required
Errors:
- phonological errors, neologisms
- Exchange errors / errors involving position (lencil for pencil)
- Additions of same letter in the wrong place (e.g., pencin for pencil)
Describe the various ways the spoken-language model may breakdown resulting in errors in PHONOLOGY.
(Mixed errors, no response, phonological errors, phonological position errors, phonological searching, neologism)
- Phonological representation itself (word form stored in the lexical) - May lose the representation of ‘dog’ within the lexical system and instead retrieve ‘frog’ as its semantic relation and similar phonology lead to greatest activation.
- segment-level/phonological output buffer impaired –> despite getting to the word ‘dog’ (intact semantics and lexical) may then have difficulty activating the phonemes normally, may activate K- O-G.
- Connections between Segment level and phonological-lexicon.
