4 - Aphasia Syndromes Flashcards
(66 cards)
In the connectionist model, what are the three layers of units?
Semantic features
Words
Phonemes
In the connectionist model, what does each word corresponds to?
A single unit in the word layer
In the connectionist model, what links words to their semantic features and phonemes?
Bidirectional Excitatory Connections
In the connectionist model, what is each word connected to?
(2)
Semantic features
Phonemes
In the connectionist models, what is lexical access achieved by?
Interactive Spreading Activation
In the connectionist model, when Semantic Units are ___________, this activation spreads throughout the ___________, and ultimately the sounds of the ___________ are retrieved.
Activated
Neural network
Intended words
What is the FIRST step in the connectionist model?
(4)
[Semantic Step/Lemma Selection]
Activation begins and spreads for a fixed amount of time
Bilateral Excitatory Connections activate all three network levels (phonemic: /k, a, t/; words: “cat”, semantic: “pet with claws, etc.”)
Semantic neighbors (“dog”) become activated due to shared semantic features
Phonemically similar words are activated due to shared phonemes (“mat,” “rat”)
(The word with the highest level of activation is from the most appropriate grammatical category)
What is the SECOND step in the connectionist model?
(4)
[Phonological Step/Phonological Encoding]
Chosen word from first step is activated
Activation Process becomes nonlinear allowing network to handle the arbitrary mapping between semantic features and phonemes
The phonemes with the highest activation are linked into slots in a phonological frame (number and kind of syllables, stress patterns)
This linking concludes phonological encoding.
When do errors in phonological encoding tend to occur?
What to these errors tend to result in?
Due to noise, one or more wrong phonemes are more active than those of selected word.
Typically results in nonword (e.g., “lat” for CAT) but can be form‐related words (e.g. “mat” or “sat” for CAT).
What are the five error patterns that can occur in the connectionist model?
Semantic (“dog”)
Formal (“mat,” “cap)
Mixed (“rat”)
Unrelated (“log”)
Nonword (“lat”)
What aphasia syndromes could appear from cortical damage?
(3)
Broca’s
Wernicke’s
Global
What aphasia syndromes could result from damage of an unknown origin?
Anomic
What aphasia syndromes could appear when there is damage to the fiber tracts?
(4)
Conduction
Transcortical motor
Transcortical sensory
Mixed Transcortical
What is the most frequently occurring aphasia?
Anomic
Besides Anomia, what other aphasia types are common?
Broca’s
Wernicke’s
Global
What type of aphasia account for 50% of cases admitted to acute stroke units?
(2)
Global
Nonclassified aphasias
When are Anomia, Brocas, Conduction, Wernickes, and Transcortical more frequent in patients?
When patients have single lesions
What are different names for Broca’s Aphasia?
(4)
Expressive Aphasia
Motor Aphasia
Anterior Aphasia
Non-fluent Aphasia
What are the characteristics of Broca’s Aphasia?
(5)
Non-fluent (Slow, laboriously and halting speech + frequent pausing between syllables, words)
Agrammatic output (telegraphic)
Comprehension relatively preserved (as opposed to expression)
Poor, nonfluent repetition
Preserved self monitoring
Why do patients with Broca’s Aphasia struggle with repetition?
Poor language and motor planning
How does Broca’s Aphasia affect writing?
(4)
Writing similar to verbal output
Agrammatic
Large letters
Function words are absent
In Broca’s Aphasia, what produces Chronic Agrammatic Aphasia?
(2)
Lesions in Broca’s areas that extend into anterior insula cortex + temporal and parietal regions
What is needed to produce Broca’s Aphasia?
Damage to deep regions
What is considered Little Broca’s?
Smaller lesions limited to Brodman Area 44 cause aphasia that resolves quickly
