8 - Language and Aphasia Flashcards
What is aphasia?
An *acquired* neurological condition whereby *language* processing is disturbed as a result of regional brain dysfunction .
Language refers to a system of communication that utilizes a variety of arbitrary symbols (letters and sounds) to convey meaning
Aphasia is not….
- Speech motor disorders
- Mutism
- Disorders of language seconary to primary thought disorders
- Isolated sensory-perceptual or motor impairments
- Developmental disorders of language
****If a patient can write, they do not have aphasia
What is the most common cause of aphasia? What are other causes? What are transient causes?
Most common: stroke
Others: TBI, brain tumor, abscess or infection, demyelinating condition, neurodegenerative conditions.
Transient: seizure, transient ischemic attack, complicated migraine
What is the most common side of lesions that cause aphasia? Who is aphasia less severe in usually?
Usually lesions to the L hemisphere (95% of right hangers and 60-70% of L handers are left hemisphere dominant)
Tends to be less severe in L handers that get it following R hemisphere damage (opposed to R handers with L hemisphere damage).
What are the five subcomponents of language?
- Phonology - organization of sounds in language; characteristics of speech sounds.
- Orthography - rules governing writing; spelling system of language.
- Semantics - word meaning
- Syntax - sentence level word organization
- Pragmatics - contributes to context; social aspects, humor/sarcasm
What is the function of the red and yellow regions?
Red - semantic storage and retrieval in the inferior temporal lob, near the angular gyrus, and in the dorsomedial prefrontal cortex.
Yellow - auditory worm form processing in the superior temporal gyrus.
What is the function of the green, dark blue, and light blue regions on the image?
Green - general verbal retrieval and selection: frontal lobe near triangular gyrus
Dark blue - phonological access and output: posterior portion of the temporal lobe
Light blue - visual word form processing: ventro-occipito-temporal region.
Where is the region for orthography located within the brain? What is the function of this region?
Visual word form area.
Located in the ventro-temporal-occipital region.
Where is the region of the brain involved in phonology? What is the function of this region?
In the superior temporal gyrus.
This region helps us decode speech sounds.
What part of the brain is involved in phonologival access/retrieval?
This region is near the supramarginal and angular gyrus.
Important for pulling out the speech sound codes to make word and sending it out.
What are the components of clincal assessment of language that are used to categorize aphasia?
Spontaneous speech
Auditory comprehension
Repetition
Naming
Reading and writing (not required but can be informative)
What is spontaneous speech and what is the brain pathway involved?
Generation of content of thought
Assemble correct speech sounds for words (orange, yellow, and red) and articulate and express thoughts (Broca’s area - blue)
How do you assess spontaneous speech? What are components of this?
Fluency which involves:
- utterance length
- rate
- effortfulness
- prosody (melodic aspectics of speech)
Describe characteristics of fluent speech
Enunciated well; little effort to produce; at least 100-200 wpm with phrase length of 5-8 works per utterance; normal prosody (melodic aspects)
Describe non-fluent speech
Poorly articulated; often hesistant and halting; less than 50 wmp and 3 words per utterance; lacks prosody (melodic aspects), telegraphic (omitting essential words)
What is auditory comprehension? What are the regions in the brain involved in this?
Decoding incoming speech sounds (light blue)
Access semantics to understand what you heard (yellow)
What is needed for speech repitition? What don’t you need for word repetition?
- Decode incoming speech sounds (light blue)
- Assemble correct speech sounds of what you heard (red)
- Articulate and express thought (dark blue)
Do not need to understand (or access semantics) to repeat
Where is Broca’s area? What occurs with Broca’s aphasia?
Broca’s area is in the inferior frontal lobe on the L side.
The region is not as discrete as was once postulated and most likely invovles many regions of the brain.
Where is Wernicke’s area? What are characteritics of Wernicke’s aphasia?
It was originally thought to be a discrete region in the posterior superior temporal lobe.
Now we think that there isn’t just one location responsible for comprehension like Wernicke believed; we know this because middle temporal lobe lesions can still cause Wernicke’s aphasia.
How does our current knowledge of brain components involved in language differ from the ideas of Broca and Wernicke?
Language is not just associated with those two discrete areas; it is more of a network of interacting systems that contribue to language.
Lesions of what part of the brain are associated with transcortical motor aphasia? What is transcortical motor aphasia?
The superior frontal/middle frontal lobe
Like broca’s aphasia, but their ability to repeat is in tact.
Lesions of what part of the brain are associated with transcortical sensory aphasia? What is transcortical sensory aphasia?
The middle temporal and parietal regions (yellow)
Like Wernicke’s aphasia but they are able to repeat.
Lesions of what part of the brain are associated with conduction aphasia? What are characteristics of conduction aphasia?
Located near the termination of the sylvian fissure (red).
People with conduction aphasia make a lot of paraphasic errors and cannot repeat because of how many paraphasic errors they make.
