L32. Disorders of Language: Aphasia Flashcards
What is meant by the term aphasia?
A disturbance in language as a result of brain damage. (without speech)
What is the relationship between language and speech
Language is produced through a number of modes one of them being speech (and another writing)
What are some causes of acute onset aphasia? [3]
- Stroke
- Penetrating head injury
- Surgical resection of the head
What are some causes of insidious onset/progressive aphasia? [2]
- Dementia
- Neoplastic changes
A patient with a severe language deficity with no meaningful production, but rather repeating the same word over and over again eg.”tan tan tan tan” likely has a lesion/dysfunction of what area of the brain?
Broca’s Area (the left frontal lobe)
What is meant by hemispheric dominance?
This is also called laterisation of function
It is when one hemisphere of a person’s brain is more dominant in controlling one particular function over the other.
It is important to recognise that this is not a definite lateralisation and that it is not the same in every individual.
Describe the lateralisation of language for 95% of right handers and 70% of left handers
- Right hemisphere for visuospatial functioning
- Left hemisphere for language production
The right hemisphere may have a role in language, what kind of role is this?
- Non-propositional speech (counting and recitation like alphabet)
- Prosody (patterns of rhythm, intonation and stress of words)
- Paralingistic aspects (vocal and non-vocal signs accompanying speech like emotion and body language)
What major artery supplies the lateral surface of the two hemispheres?
The middle cerebral artery (it has 2 subdivisions: superior and inferior)
What does the superior divison of the middle cerebral artery supply?
What will a stroke in this region cause?
- The sensory motor cortex
- Ventrolateral prefrontal cortex
A stroke in this area would cause:
- Hemipariesis
- Executive functioning disorders
- Language difficulties (expressive aphasia - Broca’s area)
What does the inferior divison of the middle cerebral artery supply?
What will a stroke in this region cause?
- Temperoparietal cortex
- Visual Tracts
A stroke/lesion in this area would lead to
- Visual Loss
- Language difficulties (receptive aphasia - Wernicke’s area)
What are the two functional processes of the language system?
- PRODUCTION - Producing output sentences by choosing the words and putting them together in the correct way (grammar)
- SELECTION - Choosing the appropriate content
If there is a problem with production processes what kind of aphasia presents?
Non-fluent aphasia
If there is a problem with selection processes what kind of aphasia presents?
Fluent aphasia
What is Broca’s Area?
A region of the brain concerned with the production of speech, located in the cortex of the dominant frontal lobe. (usually the left)
What is Wernicke’s Area?
A region of the brain concerned with the comprehension of language, located in the cortex of the dominant temporal lobe (usually left).
Describe non-fluent aphasia in terms of…
- Area of a lesion causing it (including artery)
- Presentation
- Content
- Is it Broca or Wernike?
- Anterior lesion (superior division of the middle cerbral artery)
- Loss of grammatical and sequential structure
- Intact selection of content (limited and effortful)
- Broca’s Aphasia
Describe fluent aphasia in terms of…
- Area of a lesion causing it (including artery)
- Presentation
- Content
- Is it Broca or Wernike?
- Posterior lesion (inferior division)
- Grammar and sequence are intact (relatively meaningless statements)
- Impaired selection of content
- Wernicke’s aphasia
The main language structure supplied by the superior division is Broca’s area and is made up of two main gyruses, what are these?
- Pars triangualris
- Pars opercularis
What is the temperoparietal association neocortex? What are the two main gyruses in this?
This association area is responsible for the assembly of auditory, visual, and somatosensory system information.
In the left hemisphere (dominant) it is involved in language recognition (reading, listening, and braille), but is not entirely responsible for these tasks.
- Supramarginal gyrus for the articulation of words
- Angular gyrus for the understanding of metaphors
What is the arcuate fasiculus?
A hypothetical tract that is believed to link Broca’s and Wernike’s areas and a disconnection along this tract causes language disturbances as well
Describe the syndrome of Wenicke’s aphasia
- Fluent jargonistic language
- Neologisms (coining new, made up words)
- Parphasic errors including semantic (related but not quite right) and phenemic (closely related but not correct)
- Impaired comprehension
- Right quadrantanopsia (visual tract impairment)
- No motor weakness
Describe the syndrome of Broca’s aphasia
- Non-fluent, highly effortful language
- Telegramattic: lacks grammatical structure
- Preserved comprehension abilities
- Often associated with right face and arm weakness
Other aphasic syndromes exist, what are the two other major types or aphasia?
- Conduction aphasia
- Transcrotical motor aphasia
Describe conduction aphasia
- A fluent aphasia with more meaningful production that Wernicke’s
- Auditory comprehension is relatively intact
- Poor repetition of words
Describe transcortical motor aphasia
- Non-fluent aphasia (similar to Broca’s)
- Muteness at the most severe
- Repetition ability is preserved
Are the mechanisms for recovery of aphasias? Describe them [2]
There are two types described:
- Contralateral transfer: getting the other hemisphere to take over lost functions (require early intervention only: early hemispherectomy, neonatal infarction, major developmental anomalies)
- Ipsilateral re-organisation: focal damage to an area
What is the finding of the success of contralateral vs. surrounding focal tissue reorganisation in terms of recovery?
Contralateral activation through therapy doesn’t give as good a recovery of the Penumbra (peripheral or indeterminate area of tissue surrounding the damage).
