The Neuropsychological Organisation of Language Flashcards
What is language?
The ability to encode ideas into signals.
How do we know that language is primarily processed in the left hemisphere?
The Wada test. This is where one hemisphere at a time is anaesthetised (by injecting a drug into either the left or the right carotid artery)
- If the left hemisphere is anaesthetised, language is disrupted in most people - If the right hemisphere is anaesthetised, language is largely intact in most people
The left carotid artery supplies…
the left ACA and MCA
The two main areas involved in language processing are…
Broca’s area and Wernicke’s area
Wernicke’s area is specialised for…
Language comprehension (input)
Broca’s area is specialised for…
Language production (output)
To have Broca’s aphasia does the damage need to be directly to Broca’s area?
You can have Broca’s aphasia without damage directly to Broca’s area.
Broca’s aphasia is named after the neurologist who discovered the area that was damaged in relation to the symptoms.
We have better imaging now so we can be more accurate about where the damage is; not necessarily damage to that specific area —> can be damage deeper to the insula cortex.
Where is Wernicke’s area?
Wernicke’s area lies in the superior temporal lobe, posterior to primary auditory cortex.
Where is Broca’s area?
Broca’s area is in the frontal lobe, anterior to the region of primary motor cortex that controls the movements of facial expression and speech.
Wernicke’s and Broca’s areas are joined by a bi-directional pathway (white matter tract) called the..
arcuate fasciculus.
What is an aphasia?
Aphasia = Acquired language disorders
Name the 6 types of aphasia.
- Wernicke’s aphasia
- Broca’s aphasia
- Conduction aphasia
- Transcortical sensory aphasia
- Transcortical motor aphasia
- Global aphasia
Name the aphasia: Fluent speech Impaired comprehension Impaired repetition Impaired naming No motor impairment
Wernicke’s aphasia
What does Wernicke’s aphasia sound like?
They speak at a normal pace but the content doesn’t make sense
To have Wernicke’s aphasia does the damage need to be directly to Wernicke’s area?
No, there are regions heading into the parietal lobe which can cause Wernicke’s.
Do Wernicke’s patients have much insight into their condition?
Many Wernicke’s patients don’t seem to have much insight into what their disabilities are.
Name the aphasia: Non-fluent speech Good comprehension Impaired repetition Impaired naming May have right hemiplegia (more likely arm than leg)
Broca’s aphasia
Do Broca’s patients have much insight into their condition?
Tend to be more aware of difficulties and can get frustrated.
Conduction aphasia is a __________ syndrome.
Disconnection
Name the aphasia: Fluent speech Good comprehension Impaired repetition Impaired naming
Conduction aphasia
Name the aphasia: Fluent speech Poor comprehension Good repetition Impaired naming
Transcortical sensory aphasia
Name the aphasia: Non-fluent speech Good comprehension Good repetition Poor naming
Transcortical motor aphasia
Where would expect the lesion to be for transcortical sensory aphasia?
Posterior to Wernicke’s area
Where would expect the lesion to be for transcortical motor aphasia?
Anterior or superior to Broca’s area
Name the aphasia: Non-fluent speech Impaired comprehension Impaired repetition Impaired naming Right hemiplegia
Global Aphasia
Name two disorders of language processing (reading and writing), that often parallel aphasia.
Alexia is the loss of the ability to read as a result of brain damage.
Agraphia is the loss of the ability to write as a result of brain damage.
Patients with aphasia usually also have…
Agraphia, as normal writing requires intact functioning of the entire language apparatus. Thus, patients with alexia typically also have agraphia.
Diagnosis?
The patient is able to see and understand language, but is unable to read.
Why can this patient see and understand language?
Alexia without Agraphia.
The patient is able to see because the visual area in the right hemisphere are intact.
The patient is able to understand language because the language areas in the left hemisphere are intact.
Why is it that a patient with Alexia without Agraphia can’t read?
The patient is unable to read because the visual information from the intact right hemisphere visual cortex is disconnected from the language areas because there’s damage to the splenium of the corpus callosum.
Which arteries irrigate the occipital lobe and splenium?
The left and right posterior cerebral arteries.
