*L16 - Higher cortical function: language Flashcards
What are the two main components of language?
Understanding and expressing speech
Where is the cortical area of speech?
It is in the dominant hemisphere e.g. the left hemisphere in most right handed people.
Which parts of the dominant hemispheres are involved in speech?
The inferior frontal gyrus and superior temporal gyrus. These are connected by the arcuate fasciculus.
Where are the motor inputs to speech from?
From the corticobulbar pathway, basal ganglia and cerebellum. Cranial nerves X (supplies larynx) and XII (supplies tongue) also help.
What is the mechanics behind speech?
The muscles such as the diaphragm and intercostals act as bellows. This forces air through the larynx that generates the voice. This is then modulated by sinuses and oropharynx.
What are the four main components of speech and what can problems associated with them lead to?
Phonation (sound and volume)- Aphonia or dysphonia
Articulation- Dysarthia
Comprehention of the language- Aphasia or dysphasia
Production of the language-Aphasia or dysphasia
What is Aphonia or dysphonia?
Lack of phonation resulting in a low volume of speech, this may be from muscles weakness or vocal cord paralysis.
What is Anarthia or dysarthia?
Lack of ability to articulate resulting in slurring (often sounding drunk) this can be through weakness of articulation muscles, potentially partial vocal cord paralysis.
What are the two types of Aphasia/Dysphasia?
Expressive - able to comprehend but not speak
Receptive - able to speak but not comprehend so speech is unintelligible.
What is Broca’s aphasia?
This is expressive aphasia which results from a lesion in the inferior frontal gyrus. This causes non fluent speech with full comprehension.
What is Wernicke’s aphasia?
This is receptive aphasia which results from a lesion in the superior temporal gyrus. This causes fluent speech but a lack of comprehension so the speech does not make any sense.
How would you clinically examine speech?
Need to test fluency of speech and understanding of speech. Can test these by asking questions, giving commands and asking patients to repeat things.
