Stroke presentations Flashcards
What is dysarthria?
Where could the lesion be?
Problem with the muscles of speech
Could be problem with the brainstem (controls the bulbar muscles), nerve fibres connecting cortex to brainstem, cerebellum or basal ganglia
Where is Broca’s area located?
Left hemisphere frontal lobe
Where is Wernicke’s area located?
Left hemisphere temporal lobe
What is receptive aphasia?
A problem with comprehending what they are saying but able to speak meaningless stuff fluently (problem with Wernicke’s area)
What is expressive aphasia?
A problem with fluent speech and finding the correct word/sentence but understand what is being said (problem with Broca’s area)
Function of the basal ganglia?
A group of nuclei that form connections between the cortex and thalamus
Most prominent is their role in creating pathways to inhibit/promote movement.
E.g. Basal ganglia inhibit flexion of your arm when you want to extend your arm to reach for a pencil
Function of the thalamus?
How does the basal ganglia work to inhibit movement?
Which basal ganglia structures are involved?
The brain is constantly at work to inhibit unwanted movements.
Thalamic neurones project to the motor cortex to stimulate movements.
However the basal ganglia (substantia nigra and globus pallidus) continuously inhibit the thalamic neurones to stop them communicating with the cortex and therefore inhibit movements.
How does the basal ganglia work to stimulate movement?
Direct/indirect model: when a movement is desired, a signal to initiate the movement is sent from the cortex to the basal ganglia, arriving at the caudate or putamen (collectively known as the striatum). Then, the signal follows a circuit in the basal ganglia known as the direct pathway, which leads to the silencing of neurons in the globus pallidus and substantia nigra. This frees the thalamus from the inhibitory effects of the basal ganglia and allows movement to occur.
There is also a circuit within the basal ganglia called the indirect pathway, which involves the subthalamic nucleus and leads to the increased suppression of unwanted movements.
It is thought that a balance between activity in these two pathways may facilitate smooth movement.
Presentation of ACA occlusion?
Dysarthria (can’t speak)
Facial drooping
Anterior circulation: Internal carotid artery branches to which blood vessels?
Anterior cerebral artery
Middle cerebral artery
Posterior circulation: Vertebral arteries branch to which arteries?
Spinal artery
Posterior inferior cerebellar artery
Posterior circulation: Basilar artery branches to which arteries?
Anterior inferior cerebellar artery
Superior cerebellar artery
Posterior cerebral artery
Distribution of ACA supply?
Medial and superior surface of frontal and parietal lobes (it extends up to the parietal-occipital sulcus)
basal ganglia, corpus callosum
Distribution of MCA?
Lateral surface of cerebrum frontal, parietal, temporal lobes), except for superior frontal and parietal and inferior temporal lobe.
