Podcast
Questions and Answers
What is the primary function of the primary sensory cortex?
What is the primary function of the primary sensory cortex?
Which type of stroke accounts for 80% of all strokes?
Which type of stroke accounts for 80% of all strokes?
What is a classic presentation of a stroke involving the middle cerebral artery?
What is a classic presentation of a stroke involving the middle cerebral artery?
Which area is most affected in patients with lesions in the primary sensory cortex?
Which area is most affected in patients with lesions in the primary sensory cortex?
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What does the WHO define as a stroke?
What does the WHO define as a stroke?
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Which artery is most commonly associated with ischaemic strokes?
Which artery is most commonly associated with ischaemic strokes?
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What kind of difficulty is associated with left hemisphere lesions in stroke patients?
What kind of difficulty is associated with left hemisphere lesions in stroke patients?
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What is a notable sign of cortical sensory loss in strokes affecting the sensory association cortex?
What is a notable sign of cortical sensory loss in strokes affecting the sensory association cortex?
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Study Notes
Stroke Overview
- Stroke is a rapidly developing clinical sign of focal disturbance of cerebral function.
- It is typically of presumed vascular origin and lasts more than 24 hours.
- Stroke types include ischaemic, primary intracerebral haemorrhage (ICH), and subarachnoid haemorrhage (SAH).
Cerebral Cortex
- The cerebral cortex is a vast collection of cell bodies, axons, and dendrites covering the cerebral hemispheres.
Localized Function of Cerebral Cortex
- Primary sensory cortex: discriminates intensity and quality of sensory information.
- Sensory association cortex: performs complex analysis of sensation.
- Motor planning areas: control motor output
- Primary motor cortex: descending control of motor output.
- Association cortex: controls behavior, interprets sensation, and processes emotions and memory.
- Temporal and Occipital cortices: (implied functional roles, but specific details are not described further).
Homunculus
- The homunculus illustrates the disproportionate representation of body parts in the primary motor cortex.
- The diagram shows that certain body parts, like the hands and face, occupy more cortical space than others.
Stroke Types
- Ischaemic strokes account for 80% of all strokes.
- These are caused by occlusions (blockages) due to either atheroma or emboli.
- The most common site of ischaemic stroke is the middle cerebral artery (MCA).
- Other frequently affected arteries are the posterior cerebral artery (PCA) and the anterior cerebral artery (ACA).
- Brainstem strokes originate from disease in the vertebral and basilar arteries.
Middle Cerebral Artery (MCA) Stroke
- The middle cerebral artery (MCA) supplies blood to the majority of the outer brain surface and the basal ganglia and portions of the internal capsule.
- Infarcts (tissue death) in these areas result in various neurological consequences.
Stroke Involving MCA/ACA (Anterior Circulation Stroke)
- MCA and ACA supply nearly the entire outer brain surface, the basal ganglia, and the internal capsule.
- Infarcts lead to diverse neurological sequelae (symptoms).
- Classic presentations include dense contralateral hemiplegia, contralateral hemianopia, cortical sensory loss, speech and language difficulties (dysphasia or dysarthria), swallowing difficulties (dysphagia), and visuospatial disturbance.
- Other potential issues include unilateral neglect/inattention, memory problems, bladder control issues, executive function problems, and altered reflexes (e.g., hypertonicity/hypotonicity).
Lesion Effects on Primary Sensory Cortex (PSC) and Sensory Association Areas (SAA)
- Lesions affecting PSC (Primary Sensory Cortex) impact the localization and perception of tactile stimuli and proprioception.
- Quality and intensity of sensory stimuli can be altered.
- Lesions affecting SAA (Sensory Association Areas) can lead to agnosia.
- Agnosia is characterized by a difficulty recognizing familiar objects or stimuli in the following modalities: visual, auditory, or stereognosis.
Lesion Effects on Motor Planning Areas
- Damage to premotor or supplementary motor areas can cause apraxia.
- Apraxia is the inability to perform a simple movement or a sequence of movements, despite the person having intact sensation and understanding of the required task.
- Damage to these areas can also cause motor perseveration.
- Broca's aphasia is another possible effect.
Lesion Effects on Primary Motor Cortex (PMC)
- Lesions affecting the primary motor cortex (PMC) result in contralateral paresis.
- This means weakness or paralysis develops on the body side opposite the damaged area in the brain.
- The ability to perform complex movements (loss of fractionation of movement) as well as dysarthria (speech difficulties) is often affected.
- Different types of motor weakness are possible (e.g., spastic and flaccid).
Lesion Effects on Association Cortex
- Lesions in the prefrontal cortex can result in a loss of executive function and apathy (lack of motivation or enthusiasm), leading to inappropriate behavior and poor judgment.
- Damage to the parietotemporal area can affect communication skills, understanding of space, emotion, and memory.
Secondary Complications
- Secondary complications of stroke often include gait, balance, postural alignment, muscle strength, reduced range of movement, falls, and psychosocial issues.
Stroke Patient Walking
- Further information or resources regarding patient walking following stroke are provided in an online video.
Questions
- Questions were presented for further discussion.
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Description
This quiz explores the key concepts related to stroke, including its types and significance, as well as the functions of the cerebral cortex. Participants will learn about primary sensory and motor areas and their roles in processing sensations and controlling motor outputs. Test your understanding of these critical neurological concepts.