PHYS - STROKE Flashcards
Explain the motor consequences of unilateral damage to the facial nerve nuclei (CN VII) (5)
- Facial nerve - mainly motor function
- Lesion does not affect upper half of face. Lower half of contralateral face shows weakness.
- Part of N. VII nucleus innervating upper face receives bilateral projections from cerebral cortex (motor cortex; motor homunculus; precentral gyrus) – upper face is spared
- Part of N. VII nucleus supplying lower part of face receives unilateral, contralateral projections from cerebral cortex (motor cortex; motor homunculus; precentral gyrus) and affects lower half of face on same side
68 y/o male, heavy smoker, known with hypercholesterolaemia and hypertension. Rushed to the GP after wife noticed he had slurred speech and when he tried to walk to the bathroom he was clumsy and off balance. 30 minutes later in the GP surgery, he was completely unable to stand up, walk or talk. O/E expressive aphasia, R-sided weakness and sensory loss.
Explain the patient’s slurred speech, clumsy, off-balance movements, right-sided weakness and sensory loss. Use a diagram to illustrate the neural pathways involved (6)
- Slurred speech – left cerebral hemisphere ischaemia involving motor cortex (area that projects to brain stem nuclei that control muscles in the face and tongue) (1)
- Clumsy, off balance movements – ischaemia in motor cortex in the left hemisphere (1)
- Right-sided weakness - ischaemia in left hemisphere impairing function of UMNs in 1o/premotor cortex (1)
- Right-sided sensory loss - ischaemia in left hemisphere impairing function of somatosensory cortex (1)
- Diagram showing ischaemic injury to motor nuclei in primary/premotor cortex, and somatosensory cortex in the left cerebral hemisphere, and descending pathways innervating medial motor neurons that control posture as well as lateral motor neurons that decussate in the medulla and control skeletal muscles (2)
62 y/o smoker who has been on anti-hypertensive drugs for the last six years. Notices that his left arm feels numb and weak which he attributes to stress. Decides to rest but wakes up later that night with a headache. He informs his wife who immediately notices that his speech appears slurred and he is walking clumsily. Taken to the hospital where he is examined & sent for a CT scan.
Explain the patient’s numbness and weakness in his left arm. Use a diagram to illustrate the neural pathways involved (4)
Numbness - Left-sided sensory loss - ischaemia in right hemisphere impairing function of somatosensory cortex (1)
Left-sided weakness - ischaemia in right hemisphere impairing function of upper motor neurons in 1o/premotor cortex (1)
Diagram showing ischaemic injury to motor nuclei in primary/premotor cortex in the right hemisphere, and descending corticospinal pathways that decussate in the medulla and control lower motor neurons that project to skeletal muscles in the left arm in the ventral horn of the spinal cord (2)
Explain the patient’s slurred speech (1)
Right or left hemisphere ischaemia involving upper motor neurons in primary motor cortex area that project to brain stem nuclei that control movement of the tongue
83 y/o pensioner living in a home for the elderly. One morning the day nurse finds the patient lying on her bedroom floor. She was conscious but was unable to speak and could not stand or move her arms or legs on command. A CT scan on the brain showed a substantial Left-sided cerebral infarct. Dr informed patient’s family of the poor prognosis. Palliative care was discussed.
Explain why the patient was unable to speak, to stand or move her arms or legs on command. May use a diagram (7)
Left-sided cerebral infarct caused damage to left hemisphere upper motor neurons (1)
Inability to speak is likely due to damage to Broca’s area (1)
located in frontal lobe, anterior to primary motor cortex controlling muscles used for speech (1)
the fact that she could not stand suggests that the lesion included the primary motor cortex, affecting the upper motor neurons that control the proximal muscles that control posture and balance (2)
The fact that she could not move her arms or legs suggests that the lesion included the primary motor cortex, affecting the upper motor neurons that control distal muscles (2)
52 y/o moderately obese (BMI of 32) man, has smoked two packs of cigarettes a day for the past 38 years. He awakes one morning with weakness on his right side. He is slightly confused, sees double, and his speech is slurred. When he attempts to walk to the bathroom, he stumbles a few times and falls. O/E has a right hemiparesis, and diminished pinprick sensation and two-point discrimination on the right arm and right side of his head. His systemic BP 160/110. His deep tendon reflexes are brisk on the right and there is a Babinski reflex on the right. He has difficulty articulating, speaking only a few words and frequently responding with a single word. His ability to respond appropriately to complicated verbal commands is not impaired.
With the aid of a diagram, indicate the areas of the patient’s brain that are impaired (5)
Diagram of the brain, identifying left hemisphere pre- and post-central gyri, Broca’s and Wernicke’s areas and possibly occipital and prefrontal cortices.
Name ten (10) of the patient’s functional impairments and list the brain regions that would be expected to be damaged in order to produce the impairment (10)
Any 10 of the following:
- Weakness (hemiparesis) on right side of his body – left cerebral hemisphere primary motor cortex (left precentral gyrus)
- Confused – prefrontal cortex
- Sees double – occipital cortex (or brain stem nuclei, superior colliculus etc)
- Slurred speech – Broca’s area (posterior inferior frontal gyrus in the frontal cortex of the left hemisphere)
- Stumbles and falls – visual cortex is required for visually guided motor activity
- Diminished pinprick sensation on his right arm and right side of his head – damage to left somatosensory cortex, post central gyrus and/or other pain perceiving areas of the brain e.g. insular cortex and cingulate cortex
- Diminished two-point discrimination on his right arm and right side of his head – left primary somatosensory cortex, post central gyrus.
- BP of 160/110 – impaired subcortical control of autonomic nervous system (hypothalamus & amygdala)
- Brisk deep tendon reflexes on the right – reduced cortical inhibition by left hemisphere
- Babinski reflex on the right – damage to upper motor neuron in left motor cortex (left hemisphere precentral gyrus)
- Difficulty speaking – Broca’s Areas (Brodmans area 44 & 45 (inferior left frontal gyrus)
Explain why the patient is experiencing diminished pin-prick sensation on the right side of his head. Include in your answer the appropriate pathways and structures involved. Use a diagram if you wish (5)
Diagram indicating:
- Nociceptor in skin on right side of head
- Trigeminal nerve (cranial nerve V)
- Sensory (spinal) trigeminal nucleus in brain stem, axon of 2nd order neuron project to opposite side of brain
- To ventrolateral region of the primary somatosensory cortex (gyrus posterior to central sulcus) representing the skin of the head
- Damage to this region of the somatosensory cortex will impair perception (feeling) of pain. The sensation would normally be projected to the site of injury but damaged somatosensory neurons unable to function
