Lecture 13: Apraxias Flashcards
What is Apraxia?
- Disorder of learned movement
- The movement was learned before lesion
- Problem in the organization of actions
- Not accounted for by deficits in:
- coordination
- weakness
- incomprehension
- etc.
Who was the first to describe this syndrome?
Carl Wernicke with his patient Hugo Liepmann
What does these pictures represent?
- This is a picture of the brain system that is recruited for motor action
- Example: Verbal command:
- Left:
- command
- Wernicke’s to the left motor area
- if need to move left member then crosses the CC to right hemisphere
- anterior (premotor to premotor)
- posterior (Wernicke to Wernicke)
- if need to move left member then crosses the CC to right hemisphere
- Left:
How do we know that there is a preferred way?
- Through studies
- lesion in area connecting temporal areas doesn’t lead to the symptoms of apraxia
- lesions in the anterior CC causes apraxia
What are the 5 different types of lesions that can lead to apraxia?
- Lesion in CC (apraxia)
- Lesion left premotor cortex (facial apraxia)
- Lesion connections between Wernicke’s and premotor area (facial apraxia)
- Lesion in Wernicke’s area (no apraxia)
- Lesion left parietal operculum
What are the symptoms of apraxia resulting from damage to the CC?
- Can carry out commands with the right arm
- Left arm is incorrect
- Can do daily tasks or imitate gestures
- face movements if asked
- ex: blow a candle
Why patients with apraxia due to damage to the CC are able to move their face correctly?
Because the face area of the motor cortex can control the cranial muscle on both sides.
So they can do movements on command.
What are the symptoms of a patient with apraxia and damage to the left premotor region?
- Facial apraxia
- Lesion affects motor are and Broca and destroyed callosal fibres connecting left and right premotor cortex
- if large: paralysis of right side
- Can’t carry out facial movements
- info from left Wernicke’s area does not reach motor area since it is destroyed
What are the symptoms of a patient with damage to the connections between Wernick and the premotor area?
- Intrahemispheric damage
-
conduction aphasia
- impairment in repetition
-
conduction aphasia
- If near precentral motor cortex:
- paralysis
- CAN’T:
- carry out movement with right or left side since info doesn’t reach motor
- no transfer through CC
- no info to face area
What are the symptoms of a patient with damage on Wernicke’s area?
- Fail to respond to verbal command
- NO APRAXIA
What are the symptoms of a patient with damage to the left parietal operculum?
- Normal comprehension
- Difficulty executing verbal commands
- left, right limbs and face
- Axial movement good
Why do patients with damage to the left parietal operculum doesn’t seem to have many problems?
Because of the pyramidal system which is that there are two pathways to the upper motor neurons for voluntary movement
What is the pyramidal tract?
- It is a descending tract
- Voluntary movement and control of the musculature of the opposite side of the body
What is decussation at the medullary pyramid?
It’s the twist part of the descending tracts to control the contralateral side of the body.
What are the two types of pyramidal tracts?
-
Lateral corticospinal tract
- Anterior corticospinal tract
What is a lateral corticospinal tract?
- About 10%
- do not decussate at the pyramids
- continue ipsilateral
- control of trunk, neck, etc.
What is an anterior corticospinal tract?
- Not entirely contralateral
- movements of the body trunk involve both sides
- coordinate postural muscles in broad movements of the body
- coordinating axons in the anterior corticospinal tract are often considered bilateral
- both ipsilateral and contralateral
Where is the lateral corticospinal tract?
Axial control
- Anterior corticospinal tract:
- controls muscles of trunk
- Axons do not decussate in medulla
- remain in anterior position
- Upon reaching appropriate level:
- axons decussate
- enter ventral horn on opposite side
Where are the lower motor neurons located?
In the medial regions of the ventral horn since they control the axial muscles of the trunk
Where is the ventral horn?