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?
So what happens if you have lesions in the lower parietal areas?
- They can prevent the information to reach the pyramidal system
- can’t carry limb movement
- can command trunk motion
Which are the two main different branches of apraxia?
- Ideational apraxia
- Ideomotor apraxia
What is ideomotor apraxia?
- Alteration in the transmission between the ideation and the motor gesture
- Deficits in elementary (all) gestures
- difficulty in production of movements
- difficulty in imitation
- use of body as object
- correct execution in real-life context
- can name, describe and understand gesture
- no semantic problem
- CAN’T plan the gesture
-
Lesion
- parietal
- disconnect left auditory from motor
- if unilateral left apraxia:
- RH lesion or CC
What is ideational apraxia?
- Alterations of the mental representation of the action to accomplish
- Affects:
- complex gestures
- spontaneous and on command gestures
- Observed when incorrect manipulation of tools
- looks like the patient doesn’t remember the purpose of an object and how to use it
- Different parts of the action are there but the sequence is mixed up
- semantic information of tools is affected
-
Lesions
-
temporo-parieto-occipital junction
- semantic
-
temporo-parieto-occipital junction
What are the roles of the posterior parietal areas?
Construct a visual world, spatial relationship and attention
What is the role of the left side of the posterior parietal areas?
- Writing
- Mathematical thoughts
- Awareness of what you do with your body
- Usage of body to convey information
What is the role of the right side of the posterior parietal areas?
Spatial relationship between objects
List of different apraxias
- Facial apraxia
- Ideomotor apraxia
- Ideational apraxia
- sympathetic apraxia
- dressing apraxia
- apraxia of gait
- constructional apraxia
- pure constructional apraxia
What is Sympathetic Apraxia?
- type of ideomotor apraxia
- Posterior language comprehension area is intact
-
Lesion:
- left inferior frontal area
-
Symptoms:
- Right arm paralysed
- Left arm apraxic
- Left hemisphere dominance for skilled movement (right handed)
Why do we say that for a patient with sympathetic apraxia their right arm is paralysed and their left arm is apraxic?
- Patient holds damage on the left hemisphere (inferior frontal area, so the motor area)
- thus paralyzed right arm
- The right hemisphere is intact thus they can move their left arm
- Command is not received from the left motor cortex to the CC because left motor area is damaged
What is dressing apraxia?
- Automatic and spontaneous ability to dress is lost
-
Lesion:
- Right Parietal
- Left Parietal
-
Symptoms:
- R: sequence to dress and what to put where is lost
- L: Related to general deficits of planning of gestures with both limbs
True or False
Dressing apraxia is the same deficit as hemineglect
FALSE
What is apraxia of gait?
- motor planning deficit
- hard time to get walking
- commonly seen in dementia
- Advanced stages of parkinson’s
- no motor weakness
- disorder of locomotion characterized by inability in lifting the feet from the floor and disequilibrium
-
Lesion:
- frontal lobe
- dorsomedial frontal cortex
- SMA region
- Note: these are regions where the feet are mapped
-
Basal ganglia
- for planning (?)
What is gait?
A person’s manner of walking
it recruits a complex brain network
What is constructional apraxia?
- Inability to understand spatial relationship between objects
-
Lesions:
-
Parietal lobe lesions
- Mostly right but also left
-
Parietal lobe lesions
Which hemisphere is better for spatial construction, orientation and distributing out attention in space
Right hemisphere
What are visuoconstructional disabilities?
The failure in drawing or assembling tasks
Who introduced the concept of constructional apraxia?
Kart Kleist
True or False
Constructional apraxia can be explained by only the visuoperceptual deficits
False
What is pure construction apraxia?
- Normal visual perception
- Normal abilities to localize objects
- No ideomotor apraxia
- No motor diability
- Problems in execution or praxis
- the process of using a theory or something that you have learned in a practical way
For patients with constructional apraxia symptoms, before Kleist, what was the explanation the doctors gave?
bilateral occipitoparietal disease
What is Kleist’s model?
- Visuomotor integrative process underlying constructional performances:
- LH then sent to the RH by CC
- you need both hemispheres
- Right parietal mediates the bilateral constructional activity
- LH then sent to the RH by CC
How can you get unilateral constructional apraxia?
If you damage the CC
Dominant hemisphere can’t send information to the non-dominant side
What lesions cause constructional apraxia?
Either left or right parietal lesions but right are more common. Lesions to CC can also result in constructional apraxia (unilateral)
Given a patient who has constructional apraxia, but their visuoperceptual performance is ok, where is the damage?
- Left occipito-parietal area
According to Kleist’s formulation, what are the two main areas for conductional apraxia?
- Left occipito-parietal areas
- Right hemisphere
Damage in which of the areas cause constructional apraxia with visuoperceptual impairments?
Right hemisphere parietal lesion
How can you test for constructional apraxia?
- Stick-arranging test
- Block design
- Drawing from memory
- Copy drawing
- Rey Osterrieth Complex Figure
What is the Stick-arranging test?
Reproduce a pattern with sticks
What is the Block design test?
Reproduce a construction with 3D blocks from a 2D picture
What is the Rey Osterrieth Complex Figure?
- Goal: copy the figure
How does someone with left hemisphere lesion, draw the Rey Osterrieth Figure?
- Piece by piece
How does someone with right hemisphere lesion, draws the Rey Osterrieth figure?
Uses a more global approach and then fill out the details
