Movement Disorders Flashcards
Define Apraxia
Disorder of Skilled Movement
List traits that are NOT caused by Apraxia
1) Impaired primary motor ability
- weakness, akinesia, deafferentation
- abnormal tone or posture, primary movement disorder
2) Impaired comprehension
In right handers where are the focal lesions associated with?
The left hemisphere
Right hand is often paralyzed
- Often have hemiplegia; test it in left (nondominant) hand
What are the 4 types of Clinical Assessments used for apraxia patients?
1) Limb Gesture
2) Limb Manipulation
3) Buccofacial Gesture
4) Buccofacial Manipulation
Give an example of a Limb Gesture
Wave goodbye
Give an example of a Limb Manipulation
Open a door with a key
Give an example of a Buccofacial Gesture
Stick out toungue
Give an example of a Buccofacial Manipulation
blow a kiss
What is the grading of questions used in a clinical assesment for an apraxia patient?
pantomime -> imitation -> object use
Define Ideomotor/Ideational Apraxia
Clumsy; difficulty with the selection, sequencing, and spatial orientation of movements
- Often use body-parts as objects
Why do patients rarely complain of apraxic disturbances?
- Often paralyzed in right arm
- Attribute clumsiness to using nondominant hand
- Apraxia most severe when asked to pantomime a skilled act, and mildest when actually using the object
What did Geschwind think caused apraxia?
Geschwind invoked a language mechanism: Localized to LH
Describe the pathway that Geschwind proposed?
Right Hand
- Command goes from Wernicke’s to premotor to primary motor in LH
Left Hand
- Command must also pass through Wernicke’s to pre-motor in LH, then to premotor in RH
Geshwind’s Patient #1
What part of his brain was damaged?
Describe his behavior
Damage
- The anterior fourth fifths of corpus collosum
Behaviour
- Would carry out command with right arm correctly
- When given commands to use left arm, would make no or incorrect response
- Could imitate or use actual object with left arm
In terms of Geschwinds pathway, what function was impaired in patient #1?
Patient #1
- Verbal information could not reach RH to control left hand
Why could patient #1 imitate?
He could perform those functions because they were not dependent on language
Patient #2 had damage in his left premotor region
Describe his impairments
- Paralysis of right limbs
- Failure to carry out commands in left limbs
Patient #3 had damage in the pathway between wernickes and premotor area in the left hemisphere
Describe his impairments
- No paralysis in either arm
- Apraxic in left and right arms
language can not get to the premotor area in both hemispheres
List reasons that disprove Geshwinds pathway
1) Other studies have not found a close relationship between aphasia apraxia
2) Unlike Geschwind’s patient, most apraxia patients are impaired on imitation
Describe why apraxic patients being impaired in imitation might disprove Geshwinds pathway?
If apraxia is due to disconnection of language areas, then these patients should be able to imitate - but they can not
what did Liepman & Mass propose?
1) Left hemisphere is not only dominant for language
2) Left hemisphere contains motor engrams
Why is left hemisphere dominant for
- Superiority of right hand is not just in greater strength, but greater skill
Describe motor engrams?
- “movement formulas”
- “time-space-form picture” of movement
- skill of left hand is “borrowed” from the left hemisphere
What is the broad reasoning behind why most apraxic patients can’t imitate
A Callosal region accounts causes accounts for function of language and motor engrams
Describe the effects of a callosal lesion?
What does this account for
1) Disconnects language
2) Separates left hemisphere motor engrams from the motor areas of the right hemisphere
Accounts for finding that the left hand of patients with right hemiplegia is more clumsy than that of people who broke their right hand
Where is the motor engram of a left-handed person located?
On their right hemisphere
Where are motor engrams stored?
In the parietal lobe of dominant hemisphere