Ppt

1. APRAXIA: DEGENERATIVE
DISEASES
Kenneth M. Heilman M.D.
Distinguished Professor Emeritus of Neurology
Emeritus, University of Florida, College of
Medicine,
GRECC, VAMC, Gainesville, Fl.

2. Definition
• Exclusionary: The loss of the ability to perform
purposeful skilled movements when this deficit can not
be explained by motor deficits (e.g., weakness), sensory
defects, movements disorders (tremor, ataxia, chorea,
athetosis, ballismus, myoclonus etc) or certain cognitive
disorders (e.g., poor comprehension).
• Inclusionary: There are 5 major types of apraxia and
each are defined by the task demands and types of
errors.

3. Types of Limb Apraxia
• 1. Limb-kinetic
• 2. Ideomotor
• 3. Dissociation and Conduction
• 4. Ideational
• 5. Conceptual

4. LIMB-KINETIC APRAXIA
• Testing: 1) pegboard; 2) pincher grasp to pick up small
coins; 3) coin rotation.
• Error Type: Loss of finger deftness or dexterity. Loss of
the ability to perform independent, but coordinated
precise finger movements.
• Pathophysiology: Injury to corticospinal system and/or
convexity premotor cortex. Left hemisphere dominance
(Left hemisphere damage causes bilateral LKA and
corpus callosum injury LKA of left hand).
• Diseases: cerebrovascular disease, head trauma,
Parkinson’s disease, corticobasal degeneration, vascular
dementia

5. IDEOMOTOR APRAXIA
• Testing: 1. Performance of transitive movement to
command (e.g., show me how you would slice bread
with a knife.
2. Imitation of transitive movements.
3. Use of actual tools and implements
4. Discrimination between correct and
incorrect postures and movements.

6. IDEOMOTOR APRAXIA…CON’T
• Error Types
– 1. Postural Errors: a) Incorrect posture; b) Body-part as tool.
– 2. Movement Errors: a) Movement of incorrect join or joints; b)
Poor joint coordination.
– 3. Orientation Error: Not properly directing action toward target.
– 4. Timing-Speed Errors:

7. PATHOPHYSIOLOGY
1. Callosal Lesions
A) Geschwind and Kaplan, right arm normal, left impaired to
command only…possible language disconnection (see Fig.)
B) Watson and Heilman, right arm normal, left arm impaired to
command, imitation, and use of actual objects…disconnection of
movement representations.
2. Left Hemisphere Lesions
A) Asymbolia – apraxia and aphasia can be dissociated
B) Geschwind Intrahemispheric disconnection-cannot explain
impaired imitation and actual object use (see Fig).
C) Heilman-Rothi- lateralized movement representations in left
parietal lobe (see Fig).

8. Diseases Associated with Ideomotor
Apraxia:
Stroke
Head Trauma
Alzheimer’s
Parkinson’s
Corticobasal degeneration
Huntington’s

9. CALLOSAL APRAXIA-VERBAL DISCONNECTION
Lexical-
Sematics
MC
PMC
SSC
VC
VAA
LT RT

10. Geschwind’s Model of Ideomotor Apraxia
Auditory
cortex
Wernicke’s
area
Left
Premotor
Cortex
Left
Motor
Cortex
Right
Premotor
Cortex
Right
Motor
Cortex

11. IDEOMOTOR APRAXIA
Lexicon
Movement
Formula
SMA
Premotor
Cortex
Convexity
Premotor
Cortex
LT
MOTOR
CORTEX
Object
Recognition
Units
RT
MOTOR
CORTEX

12. Conceptual Apraxia
• Definition: A loss of mechanical knowledge, such that a
patient cannot select the proper tools to perform a tasks,
or does not understand the mechanical advantage
offered by tools.

13. Conceptual Apraxia Continued
• Testing:
• 1) Tool Selection (e.g., Patient is shown incomplete task, such a
partially driven in nail and tools such as a hammer, screwdriver,
hand saw, wrench, and can opener. The patient is asked to point to
the tool need to complete the task.
• 2) Alternate Tools (e.g., The hammer is taken away and the patient
is asked, “What tool would you use now?”
• 3) Developing Tools (e.g., The patient is shown a wooden block with
an eye hook on top which is sitting on the bottom of a plexiglass
tube. The patient is given a wire and asked to retrieve block. The
patient needs to make hook.)

14. Conceptual Apraxia Continued
• Errors: Inability to correctly perform the tests
mentioned above.
• Pathophysiology: Loss of action-tool semantics.
In the right handed people this knowledge is
stored in the left hemisphere and functional
imaging suggests that the left parietal lobe might
also be important for storing these
representations.

15. Conceptual Apraxia
Movement
Formula
SMA
Premotor
Cortex
Convexity
Premotor
Cortex
Motor
Cortex
Object
Recognition
Units
Action-Tool
Semantics
Lexical
Semantics
Motor Neurons

16. Diseases Associated with
Conceptual Apraxia:
• Alzheimer’s disease
• Vascular Disease

17. Ideational Apraxia
• Definition: Loss of the ability to order a series of acts to
achieve a goal.
• Testing: Present patient with items needed to complete a
task such as making a sandwich (bread, lettuce,
tomatoes, cheese, mayo, ham, and a knife). The ask
patient to make sandwich.
• Errors: Patient makes errors in ordering a series of acts
(e.g., cuts bread in half before putting on the ham etc.
• Pathophysiology: Not fully investigated, but suspect left
frontal lobe may be critical.
• Diseases: Parkinson’s disease, vascular, others???

18. PRAXIS SYSTEMS
CORPUS CALLOSUM
OBJECT
UNITS
PREMOTOR
COREX
MOVEMENT
REPRESENTATIONS
ACTION
SEMANTICS
LEXICAL-
SEMANTICS
PREMOTOR
CORTEX
Auditory input
Visual input
To spinal cord
To spinal cord
Right
Hemisphere
Visual gesture input

19. Figure: TYPES OF APRAXIA
a=conceptual apraxia; b=ideomotor apraxia; c=limb-kinetic apraxia;
d=conduction apraxia; e=verbal dissociation apraxia; f= ideational apraxia
Output
Praxicon
SMA
Premotor
Cortex
Convexity
Premotor
Cortex
Motor
Cortex
Object
Recognition
Units
Action-Tool
Knowledge
Lexical -
Semantics
a
b
b
b
c
c
c
V-5
Input-
Praxicon
d
e
Left Prefrontal f