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