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The Neuropsychology of Urea Cycle Disorders M. Cullen Gibbs, Ph.D. Pediatric Neuropsychologist Children’s National Medical Center
Neuropsychological Implications of UCD Inherited urea cycle disorders (UCD) represent one of the most common groups of inborn errors of metabolism; however, little information is available on the natural disease progression in persons with UCD.  In UCD the failure of the urea cycle to rid the body of excess ammonia causes hyperammonemia episodes. These episodes result in toxic effects on the white matter of the central nervous system.
 
The Importance of White Matter White matter is, in essence, the mechanism by which different regions of the brain communicate with each other. White matter fibers in the brain allow communication between the left and right cerebral hemispheres, within the cerebral hemispheres, and between the brain stem and the cerebral hemispheres  Damage to the white matter interferes with the ability of different regions of the brain to communicate, resulting in cognitive impairment.
Why is the Impact of Disease Processes on Neuropsychological Functioning Difficult to Identify in Children?  Opposing vectors of development and deterioration mask effects of disease The premorbid level of ability is a  rate  of development, not a level of performance.
Developmental  status Chronological age Vector of normal development Vector of disease effect Hypothetical Effects of Disease and Normal Development on Growth Trajectory Courtesy of Dr. Elsa Shapiro; University of Minnesota Medial School. 0 2 4 6 8 10 3 4 5 6 7 8 9 10 Resultant of vectors of development  and disease in affected child
Problems in the Assessing the Cognitive Impact of Disease Processes in Childhood Unknown premorbid intellectual level Difficult to identify cognitive changes in early stages of disease Impact may vary according to age of onset
Problems Assessing the Cognitive Impact of Disease Processes in Childhood Because certain mental functions are not yet developed at the outset of the disease and cannot be measured, the extent of the impact may not be detected until those functions are developmentally ready to emerge. Presence of confounding factors, both biological and environmental.
What is Neuropsychology?   The study of learning and behavior in relationship to a child’s developing brain.  A framework that draws from cognitive sciences, neurology, neuroanatomy, and clinical, social, developmental, biological psychology.
What is a Neuropsychological Evaluation? Examination of external behavior to make inferences about internal brain function and structure. Formal testing of abilities such as memory and language skills assesses brain functioning. By comparing a child’s test scores to children of a similar age, it is possible to create a profile of the child’s strengths and weaknesses.
What is the Purpose of a Neuropsychological Evaluation? To understand, explain and predict behavior Develop a profile of an individual's cognitive strengths and weaknesses Describe presence and degree of cognitive impairments and explain mechanisms responsible for their perpetuation
What is the Purpose of a Neuropsychological Evaluation? Measure presence and degree of behavioral difficulties resulting from neurological bases Establish baseline of functioning for systematic comparisons across time Measure the cognitive or behavioral impact of rehabilitation, pharmacological, surgical or therapeutic interventions
What is the Purpose of a Neuropsychological Evaluation? Help formulate appropriate treatment plans Guide remedial educational or vocational rehabilitation programs  Predict individual's ability to achieve success in particular settings Needs for settings to accommodate to the individual versus individuals' ability to adapt to the setting
Left Right Anterior Posterior
Anterior - Posterior Axis Anterior Systems  --    Posterior Systems Anticipates  -  Receives  Selects Goals -  Encodes Organizes/ Plans -  Stores Orchestrates -  Structure Organization -  Knowledge Base Monitors Modulates <---->  Complimentary Relationship
Lateral Axis Left Hemisphere Systems Preferentially  involved with: Building blocks of language Parts of complex materials Temporal processing Processing unimodal, codable information Executive of discrete motor Right Hemisphere Systems Preferentially  involved with: Spatial information Relationship between parts Configuration of complex Processing multi-modal novel information Emotional tone in speech <-->
Domains of Neuropsychological  Functioning General cognitive functioning Attention Executive-regulatory function Language Visual/Nonverbal processing Memory& Learning Sensory and Motor Academics Social & emotional
What are the Potential Neuropsychological Implications of Damage to the White Matter? Impaired executive functions Slowed speed of processing Impaired spatial processing Impaired coordination Dysarthric speech Depressed mood Cummings, 1990
What are the Executive Functions? An “umbrella” term, encompassing… those interrelated skills necessary for purposeful, goal-directed activity”  ( Anderson, 1998) “ Capacities that enable a person to engage successfully in independent, purposeful, self-serving behaviors”  (Lezak, 1993)
Role of the Executive Conductor  of the orchestra&quot;  “ CEO  of the corporation” “ General  of the army” “ Domain  general  processes”
Executive Functions as the “Conductor of the Orchestra”
Functions of the “Conductor” 1.  Initiate goal-oriented action 2.  Working Memory 3.  Plan & Organize 4.  Self-monitor & evaluate 5.  Inhibit 6.  Flexibility 7.  Emotional regulation 8.  Self-awareness
Functional Domains of  The Executive Inhibit - stop an action or not react to impulse Shift - move from one task or situation to another Emotional Control - regulate emotional response Initiate - begin task, activity, attention Working Memory - hold information actively in mind Plan -  anticipate future events and develop steps Organize - establish, maintain order Self-monitor - attend to behavior/output; revise
Functions of the “Orchestra” 1. Perception 2. Conceptual thinking 3. Language processes 3. Visual-spatial processes 4. Memory 5. Sensory inputs 6. Motor outputs 7. Emotion 8. Knowledge & skills social non-social
Functions of the “Conductor” 1.  Initiate goal-oriented action 2.  Working Memory 3.  Plan & Organize 4.  Self-monitor & evaluate 5.  Inhibit 6.  Flexibility 7.  Emotional regulation 8.  Self-awareness Functions of the “Orchestra” 1. Perception 2. Conceptual thinking 3. Language processes 3. Visual-spatial processes 4. Memory 5. Sensory inputs 6. Motor outputs 7. Emotion 8. Knowledge & skills social non-social
Critical features of Executive Control Functions   (Denckla 1995) Provide for delayed responding Future-oriented Strategic action selection Intentionality Anticipatory Set Freedom from interference Ability to sequence behavioral outputs
Demand Situations for Executive Functions Multi-step tasks/ learning Novelty (lack of experience base) vs Automaticity (familiar) High vs low stress Future vs present orientation Intentional action selection
Outcome of “Good” Executive Function Purposeful, goal-directed activity Active problem solving  Self-control Independence Reliability and consistency Positive self-efficacy  Internal locus of control
The Frontal lobes:  Strategic executive Conductor Orchestra
Neuroanatomic Organization: Frontal lobes are densely connected with other cortical and subcortical regions Prefrontal system is highly, reciprocally interconnected  with the  limbic (motivational) system, reticular activating (arousal) system posterior association cortex (perceptual/ cognitive processes and knowledge base) motor (action) regions of the frontal lobes
Interventions: General Principles Teach  goal-directed  problem-solving  process , within everyday meaningful routines, having real-world relevance and application, using key people (parents/ teachers/ peers) as models, “coaches”  (Co-conductor).
Interventions:  General Principles External to internal process External models of multi-step problem-solving routines External guidance to develop & implement everyday routines Practice application/ use of routines Fade external support to cueing internal generation & use of routines
Interventions:  General Principles External to internal process Internal control to generate & use specific problem-solving routine Generalization to new situation, requiring some external guidance Accumulate experience, examine conditions for selective use of various routines Feedback throughout (i.e., reward)
Structuring an executive function intervention program  Use of everyday routines with (e.g., Goal-Plan-Do-Review) Support working memory via “hard copy” of routine Allowing child to become increasingly more active in formulating plans and reviewing their performance
What Do We Hope to Learn? By using a developmental approach to analyzing both natural history and response to treatment we hope to discover information about  . . . neurobehavioral/neuropsychological associations with localized dysfunction Age related differences in neurobehavioral/ neuropsychological sequelae Other phenomena such as how intervention might change the trajectory of development
What Do We Hope to Learn? Neuropsychological studies of UCD can help to identify specific effects on the brain associated with UCD and correlate these findings with behavior and outcome.  The impact of UCD occurring at different stages of development will help us to better understand the impact of the disease process on the developing brain.  The quantification of neuropsychological and neurobehavioral outcomes will be increasingly important in determining the efficacy of interventions.  Efficacious educational/ behavioral interventions for children with UCD based on their neuropsychological profile.

More Related Content

Neuropsychological Implications Of Ucd

  • 1. The Neuropsychology of Urea Cycle Disorders M. Cullen Gibbs, Ph.D. Pediatric Neuropsychologist Children’s National Medical Center
  • 2. Neuropsychological Implications of UCD Inherited urea cycle disorders (UCD) represent one of the most common groups of inborn errors of metabolism; however, little information is available on the natural disease progression in persons with UCD. In UCD the failure of the urea cycle to rid the body of excess ammonia causes hyperammonemia episodes. These episodes result in toxic effects on the white matter of the central nervous system.
  • 3.  
  • 4. The Importance of White Matter White matter is, in essence, the mechanism by which different regions of the brain communicate with each other. White matter fibers in the brain allow communication between the left and right cerebral hemispheres, within the cerebral hemispheres, and between the brain stem and the cerebral hemispheres Damage to the white matter interferes with the ability of different regions of the brain to communicate, resulting in cognitive impairment.
  • 5. Why is the Impact of Disease Processes on Neuropsychological Functioning Difficult to Identify in Children? Opposing vectors of development and deterioration mask effects of disease The premorbid level of ability is a rate of development, not a level of performance.
  • 6. Developmental status Chronological age Vector of normal development Vector of disease effect Hypothetical Effects of Disease and Normal Development on Growth Trajectory Courtesy of Dr. Elsa Shapiro; University of Minnesota Medial School. 0 2 4 6 8 10 3 4 5 6 7 8 9 10 Resultant of vectors of development and disease in affected child
  • 7. Problems in the Assessing the Cognitive Impact of Disease Processes in Childhood Unknown premorbid intellectual level Difficult to identify cognitive changes in early stages of disease Impact may vary according to age of onset
  • 8. Problems Assessing the Cognitive Impact of Disease Processes in Childhood Because certain mental functions are not yet developed at the outset of the disease and cannot be measured, the extent of the impact may not be detected until those functions are developmentally ready to emerge. Presence of confounding factors, both biological and environmental.
  • 9. What is Neuropsychology? The study of learning and behavior in relationship to a child’s developing brain. A framework that draws from cognitive sciences, neurology, neuroanatomy, and clinical, social, developmental, biological psychology.
  • 10. What is a Neuropsychological Evaluation? Examination of external behavior to make inferences about internal brain function and structure. Formal testing of abilities such as memory and language skills assesses brain functioning. By comparing a child’s test scores to children of a similar age, it is possible to create a profile of the child’s strengths and weaknesses.
  • 11. What is the Purpose of a Neuropsychological Evaluation? To understand, explain and predict behavior Develop a profile of an individual's cognitive strengths and weaknesses Describe presence and degree of cognitive impairments and explain mechanisms responsible for their perpetuation
  • 12. What is the Purpose of a Neuropsychological Evaluation? Measure presence and degree of behavioral difficulties resulting from neurological bases Establish baseline of functioning for systematic comparisons across time Measure the cognitive or behavioral impact of rehabilitation, pharmacological, surgical or therapeutic interventions
  • 13. What is the Purpose of a Neuropsychological Evaluation? Help formulate appropriate treatment plans Guide remedial educational or vocational rehabilitation programs Predict individual's ability to achieve success in particular settings Needs for settings to accommodate to the individual versus individuals' ability to adapt to the setting
  • 14. Left Right Anterior Posterior
  • 15. Anterior - Posterior Axis Anterior Systems  --  Posterior Systems Anticipates - Receives Selects Goals - Encodes Organizes/ Plans - Stores Orchestrates - Structure Organization - Knowledge Base Monitors Modulates <----> Complimentary Relationship
  • 16. Lateral Axis Left Hemisphere Systems Preferentially involved with: Building blocks of language Parts of complex materials Temporal processing Processing unimodal, codable information Executive of discrete motor Right Hemisphere Systems Preferentially involved with: Spatial information Relationship between parts Configuration of complex Processing multi-modal novel information Emotional tone in speech <-->
  • 17. Domains of Neuropsychological Functioning General cognitive functioning Attention Executive-regulatory function Language Visual/Nonverbal processing Memory& Learning Sensory and Motor Academics Social & emotional
  • 18. What are the Potential Neuropsychological Implications of Damage to the White Matter? Impaired executive functions Slowed speed of processing Impaired spatial processing Impaired coordination Dysarthric speech Depressed mood Cummings, 1990
  • 19. What are the Executive Functions? An “umbrella” term, encompassing… those interrelated skills necessary for purposeful, goal-directed activity” ( Anderson, 1998) “ Capacities that enable a person to engage successfully in independent, purposeful, self-serving behaviors” (Lezak, 1993)
  • 20. Role of the Executive Conductor of the orchestra&quot; “ CEO of the corporation” “ General of the army” “ Domain general processes”
  • 21. Executive Functions as the “Conductor of the Orchestra”
  • 22. Functions of the “Conductor” 1. Initiate goal-oriented action 2. Working Memory 3. Plan & Organize 4. Self-monitor & evaluate 5. Inhibit 6. Flexibility 7. Emotional regulation 8. Self-awareness
  • 23. Functional Domains of The Executive Inhibit - stop an action or not react to impulse Shift - move from one task or situation to another Emotional Control - regulate emotional response Initiate - begin task, activity, attention Working Memory - hold information actively in mind Plan - anticipate future events and develop steps Organize - establish, maintain order Self-monitor - attend to behavior/output; revise
  • 24. Functions of the “Orchestra” 1. Perception 2. Conceptual thinking 3. Language processes 3. Visual-spatial processes 4. Memory 5. Sensory inputs 6. Motor outputs 7. Emotion 8. Knowledge & skills social non-social
  • 25. Functions of the “Conductor” 1. Initiate goal-oriented action 2. Working Memory 3. Plan & Organize 4. Self-monitor & evaluate 5. Inhibit 6. Flexibility 7. Emotional regulation 8. Self-awareness Functions of the “Orchestra” 1. Perception 2. Conceptual thinking 3. Language processes 3. Visual-spatial processes 4. Memory 5. Sensory inputs 6. Motor outputs 7. Emotion 8. Knowledge & skills social non-social
  • 26. Critical features of Executive Control Functions (Denckla 1995) Provide for delayed responding Future-oriented Strategic action selection Intentionality Anticipatory Set Freedom from interference Ability to sequence behavioral outputs
  • 27. Demand Situations for Executive Functions Multi-step tasks/ learning Novelty (lack of experience base) vs Automaticity (familiar) High vs low stress Future vs present orientation Intentional action selection
  • 28. Outcome of “Good” Executive Function Purposeful, goal-directed activity Active problem solving Self-control Independence Reliability and consistency Positive self-efficacy Internal locus of control
  • 29. The Frontal lobes: Strategic executive Conductor Orchestra
  • 30. Neuroanatomic Organization: Frontal lobes are densely connected with other cortical and subcortical regions Prefrontal system is highly, reciprocally interconnected with the limbic (motivational) system, reticular activating (arousal) system posterior association cortex (perceptual/ cognitive processes and knowledge base) motor (action) regions of the frontal lobes
  • 31. Interventions: General Principles Teach goal-directed problem-solving process , within everyday meaningful routines, having real-world relevance and application, using key people (parents/ teachers/ peers) as models, “coaches” (Co-conductor).
  • 32. Interventions: General Principles External to internal process External models of multi-step problem-solving routines External guidance to develop & implement everyday routines Practice application/ use of routines Fade external support to cueing internal generation & use of routines
  • 33. Interventions: General Principles External to internal process Internal control to generate & use specific problem-solving routine Generalization to new situation, requiring some external guidance Accumulate experience, examine conditions for selective use of various routines Feedback throughout (i.e., reward)
  • 34. Structuring an executive function intervention program Use of everyday routines with (e.g., Goal-Plan-Do-Review) Support working memory via “hard copy” of routine Allowing child to become increasingly more active in formulating plans and reviewing their performance
  • 35. What Do We Hope to Learn? By using a developmental approach to analyzing both natural history and response to treatment we hope to discover information about . . . neurobehavioral/neuropsychological associations with localized dysfunction Age related differences in neurobehavioral/ neuropsychological sequelae Other phenomena such as how intervention might change the trajectory of development
  • 36. What Do We Hope to Learn? Neuropsychological studies of UCD can help to identify specific effects on the brain associated with UCD and correlate these findings with behavior and outcome. The impact of UCD occurring at different stages of development will help us to better understand the impact of the disease process on the developing brain. The quantification of neuropsychological and neurobehavioral outcomes will be increasingly important in determining the efficacy of interventions. Efficacious educational/ behavioral interventions for children with UCD based on their neuropsychological profile.