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HISTORICAL OVERVIEW OF ADHD. 1920-1937Post-encephalitic syndrome1937Minimal Brain Damage 1960s Minimal Brain Dysfunction 1968 Hyperkinetic Reaction of Childhood (DSM-II) 1980 Attention Deficit Disorder, with or without hyperactivity (DSM-III) 1987 Attention Deficit Hyperactivity Disorder (DSM III-R) 1994 Attention Deficit/Hyperactivity Disorder (DSM-IV).
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1. NEUROPSYCHOLOGICAL CONSIDERATIONS IN THE EVALUATION OF ADHD Francis M. Crinella, Ph.D.
Clinical Professor of Pediatrics, Psychiatry & Human Behavior, & Physical Medicine & Rehabilitation
Director, Neuropsychology Laboratory
Child Development Center
University of California, Irvine
3. DSM-IV SYMPTOMS OF ADHD INATTENTION
CAN�T ATTEND TO DETAILS
CAN�T SUSTAIN ATTENTION
DOESN�T LISTEN
FAILS TO FINISH
CAN�T ORGANIZE TASKS
AVOIDS SCHOOLWORK
LOSES THINGS
EASILY DISTRACTED
FORGETFUL HYPERACTIVITY/IMPULSIVITY
FIDGETS
CAN�T STAY SEATED
RUN ABOUT AND CLIMBS
CAN�T PLAY QUIETLY
IS OFTEN ON THE GO
TALKS TOO MUCH
BLURTS OUT ANSWERS
CAN�T WAIT TURN
INTERRUPTS OR INTRUDES
8. METHODS OF ARRIVING AT DIAGNOSIS OF ADHD BEHAVIORAL
PSYCHIATRIC INTERVIEW/BIOSOCIAL HISTORY
STANDARDIZED RATING TECHNIQUES
CHECKLISTS/minimum criteria (e.g., DSM-IV criteria)
RATING SCALES/cut-off scores (e.g., Conners, SWAN)
DIRECT OBSERVATION
BEHAVIOR SAMPLING
PSYCHOMETRIC
NEUROPSYCHOLOGICAL
9. CRITIQUE OF BEHAVIORAL METHODS PSYCHIATRIC INTERVIEW
Biosocial history--95% of diagnosis is history (Adolf Meyer, 1915)
But:
Getting adequate history is an extraordinarily lengthy process
Focus of history may be based on interviewer experience and/or idiosyncracies (e.g., adaptation level)
Interviewee may not be accurate (or even biased)
10. CRITIQUE OF BEHAVIORAL METHODS PSYCHIATRIC INTERVIEW
Biosocial history augmented by in-office observations
Artificial setting�symptoms of concern may not be observed
11. CRITIQUE OF BEHAVIORAL METHODS RATING TECHNIQUES
CHECKLISTS
Minimum criteria for diagnosis (e.g., DSM-IV criteria)
Must be observed in more than one setting
Problem: Different sets of items will all satisfy Diagnostic Criteria
12. SAMPLE CONFIGURATION OF A CHILD�S DSM-IV SYMPTOMS OF ADHD�CASE MEETS CRITERIA FOR PRIMARILY HYPERACTIVE SUBTYPE
13. SYMPTOM CHECKLISTS FOR TWO CHILDREN WHO MEET CRITERIA FOR ADHD, HYPERACTIVE/IMPULSIVE SUBTYPE
14. NUMBER OF POSSIBLE DSM-IV SYMPTOM CONFIGURATIONS THAT MEET CRITERIA FOR DIAGNOSIS OF ADHD FOR HYPERACTIVE SUBTYPE:
NUMBER OF VARIATIONS ON 9 CRITERIA
9/6 = 84
9/7 = 36
9/8 = 9
9/9 = 1
? = 130
15. CRITIQUE OF BEHAVIORAL METHODS RATING SCALES
Score based on sum of scores for individual items (e.g., �fidgety� Always = 3; Often = 2; Sometimes = 1; never = 0)
Total score used for cut-off lacks differentiation
Profile analysis reveals multiple subtypes
Subtype profiles lack external validation
16. RATING ITEM: �FIDGETS�
17. UCI-CDC Parent/Teacher Ratings of Behavioral Competencies
48 items
Subjects rated on positive traits
Age-based reference group (i.e., �Compared to same-age children, how well is your child able to sit still in class?�)
Rating scheme:
1. Very poorly�worse than all but as few children this age
2. Not too well�most children this age do better (well <average
3. Fair�better than quite a few children this age (slightly <average)
4. Fairly well�better than many children this age, (slightly >average)
5. Good�better than most children this age (well >average)
6. Excellent�better than all but a few children this age
18. UCI-CDC PARENT/TEACHER RATINGS OF BEHAVIORAL COMPETENCIES ADVANTAGES:
Multiple dimensions of behavior determined by factor analysis
Inter-rater reliability established for each dimension
Norms for mothers, fathers & teachers
Raw scores converted to percentile rankings
19. TYPICAL DISTRIBUTION OF RATINGS ON UCI-CDC PARENT-TEACHER RATING SCALE
22. UCI-CDC Parent/Teacher Ratings of Behavioral Competencies Major drawbacks:
Must clinically account for differences among raters
Fails to elucidate neurocognitive processes underlying behavioral competencies
23. NEUROPSYCHOLOGICAL EVALUATION Assumptions:
ADHD has a biological basis
ADHD reflects dysfunction in specific neural networks
Variations in neuropsychological test performance reflect integrity of underlying neural systems
Specific neurocognitive deficits in ADHD reflect impairment of attentional network
24. EVIDENCE FOR BIOLOGICAL BASIS OF ADHD NEUROCHEMICAL
GENETIC
ELECTROPHYSIOLOGICAL RECORDINGS
FUNCTIONAL IMAGING
CORRELATIVE NEUROANATOMICAL STUDIES
26. BIOLOGICAL BASIS OF ADHD
NEUROCHEMICAL
PSYCHOPHARMACOLOGY
MOST EFFECTIVE TREATMENT--CNS STIMULANTS
DEXTROAMPHETAMINES
METHYLPHENIDATES
EFFECTS:
Improved classroom behavior
Improved academic productivity
Improved peer/adult interactions
Less frequent oppositional conduct
Reduced aggression
27. BIOLOGICAL BASIS OF ADHD GENETIC
BEFORE MOLECULAR BIOLOGY
Catecholamine hypothesis�genetic variations in brain neurochemistry (Wender, 1971)
Family genetic studies (e.g., Faroane, Biederman, Chen et al., 1992)
AFTER MOLECULAR BIOLOGY
Subsensitive dopamine receptor hypothesis; DRD4 gene (LaHoste, Swanson, Wigal, et al., 1996)
Dopamine transporter gene (Cook, Stein, Krasowski, et al., 1995)
28. BIOLOGICAL BASIS OF ADHD GENETICS
Coding region of DRD4 gene for D4 receptor
Located on chromosome 11p
High degree of variability in 3rd cytoplasmic loop
48 bp region can be repeated two to eleven times
Variants display different pharmacological properties
DRD4 mRNA in frontal and prefrontal brain regions
30. BIOLOGICAL BASES OF ADHD FUNCTIONAL BRAIN IMAGING
Evidence before modern imaging methods
MBD hypothesis (Clements et al, 1963)
Neuropsychology of MBD (Crinella, 1972)
Evidence from modern imaging methods
Methods used: PET; SPECT; fMRI
Results: Variations in size and symmetry of brain structures (e.g., Swanson & Castellanos, 1997)
Structures involved:
FRONTO-STRIATAL NETWORK
CAUDATE NUCLEUS
BASAL GANGLIA
33. RECENT BRAIN IMAGING STUDIES IN ADHD
34. BIOLOGICAL BASIS OF ADHD 4. ELECTROPHYSIOLOGY
Early studies of analog EEG
Satterfield, J.H., & Schell, A.M. (1984). Childhood brain function differences in delinquent and non-delinquent hyperactive boys. Electroencephalography and Clinical Neurophysiology, 57, 199-207.
Finding: Abnormal maturational effects of auditory event-related potential differentiated ADHD from non-ADHD subjects
Recent brain mapping studies
Pliszka, S.R., Liotti, M., & Woldorff, M.G. (2000). Inhibitory control in children with attention-deficit/hyperactivity disorder: event related potential identify the processing component and timing of an impaired r right-frontal response-inhibition mechanism. Biological Psychiatry, 48, 238-46.
36. BIOLOGICAL BASIS OF ADHD 5. CORRELATIVE NEUROANATOMY
TRADITIONAL APPROACH TO STUDYING BRAIN-BEHAVIOR RELATIONSHIPS
Experimental removal of brain structures
Observation of effect on specific behavioral functions
Necessary to identify functions affected by ADHD
37. DEFINITIONS OF ATTENTION �A special function was instituted which had periodically to search the outer world in order that its data might be already familiar if an urgent inner need should arise: This function was attention. Its activity meets the sense impressions half way, instead of awaiting their appearance. At the same time, there was probably introduced a system of notation, whose task was to deposit the result of this periodic activity of consciousness�a part of which we call memory.�
38. �A special function was instituted which had periodically to search the outer world in order that its data might be already familiar if an urgent inner need should arise: This function was attention. Its activity meets the sense impressions half way, instead of awaiting their appearance. At the same time, there was probably introduced a system of notation, whose task was to deposit the result of this periodic activity of consciousness�a part of which we call memory.�
Sigmund Freud
�Formulations regarding the two principles of mental functioning.� (1911)
39. Everyone knows what attention is. It is the taking possession of the mind in clear and vivid form of one out of what seem several simultaneous object or trains of thought.
40. Attention operates by changing the relative activity within specified anatomical areas that perform computations
41. DISTINCT ANATOMICAL NETWORKS CARRY OUT SPECIFIC ASPECTS OF ATTENTION ALERTING NETWORK
LOCATION: ARAS, ETC.
FUNCTION: ACHIEVE AND MAINTAIN STATE OF READINESS
ORIENTING NETWORK
LOCATIONS: PARIETAL LOBE, SUPERIOR COLLICULUS & PULVINAR
FUNCTION: REACT TO SENSORY STIMULI
EXECUTIVE NETWORK
LOCATION: ANTERIOR CINGULATE; DORSOLATERAL FRONTAL CORTEX & BASAL GANGLIA
FUNCTIONS:
CONTROL NEURAL RESPONSES TO STIMULI
GENERATE NEW INFORMATION FROM LONG TERM MEMORY
PRIORITIZE OPERATION OF OTHER BRAIN AREAS
42. ADHD and EF ADHD is a disorder of Executive Function (Barkley, 1997)
43. SOME FEATURES OF EXECUTIVE FUNCTION Decision as to just what the problem is that needs to be solved
Selection of lower-order components
Selection of one or more representations of organizations for information
Selection of a strategy for combining lower order components
Decision regarding tradeoffs in the speed and accuracies with which various components are executed
Solution monitoring
44. BRIEF DEFINITIONS OF EXECUTIVE FUNCTION
Processes used to plan, monitor and revise strategies of information processing (STERNBERG. 1985)
Appropriate set maintenance to achieve a future goal (PENNINGTON, WELSH & GROSSIER, 1990)
A process which enables the brain to function as many machines in one, setting and resetting itself dozens of times in the course of a day, now for one type of operation, now for another (SPERRY, 1955)
A process that alters the probability of subsequent responses to an event, thereby altering the probability of later consequences (Barkley, 1997).
49. EXECUTIVE FUNCTION DEFICITS ASSOCIATED WITH LESIONS IN RODENT DOPAMINE NETWORK
Shifting cognitive sets
Planning behavioral sequences
Inhibition of motor reactivity
Response flexibility
50. TESTS OF EXECUTIVE FUNCTION IN THE HUMAN NEUROPSYCHOLOGY LABORATORY By definition, no test can be performed in the absence of executive control
Executive functions must be differentiated from other cognitive
abstract reasoning
crystallized problem solving
long term memory
sensory-perceptual processing
motor control systems
Motivational states
Which tests do this best?
51. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD WISC-III:
PERFORMANCE > VERBAL IQ
VERBAL > PERFORMANCE IQ
ACID/ACIDS PROFILE
FREEDOM FROM DISTRACTIBILITY INDEX
PROCESSING SPEED INDEX
52. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD
WISC-III
1. PERFORMANCE > VERBAL
53. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD
Critique: PERFORMANCE > VERBAL
Same pattern occurs in:
English as 2nd language
Receptive and/or expressive dysphasia
Left hemisphere tumors
Conduct disorder
Specific learning disabilities
54. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD
WISC-III
2. VERBAL>PERFORMANCE
EVIDENCE OF INATTENTIVE SUBTYPE?
55. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD
Critique: VERBAL>PERFORMANCE
Same pattern occurs in:
Non-verbal learning disability
Cerebral palsy/fine motor control deficits
Depression
Obsessive compulsive disorder
Visual-spatial defects
56. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD WISC-III
3. �ACIDS� Index:
Arithmetic
Coding
Information
Digit Span
Symbol Search)
57. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD Critique of ACIDS Index
Arithmetic is sensitive to specific learning disabilities (e.g., dyscalculia secondary to developmental Gerstmann syndrome), dysphasias, anxiety states, psychotic states, etc.
Coding is sensitive to deficits in motor control, visual perception, anxiety, depression, OCD, etc.
Information is sensitive to cultural bias, lack of educational opportunity, specific learning disabilities (e.g., dyslexias), dysphasias, long term memory disorders, etc.
Digit Span is affected by anxiety, schizophrenia, bipolar illness, dysphasia, etc. Digits reversed, but not forward, has high correlation with general intelligence.
Symbol Search is sensitive to deficits in visual acuity, visual perception, motor control, depression, anxiety, obsessive compulsive disorder, etc.
58. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD WISC-III
4. Processing Speed index
Based on Coding and symbol search subtests
59. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD Critique of Processing Speed index:
Both Coding and Symbol search are are timed
Coding is sensitive to deficits in motor control, visual perception, anxiety, obsessive compulsive disorder, depression, etc.
Symbol Search is sensitive to deficits in visual acuity, visual perception, depression, anxiety, obsessive compulsive disorder, etc.
60. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD WISC-III
FREEDOM FROM DISTRACTIBILITY
Based on Arithmetic and Digit Span
61. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD CRITIQUE OF FREEDOM FROM DISTRACTIBILITY INDEX:
Arithmetic is sensitive to specific learning disabilities (e.g., dyscalculia), dysphasias, anxiety states, psychotic states, etc.
Digit Span is affected by anxiety, schizophrenia, bipolar illness, dysphasia, etc.
Digits Backward, but not forward, has moderately high correlation with general intelligence
62. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD
PERFORMANCE DISCREPANCY SCORE
Observed academic achievement vs IQ-based academic achievement expectation
63. TRADITIONAL PSYCHOMETRIC APPROACHES TO IDENTIFICATION OF ADHD
Critique: Observed vs expected achievement
Can reflect specific learning disabilities, low motivation, depression, adjustment disorder, test-taking anxiety, memory defects, etc.
64. MORE SPECIFIC NEUROPSYCHOLOGICAL APPROACHES TO IDENTIFICATION OF ADHD
BASED ON LABORATORY MEASURES OF EXECUTIVE FUNCTION
CONTINUOUS PERFORMANCE TEST
FOCUSES ON SPECIFIC AREAS OF EXECUTIVE FUNCTION
TASK PERSISTENCE
VIGILANCE
IMPULSE CONTROL
REGULATION OF AROUSAL LEVEL
65. MORE SPECIFIC NEUROPSYCHOLOGICAL APPROACHES TO IDENTIFICATION OF ADHD
1. CONTINUOUS PERFORMANCE TEST
FOCUSES ON SPECIFIC AREAS OF EXECUTIVE FUNCTION
TASK PERSISTENCE
VIGILANCE
IMPULSE CONTROL
REGULATION OF AROUSAL LEVEL
66. PRESS BUTTON EVERY TIME A LETTER APPEARS
67. EXCEPT WHEN THE LETTER �X� APPEARS
68. CONTINUOUS PERFORMANCE TEST SCORING CATEGORIES:
Omissions
Commissions
Overall Processing Speed
Overall Attentional Variability
Perceptual Sensitivity
Risk Taking
Perseverations
Speed Decrement Over time
Variability Over time
Activation/arousal
72. CONTINUOUS PERFORMANCE TEST NON-ADHD CONDITIONS THAT CAN AFFECT SCORES:
Commissions: anxiety; toxic exposure
Omissions: depression; dyspraxia
Overall Processing Speed: depression; anxiety
Perceptual Sensitivity: Visual acuity; dyseidetic dyslexia
Risk Taking: psychopathy; anxiety
Perseverations: psychomotor retardation; frontal lobe damage
Speed Decrement Over time: diabetes; hypothyroidism
Activation/arousal: schizotypal conditions (blocking)
73. MORE SPECIFIC NEUROPSYCHOLOGICAL APPROACHES TO IDENTIFICATION OF ADHD
2. WISCONSIN CARD SORTING TEST
FOCUSES ON SPECIFIC AREAS OF EXECUTIVE FUNCTION:
SET FORMATION
SET MAINTENANCE
SET SHIFTING
74. WISCONSIN CARD SORTING TEST
75. MORE SPECIFIC NEUROPSYCHOLOGICAL APPROACHES TO IDENTIFICATION OF ADHD
CRITIQUE OF WISCONSIN CARD SORTING TEST
Set formation can be affected by depression, lowered motivational states, frank retardation
Set shifting difficulties are sometimes seen in anxious people
Loss of set is seen in major psychiatric illness, substance abuse, etc.
76. MORE SPECIFIC NEUROPSYCHOLOGICAL APPROACHES TO IDENTIFICATION OF ADHD
3. WIDE RANGE ASSESSMENT OF LEARNING AND MEMORY (WRAML)
FOCUSES ON SPECIFIC AREAS OF EXECUTIVE FUNCTION:
WORKING MEMORY
SEQUENCING AND MENTAL CONTROL
RESISTANCE TO INTERFERENCE
78. MORE SPECIFIC NEUROPSYCHOLOGICAL APPROACHES TO IDENTIFICATION OF ADHD
CRITIQUE OF WIDE RANGE ASSESSMENT OF LEARNING AND MEMORY (WRAML)
AUDITORY WORKING MEMORY DEFICITS MUST BE DIFFERENTIATED FROM AUDITORY PROCESSING DEFICITS, DYSPHASIAS, ANXIETY STATES, ETC.
SEQUENCING AND MENTAL CONTROL DEFICITS ARE ALSO CHARACTERISTICS OF THOUGHT AND DISORDERS
SUSCEPTIBILITY TO INTERFERENCE MAY BE ASSOCIATED WITH ALMOST ANY NEURODEVELOPMENTAL OR PSYCHIATRIC CONDITIION
79. CONCLUSIONS
THE BEST WAY TO ENSURE AN ACCURATE DIAGNOSIS IS TO USE A COMBINATION OF HISTORY, RATING SCALES, DIRECT OBSERVATIONS, AND A CAREFULLY SELECTED BATTERY OF NEUROPSYCHOLOGICAL TESTS
NEUROPSYCHOLOGICAL TESTS THAT ARE BASED ON LABORATORY METHODS OF ASSESSING EXECUTIVE FUNCTION PROVIDE INFORMATION THAT IS MOST PERTINENT TO THE COGNITIVE DEFICITS FOUND IN ADHD
NEVERTHELESS, PERFORMANCE DEFICITS ON SPECIFIC TESTS MAY BE ATTRIBUTABLE TO ANY NUMBER OF NON-ADHD SYMPTOM COMPLEXES