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Theoretical Models of Explanation. Robert A. Leark, Ph.D. Fellow, National Academy of Neuropsychology Associate Professor, Behavioral & Social Sciences Pacific Christian College, Fullerton, CA Vice President, Research & Development, UAD., Inc. Theoretical Models of Explanation.

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slide1
Theoretical Models of Explanation

Robert A. Leark, Ph.D.

Fellow, National Academy of Neuropsychology

Associate Professor, Behavioral & Social Sciences

Pacific Christian College, Fullerton, CA

Vice President, Research & Development, UAD., Inc

theoretical models of explanation
Theoretical Models of Explanation
  • Multiple models of explanation for ADHD
  • Two have emerged as primary theories
    • Barkley & Gordon
    • Brown
  • Attention & executive functioning is multifaceted: difficult to map
theoretical models of explanation1
Theoretical Models of Explanation
  • Recent Historical Models
    • Attention is not a unitary construct
    • Zubin (1995): attention conceptualized as having multiple components or elements
    • Psychiatric models:attention is process that controls the flow of information processing
theoretical models of explanation2
Theoretical Models of Explanation
  • Recent Historical Models
    • Psychiatric models: 3 components of attention:
      • selectivity
      • capacity
      • sustained concentration
      • All of these must be sufficient enough to interfere with daily activities
theoretical models of explanation3
Theoretical Models of Explanation
  • Recent Historical Models
    • Neuropsychologists typically conceptualize attention as:
      • selective processing
      • awareness of stimuli
theoretical models of explanation4
Theoretical Models of Explanation
  • Recent Historical Models
    • Neuropsychologists use attention to refer to:
      • initiation or focusing of attention
      • sustaining attention or vigilance
      • inhibiting response to irrelevant stimuli (selective attention)
      • shifting of attention
theoretical models of explanation5
Theoretical Models of Explanation
  • Riccio, Reynolds & Lowe (2001) summarize components of attention
      • Arousal/alertness
        • motor intention/initiation
      • Selective Attention
        • focusing of attention (inhibiting/filtering)
        • divided attention
        • encoding, rehearsal & retrieval
      • Sustaining attention/concentration
      • Shifting of attention
theoretical models of explanation6
Theoretical Models of Explanation
  • Historical
    • Broadbent (1973) - capacity to take in information is limited, thus information not relevant needs to be filtered out. Information filtered out dependent upon stimulus characteristics (intensity, importance, novelty, etc.)
theoretical models of explanation7
Theoretical Models of Explanation
  • Historical
    • 2nd model stresses arousal - here optimal arousal (alertness) is necessary for effortful, organized function (Hebb, 1958)
    • Pribram (1975) - arousal is short-lived response to stimulus. Arousal is the general state of the individual that allows for & effects attentional processing
theoretical models of explanation8
Theoretical Models of Explanation
  • Historical
    • Mirsky (1987) proposed three factor model for attention
      • focusing of attention
      • sustaining of attention
      • shifting of attention
theoretical models of explanation9
Theoretical Models of Explanation
  • Historical
    • Mirsky model
      • selective attention: part of process of focusing attention (level of distractibility if deficient)
      • Sustained attention: ability to maintain that focus over time
      • Shifting of attention: necessary for adaptation & inhibition
theoretical models of explanation10
Theoretical Models of Explanation
  • Historical
    • Luria’s model
      • attention central to model
      • 2 attentional systems: reflexive & nonreflexive
      • reflexive: orienting response/appears early in development
      • nonreflexive: result of social learning/develops slower
      • limbic system & frontal lobe mediate attention
theoretical models of explanation11
Theoretical Models of Explanation
  • Historical
    • Luria’s model
      • executive functions linked to mediating attention
      • executive functions:
        • self-direction
        • goal directedness
        • self-regulation
        • response selection
        • response inhibition
theoretical models of explanation12
Theoretical Models of Explanation
  • Mesulam (1981): model similar to Luria’s
    • Model was specific to understanding phenomenon of hemiattention or hemineglect as result of brain damage
    • Attentional processes: reticular system, limbic system, frontal cortex & posterior parietal cortex
theoretical models of explanation13
Theoretical Models of Explanation
  • Mesulam (1981)
    • Subcortical influences from limbic system, RAS & hypothalamus part of system matrix needed for control of attention
    • Frontal lobes influenced by & also influence the subcortical activity
theoretical models of explanation14
Theoretical Models of Explanation
  • Historical
    • Summary: attention involves at least two separate neural systems
      • activation system: thought to be centered in left hemisphere & involved in sequential/analytic operations
      • arousal: thought to be centered in right hemisphere & involved in parallel or holistic processing & maintenance of attention
theoretical models of explanation15
Theoretical Models of Explanation
  • Barkley & Gordon (1994,1997,1998,2001)
    • inattention emerges alongside a general pattern of impulsiveness & hyperactivity
    • deficits in self-control lead to secondary impairments in four executive functions
theoretical models of explanation16
Theoretical Models of Explanation
  • Barkley & Gordon (1994,1997,1998,2001)
    • Nonverbal working memory - sensing to the self
    • verbal working memory - internalized speech
    • emotional/motivation self regulation - private emotion/motivation to the self
    • reconstruction or generativity - cover play & behavioral simulation to the self
theoretical models of explanation17
Theoretical Models of Explanation
  • Barkley & Gordon (1994,1997,1998,2001)
    • basal ganglia
    • dopaminergic
    • disinhibition key factor to etiology
theoretical models of explanation18
Theoretical Models of Explanation
  • Barkley & Gordon (2001)
    • ADHD is a longstanding, pervasive and chronically impairing consequence of poor inhibition and/or inattention
    • model is consistent with the DSM-Ivr criteria
    • symptoms occur prior to age 7
theoretical models of explanation19
Theoretical Models of Explanation
  • Brown (1996)
    • etiology is on purely inattentive
    • stresses there has been an over-focus on disinhibition and an under appreciation of arousal, activation and working memory
    • onset of symptoms can occur after age 7
theoretical models of explanation20
Theoretical Models of Explanation
  • Brown
    • ADHD criteria includes inattentive individuals who are not impulsive
    • “all inattention is ADD/ADHD”
    • ADHD is a suitable diagnosis for a broad range of symptoms
    • Brown’s rating scale: BADDS - modeled upon this theoretical approach
theoretical models of explanation21
Theoretical Models of Explanation
  • Brown - ADD/ADHD is still an executive dysfunction of five clusters
    • organizing & activating to work
    • sustaining attention & concentration
    • sustaining energy & effort
    • managing affective interference
    • utilizing working memory & recall
theoretical models of explanation22
Theoretical Models of Explanation
  • Key components of models
    • inattention is the king of all nonspecific symptoms (Gordon, 1995)
    • inattention can emerge as a feature from a variety of psychiatric & medical circumstances
clinical care
Clinical Care
  • History - conception through current age
    • early life predictors
      • poor or inability to establish early life routines
      • motor hyperactivity at early age
    • ADHD is a diagnosis by exclusion:
      • low APGAR
      • hypoxia
      • central nervous system diseases
clinical care1
Clinical Care
  • History
    • ADHD is a diagnosis by exclusion:
      • head injury/loss of consciousness
      • metabolic disorders
      • seizure disorders
      • apnea
      • other medical conditions
      • Other psychiatric conditions
clinical care2
Clinical Care
  • History
    • ADHD is a diagnosis by exclusion:
      • ADHD is diagnosed only when other disorders do not best account for the symptoms
      • symptoms may be same, etiology somewhat different (or unknown)
      • treatment may even be the same
clinical care3
Clinical Care
  • History
    • Problems with overlapping co-morbidity create need to be able to stick to DSM IV criteria: age 7 issue
    • May not be possible to determine if signs & symptoms might have been present (such as trauma-abuse cases) if such trauma had not occured
clinical care4
Clinical Care
  • Diagnostic procedures
    • Behavioral rating scales
    • Measure of sustained attention & impulse control
    • Medication follow-up
clinical care5
Clinical Care
  • Behavior Rating Scales
    • Child-Behavior Checklist (CBCL)
      • Parent Rating
      • Teacher Rating
      • Item pure scales: no item overlap
clinical care6
Clinical Care
  • Behavior Rating Scales
    • BASC (Reynolds & Kamphaus)
      • Ages 2 - 18
      • Item pure scales: no item overlap
      • easy to administer
      • shorter: about 140 items
clinical care7
Clinical Care
  • Behavior Rating Scales
    • BASC (Reynolds & Kamphaus)
      • 2-6: parent/other ratings
      • 7-12: self rating

parent rating

teacher rating

student observation guide

clinical care8
Clinical Care
  • Behavior Rating Scales
    • BASC (Reynolds & Kamphaus)
      • 13-18: self

parent

teacher

student observation guide

clinical care9
Clinical Care
  • Behavior Rating Scales
    • BASC (Reynolds & Kamphaus)
      • New: ADHD predictor

derived from discriminant function analysis using best predictors

clinical care10
Clinical Care
  • Behavior Rating Scales
    • Parent Ratings generally show more impairment for child than do Teacher Ratings
    • May want to use “blind” ratings from Teacher - where Teacher is unaware of use of medication
    • helpful with treatment follow up studies
clinical care issues
Clinical Care Issues
  • Treatment Issues
    • Treatment consistent with theoretical models for ADHD?
    • NIMH Treatment Guidelines
      • Medication effective, data indicated medication alone more effective than
        • Medication & behavioral treatment
        • Behavioral treatment alone
        • Other modalities
clinical care issues1
Clinical Care Issues
  • Behavioral therapies
    • Treatment goal: improve/increase inhibition
      • Treatment strategies must be consistent with goal
      • Treatment strategies must be incorporated into family system
        • Often source of increase problems if family not stable
        • Noncompliance by parents
clinical care issues2
Clinical Care Issues
  • Newer treatment modalities
    • Neurofeedback
      • Issues:standardization of treatment
      • Length of treatment
      • Treatment cessation: maintenance of gains
clinical care11
Clinical Care
  • Treatment considerations
    • Stimulant medication is standard of care
    • NIMH revenue of ADHD studies suggested that
      • Stimulant medication alone better than stimulant medication and behavioral therapy, behavioral therapy alone or placebo.
clinical care12
Clinical Care
  • Treatment considerations
    • Medications
      • methylphenidate hydrochloride
        • Ritalin
        • Sustained Release
        • Concerta
      • Amphetamines
        • Adderall
        • Dexedrine
clinical care13
Clinical Care
  • Treatment considerations
    • Medication Issues
      • kg/mg - is this an appropriate method for titration?
        • Titration to cognitive measures produces an overall lower mean dosage than for behavioral measures
      • b.i.d. or t.i.d.
        • Dosage?
        • Time of day?
clinical care14
Clinical Care
  • Treatment considerations
    • Behavioral Treatment
      • home and classroom based intervention strategies
      • requires cooperation of parents & teachers
      • effective - but best when used with medication
clinical care15
Clinical Care
  • Treatment considerations
    • Family Therapies
      • Family system with behavioral interventions for child
      • Does require intact family system
clinical care16
Clinical Care
  • Treatment considerations
    • Stimulant medication is standard of care
    • NIMH revenue of ADHD studies suggested that
      • Stimulant medication alone better than stimulant medication and behavioral therapy, behavioral therapy alone or placebo.
clinical care issues3
Clinical Care Issues
  • Summary: treatment goals and plans need to be consistent with theoretical models of ADHD
  • Medication: ritalin, adderall, others
clinical care issues4
Clinical Care Issues
  • Summary: treatment goals and plans need to be consistent with theoretical models of ADHD
  • Medication: ritalin, adderall, others
slide49
Grew out of need to provide for a measurement of attention and impulse control
  • Wanted actual measurement not behavioral attributes
slide50
Advances in electronics provided format
  • Historically, measures of sustained attention are intrical to the history of psychology
  • Study cited as the basis for the origin of cpts is: Rosvold, Mirsky, Sarason, Bransome & Beck (1956). A continuous performance test of brain damage. Journal of Consulting Psychology, 20, 3343-350.
background history
Background & History
  • For the Rosvold et al study (1956) the purpose was to study vigilance.
  • The designed task was for a letter to appear one at a time using a fixed rate of presentation (ISI) at 920 ms.
  • Press the lever whenever the letter x appeared
background history1
Background & History
  • The subject also had another task - to inhibit responding when any other letter appeared.
  • Task became known as the X type cpt
  • Rosvold et al (1956) also reported use of a second type cpt: the AX-type
  • For this task, the subject was to press the lever if a letter A preceded the letter X
continuous performance tests1
Continuous Performance Tests
  • Still needed to inhibit action
  • Authors found the task to adequately classify 84.2% to 89.5% of younger subjects who had brain damage
  • Greater classification was for AX-type
continuous performance tests2
Continuous Performance Tests
  • Since this study - have been literally hundreds of studies utilizing a cpt task of some sort- also report Riccio,Reynolds & Lowe (2001) over 400 articles using cpts
  • Riccio et al (2001) reported finding 162 research studies using some form of group comparison with children and some sort of cpt task
continuous performance tests3
Continuous Performance Tests
  • Research studies may use a cpt designed only for that study
    • lacking normative development
    • increased difficulty with study replication
  • Easy to program (if you find programming easy)
  • Many variations of design
continuous performance tests4
Continuous Performance Tests
  • Cpt variations
    • stimulus presentation
    • interval of stimulus
    • stimulus modality
    • distraction modes
    • adaptive cpts
    • length of task
    • target/nontarget ratio
variations of cpts
Variations of CPTs
  • Stimulus Presentation
    • X- type (easier task)
    • AX- type (more difficult task)
    • XX-type
    • Numeric (variation of X or AX type)
      • GDS uses numeric stimulus
      • 1 - 9 type task (number 1 followed by number 9)
variations of cpts1
Variations of CPTs
  • Interstimulus Interval (ISI) variations
    • Rosvold et al (1956) used 920 ms
    • some have used from 50 to 1500 ms (Friedman, Vaughan & Erlenmeyer-Kimling (1981)
    • 500 to 1500 ms (Schachar, Logan, Wachsmuth & Chajczyk, 1988)
    • some tasks maintain consistent ISI
    • others use variable ISI within task
variations of cpts2
Variations of CPTs
  • Other component related to ISI is that of stimulus onset asynchrony (SOA)
  • This refers to the onset of the stimulus followed by the onset of the next stimulus
  • i.d., stimulus may “linger” longer allowing task recognition
  • some cpts use variable SOA, others consistent SOA
variations of cpts3
Variations of CPTs
  • ISI - SOA
    • increase ISI decrease SOA
      • shorter SOA may increase “mis-hits”
      • shorter SOA may increase omissions
    • increase ISI increase SOA
      • slower response times
variations of cpts4
Variations of CPTs
  • Stimulus Modality (Visual/Auditory)
    • Non-alphanumeric
      • Square within square (T.O.V.A.)
      • Rabbit (in development)
    • Auditory stimulus presentation models
      • auditory X or AX types
      • auditory numeric
      • tones (T.O.V.A.-A.)
variations of cpts5
Variations of CPTs
  • Distraction
    • these cpts use X or AX-type then add another dimension: interference or distraction
    • goal is to increase level of difficulty
    • distraction task varies by cpt
      • degraded or blurred
      • visual distractions common for visual X or AX cpts
      • auditory distractions
variations of cpts6
Variations of CPTs
  • Adaptive cpts
    • increase level of difficulty as success of task accomplished and maintained
variations of cpts7
Variations of CPTs
  • Length of task
    • Bremer (1989) reported “mini-cpt”
      • 3 minute task
      • 6 minute task available
    • T.O.V.A./T.O.V.A.-A
      • longest
      • 21.6 minutes
variations of cpts8
Variations of CPTs
  • Target/nontarget ratio
    • refers to presentation of targets to nontargets throughout task
    • some use variable others consistent
    • some use variable mixed with variable ISI
comments
Comments
  • Influences on cpt performance
    • directions
    • examiner presence
    • anxiety, depression and the rest of DSM-IV
    • drugs and alcohol (including caffeine)
    • environmental distractions
the big 4
The Big 4
  • 4 major cpts have emerged within the marketplace
  • all report normative and standardization
  • Alphabetical order:
    • Conners’ CPT (“The cpt”??)
    • GDS
    • IVA
    • T.O.V.A./T.O.V.A.-A.
the big 41
The Big 4
  • Conners’ CPT
    • Available from Multihealth Systems, Inc (MHS)*
    • www.mhs.com
    • 800.456.3033

* may be available from other distributors such as PAR or WPS

the big 42
The Big 4
  • Conners’CPT
    • Type: not x
    • Modality: Visual
    • Stimulus display 250 ms
    • ISI varied 1000 to 4000 ms (varied within block)
the big 43
The Big 4
  • Conners’ CPT
    • Target Letter
    • Length 14 minutes
    • Nontargets letters
    • Distraction none
    • Target ratio not varied
the big 44
The Big 4
  • Conners’ CPT
    • Block Timing yes
    • Customized available
    • Examiner presence ?
    • Practice trials yes
    • Standardized instructions yes
the big 45
The Big 4
  • Conners’ CPT Scoring
    • correct hits
    • omission/commission errors
    • d-prime/beta
    • reaction time
    • reaction time standard deviation
the big 46
The Big 4
  • Conners’CPT Scoring
    • slope of standard error
    • slope at ISI change
    • slope of standard error at ISI change
    • overall performance index
the big 47
The Big 4
  • GDS: Gordon Diagnostic System
    • Available from: Gordon Systems, Inc.*
    • www.gsi.com
    • 800.550.2343

* note: may be available from other distributors such as PAR, WPS

the big 48
The Big 4
  • GDS
    • Type AX(numeric)
    • Modality Visual
    • Stimulus display 200 ms
    • ISI 1000/2000 ms

(children adults/preschool)

the big 49
The Big 4
  • GDS
    • Target number
    • Length 9 minutes/6 for preschool
    • Nontargets numbers
    • Distraction yes
    • Target ratio not varied
the big 410
The Big 4
  • GDS
    • Block Timing yes
    • Customized available
    • Examiner presence yes
    • Practice trials yes
the big 411
The Big 4
  • GDS Scoring
    • correct hits
    • omission/commission errors
    • reaction time
    • target related error / random error
the big 412
The Big 4
  • Intermediate Visual and Auditory CPT (IVA) also known as Integrated Visual & Auditory CPT
    • Available from: BrainTrain*
    • www.braintrain-online.com
    • 804.320.0105

* Note: May also be available from other distributors such as PAR, WPS

the big 413
The Big 4
  • IVA
    • Type X
    • Modality Visual & auditory in same task
    • Stimulus Display 167 auditory/500 visual
    • ISI 1500 ms
the big 414
The Big 4
  • IVA
    • Target number
    • Length 13
    • Nontargets numbers
    • Distraction no?
    • Target ratio varied
the big 415
The Big 4
  • IVA
    • Block Timing yes
    • Customized no
    • Examiner presence yes
    • Practice trials yes
the big 416
The Big 4
  • IVA Scoring
    • response control quotient (auditory,visual, full)
    • attention quotient (auditory, visual, full)
    • auditory & visual prudence scores
    • vigilance
    • consistency
    • stamina
the big 417
The Big 4
  • IVA Scoring
    • focus
    • speed
    • balance
    • persistence
    • fine motor/hyperactivity
the big 418
The Big 4
  • IVA Scoring
    • sensoriomotor
    • readiness
    • comprehension
the big 419
The Big 4
  • Test of Variables of Attention (T.O.V.A.) & Test of Variables of Attention-Auditory (T.O.V.A.-A.)
    • Available from: Universal Attention Disorders, Inc.
    • www.tovatest.com
    • 800.729.2886 (800-PAY-ATTN)

*Note: Also available from other distributors such as PAR, WPS

the big 420
The Big 4
  • T.O.V.A./T.O.V.A.-A.
    • Type: X
    • Modality: Visual/Auditory
    • Stimulus display 100 ms
    • ISI 2000 ms
the big 421
The Big 4
  • T.O.V.A./T.O.V.A.-A.
    • Target position of square
    • Length 21.6 mins
    • Nontargets position of square
    • Distraction no
    • Target ratio varied
the big 422
The Big 4
  • T.O.V.A./T.O.V.A.-A.
    • Block Timing yes
    • Customized yes
    • Examiner presences yes
    • Practice trials yes
the big 423
The Big 4
  • T.O.V.A./T.O.V.A.-A. Scoring
    • omission/commission errors
    • response time
    • response time variability
    • d prime
the big 424
The Big 4
  • T.O.V.A./T.O.V.A.-A. Scoring
    • multiple responses
    • anticipatory Responses
    • ADHD scale
    • post commission error response time
t o v a
T.O.V.A.
  • Non-language based stimulus
  • X-type
  • Square within square stimulus
  • Square at top – target
  • Square at bottom - nontarget
t o v a1
T.O.V.A.
  • T.O.V.A.-A. uses two tones:
    • Middle c: non-target
    • G above middle C: target
  • Consistent with paradigm: top is the target
t o v a2
T.O.V.A.
  • Standardized instructions: to be given in language appropriate for subject (native)
  • Examiner must be present: standardization group did have examiner present
  • Prompt for subject to respond as quickly as possible when sees target
t o v a3
T.O.V.A.
  • Separate standardization samples
  • Over 2500 subjects in T.O.V.A.-A.
    • Age 6 & above
    • Ages 19-30
  • Over 2000 subjects in T.O.V.A.
    • Age 4-5: 11.3 minute version
    • One quarter of target frequent/infrequent
t o v a4
T.O.V.A.
  • T.O.V.A.
    • One year age increments ages 6 to 19
    • Data by gender
    • Ages 20 & above: by decade
    • Data by gender
t o v a5
T.O.V.A.
  • Two conditions: target infrequent & target frequent
  • 3.5:1 non-targets for every target (infrequent)
  • 3.5:1 targets for every non-target: (frequent)
  • Stimuli presented in a fixed random model
t o v a6
T.O.V.A.
  • Quarter 1 & 2: target infrequent
    • Subject who is inattentive likely to miss target
    • Measure of attention
    • Omission errors likely
  • Quarter 3 & 4: target frequent
    • Subject who is impulsive likely to “mis-hit”
    • Measure of impulse control
    • Commission errors likely
t o v a7
T.O.V.A.
  • Scores presented by quarters, halves & total for each variable
  • Scoring uses derived standard scores, 100 mean, 15 standard deviation
  • Higher scores reflect better performance, lower scores reflect poorer performance
t o v a8
T.O.V.A.
  • In addition:
    • Z scores
    • Percentiles for RT & RTV
  • Anticipatory errors
    • Responses presented from 200 ms prior to stimulus onset to 200 ms after onset
t o v a9
T.O.V.A.
  • Multiple Responses: pressing button more than once
  • Post-Commission Response Time: following commission error, response time for next correct target identification is recorded
t o v a10
T.O.V.A.
  • Multiple responses rare in standardization group
    • Increased multiple responses decrease validity of subject performance
  • Error Analysis: examiner is able to review all responses to all stimuli over duration of test
t o v a11
T.O.V.A.
  • ADHD score
    • Based upon ROC discriminant function analysis
    • Best 3 predictors for placing subjects in ADHD prediction group
    • Uses subject z scores
t o v a12
T.O.V.A.
  • ADHD score
    • Scores less than or equal to zero (0) indicate subject more likely to be placed in ADHD group
    • Scores above zero (0) indicates subjects less likely to be placed in ADHD group

NOTE: RECALL THAT Z SCORES ARE USED TO DERIVE SCORES

t o v a13
T.O.V.A.
  • D Prime
    • Measure of performance consistency over duration of task
  • Beta: not found to be significant between groups, thus is not reported
t o v a14
T.O.V.A.
  • Construct validity

Actual

Predicted Normal ADHD

Normal 75% 25%

ADHD 23% 77%

Leark, R.A., Dixon, D., Llorentes, A., Allen, M. (2000) Cross-validation & Performance Discriminant Abilities of the T.O.V.A. using DSM-IV criteria. Poster presentation at the 20th Annual Meeting of the National Academy of Neuropsychology. Orlando, FL.

t o v a15
T.O.V.A.
  • Sensitive to malingering
    • Increased errors across all 4 quarters, both halves and total score for omission & commission
    • Decreased response time
    • Increased variability of response time

Leark, R.A., Dixon, D., Hoffman, T. & Hunyh, D.(in press). Effects of Fake Bad performance on the T.O.V.A. Archives of Clinical Neuropsychology

t o v a16
T.O.V.A.
  • Relationship to IQ
    • Greenberg has reported need to adjust T.O.V.A. scores for IQ
    • HOWEVER – Research has indicated this to be a false assumption
t o v a17
T.O.V.A.
  • Chae (1999)
    • T.O.V.A. not found to be significantly correlated with VIQ/PIQ/FSIQ
    • PIQ/FSIQ is moderately related to Omission total scores ( .46 & .44)
    • Picture Arrangement & Object Assembly correlated at -.50 & -.54
t o v a18
T.O.V.A.
  • Chae (1999)
    • Freedom from Distractibility factor not significantly correlated
    • Processing Speed factor not significantly correlated
t o v a19
T.O.V.A.
  • Other studies have reported similar findings
    • At best there is approximately a .50 correlation between FSIQ and T.O.V.A. scores
    • Third factor not significantly correlated with T.O.V.A. scores
  • IQ not factor in T.O.V.A. performance
t o v a20
T.O.V.A.
  • Construct validity for T.O.V.A.-A
    • ADHD (DSM-IV) to normal control children
    • Diagnosis independent of T.O.V.A.-A. performance

All subjects correctly classified using z scores

Leark, R.A., Golden, C.J., Escalande, A. & Allen, M. (2001) Initial Dicriminant Abilities of the T.O.V.A.-A. Poster paper presented at the 21st Annual Meeting of the National Academy of Neuropsychology

t o v a21
T.O.V.A.
  • Temporal Stability of T.O.V.A.
    • Internal coefficients not appropriate for timed tasks
    • Temporal stability: reasonable time interval
      • 90 minutes
      • 1 week
t o v a22
T.O.V.A.
  • 90 Minute Interval

Scalecoefficient

Omission 0.80

Commission 0.78

RT 0.93

RTV 0.77

t o v a23
T.O.V.A.
  • 1 Week Interval
    • ScaleCoefficient
    • Omission 0.86
    • Commission 0.74
    • RT 0.79
    • RTV 0.87
t o v a24
T.O.V.A.
  • Sem
    • Scale 90 Minute 1 Week
    • Omission 6.71 5.61
    • Commission 7.04 7.65
    • RT 3.97 6.87
    • RTV 7.19 5.41

Note: reflects T-scores

t o v a25
T.O.V.A.
  • Relationship to behavioral rating scales
    • Forbes (1998) reported that the T.O.V.A. provided distinct information that added to increased diagnostic accuracy
    • Correlation studies have report significant but moderate correlations between behavioral measures and test variables
t o v a26
T.O.V.A.
  • Forbes (1998)
    • ACTers Hyper OM -.37 COM -.30
    • Oppos OM -.38 COM -.25
    • Attn OM -.25 COM -.16
t o v a27
T.O.V.A.
  • Selden, Pospisil, Michael & Golden (2001)

CBCL-TRF Attention Index

ADHD score .393

TOVA-A COM .372

CPRS Hyperactivity Scale

TOVA OM .423

PIC-R Hyperactivity Scale

TOVA COM .325

t o v a28
T.O.V.A.
  • Continuous Performance Test (CPT)
    • measure of sustained attention & vigilance
    • measure of impulse control
    • long, boring measures
t o v a29
T.O.V.A.
  • Test of Variables of Attention (Greenberg, 1992)
    • T.O.V.A. : non-language stimulus task
    • computer based
    • fixed two second interstimulus interval (ISI)
    • 21.6 minute long task
t o v a31
T.O.V.A.
  • two task paradigms: target infrequent & target frequent
  • a constant 3.5:1 ratio
    • Target Infrequent: 3.5: 1 non-targets to targets
    • Target Frequent: 3.5:1 targets to non-targets
t o v a32
T.O.V.A.
  • Internally clocked
  • Data summarized into quarters, halves and total score
  • Quarters 1 & 2 - target infrequent
  • Quarters 3 & 4 - target frequent
  • Half 1 - target infrequent
  • Half 2 - target frequent
t o v a33
T.O.V.A.
  • Extensive norm development: over 2300 subjects
  • Scaled by age and gender
  • Uses derived standard scores with mean of 100, standard deviation of 15
  • z scores also provided
t o v a34
T.O.V.A.
  • T.O.V.A. Scales
    • Omission - measure of attention/inattention
    • Commission - measure of impulse control
    • Response Time - in milliseconds
    • Response Time Variability - measure of response consistency
    • d’ (d prime) - signal detection measure response consistency
t o v a35
T.O.V.A.
  • Established construct and disciminant validity
  • Established reliability: 90 minute, 1 week, 8 week and 12 week intervals
  • Established sensitivity & specificity (80/20)
t o v a36
T.O.V.A.
  • Semrud-Clikeman & Wical (1999)
    • evaluated attentional difficulties in children with complex partial seizures (CPS), CPS & ADHD, CPS without ADHD, and controls
    • used T.O.V.A. as measure of sustained attention & impulse control

Components of Attention in Children with Complex Partial Seizures with and without ADHD. Epilepsy, 40(2): 211-215.

t o v a37
T.O.V.A.
  • Semrud-Clikeman & Wical (1999) Results:
    • Found poorest performance on the T.O.V.A. by the CPS/ADHD group.
    • Difficulty in attention was noted for children with epilepsy regardless of ADHD
    • When methylphenidate was administered to the ADHD groups - both improved on T.O.V.A. scores
t o v a38
T.O.V.A.
  • Semrud-Clikeman & Wical (1999)
    • Conclusions
      • Epilepsy may dispose children to attention problems that can significantly impair with learning
      • Improvement, as measured by improved T.O.V.A. measures was found for both ADHD groups when methylphenidate was administered
t o v a39
T.O.V.A.
  • Mautner, Thakkar, Kluwe & Leark (in press)
    • NF1, NF1 with ADHD, ADHD & controls
    • NF1 with ADHD & ADHD similar
    • over 15% of the NF1 participants displayed symptoms of ADHD
    • Both the NF1 with ADHD and the ADHD subjects had improved T.O.V.A. scores when methylphenidate was administered

Treatment of ADHD in NF1 Type 1. Developmental Medicine

clinical care17
Clinical Care
  • Treatment considerations
    • Medications
      • methylphenidate hydrochloride
        • Ritalin
        • Sustained Release
        • Concerta
      • Amphetamines
        • Adderall
        • Dexedrine
clinical care18
Clinical Care
  • Treatment considerations
    • Medication Issues
      • kg/mg - is this an appropriate method for titration?
        • Titration to cognitive measures produces an overall lower mean dosage than for behavioral measures
      • b.i.d. or t.i.d.
        • Dosage?
        • Time of day?
clinical care19
Clinical Care
  • Treatment considerations
    • Behavioral Treatment
      • home and classroom based intervention strategies
      • requires cooperation of parents & teachers
      • effective - but best when used with medication
clinical care20
Clinical Care
  • Treatment considerations
    • Family Therapies
      • Family system with behavioral interventions for child
      • Does require intact family system
clinical care21
Clinical Care
  • Treatment considerations
    • Stimulant medication is standard of care
    • NIMH revenue of ADHD studies suggested that
      • Stimulant medication alone better than stimulant medication and behavioral therapy, behavioral therapy alone or placebo.
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