Cognitive Asessment for the
Determination of Mental
Residual Functional Capacity
David J. Schretlen, PhD
OIDAP Meeting
April 29, 2009
Abstract/
Hypothetical
Specific/
Observable/Verifiable
Use Swiss-
hole
micrometer
to adjust
drill press
Use
Swiss-
hole
micrometer
to
adjust
bottling
machine
Carry heavy
Objects
(51-100lbs.)
by hand for
< 50 feet
Hand-
Held
Tools
Carry
bricks
and mortar
to masons
on
scaffolding
using hod
Sit for
long
periods
Use tape
measure
to
measure
lumber
to be
milled
Mechanical
Activities
Things
Carry
Lift
Physical
What is
923 / 27
?
What is
103 / 12
?
< 10
lbs
Managing
Emotions
“Turn the
other
cheek”
if
provoked
at work?
Data People
“Can you…”
“Does the job require you to…”
Use displays,
gauges, meters,
measuring
instruments
Physical and
Mechanical
Activities
Use sight
and visual
information
Getting
Information
Workers directly
involved in
machine
operations
Communicating
With People
Inside the
Organization
Delegate
job activities
to clerical
workers
Mathe-
matical
Reasoning
Dynamic
Strength
Organizing,
Planning,
Prioritizing
Addition
10
lbs
20
lbs
50
lbs
100
lbs
Division
Perceiving
Emotions
Justify
taking
revenge if
you were
strongly
slighted?
See small
details of
close
objects
Unload
70 pound
bags of
salt and
empty into
water
treatment
system
Visually
inspect
newly cut
diamonds
for flaws
without
magnifica-
tion aids
Mental/
Cognitive
Interpersonal/
Temperaments
Color
Discrimi-
nation
Written
Compre-
hension
Emotional
Intelli-
gence
Person-Side Job-Side
1
2
3
4
5
3 digit
by 2 digit
w/
remainder
2 digit
by 1digit,
no
remainder
Repeat-
edly
Occasion-
ally
Physical
Demands
Level
Use
Other
Senses
Abstract/
Hypothetical
Specific/
Observable/Verifiable
Use Swiss-
hole
micrometer
to adjust
drill press
Use
Swiss-
hole
micrometer
to
adjust
bottling
machine
Carry heavy
Objects
(51-100lbs.)
by hand for
< 50 feet
Hand-
Held
Tools
Carry
bricks
and mortar
to masons
on
scaffolding
using hod
Sit for
long
periods
Use tape
measure
to
measure
lumber
to be
milled
Mechanical
Activities
Things
Carry
Lift
Physical
What is
923 / 27
?
What is
103 / 12
?
< 10
lbs
Managing
Emotions
“Turn the
other
cheek”
if
provoked
at work?
Data People
“Can you…”
“Does the job require you to…”
Use displays,
gauges, meters,
measuring
instruments
Physical and
Mechanical
Activities
Use sight
and visual
information
Getting
Information
Workers directly
involved in
machine
operations
Communicating
With People
Inside the
Organization
Delegate
job activities
to clerical
workers
Mathe-
matical
Reasoning
Dynamic
Strength
Organizing,
Planning,
Prioritizing
Addition
10
lbs
20
lbs
50
lbs
100
lbs
Division
Perceiving
Emotions
Justify
taking
revenge if
you were
strongly
slighted?
See small
details of
close
objects
Unload
70 pound
bags of
salt and
empty into
water
treatment
system
Visually
inspect
newly cut
diamonds
for flaws
without
magnifica-
tion aids
Mental/
Cognitive
Interpersonal/
Temperaments
Color
Discrimi-
nation
Written
Compre-
hension
Emotional
Intelli-
gence
Person-Side Job-Side
1
2
3
4
5
3 digit
by 2 digit
w/
remainder
2 digit
by 1digit,
no
remainder
Repeat-
edly
Occasion-
ally
Physical
Demands
Level
Use
Other
Senses
Mental/Cognitive
• Individual differences in cognitive test performance predict
occupational attainment in healthy and clinical populations
• Often predicts work outcome better than primary symptom
severity (eg, TBI, MS, Schizophrenia, etc.)
• This makes cognitive function a “final common pathway”
of work disability in many diseases and conditions
• Thus, it is essential to include cognition in mental RFC
• Two ways to approach this
– Performance-based measures (IQ, memory, attention testing)
– Ratings (self- or informant-repot)
We must first decide what
abilities to assess before we
decide how to assess them
Clinical approach: A view from the
the perspective of what goes wrong
Domain affected Disease/condition Manifestation
Intelligence Fragile X Intellectual disability
Language Stroke Aphasia
Attention Traumatic brain injury Distractibility/ADD
Learning/memory Korsakoff Amnesia
Processing speed Parkinson Bradyphrenia/bradykinesia
Visual-spatial abilities Lewy body Agnosia
Executive functioning Schizophrenia Dysexecutive & abulia
Arithmetical abilities Developmental Acalculia
Skilled movement Brain tumor Apraxia
Wakefulness Narcolepsy Drowsiness
Psychometric approach: A view from
the perspective of factor analyses
• EFA (exploratory factor analysis) is used to elucidate an
underlying factor structure
• CFA (confirmatory factor analysis) is used to test a priori
hypotheses
– Based on a conceptual model or previous findings
– Evaluate a model and compare it to specific alternatives
– Test how well hypothesized models fit the observed data
• Compare “nested” models (in which some models combine factors
from preceding ones)
FACTOR ANALYSES
CFA: Confirmatory Factor Analysis, EFA: Exploratory factor analysis, BCPA: block principal component analysis, RCA: Reliable
Components Analysis, PCA: Prin
Components Analysis; SCFA: Single Confirmatory Factor Analysis, PAF: Prin
Axis Factoring
HEALTHY SAMPLES Sample / Tests in Domain Analysis # Vars # Factors
Gomez et al., 2006
521 Spanish-speaking Normal Control EFA 27 6
1. Attentional-executive category formation test, visual search, semantic verbal fluency,
phonological verbal fluency, design fluency
2. Contextual-exec memory LMI, LMD, Verbal paired associates Immediate, & Delayed, motor functions
3. Verbal memory word list encoding, free recall, cued recall, recognition
4. Sustained attention time orientation, digit detection, mental control, faces immediate, faces delayed recall
5. Atten
-
working memory digit span forward, & backward, spatial span forward, & backward
6. Orientation place orientation, person orientation
Tulsky
et al., 2003
1,250 Normal Control (healthy adults aged 16 -
89) CFA 26 6
1. Verbal comprehension Vocabulary, Information, Similarities, Comprehension (Verbal Comp of WAIS-III)
2. Perceptual organization Matrix Reasoning, Block Design, Picture Completion (WAIS-III) Picture Arrangement (WMS-III)
3. Auditory memory Logical Mem I, Logical Mem II, Verbal Paired I, Verbal Paired II, Word List I, Word List II
4. Visual memory Faces I, Faces II, Family Picture I, Family Pictures II, Visual Reproduction I, Visual Reproduction II
5. Working memory Letter Number Sequencing, Digit Span, Arithmetic, Spatial Span
6. Processing speed Symbol Search, Digit Symbol
Rowe et al., 2007
1,316 Normal Controls (mean age = 33, range 6-16) PCA 19 7
1. Info processing & speed Verbal Interference Test Part I, and II, Switching of Attention Test Parts I, and II, Choice Reaction Time test
2. Verbal memory Verbal Learning and Recall Test: delayed, recognition, immediate
recall
3. Viligance/sustained atten CPT Reaction Time, CPT Errors
4. Working memory Digit Span forward, Digit Span backward, Span of Visual Memory Test
5. Sensori-motor function average pause between taps on tapping test for dominant and non-dominant hands
6. Verbal processing Letter Fluency, Category Fluency
7. Executive function Maze complettion
time, Maze overrun errors, Span of Visual Memory Test
Salthouse, 1998
Three healthy groups: children (age 5-17) n = 3,155 ; college students (age 18-22) n = 735; nonstudents
(age 18-94) n = 1580
1. General higher-order factor
concept formation, calculation, app probs, science, social studies, humanities, incomplete words, visual closure, sound blending,
memory for names, Visual-Auditory learning, memory for sentances, memory for words, visual matching, cross out SCFA 16 1
Colom et al., 2009
1. g (General Intelligence) Adv Progressive Matrices (APM), Induct reason (PMA-R), abs reason (DAT-AR), vocab
(PMA-V), verbal reason (DAT-VR)
1. Gf
(fluid intelligence) Advanced Progressive Matrices (APM), Inductive reasoning subtest
(PMA-R), abstract reasoning (DAT-AR)
2. Gc (crystallized intelligence) vocabulary (PMA-V), verbal reasoning (DAT-VR), numerical reasoning (DAT-NR)
3. Gv (verbal intelligence) Solid Figures, mental rotation (PMA-S), spatial relations (DAT-SR)
Visser et al., 2006
200 Normal Controls (age range = 17-66, M = 22.7 (6.1))
1. g (General intelligence) Nec Arith Operations, Diagramming Relationships, Opposites, Paper Folding, Social Translations, Vocab, Map Planning, PAF 15 1
Subtraction and Multiplication, Consistency, Cartoon Predictions, Stork Stand, Mark Making, Tonal Accuracy
MIXED/MULTIPLE GRPS
Dickinson et al., 2004
97 Schizophrenia & 87 Normal Conrols
1. Common Factor Vocab, Sim, Info, PC, BD, MR, LNS, Spatial Span, DSym, Sym Search, LM I, LM II, VP I, VP II, Fac Rec I, II, Famly Pict I, II SCFA 18 1
Dickinson et al., 2006
157 Normal Control CFA 17 6
148 Schizophrenia CFA 17 6
1. Verbal comprehension Vocab (WAIS-R), Visual Naming (MAE)
2. Perceptual organization Block Design (WAIS-R), Line Orientation (Benton)
3. Verbal learning/memory Trials 1-5 & Delayed Free Recall (CVLT), Logical Mem immediate & delayed (WMS-R)
4. Visual learning/memory Figural Memory immediate & delayed (WMS-R)
5. Info processing speed Symbol Cancellation Test, Trls A, Animal Naming (BDAE)
6. Exec/Working memory Digit Span (WAIS-R), Trls B, Categories & Persev. Erros (WCST)
Genderson et al., 2007
125 NC (-5 due to kurtosis) CFA* 21 7
162 probands (-5 due to kurtosis) CFA* 21 7
94 SZ (-5 due to kurtosis) CFA* 21 7
382 full sample (-15 due to kurtosis) CFA* 21 7
1. Speed Trls A, Trls B, Let. Fluency, Cat. Fluency
2. Target detection CPT distraction, CPT viligance, Zero-back
3. N back updating/ exec One Back, Two Back, Three Back
4. Verbal episodic memory CVLT Trails 1-5, WM Log Memory, WM Pair Assoc I, Pair Assoc II
5. Visual processing/memory WM Visual Reprod I, Visual Reprod II, Benton Line,
6. WCST executive function WCST Persev Errors, WCST Categories
7. Digit span WMSR Forward, WMSR Backward
Gladsjo et al., 2004
209 Psychotic Disorder CFA 21 6
131 Normal Control CFA 21 6
1. Verbal crystalized WAIS-R Vocab, Info, Similarities; Boston Naming
2. Attention/working mem WAIS-R Arith, Digit Span
3. Verbal episodic CVLT Monday Total, Story Learning, CVLT Long-Deay Free Recall
4. Speed of info processing WAIS-R Digit Symbol, Trls A, Trls B, GPB, Digit Viligance, Let. Fluency
5. Visual episodic Figure Learning, Figure Delay
6. Reasoning/problem solving Block Design, Category, WCST
Johnson et al., 2009
191 Normal Controls ( mean age = 75) CFA 12 4
115 autopsy confirmed AD (mean age = 80) CFA 12 4
1. General (all measures) ** all of the tests are included in this factor
2. Verbal memory Information, Paired Associates Learning, BNT, Logical Memory
3. Visuospatial BVRT (Benton Visual Rec. Test), Digit Symbol, Trls A, Block Design
4. Working memory Word Fluency, Mental Control, Digit Span Backward, Digit Span Forward
Schretlen et al., 2009
340 Normal Control CFA 15 6
126 Bipolar Disorder CFA 15 6
110 Schizophrenia CFA 15 6
1. Attention BTA-L, BTA-N, CPT-II
2. Speed TMT-A, TMT-B, GPT
3. Fluency Letter, Category, Design
4. Visual memory BVMT 1-3, BVMT Del
5. Verbal memory HVLT 1-3, HVLT Del
6. Executive function WCST Cat, WCST Err
Siedlecki et al., 2008
322 Normal Control CFA 15 5
878 Questionable Dementia CFA 15 5
639 Alzheimer Disease CFA 15 5
1. Processing speed Shape Time (shapes) and TMX Time (letters) of Cancellation Task
2. Memory SRT (Selective Reminding Task) Total Recall, Delayed Recall, Delayed Recog, BVRT (Benton Visual) Recog
3. Language Naming (BNT), Repitition, Comprehension, Letter Fluency, Category Fluency
4. Reasoning visual/spatial WAIS Similarities, Identities/Oddities (MDRS), Rosen (drawing test), BVRT Matching (Benton Visual)
5. Attention TMX Omits (Letters)& Shape Omits of Cancellation Test,
CLINICAL SAMPLES
Frazier et al., 2004
1,364 mixed patient sample RCA 21 4
1. Memory WMS-III Auditory Immediate, Visual Immediate, Auditory Delayed, Visual Delayed, Auditory Recognition
2. Visual motor Trls A, Trls B, WAIS-III PSI, WAIS-III POI, Finger Tapping Dominant, Finger Tapping Non-Dominant, GBP Dom, GPB Ndom
3. Language WAIS-III VCI, WAIS-III POI, WRAT-3 Reading, BNT, Verbal Fluency
4. Executive WCST Perseverative Errors, WCST Categories
Friis et al., 2002
219 Schizophrenia EFA 17 5
1. Working memory
Controlled Oral Word Association Task (COWA), Digit Span w/distractor, Digit Span w/out distractor (Digit Span
Distractability Test), CPT hits
2. Executive function WCST Categories, WCST Perseverative Responses, WCST # attempts to first category
3. Verbal learning CVLT immediate recall, CVLT delayed free recall, CVLT errors
4. Impulsivity CPT false alarms (comissions), CPT Reation Time
5. Motor speed Finger Tapping
Jaeger et al., 2003
156 Schizophrenia BPCA 44 6
1. Attention Concen Endurance (Letters -Errors), Stroop-Words, Stroop-Colors, Trls A, WMS-R Visual Mem, WAIS-R Digit Symbol
2. Working memory
Concentration Endurance Test (Fluctuation), WAIS-R DS Forward, Letter Number Span # Correct, Longest, WAIS-R Arith,
WAIS-R DS Backward, LMI
3. Ideational fluency + WCST persev. Ruff Fugural Fluency-
Unique Designs, COWAT, Animal Naming, WCST Per Errors
4. Learning WMS-R LM I, LM II, WMS-R Verbal Paired I, Verbal Paired II, WMS-R VR I, VR II, WMS-R Visual Paired I, Visual Paired II
5. Verbal knowledge WAIS-R Vocab, Info, Comp, Similarities
6. Non-Verbal function WMS-R VR I, VR II, WAIS-R Block Design, Object Assembly, Pict Comp, Pict Arrangement
Czobor et al., 2007
185 Schizophrenia, 65 Schizoaffective EFA 29 6
155 Bipolar Disorder EFA, CFA 29 6
1. Attention Concentration Endurance Test (Letters -Errors), Stroop-Words, Stroop-Colors, Trls A, WAIS-R Digit Symbol
2. Working memory Concen Endurance (Fluctuation), WMS-R DS Forward, Letter Number Span , WAIS-R Arith, WAIS-R DS Backward, LMI
3. Ideational fluency + WCST persev. Ruff Fugural Fluency-
Unique Designs, COWAT, Animal Naming
4. Learning WMS-R Verbal Paired I, Verbal Paired II, WMS-R Visual Paired I, Visual Paired II
5. Verbal knowledge WAIS-R Vocab, Info, Comp, Similarities
6. Non-Verbal function WAIS-R Block Design, Pict Comp, Pict Arrangement
Keefe et al., 2006
1,493 Schizophrenia (includes medical and substance abuse comorbidities) PCA 24 5
1. Processing speed COWAT, Category instance, GPB, WAIS-R Digit Symbol
2. Reasoning WCST (Perseverative errors & categories)
3. Verbal memory HVLT (total recall)
4. Working memory Computerized test of visuospatial working memory, letter-number sequencing (# correct)
5. Viligance CPT (d-prime)
Williams et al., 2008 *verified factor structure found in Rowe et al. (2007)
56 First Episode Schizophrenia (mean age = 20) PCA 19 7
1. Information processing & speed Verbal Interference Test Part I, and II, Switching of Attention Test Parts I, and II, Choice Reaction Time test
2. Verbal memory Verbal Learning and Recall Test: delayed, recognition, immediate
recall
3. Viligance/sustained attention CPT Reaction Time, CPT Errors
4. Working memory capacity Digit Span forward, Digit Span backward, Span of Visual Memory Test
5. Sensori-motor function average pause between taps on tapping test for dominant and non-dominant hands
6. Verbal processing Letter Fluency, Category Fluency
7. Executive function Maze complettion time, Maze overrun errors, Span of Visual Memory Test
General Findings
• Several models of latent cognitive structure have found
empirical support in one or more population
– A few have been replicated in multiple samples
– And a few have been confirmed by CFA
• The measures included in an assessment strongly affect
the nature of the latent cognitive model that is found
• Three “levels” of model complexity deserve particular
attention
– Single factor model: General cognitive ability (g)
– Two-factor models: Crystallized and fluid abilities (Gc & Gf)
– Multiple-factor models: Multiple cognitive domains
Lumping vs. splitting
• A single summary measure of impairment or cognitive
RFC ability has advantages
– It is easily understood
– More reliably measured than specific cognitive domains
– Separate factors share common variance anyway
– Summary measures correlate best with most outcomes
• Multiple factors have advantages too
– No theoretical cognitive construct maps onto a summary
impairment index
– Summary scores might mask specific impairments or aspects
of RFC that preclude or support employability
– Scores for multiple measures are no harder to understand
than a single summary score
One-Factor Model: g
• Hundreds of studies document the existence of a single
general mental ability, g, on which individuals differ
• g is a construct
– That is not directly observable
– Determined by genetic and environmental factors
• Arises from fact that performances on all cognitive tasks
are positively correlated
– All cognitive tests measure g (to varying degrees)
– Thus, g is not tied to any specific test content such as words,
numbers, or geometric patterns
– Nor is g bound to any sex, age, or cultural group
• The g component of tests accounts for most of their
predictive power
Some Implications & Questions
• 25% of workers fall below 1
st
quartile
• What point in the distribution of
incumbents’ scores defines insufficient
RFC to meet job demands?
– 25
th
%ile, 2
nd
%ile
• How “well” must a disability applicant
be able to perform a job in order to be
not
disabled?
– Poor employees are the first laid off
– Job placement vs. job maintenance
• What is “fair” to non-disabled workers?
Comment
• The single-factor g model has advantages
– It is parsimonious
– g is well documented and highly defensible
– We can measure it reliably in many languages
– Individual differences in g are robust, easily assessed, and
strongly predictive of occupational attainment, work
performance, and income in normal, healthy persons
– We can obtain a reasonable estimate of g in a few minutes,
using such instruments as the Wonderlic Personnel Test
• It also has limitations
– Lacks sensitivity to many types of brain dysfunction
– Does not capture more circumscribed cognitive deficits
– Thus, might not measure residual
functional capacity very well
Two-Factor Model
• Many studies distinguish between highly over-learned skills
or knowledge (Crystallized abilities or Gc) and current,
online information processing (Fluid abilities or Gf)
– Gc: vocabulary, fund of information, mathematical ability
– Gf: novel problem solving, reasoning, speed of processing
– Gc grows rapidly in childhood, and more slowly in adulthood,
and then declines in very late life
– Gf grows rapidly in childhood, peaks around age 20, and then
declines throughout adulthood
– Gc is more affected than Gf by education
– Gf is more sensitive than Gc to brain dysfunction
Application of a
Two-Factor Model
(well, sort of)
MSE-TV in SSDI/SSI Beneficiaries
Variable
ABC Full Sample
(n = 234)
ABC Matched
Sample (n = 139)
SSA Sample
(n = 139)
Age (years) 54 + 17 43 + 13 41 + 11
Sex (M:F%) 44:56 42:58 45:55
Race (W:B:O%) 79:18:2 68:29:3 26:64:5
Educ. (years) 14 + 3 14 + 3 N/A
MMSE 28 + 2 28 + 2 24 + 4
PCA with Varimax Rotation Factor
Loadings for ABC and SSA Samples
Question
Factor 1
General Ability
Factor 2
Learning/Memory
Factor 3
Orientation
ABC SSA ABC SSA ABC SSA
Orientation
.93 .99
Word recall (1)
.75 .84
Word recall (2)
.83 .86
Serial 7’s
.77 .79
Opposites
.68 .80
Arithmetic
.60 .80
Information
.73 .69
Word recall (3)
.82 .78
Correlations of MSE-TV Scores with
Other Cognitive Measures
Variable
MSE-TV
Total
MMSE
Total
Factor 1
General
Ability
Factor 2
Learning &
Memory
Factor 3
Temporal
Orientation
WAIS-R Sum SS
0.63** 0.53** 0.66** 0.42** 0.02
NART IQ
0.58** 0.37** 0.69** 0.32** 0.03
HVLT Learning
0.48** 0.30** 0.27** 0.50** 0.05
HVLT Delay
0.44** 0.27** 0.27** 0.45** 0.13
BVMT Learning
0.44** 0.33** 0.27** 0.40** 0.06
BVMT Delay
0.35** 0.33** 0.21** 0.40** 0.07
Group Differences in MSE-TV Scores
MSE-TV
Variable
Healthy
Controls
(N = 139)
Affective
Disorder
(N = 59)
Schizophrenia
Spectrum
(N = 36)
Cognitive
Disorder
(N = 18)
Mental
Retardation
(N = 20)
Total
39.0 + 5.5
a
31.4 + 7.5
b
29.2 + 5.8
b
27.1 + 6.6
b
20.8 + 6.4
c
Factor 1
14.5 + 3.2
a
10.9 + 4.4
b
10.8 + 3.5
b
8.9 + 4.5
b
4.7 + 3.0
c
Factor 2
20.6 + 3.4
a
16.5 + 3.9
b
14.5 + 3.8
b
14.2 + 4.0
b
12.2 + 4.5
c
Factor 3
3.9 + 0.3 4.0 + 0.0 3.9 + 0.4 3.9 + 0.2 4.0 + 0.2
Comment on Two-Factor Models
• Allow for slightly more fine-grained assessment of
cognitive functioning and impairments
• Gc reflects over-learned “premorbid” verbal abilities that
are relatively in
sensitive to aging and brain dysfunction
• Gf reflects current nonverbal problem solving abilities
that are sensitive to age and brain dysfunction
• These two factors can be combined into one
Multiple-Factor Models
• Several multiple-factor models emerged from our
(selective) review of the literature
• The most robust and well-replicated factors include
– General mental ability (g)
– Verbal learning and memory
– Processing speed
• Somewhat less clear (in terms of independence)
– Working memory
– Attention/concentration
– Executive functioning
– Ideational fluency
Johns Hopkins Confirmatory Factor
Analysis in Three Populations
• Determine whether the same hypothesized latent factors
would characterize cognitive functioning in three groups
• Test hypothesized model against specific alternatives
• Hypothesized model based on previous study (Schretlen
et al, 2007)
NC
(n = 340)
SZ
(n=110)
BD
(n=126) Statistic p
Age (years)
54 ±
19 40 ±
11 42 ±
11
F
(2,571)
= 44.1 <.001
Sex (male, %) 44 70 40
χ
2
(2)
= 28.2
<.001
Race (w:b:o %) 79:18:3 39:55:6 55:40:5
χ
2
(4)
= 68.9
<.001
Education (years)
14 ±
3 12 ±
2 14 ±
3
F
(2,571)
= 19.5 <.001
Est. premorbid IQ
105 ±
10 97 ±
11 103 ±
12
F
(2,,571)
= 23.3 <.001
Participants and Method
Recruited 576 participants, including 340 reasonably healthy adults
(NC), 110 relatively stable individuals with schizophrenia (SZ), and 126
relatively stable persons with bipolar disorder (BD).
All participants underwent cognitive testing.
Clinical Characteristics of the Patients
SZ
(n=110)
BD
(n=126)
Statistic p
Age at onset , years
23 ±
7 25 ±
9 t
(212)
= −1.8
.064
Illness duration, years
17 ±
11 18 ±
11
t
(212)
=-0.6 .519
# Hospitalizations
5.0 ±
5.6 3.7 ±
5.1
t
(210)
=1.8 .066
SANS (sum)
8.9 ±
5.5 1.8 ±
2.4
t
(193)
=8.6 .001
SAPS (sum)
4.7 ±
3.8 1.0 ±
1.8
t
(191)
= 11.9 .001
Typical antipsychotic (%) 34 5
χ
2
(1)
= 14.7
.001
Atypical antipsychotic (%) 74 47
χ
2
(1)
= 13.9
.001
Antidepressant (%) 23 48
χ
2
(1)
= 12.0
.002
Lithium (%) 4 56
χ
2
(1)
= 58.6
.001
Anticonvulsant (%) 12 44
χ
2
(1)
= 23.7
.001
Competing Models
Six-Factor Model
Factor Measures
Psychomotor Speed TMT-A, TMT-B, and GPT (mean of both hands)
Attention BTA-L, BTA-N, and CPT Hit RTse
Ideational Fluency Letter, Category, and Design Fluency
Verbal Memory HVLT-R Learning and delayed recall
Visual Memory BVMT-R Learning and delayed recall
Executive Function mWCST category sorts and errors
Six-Factor Model with TMT-B on EF
Factors Measures
Psychomotor Speed TMT-A and GPT (mean of both hands)
Attention BTA-L, BTA-N, and CPT Hit RTse
Ideational Fluency Letter, Category, and Design Fluency
Verbal Memory HVLT-R Learning and delayed recall
Visual Memory BVMT-R Learning and delayed recall
Executive Function TMT-B, mWCST categories and errors
Five-Factor “Speed” Model
Factors Measures
Psychomotor Speed TMT-A, TMT-B, GPT, Letter, Category, and Design
Attention BTA-L, BTA-N and CPT Hit RTse
Verbal Memory HVLT-R Learning and delayed recall
Visual Memory BVMT-R Learning and delayed recall
Executive Function mWCST category sorts and errors
Five-Factor “Memory” Model
Factors Measures
Psychomotor Speed TMT-A, TMT-B and GPT (mean of both hands)
Attention BTA-L, BTA-N and CPT Hit RTse
Ideational Fluency Letter, Category, and Design Fluency
Memory HVLT-R and BVMT-R learning and delayed recall
Executive Function Wcst categories and Wcst errors
Four-Factor Model
Factors Measures
Psychomotor Speed TMT-A, TMT-B, GPT, Letter, Category, and Design
Attention BTA-L, BTA-N and CPT Hit RTse
Memory HVLT-R and BVMT-R learning and delayed recall
Executive Function mWCST category sorts and errors
One-Factor Model
Factors Measures
General Cognition All measures
Evaluating CFA Results
Statistic Name Recommended Values
χ
2
/df
Chi-square/df < 3 is a good fit
RMSEA
Root mean square error of
approximation
< 0.05 is a very good fit
< 0.08 is a reasonable fit
NNFI Non-normed fit index
> 0.95 is a close fit
> 0.90 is a good fit
CFI Comparative fit index
> 0.95 is a close fit
> 0.90 is a good fit
CFA Results: Six-Factor Models
Group χ
2
/df RMSEA NNFI
CFI
Combined 2.50
0.051
0.99 0.99
NC 1.79
0.048
0.98 0.99
BD 1.63
0.071
0.96 0.97
SZ 1.40
0.060
0.98 0.98
Six-Factor Model
Group χ
2
/df RMSEA NNFI
CFI
Combined
4.92 0.083 0.95 0.96
NC
3.44 0.085 0.93 0.95
BD
1.93 0.087 0.94 0.95
SZ
2.03 0.097 0.92 0.94
Six-Factor Model
with TMT-B in EF
CFA Results: Five-Factor Models
Group χ
2
/df RMSEA NNFI
CFI
Combined
4.75 0.081 0.96 0.97
NC
3.38 0.084 0.95 0.96
BD
1.82 0.081 0.95 0.96
SZ
1.54 0.071 0.96 0.97
Five-Factor “Speed”
Model
Group χ
2
/df RMSEA NNFI
CFI
Combined
10.16 0.126 0.89 0.92
NC
4.41 0.100 0.91 0.93
BD
2.59 0.112 0.87 0.90
SZ
2.68 0.124 0.89 0.91
Five-Factor “Memory”
Model
CFA Results: Remaining Models
Group χ
2
/df RMSEA NNFI
CFI
Combined
11.01 0.132 0.90 0.92
NC
5.69 0.117 0.89 0.91
BD
2.75 0.118 0.87 0.89
SZ
2.76 0.127 0.88 0.91
Four-Factor Model
Group χ
2
/df RMSEA NNFI
CFI
Combined
18.89 0.176 0.76 0.80
NC
12.15 0.181 0.70 0.74
BD
3.95 0.165 0.78 0.81
SZ
4.65 0.171 0.72 0.76
One-Factor (g) Model
Comment
• In this CFA, the hypothesized six-factor model showed a
good to excellent fit by all evaluative measures
• Other hypothesized models did not fit the data as well
• However, another ensemble of tests almost certainly
would yield a different “optimal” solution
• Therefore, the question of whether to assess mental FRA
using a multi-factor model probably should precede the
selection of which domains to assess
– My personal recommendation is to assess 3–6 domains
Other Big Issues
• Shall we use performance-based measures or informant
rating scales, or both?
– And who should administer them? Change models?
• How shall we validate decision criteria?
– I know of no existing data defining disability “thresholds”
• Shall we use available measures or create a proprietary
set that SSA creates, standardizes, and updates?
– This would be my recommendation for many reasons
– Existing tests become obsolete, raise royalty issues
• There is a theme: The need to design and conduct a
couple studies
