Download personal_injury_II_06

Forensic Neuropsychology in
Personal Injury Cases II
Russell M. Bauer, Ph.D.
July 20, 2006
“Noninjury” Contributors to
Neuropsychological Impairment in MHI

Adversarial patient-examiner relationship

Exaggeration or poor effort
– Impairment as communication
– Frank malingering for gain; financial incentives
– Factitious disorders

Fatigue, pain, other physical factors

Psychiatric disturbance (e.g., psychosis, anxiety,
depression)

Pre-existing factors affecting neuropsychological
performance (e.g., learning disability, limited education)

Occupational/life experience factors
Financial Incentives
and Disability
 Binder
& Rohling (AJP, 1996, 153, 7-10)
– Meta-analytic review of financial incentives
and symptoms
– 18 study groups, 2,353 subjects
– Weighted mean effect size of difference
between groups with and without financial
incentives was 0.47
– More late-onset symptoms in
compensation-seeking groups
Checks against False Positives:
Consistency Analysis
Consistency of results between/within
domains
 Consistency with known syndromes
– example: “hemi-anomia”
 Consistency with injury severity
 Consistency with other aspects of behavior
– e.g. memory abilities during vs. apart from
formal testing

Post-Concussion Syndrome
Post-Concussion Syndrome: DSM-IV
Definition
 “acquired
impairment in cognitive
functioning, accompanied by specific
neurobehavioral symptoms, that occurs
as a consequence of closed head injury
of sufficient severity to produce a
significant cerebral concussion” (LOC,
PTA, etc.)
PCS: DSM-IV Criteria
A
B
C
Hx of head trauma that has caused significant
cerebral concussion
Evidence from NP testing or quantified cognitive
assessment of difficulty in attention or memory
Three (or more) of the following occur shortly after
trauma and last at least 3 months:
–
–
–
–
–
–
–
–
easy fatigue
disordered sleep
headache
dizziness/vertigo
irritability or aggression with little/no provocation
anxiety, depression, or affective lability
changes in personality
apathy or lack of spontaneity
PCS: DSM-IV Criteria (cont’d)
D.
E
F
Symptoms begin after head trauma or else
represent a worsening of pre-existing
symptoms
Significant impairment in social or
occupational function; decline from previous
functional level
Do not meet criteria for dementia and are
not better accounted for by another mental
disorder
PCS-Like Complaints of NP
Dysfunction
 Common
 Nonspecific
 Potentially
related to non-neurological
factors (anxiety, depression, fatigue,
stress)
 Correlate better with distress than with
objective indicators of CNS injury
 Easy to feign or exaggerate
Complaints as “Evidence”



In the absence of objective neuro-psychological
deficit, complaints are often taken to indicate the
existence of occult disease
There is a difference between symptoms (subjective
evidence) and signs (objective evidence) of illness
Symptom reports subject to cognitive distortions and
attributional processes

Complaints (N=45) as “Evidence”
“She reports feeling tired, moving slowly, losing her balance, tripping over
things, and feeling weak and dizzy. She also reported increased sensitivity to noise,
altered perception of the ambient temperature (feeling warm when others are
comfortable), poor concentration, forgetfulness, finding once routine activities now
complicated, diminished sexual functioning, sleep problems, fatigue and low energy
level, anxiety and nervousness, “panic attacks”, lack of patience, decline in handling
household chores, fear of certain situations, decline in recreational activities, concerns
and worried about her health, depressed mood, decline in her ability to work, diminished
interest in pleasurable activities, weight gain of 55 pounds, feelings of worthlessness
and guilt, difficulty with language and word-finding, difficulty with concentration and
thought processing, difficulties with making conversation and understanding it, writing
slowly and illegibly, finding it difficulty to get started on things, trouble making
decisions, difficulty pronouncing words, forgetting people’s names, getting her mind off
certain thoughts, misplacing things, and becoming easily distracted. Scattered and
confused behavior permeates all aspects of her life. She also reports periods of time
where she becomes completely disoriented to her place and purpose. She experiences
severe headaches, shoulder, neck, back, and leg problems, severe depression and
cognitive dysfunction”.
Problems with Using
Complaints as Evidence of
MHI
 Mittenberg
et al. (1992, 1997):
“expectation as etiology”
– ‘imaginary concussion’ produces symptom
complaint cluster identical to that reported
by patients with ‘real’ head injury
– patients with minor TBI significantly
underestimate degree of pre-injury
problems
Major PCS
Symptoms
“Imaginary
concussion”
produces a
pattern of
symptom
reports
virtually
identical to
that seen after
MHI
MHT patients
significantly
underestimate
preinjury
symptoms
compared to a
noninjured
control group
Base Rates of Post-Concussion Symptoms (Larrabee
( Larrabee,,
1997, based on Lees-Haley & Brown, 1993)
Symptoms
Headaches
Fatigue
Dizziness
Blurred Vision
Bothered by Noiseb
Bothered by Light
Insomniab
Poor Concentration
Irritability
Loss of Temper
Memory Problems b
Anxiety
aNon
Medical Controls
62%
58%
26%
22%
18% c
52% d
26%
38%
20%
54%
Non-CNS Litigantsa
88%
79%
44%
32%
29% c
92% d
78%
77%
53%
93%
CNS Litigants: in litigation for emotional or industrual stress, but not for CNS
injuries, bsignificant difference from controls at 1m, but not 1y in Dikmen et al.,
1986; c ”hearing problems in Lees-Haley & Brown, 1993; d”sleeping problems in LeesHaley & Brown, 1993
Conclusions
You don’t have to have had a head injury to
have post-concussion symptoms
 Once something bad has happened to you,
you tend to attribute more of your problems
to it
 Complaints reflect the subjective, not
necessarily the objective, consequences of
MTBI

Implications for Understanding PCS
5% of MHI patients have persistent deficits
 Physiogenic causes likely operative in the first
1-3 months
 Psychogenic causes important thereafter
 Complaints have low specificity for MHI
 Baserate issues important
 Attributional processes important
 Suggests need for a scientific approach to
assessing persistent complaints after MHT

Assessment of Malingering
and Poor Effort

Issues with definition
– Intentional (intention)
– Fabrication or exaggeration (action)
– For purposes of gain (motive)

Explanatory models (Rogers, 1997)
– Pathological (mental disorder)
– Criminological (fake)
– Adaptational (meeting adversarial demands)

Cognitive vs. Somatic Malingering
Effort, Motivation, & Response Styles
Frederick et al., 2000
Slick (1999)
 Considers
evidence from NP and self
report
 NP criteria
– Definite or probable response bias
– Discrepancies/inconsistencies between NP
data and patterns of brain functioning,
collateral reports, reports of past
functioning
Slick et al, 1999 (cont’d)




DEFINITE MND
Presence of financial
incentive
Definite negative
response bias
Behaviors that meet
criteria for negative
response bias that are
not fully accounted for
by psychiatric,
neurological, or
developmental factors



PROBABLE MND
Presence of financial
incentive
Two or more types of
evidence from NP,
excluding definite
response bias, or one
piece of evidence from
NP and one from selfreport
Malingering Research Literature
Case study
 Simulation studies

– Interpretive issues
– Appropriate designs

Differential prevalence design
– contrasting high and low baserate groups

Known-groups design
– Selecting groups on the basis of malingering
criteria (e.g., Slick, et al)
Selecting Specialized Cognitive
Effort Tests
 Ease
of use
 Credibility of rationale
 Operating Characteristics
– Incremental validity
– TBI vs. PPCS
 Coaching
issues
 Not likely to be a “best” test
Commonly Used Specialized
Tests









Portland Digit Recognition
Digit Memory Test
Computerized Assessment of Response Bias (CARB)
Word Memory Test (WMT)
Victoria Symptom Validity Test
Test of Memory Malingering
Validity Indicator Profile
Rey 15-Item Test
Dot Counting Test
Why being a knowledgeable
neuropsychologist is important
 You
know likely patterns of impairment
 You know psychometric relationships
among tests
 You know course of recovery
 You know about contributory factors
(e.g., LD, depression, etc.)
 You can compare what you see to what
you expect

Neuropsychology for Physicists:

“Neuropsychological testing was highly consistent with her 2/8/97 automobile
accident. That is, she showed evidence suggestive of significant shearing damage, the
frontal system being damaged bilaterally, with relative sparing of the intentional
memory system structures and posterior brain areas, a pattern expected with an injury
in which the brain is spun and then violently counterspun within the skull. She also
showed significant deficits with passive attention plus more problems with incidental
than intentional memory. This suggests reticular activating system damage such as
would occur with significant shearing and/or when the brain is slammed down against
the tentorium. Hypothalamic symptoms were numerous. Damage to this nucleus is
quite common in this type of injury as well. Finally, Ms. X showed some right
posterior deficits, but sparing of left posterior function. This suggests a possible right
posterior/left frontal coup/contracoup pattern overlaying the bilateral frontal system
shearing. This dual pattern can occur in an accident such as hers where the driver is
seat-belt restrained and the left front of her car is hit. Ms. X reported symptoms
consistent with mild to moderate depression. The pattern of her neuropsychological
deficits was inconsistent with scores of non-head-injured patients suffering from
depression. The pattern of Ms. X’s neuropsychological damage and residual strengths,
the nature of her 2/8/97 MVA, and the timing of symptom onset all indicate the cause
of her present brain damage to be the 2/8/97 accident.
Common “suspect” neuropsychological
signs on NP testing
Recognition << recall (hits, discriminability)
 Extremely poor DS in the context of normal
auditory comprehension (RDS)
 Motor slowing (e.g., reduced tapping) relative
to overt motor disability
 Excessive failures-to-maintain-set on WCST
 Discrepancies between test level and level
during informal interaction
 Other “impossible” signs

– Hemi-anomia
Detecting Somatic Malingering
Symptom report, as well as cognitive
performance, can be controlled by the litigant
 Use of MMPI-2

–
–
–
–
–

F-scale, F(p)
VRIN, TRIN
Subtle-Obvious
F-K index
Revised Dissimulation Scales
These scales may not be sufficiently sensitive
to TBI-related claims, despite
neuropsychological differences
Lees-Haley FBS
 Model
of goal-directed behavior:
– Want to appear honest
– Want to appear psychologically normal
except for the influence of injury
– Avoid admitting longstanding problems
– Minimize pre-existing complaints
– Minimizing pre-injury antisocial or illegal
behavior
– Presenting plausible injury severity
Lees-Haley FBS (cont’d)
 18
“True” , 25 “False”
 Does not correlate very strongly with Fscale derivatives
 Most scale items overlap with
“neurotic” side of MMPI
 Cut-off mid 20’s, with varying false
positive rates; increasing security with
scores > 25-27
Patient after MVA, with no LOC, undergoes neuropsychological testing, has a normal neuropsychological
evaluation. He has a VIQ of 106 and a PIQ of 89. On WMS, he has an MQ of 108, but only remembers
an average of 6 items on Logical Memory. Other verbal memory tests are normal. The patient is mildly
depressed and faces several orthopedic surgeries for lower extremity injuries. The neuropsych is
summarized:
“Based on the present test results there is evidence that Mr. X is experiencing significant cortical
dysfunctioning. His organic deficits appear to be highly lateralized and focal in nature. Specifically, he is
manifesting significantly impaired visual motor skills relative to verbal skills. This finding is consistent
with Organic Brain Dysfunction and in particular consistent with Nondominant Hemisphere Dysfunction.
In addition, when one compares Mr. X’s premorbid level of intellectual functioning to his present level of
intellectual functioning it is clear that his overall intelligence has declined (no records obtained by him,
attentional problems/poor school attendance later discovered from records I obtained). In addition, test
results indicate localized organic impairment for both short term verbal memory functioning as well as
delayed verbal memory functioning. This finding is highly consistent with dominant temporal cortex
lesioning. With regard to psychological functioning, there is evidence of clinically significant levels of
depression (MMPI 2-scale at 68, no other scales elevated, patient reports loss of interest and mild
dysphoria). It is strongly believed that the patient’s organic dysfunctioning and depression are directly
related to the automobile accident on February 8, 1997.”