Forensic Neuropsychology
Scope and Limits of
Neuropsychological Testimony
June 2, 2014
Class Topics
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Description of criminal and civil process
Professional and ethical issues for neuropsychologists and other mental health experts
Issues discussions:
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Should mental health practitioners be experts?
Is our science sufficiently advanced?
Ethical scenarios and solutions
Criminal Proceedings
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Detention for probable cause (40-50% certainty)
Booking at police station
Initial hearing 48-72 hrs
Defense motions and discovery
Prima Facie showing – “on first look”, or “on its face”; evidence
presented to Grand Jury that leads to indictment
Arraignment – notified of charges, enters plea, bail set
Trial
Disposition
Appeal
Collateral Attack – challenging ruling by filing another case
Dispositional Review
Post-sentence Treatment Hearings
Civil Proceedings
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Complaint
Pretrial Motions
Discovery
 pretrial depositions
 interrogatories
 requests to produce
Settlement or Trial
 civil jury returns majority verdict
 federal court: unanimous unless stipulated
beforehand
Common Law and Statutory Duties of
Evaluator I: Confidentiality
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Normal caveats regarding confidentiality do
not normally apply; has implications for
outcome of evaluation
When defendant raises mental issue,
generally forfeits right to doctor-patient
privilege
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Confidentiality and prior treaters
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What patients must be told (see next slide)
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Who is the client?
Common Law and Statutory Duties
II: Clarifying Relationships
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Must clarify for all one’s various loyalties and
obligations (e.g., philosophical opposition to
death penalty)
Must specify:
 who has asked you to perform evaluation
 purpose of evaluation
 who will see report
 potential future activities (e.g., deposition,
trial testimony)
Should assess patient’s understanding of these
issues- in their own words
Common Law and Statutory
Duties III: Tarasoff Duty
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Tarasoff case review
Duty to warn in the event of dangerousness
General Guidelines:
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person in danger must be named or evident (doesn’t apply
to overly general threats)
notification of police, not necessarily direct warning of
person, is permissible
Three varieties: mandatory, permissible, no law
Question: Do you warn in a non-Tarasoff state?
Variations: warning re HIV/AIDS, genetically
transmissible disease?
Common Law and Statutory Duties
IV: Freedom of Choice to Participate
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Normally a part of clinical service delivery, informed
consent is (technically) minimally relevant to forensic
evaluations
Consent to participate is patient’s choice, but (s)he
should be made aware of consequences of their
choice; there may be law-sanctioned consequences
If patient declines:
 outline possible sanctions
 talk to attorney
 advise whether a report will be sent nonetheless
 don’t use scare tactics (“you’ll fry for this!”)
Issue: Is patient “compelled” to participate?
Common Law and Statutory
Duties V: Invasion of Privacy
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Avoid undue invasion of privacy, whatever
the context
Avoid two types of intrusions:
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avoid eliciting damaging but irrelevant info (e.g.,
eliciting info about sexual behavior that is not
relevant to the legal issue)
avoid addressing other forensic issues not raised
in the referral question (e.g., in determining
circumstances surrounding event, uncover
information about past unsolved crime)
Common Law and Statutory Duties VI:
Records and the Public Domain
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Exchange/release of raw data to adversary
“Test data” v. “Test materials”
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Test data (9.04) is, “raw and scaled scores, client/patient responses to test
questions or stimuli, and psychologists’ notes and recordings conerning
client/patient statements and behavior during an examination. Those
portions of test materials that include client/patient responses are included
in the definition of “test data”. Persuant to a patient/client release,
psychologists provide test data to the client/patient or other persons
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identified in the release. Psychologists may refrain from releasing test data
to protect a client/patient or others from substantial harm or misuse or
misrepresentation of the data or the test, recognizing that in many
instances release of confidential information under these circumstances is
regulated by law.
Test materials (9.11) “refers to manuals, instruments, protocols, and test
questions or stimuli and does not include test data as defined in Standard
9.04. Psychologists make reasonable efforts to maintain the integrity and
security of test materials and other assessment techniques consistent with
law and contractual obligations, and in a manner that permits adherence to
this Ethics Code.”
Specialty Guidelines for Forensic
Psychologists (2008)
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Responsibilities
Competence
Diligence
Relationships
Fees
Notification, Assent, Consent, and Informed Consent
Conflicts in Practice
Privacy, Confidentiality and Privilege
Methods and Procedures
Assessment
Professional and Other Public Communications
Specialty Guidelines (cont’d)
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Public & Professional Communication
 restriction of psychological data to colleagues
 treat colleagues with respect
 avoid making statements about legal proceedings
 present findings fairly; avoid distortion
 actively disclose all sources of information
 observations, opinions, conclusions must be
distinguished from legal facts, opinions, and
conclusions
Notes on APA Ethics Code
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Principles (aspirational goals) vs. standards
(enforceable rules of conduct)
Validity and normative concerns
Documentation should be appropriate for the
assessment task (higher level of specificity
typically required in forensic settings?)
Avoid harm: this is complex, since any
forensic opinion will involve “harm” to one
party; therefore, avoid unnecessary harm
Criticisms of Forensic
Psychology (Morse, 1982)
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Mental health professionals have less to contribute
than is commonly supposed
Most lay people are quite competent to make
judgments regarding mental disorder
All mental health law cases involve primarily moral
and social issues, and only secondarily scientific ones
Overreliance on experts promotes the idea that such
moral and social issues are, in fact, scientific ones
Professionals should recognize this difference and
should refrain from drawing social and moral
conclusions about which they are not expert
Method Skeptic Position
(Faust, Ziskin, Hiers, et al.)
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Neuropsychological evidence is usually of
negligible value in resolving legal issues
Neuropsychology doesn’t map onto the
forensic context. Three examples:
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brain damage doesn’t directly relate to legal issues
such as competency or insanity
clouded objectivity in the adversarial context
scientific knowledge in neuropsychology relates
minimally to questions of legal interest
Method Skeptics (cont’d)
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Subtle-Obvious problem: most tests
validated on “obvious” damage; how will they
perform under subtle conditions?
Ecological validity: most NP tests have
unproven ecological validity in forensic
context
Base-rate problem: validity, reliability,
predictive value, and base rates. Some of
these points are well-taken, and are reviewed
on the next slides:
Method Skeptics –Common
Interpretive Errors
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Hindsight bias – diagnose that which is
already diagnosed
Confirmatory bias
Overreliance on salient data – use of
“pet” tests as pathognomic
Underutilization of base rates
Failure to take covariation into account
– administering correlated tests as
confirmatory evidence
Signal Detection Framework for
Diagnostic Decision-Making
Sign Absent
Sign Present
Disease Present
False Negative
True Positive
Disease Absent
True Negative
False Positive
Operating Characteristics of Tests
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Sensitivity: If a person truly has a disorder,
how likely is the test to pick it up?
Specificity: If a person truly does not have
the disorder, how likely is it that the test will
be normal?
Positive Predictive Power: Knowing that
there is a positive sign, how likely is the
person to have the disorder?
Negative Predictive Power: Knowing that
there is a normal test result, how likely is the
person to be healthy?
Operating Characteristics of Benton
TFR at Prevalence = .11
Sign
Absent
Sign
Present
Disease
Absent
276
10
286
Disease
Present
17
19
36
293
29
322
Prevalence = 36/322 = .11
Sensitivity = 19/36 = .53
Specificity = 276/286 = .965
Positive Predictive Power = 19/29 = .66
Negative Predictive Power = 276/293 = .94
Overall Predictive Power = (19+276)/322 = .92
Operating Characteristics of Benton TFR at
Prevalence = .02
Sign
Absent
Sign
Present
Disease
Absent
305
11
316
Disease
Present
3
3
6
308
14
322
Prevalence = 6/322 = .02
Sensitivity = 3/6 = .50
Specificity = 305/316 = .965
Positive Predictive Power = 3/14 = .21
Negative Predictive Power = 305/308 = .99
Overall Predictive Power = (3+305)/322 = .92
mTBI
No mTBI
TOTALS
Positive
(Abnormal)
19
a
b
10
29
Negative
(Normal)
17
c
d
276
293
Totals
36
286
322
Sensitivity = a/(a+c) = 19/36 = .53
Specificity = d/(b+d) = 276/286 = .97
Positive Predictive Power = a/(a+b) = 19/29 = .67 (also known as PTL+)
Negative Predictive Power = d/(c+d) = 276/293 = .94
Prevalence = (a+c)/(a+b+c+d) = 36/322 = .11 (pretest probability of d/o)
Pre-test Odds = PTP/(1-PTP) = .11/.89 = .12 (.12:1)
Post-Test Odds of mTBI given Positive Result = .67/(1-.67) = 2.03 (>10 is strong)
Post-Test Odds of mTBI given Negative Result = 1-NPP = .06
Likelihood Ratio of Positive Test = [a/(a+c)]/[b/(b+d)] = Sens/(1-Spec) =
.5378/.0346 = 15.10 (15.10:1)
Likelihood Ratio of Negative Test = [c/(a+c)]/d/(b+d)] = (1-Sens)/Spec =
.47/.97 = .48 (.48:1)
Diagnostic Odds Ratio = LR+/LR- = 17.67/.48 = 36.81
Method Skeptics (cont’d)
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Lack of standardized practices:
variations in procedure make it difficult to
provide a standard description of
neuropsychology
Assessment of credibility: individuals can
fake performance on many measures
Difficulty determining prior functioning
Information-processing limitations
False markers of accuracy
Limitations of Neuropsychological
Testimony in FL – mostly of historic value
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Executive Car & Truck Leasing v. DeSerio (1985):
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Limitation of psychological testimony by denying
psychologists permission to testify as to physical causation
of brain injury
Instances where causation does not require a “medical
opinion”
Broward County School Board v. Luis John Cruz
(2000) – 4th DCA:
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Due to substantial evolution of psychology since the case of
Executive, court recedes from prior ruling
2 judges concur specially, basing their opinion on the idea
that the original decision was wrong in the first place
Trilogy + FRE =
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Knowledge Test: expert has “scientific,
technical or other specialized knowledge”
(what do you know?)
Helpfulness Test: must assist trier of fact (is
what you know useful?)
Qualifications Test: expert must have
“specialized knowledge, skill, training, or
education” (how did you come to know what
you know?)
Daubert Ruling
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District court threw out animal testimony
because it was “generally accepted”
that only human studies would do
Would not admit a re-evaluation of
existing data conducted by a plaintiff
witness because it had not been “peer
reviewed” but prepared only for trial
9th DCA affirmed; then went to USSC
Daubert Issues
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Seen as vehicle by which bogus
scientific testimony (so-called “junk
science”) could be addressed
22 amicus briefs submitted (8 for
petitioner; 14 for respondent)
One of the key questions is, “is this
scientific”?, or, “what constitutes
scientific evidence”?
Frye v. Daubert compared
Daubert
Frye
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Scientific principle or discovery
must be “sufficiently established to
have gained general acceptance in
the particular field in which it
belongs”
Pretrial ruling
No real systematic test, and no
direct test of whether “general
acceptance” is correct
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Reasoning or methodology
underlying testimony must be
“scientifically valid”
Preliminary ruling based on FRE
4 indicia (some say 6)
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‘widespread acceptance’
Peer review
Publication
Known/potential rates of error
Testing
Existence of standards
Fixed v. Flexible Batteries
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General acceptance – what percentage of
practitioners say they use flexible batteries?
Peer review
Publication
Known (or potentially known) rates of error
Existence of standards
Testing
Chapple v. Ganger (1994)
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Fixed v. flexible battery pitted against one another
Court accepted fixed battery and only portions of
flexible battery (both were admitted, but greater
weight was given to fixed)
Court held that entire reasoning process, not just
part of the process upon which the neuropsychologist
derives a conclusion, must be scientific (Question:
how does the reasoning process for fixed and flexible
batteries differ?)
Nothing beats GOOD PRACTICE
Should the fixed vs. flexible
battery issue worry you?
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Likely not; judges are not journal editors
Key issues
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Generally accepted?
Known, or potentially known, error rate?
Peer review?
Existence of standards?
More about error rate on the next slide
Everything I say has an exception! So be prepared!
Key issue: Know your interpretive strategy and its
strengths and weaknesses and be able to defend it
strongly
HRNB v. Flexible on error rate
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Main HRNB data: GNDS Scale (Reitan
& Wolfson)
Only works for subjects matching the
BD and demographic characteristics of
Reitan & Wolfson
Available data do not demonstrate a
reliable superiority of HRNB over
flexible battery
HRNB Indices
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Average Impairment Rating (AIR)
General Neuropsychological Deficit
Scale (GNDS)
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Summarizes 42 variables
Establishment of cutoffs for “brain damage”
Considered by many the “gold standard” in
fixed battery approach for diagnostic
accuracy and efficiency
Rohling Interpretive Method (RIM)
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Converting all scores to age-adjusted T-scores as a
common metric
Calculating two test battery means as a measure of
global functioning (all items, composite items)
Calculating the percentage of tests that fall in the
impaired range
Calculating pre-morbid intelligence using regression
methods (OPIE)
Conducting one-sample t-tests on each test battery
mean to form estimates of pre-morbid general ability
Rohling et al (2003)
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Applied RIM to HRNB data (114 patients, 73
‘pseudoneurological’ controls) that had been used in
prior cross-validation research on the GNDS
Found that OTBM, ITBM, %TI had similar sensitivity,
specificity, PPV and NPV as traditional HRNB indices
Provides a benchmark against which the results of a
study with a flexible battery could be measured
Rohling, M.L., Williamson, D.J., Miller, L.S., & Adams, R.L. (2003). Using the Halstead-Reitan Battery to
diagnose brain damage: A comparison of the predictive power of traditional techniques to Rohling’s
Interpretive Method. The Clinical Neuropsychologist, 17, 531-543.
Criticisms of RIM
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Comparing performance in specific cognitive areas to
EPGA (estimated premorbid general ability)
Problems in comparing composite scores to a
normative mean of 50 (SD of composite doesn’t often
equal 10)
Problems in covariance in comparing values of
cognitive ability areas within the RIM
Need large-scale co-normed batteries to address
these issues
Palmer, B.W., Appelbaum, M.I. & Heaton, R.K. (2004). Rohling’s Interpretive Method and inherent limitations on the
flexibility of “flexible batteries”. Neuropsychology Review, 14, 171-176.
Calculating Premorbid Ability
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Demographic Regression Equations
 Barona
Combined WAIS subtest-Demographic Regression Equations
 Oklahoma Premorbid IQ Estimate (OPIE)
Reading Tests
“Hold” Tests
Lezak’s “best performance” methods – don’t use
OPIE-3
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Combines current performance on WAIS-III
subtests with demographic variables (age,
education, gender, region, ethnicity)
Five variations
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OPIE-3(4ST): V, I, MR, PC
OPIE-3(2ST): V, MR
OPIE-3V: V, for use with lateralized NV-deficit
patients
OPIE-3P (MR, PC) OPIE-3MR: MR, for use with
lateralized V-deficit patients
Limitations of Neuropsychological
Testimony
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Testifying to the ‘ultimate legal issue’ – you
are not an attorney or a judge!
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competency
mental state at offense
damages
Testifying to the physical aspects of brain
damage – you are not a physician!
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extent of brain damage
prognosis/course
Relevant Appellate Decisions
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GIW Southern Valve vs. Smith
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defendant (GIW) appealed $1.35M verdict
court ruled that psychologist could not testify as to
“prognosis of future physiological effects of
accident on plaintiff’s brain” - this is medical
distinction between present and future condition
Executive Car & Truck Leasing vs.
Deserio
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appeal based on testimony as to physical cause
of brain damage
after Jenkins, idea is that lack of medical degree
can affect weight of testimony
Issues Regarding Limitations
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Need to be cognizant of both sides of brainbehavior equation
Need to recognize lawyer’s attempts to get you to
testify medically
Need to recognize lawyer’s attempts to get you to
recognize (defer to) “authoritative” sources
Issue of “instant” causation; emphasize
behavioral, rather than physiological aspects of
damage (but is this outdated re: 4th DCA?)
Be aware of physical findings in case
Guarding Against False Positives:
Consistency Analysis
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Consistency of results between/within
domains
Consistency with known syndromes
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example: “hemi-anomia”
Consistency with injury severity
Consistency with other aspects of
behavior
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e.g. memory abilities during vs. apart from
formal testing
Other Professional Practice Issues
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Fees, retainers, and payment agreements
 “contingency fees” vs. letters of protection
 differing fee structure for forensic vs. nonforensic cases?
Allowing forensic work to change your “standard of
practice”
 Observers, video/audiotape, or court reporters
 test selection
 Use of technicians (Division 40 Task Force, new CPT
codes)
Records release
 Relevant principles from Ethics Code
 approach to problem