Lecture 11 - Forensic Testing (DN) Flashcards
What is required of the forensic Neuropsychologist?
- must demonstrate a causative link between
- cognitive impairment & the event in question
What kind of Battery should be used in a Forensic setting?
- A fixed battery
- ensures replicability
- observations can be backed up
Where did the Daubert standard come from?
- Daubert was suing a pharmaceutical company
- believed medication mother took during pregnancy caused cognitive deficits
- supported by animal studies
- problem was they couldn’t support with human studies
- led to strict guidelines for forensic assessment
What is the Daubert standard:
Standards expected for forensic testing; resulting from outcome of Daubert case.
Validity of methods are judged by
- the experts methodology must be testable
- the technique should not rely on subjective interpretation by the expert
- the theory must have been peer reviewed
- the underlying theory or technique should be generally accepted by relevant scientific community
- the techniques potential rate of error should be low
- non judicial uses of the theory or technique are also considered
What is the “Motion to Exclude” controversy?
- Various batteries, including flexible batteries do meet legal requirements if administered & interpreted properly
- the HRB is very widely used & papers published have been used by defense attorneys to exclude other approaches
- In reality - the HRB is not the only valid battery, but scientific papers are often used to imply this
- in particular it is often used to discredit flexible approaches
What special considerations should be made in a Forensic Neuropsychological Assessment?
- Interview Approach
- General Assessment Approach: Selection and Administration of Instruments
- Estimation of Premorbid Functioning
- Detection of Malingering
- Ecological Validity (apply to real life impact)
What are the goals of a forensic interview?
-
establishing causal link between deficit & legal consideration (not documenting deficit)
- e.g., Rodney King case (riots - sued for police brutality, could not prove causality)
- focus on inconsistencies
- aided by multiple sessions
- focus on dynamic evolution of symptoms
- discard alternative accounts
- confirm reported symptoms align with impact on everyday activities
23:30
How does a forensic psychologist establish premorbid functioning?
premorbid functioning must be reported in forensic settings
forensic neuropsychologists utilise:
- Records: School, Military
- History and Collateral Interview
- Resistant (crystalised) skills
- reading, writing, vocabulary, attention for familiar scenes or pictures
- Demographic variables
- e.g., rural vs city, education
- Resistant*Demographic
- combining resistant & demographic info
- “Best performance”
- Include personality assessment
How could a Forensic Neuropsychologist estimate premorbid IQ?
- no 100% reliable methods
- combine methods
- use proxi’s of IQ
- access records (school etc)
- work position etc
- collateral interviews
- reading ability is also good indicator of IQ
- all combined should provide a good picture of premorbid IQ
What psychometric properties should be considered when selecting instruments in forensic settings?
- Norms
-
Sensitivity
- accuracy to detect (signs of) existing conditions
- detect malingering
- accuracy to detect (signs of) existing conditions
-
Specificity
- accuracy to discard (signs of) non-existing conditions
- do not want to falsely classify a malingerer if they are not
- accuracy to discard (signs of) non-existing conditions
14:40 & 45:00
What is involved in the administration of instruments in forensic settings?
- multiple sessions (schedule in advance)
- rapport
- record exact dates, times, rapport, sequence of instrument administration
- stick to standard test instructions
- clearly record test outcomes, timings in timed tests
What is malingering?
- Intentional production of false or greatly exaggerated symptoms
- to attain some identifiable external reward
(Iverson & Binder, 2000)
47:50
According to the DSM-IV-TR, what are some symptoms often presented by a malingerer?
- Physical symptoms (e.g., low back pain)
- Psychological symptoms (e.g., psychotic)
- Neurocognitive problems (e.g., poor memory)
What is a very important early step in forensic evaluations?
- Clarify the referral question
- be aware of external gains
- frame referral
What should be present before diagnosing Definite Malingered Neurocognitive Dysfunction (MND)?
- Presence of a substantial external incentive
- Definite negative response bias
- the Negative response bias cannot be otherwise accounted for
What two criteria are used when performing a differential diagnosis of malingering in forensic settings?
- Control over Behaviour
- External Reward
54:00
What should be present before diagnosing Probable Malingered Neurocognitive Dysfunction (MND)?
- Presence of a substantial external incentive plus
- > 2 types of NP evidence (not including negative response bias)
or
- 1 type of NP evidence plus 1 type of evidence from self-report
- Behaviors cannot be otherwise accounted for
What are three Malingering Assessment Methods?
- Specific tests
- appear to be testing something else, but actually designed to detect malingering
- material is well protected - to minimise cheating on these tests
- Pattern analysis of standard tests
- does pattern of performance align with symptoms
- Detection of inconsistencies
1:09:30
What type of inconsistencies does a forensic psychologist seek to detect?
Inconsistencies
- Within reported symptoms (different moments)
- Between reported and recorded history
- Between reported symptoms and actual behaviour
- Between reported symptoms and collateral information
- Between reported symptoms and performance on tests
- Between expected scores (considering type and severity of dysfunction) and actual scores
- Between tests scores and behavioural observations or everyday activities
- Between tests scores and collateral reports
- Between neuropsychological domains
- Between repeated testings
141:30
- What are some forms of Standard Test Pattern Analysis?
- Easy vs. Difficult Items
- Indices measuring similar domains
- Attention vs. Memory
- Recency and Primacy effects
- Free recall vs. Recognition
- Implicit Memory tests
What are some ‘fair’ reasons that people may try to exaggerate or underperform on an assessment?
-
Assessment conditions
- Inadequate assessment conditions, poor rapport
- prison, refugee, cultural, communication difficulties
- Inadequate tests – culture, language
- Inadequate assessment conditions, poor rapport
-
Trait characteristics
- Cognitive distortions
- Somatisation, Hypochondriasis
- Conversion Disorder
-
Condition/Litiation specific states (e.g., may go on for years)
- Stress, Pain
- Bad sleep, Fatigue
- Medication, drug use
57:00
How could these ‘fair’ exaggerations be handles without labelling the peron a malingerer?
- Ensure “fair” assessment conditions
- Analyse Records, History (e.g., “hospital records”, “family history – somatisation”)
- to look at impact on client presentation
- Diagnostic Tools
- Trait/State self-reports: Mood, Stress, Sleep, Fatigue
- Biomarkers
- e.g., in drug use, check if drug in blood
100:20
What should a forensic neuropsychologist considered if Drug Use is suspected to be contributing to an over exaggeration of symptoms?
- Patterns of use
- Severity of dependence
- Withdrawal
- Craving
- Drug testing
- Saliva
- Urine
- Hair
What are some other disorders (other than malingering) that should be considered when faced with an exaggerating client?
- Factitious disorder
- Somatoform disorder
- Depression
- Personality Disorders
- Dissociative Identity Disorder
What is negative response bias?
performance below chance
normally when someone is purposely performing poorly (e.g., in malingering)
1:08:00
What is the Rey test?
- Rey 15 items
- a malingering test
- based on floor effects
- create perception it is difficult, by saying this is a difficult task, but try your best!
- it is actually difficult to get it wrong
sensitivity 49% - not that good - as most malingerers would get more than 9 correct (perhaps because it is a little too obvious that it is a malingering test???)
specificity - good - wouldn’t have false positives as most people not trying to malinger would do it right
What is the main focus of malingering tests?
identify best combination of tests to maximise sensitivity & specificity
What are some features of ‘**Specific Tests’ **used to detect Malingering?
- Based on floor effects (15 items)
- Based on overlearned skills (Dot Counting)
-
Forced choice recognition (VSVT, TOMM)
- Victoria Symptom Validity Test (stimuli, then blank screen, then two stimuli - choose)
- Test of Memory Malingering (booklet - 50 stimuli - present at beginning as most difficult to remember 50 items). - as its forced choice (recognition) is much easier than free recall
- More complex presentations, multiple domains
- Forced Choice vs. Simplistic
- Empirical cutoffs vs. Binomial distribution
Which Tests have sensitivity greater than 85%?
FORCED CHOICE TESTS
-
Digit Recognition
- Victoria Symptom Validity Test (VSVT)
-
Visual Recognition
- Test of Memory Malingering (TOMM)
-
Word Recognition
- Word Memory Test (WMT)
Which of the Forced Choice Tests have sensitivity between 70 - 84%?
FORCED CHOICE TESTS
-
Digit Recognition
- Digit Memory Test (DMT)
-
Visual Recognition
- Letter Memory Test
- 48-Pictures Test
SIMPLISTIC TEST
- The b Test
Which of the Tests have sensitivity between 50-69%?
FORCED CHOICE TEST
-
Verbal & Nonverbal Abilities
- Validity Indicator Profile (VIP)
Which of the Forced Choice Tests have sensitivity less than 49%?
FORCED CHOICE TESTS
-
Digit Recognition Test
- Portland Digit Recognition Test (PDRT)
-
Word Recognition Test
- 21-item Test
SIMPLISTIC TESTS
- Rey 15-item Test
- Dot Counting Test
Specificity >85%
FORCED CHOICE TESTS
-
Digit Recognition
- Digit Memory Test (DMT)
- Portland Digit Recognition Test (PDRT)
- Victoria Symptom Validity Test (VSVT)
-
Visual Recognition
- Test of Memory Malingering (TOMM)
- Letter Memory Test
- 48-Pictures Test
-
Word Recognition
- 21-Item Test
SIMPLISTIC TEST
- Rey 15-Item Test
Do current malingering tests fall short on sensitivity & specificity?
Specificity is optimal in many tests
Sensitivity is not so good
e. g., Rey test has good specifiity and not good sensitivity
128: 15
What are ‘low sensitivity’ tests usually based on?
- Floor effects
- overlearned skills
What features do tests with Good Sensitivity and Excellent Specificity usually have?
- Forced choice recognition
- More complex presentations,
- multiple domains
Which two tests have the best numbers for sensitivity and specificity?
TOMM and VSVT
Other than sensitivity & specificity; what else should be considered when testing for malingering?
- the Predictive Value (PV) of the test
- PV is the capacity of the test to actually decide if the person has or has not the disorder or not
- While sensitivity & specificity are not impacted by the prevalence of the condition in the population, PV is heavily influenced by base rates (prevalence)
- e.g., base rates - Neuropsych patients 15% / Criminal case 54%
- calculations at (1:32:20) on lecture (don’t think need to know them though)
1: 30:00
What three factors should be most highly considered when selecting a test of malingering?
- Sensitivity
- Specificity
- Predictive Value
What is another way of checking for malingering?
Pattern analysis of other standard tests
- Easy vs. Difficult Items
- Indices measuring similar domains
- Attention vs. Memory
- if one is good the other most likely should be good
- check for consistency
- Recency and Primacy effects
- Free recall vs. Recognition
- if recognition is performed worse than free recall - this would be suspicious
- Implicit Memory tests
- normally preserved even in brain dysfunctional population
What indices would be used to detect Malingering using Pattern Analysis in Standard Tests?
Pattern Analysis
-
WAIS: Digit Span
- Malingerers: Low digit span performance (< 4) (below 4 is unusual)
- Reliable Digit Span (sum of longest correct span for both trials < 7) (below 7 unusual)
- Vocabulary–DigitSpan(low digit span while vocabulary is high) (t-scores should be similar)
-
Wechsler Memory Scale
- Malingerers:Attention/Concentration< General Memory
- (memory would usually be worse)
- Opposite pattern to typical head injury
- Malingerers:Attention/Concentration< General Memory
-
Verbal learning (e.g., California Verbal Learning Test)
- Malingerers: Low recognition (hits & forced-choice)
- Cutoff scores for recall trials produce variable false-positive rates
-
Word Memory Test
- Malingerers:Inconsistentresponding,poorinitialrecognition
- Pattern should reflect severity of impairments
-
Category Test
- Malingerers:Poor performance on first 2 subtests
-
Wisconsin Card Sorting Task
- Malingerers: Poor ratios of categories completed compared to
both perseverative errors and failure to maintain set - Non-perseveration errors > Perseveration errors
- Malingerers: Poor ratios of categories completed compared to
-
Motor Functioning
▪ Malingerers: Suppress motor functioning to extreme levels
▪ Motor decline should only be associated with severe brain injury
136:35
Why would an individual exaggerate symptoms (via self report)?
- May not be intentional
- May be due to other variables (i.e., depression, pain, stress)
- e.g., Post-Concussive Syndrome persisting for more than 3 months
1:43:40
How can malingering be detected through standard tests?
- Some standard tests detect malingering e.g., MMPI-2
- Malingerers tend to show elevations in clinical scales 1, 2, 3, 7, and 8,
- the Fake Bad Scale (FBS),
- VRIN
- TRIN
- the Infrequency-Psychopathology Scale [F(p)].
- The F Scale and F – K does not appear to be as sensitive, and therefore “valid” profiles may be obtained.
- Caution should be given to interpreting the clinical scales and F Scale derivatives, as these can be easily influenced by psychiatric comorbidities
How can the ecological validity of a forensic assessment be improved?
When choosing assessment tools
- Emphasise Verisimilitude over Veridicality.
- Verisimilitude - tries to make tests very similar to real life situation (e.g., key search test from last week)
- Veridicality - more pragmatic (practical) - about doing research on the predictive validity of classical tests
- Clearly define outcomes
- define as different levels rather than (yes can work or no can’t work)
- Prioritise memory, executive & motor measures (better prediction domains)
- Consider test properties & previous evidence
- up to 51% variance explained (this is where we are at now)
What are important considerations in the administration of the assessment?
- Establishing Rapport
- provide best possible conditions for assessment
- Schedule Multiple Sessions
- Record dates, times, rapport, sequence of tests
- Stick to standard test instructions
- Clearly record test outcomes & timing in tests
- also record the way the patient is coping etc
- this minimises risk of subjective
What are some important considerations when administering tests for malingering?
- Always first
- if detect malingering, then rest of tests would be invalid
- Use multiple tests
- Adjust predictive value to number of tests
- try to maximise
- Consider face value of multiple presentation modalities
- people will normally try to malinger obvious thing (like memory)
- other tests like executive function (better disguise the test)
1:50:00
What are some guidelines for interpretation of the tests?

- Consider ALL sources: History, Observations, Tests, Collaterals info, Clinical Judgment
- don’t jump to conclusions from one tests
- Avoid subjective signs (observations, complaints)
- lack of scientific evidence regarding validity
- If there is evidence of malingering
- All other NP tests patterns should be considered invalid
- Always use probabilistic/descriptive language in reports
- (use diagnostic descriptors fron Slick, Sherman e Iverson, 1999; X% probability of malingering according to X)
- can’t label someone a malingerer
- Provide extensive referencing for your statements in reports
151:15
What are some of the challenges faced when testing for malingering?
- Inherent complexity of the assessment
- Protection of specific tests
- Coaching from lawyers
- Replicability
152:50
What is the difference between a patient who is ‘lying’ and one who ‘lacks awareness’ or is in ‘denial’
A patient who is lying has
- purposeful intention
- cognitive control
- very different to awareness or denial
- can use objective markers of lying
- e.g., fMri - shows cognitive effort involved in lying
153:50
