Malingering

Question 1

What is factitious disorder? factitious disorder by proxy?

Answer 1

• Patient attempt medical deception by presenting with symptoms that result in medical attention
• Factitious disorder by proxy is when a child becomes an object of symptom fabrication induced by a caregiver
• Occurs due to operant reward received from sick role
• Presence of second pathological entity or personality disorder

Question 2

How is malingering detected?

Answer 2

• Performance validity tests: measures whether or not test performance is an accurate measure of the examinee’s actual abilities
• Symptom validity tests: Measures whether or not test scores of self-report instruments are accurate measures of examinee’s actual symptoms experience

Question 3

What are the 3 defined categories of malingered neurocognitive dysfunction?

Answer 3

1. Definite MND: Significant worse than chance performance on two alternative forced choice testing
2. Probable MND: Failure of multiple criteria on PVTs
3. Possible: Failure of some criteria on PVTs

Question 4

How is malingered pain-related disability detected?

Answer 4

• Presence of substantial financial incentive
• Failure on cognitive test performance of PVTs
• Rule out other explanations
• Discrepancy between behaviour when patient is aware of being observed vs. being unaware of observation
• Atypical test performance and symptom report patterns from those with bona fide neurologic, psychiatric, or developmental disorders

Question 5

What are the two approaches to the development of PVTs?

Answer 5

1. Simulation designs: Compare PVT performance between non-injured examinees who are instructed to feign vs. those who aren’t instructed to feign
2. Criterion groups design: Take people who really have the disorder and compare them to controls

Question 6

What is the difference between test sensitivity and specificity?

Answer 6

• Sensitivity (true positive): Proportion of individuals validly identified as having a target condition based on results of the test
• Specificity (true negative): The proportion of individuals in a test sample correctly identified as not having the target condition based on the results of a test

Question 7

What is the difference between stand-alone and embedded PVTs?

Answer 7

• Stand-alone: Special purpose tests designed specifically to detect malingering
• Embedded: Extracting estimates of performance validity from existing scales in standardized neuropsychological and neurobehavioral tests

Question 8

What are the 4 ways that malingers differ from patients with TBI?

Answer 8

They perform worse than patients with moderate to severe TBI on:

• Perceptual tests
• Gross motor function tests
• Tests of attention and working memory
• Tests of recognition memory

On two alternative forced choice tests, malingerers perform significantly better than chance but significantly worse than patients with bona fide neurological impairments (TOMM – malingerer scored 71% while patient with TBI scored 98.2%)