Zasler, Nathan

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Zasler, Nathan

  1. 1. EFFECT OF EFFORT ON POST-TBI OUTCOMES RESEARCH: PRACTICAL AND RESEARCH IMPLICATIONS NATHAN D. ZASLER, MD CEO & MEDICAL DIRECTOR, CONCUSSION CARE CENTRE OF VIRGINIA AND TREE OF LIFE SERVICES CLINICAL PROFESSOR, PM&R, VCU, RICHMOND, VA., USA AND ASSOCIATE PROFESSOR, PM&R, UVA, CHARLOTTESVILLE, VA., USA CHAIRPERSON, IBIA
  2. 2. EDUCATIONAL OBJECTIVES <ul><li>Understand the importance of assessing effort in the context of interpreting test validity in both clinical and research contexts  </li></ul><ul><li>Identify constructs represented by symptom validity tests and make informed decisions regarding how to incorporate such constructs in TBI clinical care and research  </li></ul><ul><li>Describe some of the major controversies relating to the use of effort tests and their interpretation in TBI care and research </li></ul><ul><li>Outline areas for further research and inquiry germane to the need and use of effort testing in the context of both TBI clinical care and research </li></ul>
  3. 3. WHY IS ASSESSMENT OF EFFORT IMPORTANT? <ul><li>Without satisfactory effort, neuropsychological test results and for that matter any ability test data are going to yield invalid reflections of a person’s true capacities. </li></ul><ul><li>Poor effort on testing and exaggeration of cognitive complaints are commonplace. </li></ul>
  4. 4. WHY IS ASSESSMENT OF EFFORT IMPORTANT? <ul><li>TBI clinical practice, as well as outcomes research must therefore develop and integrate well-validated measures of effort if there is a desire to generate data demonstrating the true capacities of those be evaluated. </li></ul>
  5. 5. WHY IS ASSESSMENT OF EFFORT IMPORTANT? <ul><li>Literature shows that poor effort is seen in numerous different contexts including but not limited to: </li></ul><ul><ul><li>claims of cognitive deficits from any source including TBI </li></ul></ul><ul><ul><li>professional athletes pre- and post-concussion </li></ul></ul><ul><ul><li>university students seeking accommodations for ADHD or learning disabilities </li></ul></ul><ul><ul><li>prisoners facing sentencing </li></ul></ul><ul><ul><li>adults volunteering for normative studies or children in school. </li></ul></ul>
  6. 6. SPECTRUM OF EFFORT ON COGNITIVE TESTING <ul><li>Poor Effort Adequate Effort Outstanding Effort </li></ul>
  7. 7. REASONS TO TEST FOR EFFORT <ul><li>Poor effort during testing is, unfortunately, common (Larrabee, 2003; Mittenberg, Patton, Canyock, & Condit, 2002) </li></ul><ul><li>The effect of poor effort on neuropsychological test results is major (Vickery et al., 2001) </li></ul><ul><li>The effect of poor effort dwarfs the effect of mild traumatic brain injuries or other conditions that have modest effects on cognitive functioning. </li></ul>
  8. 8. REASONS TO TEST FOR EFFORT <ul><li>There are well-validated tests for detecting poor effort that have low false positive rates. </li></ul><ul><li>In forensic practice, must address causation and rule-out factors that might lead to incorrect inferences or interpretations. </li></ul><ul><li>It is considered standard practice in forensic psychology and neuropsychology to do employ effort as well as response bias measures. </li></ul><ul><li>The same should be said for and occur in clinical practice and in outcomes research </li></ul>
  9. 9. EXTERNAL INCENTIVES AND INFLUENCE ON EFFORT <ul><li>When there is compensation being received or when there is potential compensation to be received, then effort tends to be adversely affected at a much higher rate. </li></ul><ul><li>WC, SSDI and PI cases are red flags for increased risk of sub-optimal effort. </li></ul><ul><li>When there are reasons / incentives to look more impaired people will attempt to do so… </li></ul>
  10. 11. SPORTS CONCUSSION RESEARCH AND EFFORT <ul><li>Peyton Manning who plays quaterback for the Colts admitted recently to intentionally scoring low on NFL baseline concussion tests so that he can continue to play again after a future injury after being retested. </li></ul><ul><li>Several NFL players said they too purposely performed poorly on the test so they would not be benched after concussive injuries. </li></ul><ul><li>Brings into question sports concussion research using players as their own controls in the absence of effort testing. </li></ul>
  11. 12. ADVERSE EFFECTS ON NEUROCOGNITIVE TEST PERFORMANCE
  12. 13. CLINICAL AND RESEARCH WORK IN PERSONS WITH TBI MUST ALSO CONSIDER: <ul><li>Misattribution bias </li></ul><ul><li>Diagnosis threat and nocebo effect </li></ul><ul><li>Pre-existing psychological history </li></ul><ul><li>Involvement in litigation and risk for symptom magnification and in rare cases malingering </li></ul><ul><li>Cognitive hypochondriasis </li></ul><ul><li>Symptom minimization </li></ul>
  13. 14. IMPORTANCE OF ASSESSING RESPONSE BIAS <ul><li>Formal measures of response bias should be interspersed throughtout neuropsychological exam including use of embedded as well as free-standing measures NAN </li></ul><ul><ul><li>(Bush et al, 2005), AACN(Heilbronner et al, 2009). </li></ul></ul><ul><li>Need to understand that response bias is not constant across an exam </li></ul><ul><li>Need to understand that response biases present differently across patients </li></ul>
  14. 15. HOW TO SELECT EFFORT MEASURES <ul><li>Should be brief and ideally embedded as this best allows for continuous sampling </li></ul><ul><li>Choose measures with high effectiveness as assessed by sensitivity while maintaining adequate specificity </li></ul><ul><li>Low to moderate sensitivity tests can be used to “rule in” but not “rule out” response bias </li></ul><ul><li>Cut-off scores should be set to protect credible patients at the sacrifice of sensitivity – thus a failing score is more relevant than a passing score </li></ul>
  15. 16. HOW TO SELECT EFFORT TESTS <ul><li>Employ effort tests that tap various neurocognitive domains </li></ul><ul><li>Select tests that are not strongly correlated with each other </li></ul><ul><li>Consider group being studied and choose tests that lessen risk for false positive identification as “poor effort” on particular tests </li></ul><ul><li>Consider risk of patient education or coaching regarding specific effort measures – don’t always use same tests and try and use less common ones as well. </li></ul>
  16. 17. TYPES OF EFFORT TESTS <ul><li>Forced choice </li></ul><ul><li>Non-forced choice </li></ul><ul><li>Freestanding </li></ul><ul><li>Embedded </li></ul>
  17. 18. COGNITIVE EFFORT TESTS: FREESTANDING <ul><li>REY 15 ITEM MEMORY TEST </li></ul><ul><li>REY DOT COUNTING TEST </li></ul><ul><li>DIGIT RECOGNITION TEST (HISCOCK) </li></ul><ul><li>COMPUTERIZED ASSESSMENT OF RESPONSE BIAS (CARB) </li></ul><ul><li>TEST OF MALINGERED MEMORY (TOMM) </li></ul><ul><li>WORD MEMORY TEST (WMT), MSVT, NV-MSVT, MCI </li></ul><ul><li>WORD COMPLETION MEMORY TEST (WCMT) </li></ul><ul><li>VICTORIA SYMPTOM VALIDITY TEST (VSVT) </li></ul>
  18. 19. EMBEDDED EFFORT MEASURES <ul><li>Reliable Digit Span </li></ul><ul><li>Digit Span Scaled Score </li></ul><ul><li>Logical Memory Rarely Missed Index </li></ul><ul><li>Finger Tapping Test </li></ul><ul><li>Booklet Category Test </li></ul>
  19. 20. FORCED CHOICE TESTS <ul><li>Task is to recognize previously seen material from two choices </li></ul><ul><li>Recognition is substantially easier than free recall. </li></ul><ul><li>Can compare performance across tests to look for non-organic patterns. </li></ul><ul><li>Sensitive to feigned deficits in memory. </li></ul><ul><li>Examine performance relative to chance or set cut-offs below which few credible patients will score. </li></ul>
  20. 21. NON-FORCED CHOICE TESTS <ul><li>Standard cognitive tests that are already in an existing neurocognitive battery such as: </li></ul><ul><ul><li>WAIS-III digit span </li></ul></ul><ul><ul><li>RAVLT recognition equation </li></ul></ul><ul><ul><li>Finger tapping </li></ul></ul><ul><ul><li>Stroop test </li></ul></ul><ul><ul><li>WMS-III logical memory </li></ul></ul>
  21. 22. CONTROVERSIES IN EFFORT AND RESPONSE BIAS TESTING IN PERSONS WITH TBI <ul><li>What causes sub-optimal effort? </li></ul><ul><li>How, if at all, do fatigue, depression, anxiety, pain, interest in task, cultural background, among other factors, influence effort testing results? </li></ul><ul><li>What does “failure” on an effort test mean? </li></ul><ul><li>How does response bias correlate with effort? </li></ul><ul><li>What factors influence interpretation of response bias measures? </li></ul>
  22. 23. FUTURE DIRECTIONS <ul><li>Increased appreciation of the need for inclusion of effort and response bias measures in clinical and research practice. </li></ul><ul><li>Expanded research on development of effort measures that are specific to poor effort and not impacted by other factors such as dementia. </li></ul><ul><li>Further research on development of tests that are not impacted by age, demographics or sex </li></ul><ul><li>Collection of performance data on specific sub-groups of patients including those with affective disorders, pain, somatoform disorders, fatigue, among others. </li></ul>
  23. 24. Join IBIA in Edinburgh, Scotland for the Ninth World Congress of the International Brain Injury Association March 21-25, 2012 Visit www.internationalbrain.org
  24. 26. THE END <ul><li>DR. ZASLER’s E-MAIL: </li></ul><ul><li>[email_address] </li></ul>

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