University of South Alabama Neurobehavioural Associates Who Is Exaggerating Cognitive Impairment and Who’s Not? Martin L. Rohling, Ph.D. University of South Alabama Lyle M. Allen, III, M.A. CogniSyst, Inc. Paul Green, Ph.D. Neurobehavioural Associates

Introduction If patients failure to exert optimal effort, this may lead to errors in diagnosis, treatment, and awarding of disability resources. If a clinician claims that a patient failed to put forth adequate effort, when in fact they were performing to the best of their ability, this may result in denial of a financial award that is needed to cope with occupational disability. Although memory-complaints are often used in an evaluation, these are seldom quantified to increase accuracy of diagnosis. The best decision rules for understanding a patient’s presentation might incorporate data from each type of assessment (e.g., performance measures and self-report of symptoms).

Purpose of Study 1) Replicate the findings of Green et al. (2001) using alternative statistical procedures. 2) Examine pattern of scores on both objective tests and self-report instruments to see if there were differences between genuine and exaggerating patients. 3) If a differential pattern of scores is observed, this might be used to develop an algorithm to improve the identification of patients whose scores on tests could be considered valid, even though they failed a SVT.

Participants Outpatients for a Workers’ Comp claim (42%), a medical disability (36%), or personal injury (19%). Benefits for disability were available or had been received by the remaining privately referred patients (3%). The sample included patients referred to evaluate a TBI (54%), neurological disease (10%), psychiatric disorder (17%). The sample included patients referred for an orthopedic injury, chronic fatigue, chronic pain and/or fibromyalgia, or other various conditions (19%)

Dependent Variables NPT – mean z score on 43 neuropsychological test, which were assigned to 1 of 7 different cognitive domains: (1) Verbal-Comprehension, (2) Perceptual Organization, (3) Executive Function, (4) Auditory Memory, (5) Visual Memory, (6) Attention-Working Memory, (7) Psychomotor Speed SVT – mean z score for Word Memory Test and CARB PSX – mean z score for self-reported psychiatric sx, measured by the MMPI-2, SCL-90-R, and BDI MCI – mean z score for self-reported memory functioning using the 9 scales of the Memory Complaints Inventory All DVs converted to z scores and composite scores were generated by averaging these z scores.

Factor Loadings of Domain Scores Genuine Normal Genuine Neurologic Exaggerating Normal Objective Perform. Self-Report NPT .57 -.03 .64 -.01 .89 .11 SVT .58 -.08 .63 -.02 .87 .12 MCI .56 .04 .55 .33 .81 PSX -.07 -.06 .03 .91 Eigen 1.30 1.83 1.22 1.67 2.02 1.14 % Var. 33% 46% 30% 42% 51% 29%

Means & SDs of Composite Scores Genuine Exaggerate Normal Neurologic Neuropsych Test Scores .33 (.62) .19 (.64) -.60 (.80) -.79 (.65) Symptom Validity .51 (.38) .50 (.30) -1.25 (.94) -.50 (.52) Memory Complaints .14 (.93) .41 (.92) -.62 .49 (.54) PsychiatricSymptoms .10 (.95) .46 (.96) -.39 (.85) (.99)

Mean z score on Objective Performance Small differences between Genuine Normal & Genuine Neuro on NPT composite. No differences between Exaggerating Normal and Exaggerating Neuro on NPT composite. Deficits for Exaggerating Neuro were more modest than for Exag-gerating Normals on SVT composite. Interaction between Validity & Neuro Status.

Mean z score on Self-Report Instruments No differences between Genuine Neuro & Exag-gerating Neuro on Memory Complaints composite. No differences between Genuine & Exaggerating Neuro on Psychiatric Sx composite. Deficits for Exaggerating Normal on the Psych Sx & Memory Complaints composites; later larger. Interaction between Validity & Neuro Status.

Discussion Multiply regressing cognitive domain composites resulted in the SVT composite accounting for 43% of the variance of in neurocognitive ability. This is less than previously reported (53%; Green et al., 2001), but remains the most significant of all other independent variables. The factor structure of composite scores (i.e., NPT, SVT, MCI, & PSX) was similar for genuine normal & neurologically impaired patients. However, both of these patient groups were different from exaggerating normal patients. Neurologically impaired patients who fail SVTs may be false positives for malingering diagnoses when they complain of few memory problems & mild psychiatric sx.

References: Rohling, M. L. , Allen, L. M. , & Green, P. (2002) References: Rohling, M. L., Allen, L. M., & Green, P. (2002). Who is exaggerating cognitive impairment and who is not? CNS Spectrums, 7, 387-395. Available at http://www.cnsspectrums.com/article.php3?id=233 Green, P., Lees-Haley, P. R., & Allen, L. M. (in press). The Word Memory Test and the validity of neuropsychological test scores. Journal of Forensic Neuropsychology. Green, P., Rohling, M. L., Lees-Haley, P. R., & Allen L. M. (2001). Effort has a greater effect on test scores than severe brain injury in compensation claimants. Brain Injury, 15, 1045-1060. Lees-Haley, P. R., Fox, D. D., & Courtney, J. C. (2001). A comparison of complaints by mild brain injury claimants and other claimants describing subjective experiences immediately following their injury. Archives of Clinical Neuropsychology, 16, 689-695. Iverson, G. L., & Binder, L. M. (2000). Detecting exaggeration and malingering in neuropsychological assessment, Journal of Head Trauma Rehabilitation, 15, 829-858.