Martin L. Rohling, Ph.D. Memorial Hospital at Gulfport, MS Paul Green, Ph.D.

1. Comparisons Between the Word memory Test and Formula for the CVLT as Indicators of Suboptimal Performance Martin L. Rohling, Ph.D. Memorial Hospital at Gulfport, MS Paul Green, Ph.D. Neurobehavioral Associates, Edmonton, Alberta Lyle Allen, M.A. CogniSyst Inc., Durham, NC David J. Williamson Private Practice, Mobile, AL

2. Introduction The California Verbal Learning Test (CVLT) is a widely used measure of verbal learning and memory. Millis et al. (1995) demonstrated that short delayed free recall, long delayed free recall, and recognition hits could be used in a logistic regression equation to reliably detect patients who have exerted “incomplete effort.” The Word Memory Test (WMT, Green, Allen, & Astner, 1996) incorporates three separate measures of response bias, while also assessing verbal learning and memory. It is a computerized list learning task in which the patient is presented with 20 word pairs. There is an immediate recognition, delayed recognition, & consistency measure, all of which have been found to be sensitive to suboptimal performance.

3. Patients were consecutive outpatient referrals for compensation-related evaluations who had been given both the CVLT and the WMT. The battery included other tests of the six primary cognitive domains (Verbal-Comprehension, Perceptual Organizational, Executive Functioning, Memory & Learning, Attention-Working Memory, and Processing Speed). Cognitive ability tests were used to investigate the differences between groups of patients identified by the two methods. Purpose This study evaluated the concordance of classification between the CVLT-LOGIT formula and the WMT measures of response bias.

4. Methods Five measures of symptom validity were administered to patients who were referred to a neuropsychologist (PG) for disability evaluations. These patients were also given multiple measures of cognitive ability, psychopathology, and self-reported memory impairment. A single global index was generated for each of these four types of measures. This was accomplished using meta-analytic procedures to calculate effect sizes (Hedges’ g). Effect sizes were expressed as Z score differences within the sample. The Z scores were then averaged within each type of measure to get a single measure for each patient on the cognitive, effort, psycho-pathology, and subjective memory impairment.

5. Sample • Objective neurological indices & diagnoses were also recorded & patients were classified: • Psychiatric Patients (n = 107) • Dep = 79; Anx =16; Bipolar = 8; Psychotic = 4 • Medical Patients (n = 246) • Ortho = 77; CFS = 34; Pain/Fibro = 59; Other = 77. • Head Injured? (n = 48) • without radiological findings documented in medical record. • Mild Head Trauma (n = 329) • PTA < 24 hrs and positive radiological findings. • Definite TBI (n = 93) • PTA > 24 hrs and positive radiological findings. • Neurological Patients (n = 75) • Stroke = 21; Aneurysm = 15; MS = 11; Tumor = 8; Epilepsy = 3; Other = 17.

6. Dependent Measures • Overall Test Battery Mean OTBM (N = 32) • Verbal Comprehension VC (n = 4) • WRAT-III – Read, Spell, & Math • WAIS-R VIQ • Perceptual Organizational PO (n = 4) • Rey CFT – Copy & Recall • Judgment of Line Orientation • WAIS-R PIQ • Executive Functioning EF (n = 6) • Wisconsin Card Sort – # Sorted, & Per. Err • Category Test - Errors • Thurstone Word Fluency • Ruff Figure Fluency • Gorham’s Proverbs • Memory and Learning ML (n = 6) • Story Recall Test – Imm. & Delayed Recall • Rey CFT – Delayed FR & Rgn • Warrington –Words & Faces • Attention & Working Memory AW (n = 6) • Trail Making Test – Forms A & B • Digit Span – Forward & Backward • Visual Memory Span – Forward & Backward • Psychomotor Speed PS (n = 6) • Finger Tapping – Dom. & N’dom. • Grip Strength – Dom. & N’dom. • Grooved Pegboard – Dom & N’dom.

7. Symptom Validity SV (N = 5) • Computer Assessment Response Bias • Total score for all 3 Blocks of trials • Word Memory Test (n = 3) • Imm. & 30-m Del. Rgn (IR & DR) • Consistency • CVLT-Logit Formula (n = 1) • Emotional & Personality Variables (N=18) • Beck Depression Inventory (n = 1) • MMPI-2 (n = 8) • Hs, De, Hy, Pd, Pa, Pt, Sc, Ma • Symptom Checklist–90 Revised (n = 9) • Som, Oc, Is, Dep, Anx, Hos, Phob, Para, Psych • Self Assessment of Memory • Memory Complaints Inventory (n = 9) • General Memory Problems (GMP) • Numeric Information Problem (NIP) • Visual-Spatial Problems (VSP) • Verbal Memory Problems (VMP) • Pain Interferes with Memory (PIM) • Memory Interferes with Work (MIW) • Impaired Remote Memory (IRM) • Amnesia Complex Behavior (ACB) • Amnesia Antisocial Behavior (AAB)

8. Results • Results indicate that the methods agreed for 77% of all patients. • 513 patients (65%) were identified by both methods as genuine responders • mean Z = -.16. • 97 patients (12%) were identified as suboptimal responders by both methods • mean Z = –1.65. • 59 patients (8%) were suboptimal responders by the CVLT-Logit formula but genuine responders by the WMT • mean Z = -.45. • 114 patients (14%) were suboptimal responders by the WMT but genuine responders by the CVLT-Logit formula. • mean Z = -.86.

9. Discussion • Findings suggests that the WMT is more sensitive to suboptimal performance than is the CVLT LOGIT formula. However, both tests in combination may be the best method of assessing the validity of patients’ performance.