Some Caveats in Using the Rey 15-Item Memory Test ...

Psychological Assessment: A Journal of Consolting and Clinical Psychology 1991, Vol. 3, No. 4, 667-672

Copyright 1991 by the American Psychological Association, Inc. 1040-3590/91/$3.00

Some Caveats in Using the Rey 15-Item Memory Test to Detect Malingered Amnesia David Schretlen, Jason Brandt, and Laura Krafft Johns Hopkins University School of Medicine

Wilfred Van Gorp West Los Angeles Department of Veterans Affairs Medical Center and University o f California, Los Angeles School o f Medicine

A procedure devised to detect malingered amnesia has received increasing attention as a useful clinical method to identify exaggerated claims of memory impairment. However, none of the published studies regarding its utility has included subjects faking amnesia or genuine amnesics. In this study, we administered the Rey 15-1tem Memory Test to 76 subjects faking various mental disorders, 148 patients with amnesia, dementia, severe mental illness, or another neuropsychiatric disorder, and 80 normal control subjects. Performance was found to correlate highly with IQ (r = .55) and Mini-Mental State Examination scores (r = .81). Fewer than 15% of subjects faking mental disorders were identified by this procedure, and 27% of patients scored in the "malingering" range. Problems with the uncritical application of cutoffscores to detect malingering with this procedure are discussed.

This approach assumes that markedly below chance performance reflects a deliberate avoidance o f correct responses. A third approach, the focus of this study, involves the administration o f a very simple memory test that is presented as being quite difficult. In this study we used a procedure devised by Andre Rey (1964) to detect malingered memory impairment. It consists of a card on which five rows o f three characters each are printed. As shown in Figure 1, the items are highly related. The subject is told that there are 15 different items to be remembered but that the card will be shown for only 10 s. This emphasis is intended to make the task seem difficult. The assumption is that malingerers will be misled to perform even more poorly than those with relatively severe cognitive impairment. In her discussion o f the Rey 15-Item Memory Test, Lezak (1983) opined that "anyone who is not significantly deteriorated can recall at least three of the five character sets" (p. 619). Goldberg and Miller (1986) reported a study in which 50 adult psychiatric inpatients of average intelligence were compared with 16 mildly retarded adults using the Rey 15-Item Memory Test. All of the psychiatric patients recalled at least 9 ofl 5 items (M = 13.5, SD = 1.8), and 92% recalled I 1 to 15 items. In contrast, over 37% of retarded subjects recalled fewer than 9 items (M = 9.9, SD = 3.0). These investigators also found that the number of rows recalled correctly was negatively correlated with the Minnesota Multiphasic Personality Inventory (MMPI) Infrequency (F) scale and the Wiggins Organicity scale but positively correlated with IQ. Despite these findings, the authors concluded that "both psychiatrically disturbed and intellectually deficient individuals perform adequately on the task" and that "malingering should be suspected among individuals

Reviews of the legal literature have found that criminal defendants often claim amnesia to prove their incompetence to stand trial or to demonstrate diminished criminal responsibility (Rubinsky & Brandt, 1986; Schachter, 1986). Claims of amnesia often arise in personal injury suits and disability evaluations as well (Guthkeltch, 1980). Experts asked to evaluate the veracity of such claims traditionally have had to rely on careful interviewing and professional judgment to do so, because no empirically validated, objective methods to detect exaggerated claims of memory impairment were available. Recently, however, some promising results have emerged from tests of the hypothesis that simulators would fail to accurately reproduce the clinical picture associated with various amnestic disorders. As noted previously (Schretlen, 1988), this hypothesis has guided the psychological study of malingering with respect to many symptoms and mental disorders. Wiggins and Brandt (1988), for example, compared experimental subjects faking amnesia with genuine amnesics and normal control subjects using tasks designed to reveal group differences in autobiographical memory, implicit memory, and serial position effects in the recall o f a 20-word list. A second strategy, called symptom validity testing, involves the administration of numerous two-alternative, forced-choice recognition memory problems (Brandt, Rubinsky, & Lassen, 1985; Pankrantz, 1983).

Correspondence concerning this article should be addressed to David Schretlen, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Meyer 218, 600 North Wolfe Street, Baltimore, Maryland 21205. 667

668

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who deny remembering at least 9 items o f the Rey test" (Goldberg & Miller, 1986, p. 795). However, the absence o f any data from malingerers or experimental simulators in that study, coupled with the fact that over 37% o f retarded subjects performed below the cutoff score, makes their suggestion premature. To our knowledge, the only other investigation o f this test was reported by Bernard and Fowler (1990). In their study, 18 patients admitted to a rehabilitation hospital with neurological disorders of mixed etiology and 16 control subjects matched for age, sex, and education were administered the Rey 15-Item M e m o r y Test. Neurological patients recalled significantly fewer ( M = 11.4, SD = 2.7) items than did the controls ( M = 13.1, SD = 2.1), and no control subject recalled fewer than nine items. Sixteen o f the 18 patients recalled nine or more items; the other 2 recalled eight. The authors concluded t h a t " m a l i n g e r i n g should be suspected in individuals who deny remembering 9 or more total items" (Bernard & Fowler, 1990, p. 435). Again, however, no malingerers or simulators were included in the study. In the absence o f information about how experimental simulators or suspected malingerers perform on the Rey 15-Item M e m o r y Test, its sensitivity to faked amnesia is unknown. Until results on this test are obtained from other neuropsychiatric groups, including genuine amnesics, persons o f l o w IQ, and the severely mentally ill, its specificity for faking also remains unknown. In the present article we report data for nine subject groups, including patients, experimental and "suspected" fakers, and normal control subjects.

Method

Subjects and Procedure The subjects were recruited from a variety of settings. Some served in previous research studies, as noted. The recruitment procedures and experimental instructions given to each group are described below in the following paragraphs. The additional test data obtained from each group reflect the heterogeneity of the sources from which they were recruited. Appropriate informed consent was obtained from individuals to whom the Rey 15-Item Memory Test was administered as an experimental procedure. In a few cases, it was administered as part of a clinical evaluation and was included in the present study as archival

data. In no case was the Rey 15-Item Memory Test used to make a clinical diagnosis. Fake amnesia. As described in Wiggins and Brandt (1988), 47 community volunteers and university students were asked to feign one of three amnesia syndromes (psychogenic amnesia resulting from emotional trauma, amnesia resulting from head injury, or amnesia of unspecified etiology) for $I 5 or course credit. Subjects were given several tests of autobiographical memory, free recall, forced-choice recognition memory, and semantic priming, as well as the Rey 15-Item procedure. For the present study these simulators were combined into a single group because all three groups performed equally lower than did normal controls on most of the explicit memory tasks (Wiggins & Brandt, 1988). Fake insanity As described in Schretlen, Wilkins, Van Gorp, and Bobholz (in press), 22 inpatient substance abusers from the West Los Angeles Department of Veterans Affairs Medical Center (DVAMC) were asked to fake "insanity" (as in Schretlen & Arkowitz, 1990) for$5 worth of canteen books, redeemable for food. These subjects also took the Shipley Institute of Living Scale (Zachary, 1986) before being instructed to fake insanity, in order to estimate their Wechsler Adult Intelligence Scale-Revised (WAIS-R; Wechsler, 1981) Full Scale IQs. Suspected malingerers. Five of the 7 individuals who composed this group had sustained questionable or mild head injuries and were involved in civil litigation. They claimed significant memory disorders and were referred to the Johns Hopkins University Division of Medical Psychology Clinic or the West Los Angeles DVAMC Neuropsychology Assessment Laboratory for evaluation. The sixth person in this group was charged with murder; he pleaded not criminally responsible due to a mental disorder, but several independent forensic psychiatrists and psychologists found no evidence to support his claimed symptoms. The seventh subject was a young man with fetal alcohol syndrome who was facing charges of child sexual molestation; he appeared to malinger a mental disorder, presumably to lessen his criminal responsibility. In each case, gross inconsistencies between neuropsychological test performance and everyday behavior, or between different tests (independent of the Rey 15-Item Memory Test), were highly suggestive of malingering, although none of the subjects confessed to malingering. Amnesics. These 10 cases were referred for clinical evaluation to the Johns Hopkins University Cortical Function Laboratory or Division of Medical Psychology Clinic. For those cases of identified etiology, diagnosis was confirmed with appropriate laboratory, neuroradiologic, and psychometric testing. One patient had herpes encephalitis; another had alcoholic Korsakoff's syndrome; a third underwent resection of a ventricular tumor; and 2 patients suffered anoxic episodes. The remaining 5 patients had amnestic syndromes of uncertain etiology. In contrast to their average IQ (M= 96.0, SD = 19.1), the amnesic patients demonstrated severe memory impairment (Wechsler Memory ScaleRevised (Wechsler, 1987) General Memory Index or Wechsler Memory Scale Memory Quotient: M = 73.8, SD = 9.6). Mixed neuropsychiatric patients. This group comprised 20 men from a schizophrenia research and treatment unit at the West Los Angeles DVAMC (16 schizophrenics, 4 others) and 20 consecutive referrals to the West Los Angeles DVAMC Neuropsychology Assessment Laboratory with mixed or unclear neuropsychiatric conditions. The latter 20 cases included no more than 3 patients with any given neuropsychiatric diagnosis. Traumatic brain injury The 55 subjects in this group include 40 patients serving in a 7-year follow-up study being conducted by David Schretlen, 13 patients from an outpatient rehabilitation program, and 2 patients from the West Los Angeles DVAMC. Most sustained moderately severe injuries; the 40 follow-up study patients were hospitalized for an average of 68 ± 21.4 days with an average admission Glasgow Coma Scale (Teasdale & Jennet, 1974) score of 9.6 + 2.3.

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MALINGERED AMNESIA Table 1 Demographic Characteristics o f Subject Groups Education (years)

Age (years)

IQ

MMSE

Sex

Condition

n

M

SD

M

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47 22 7 80 40 55 9 34 10

25.8,~ 36.022 41.47 36.38o 39.04o 33.854 59.69 42.434 58.010

6.6 7.8 13.8 11.9 11.9 8.4 13.3 12.9 20.3

13.619 12.45 14.117 13.126 12.4~ 15.36 9.233 13.29

304

36.8302

13.2

12.3163

Total

SD

--

(male/female)

M

2.2 1.7 2.6 1.7 2.3 3.6 2.9 3.5

24/23 22/0 5/0 45/35 37/3 40/15 8/1 15/19 4/6

. 90.922 82.25 116.135 92.637 90.748 89.03 73.6~ 96.09

3.0

200/102

--

SD .

. 10.5 23.4 16.0 15.3 14.6 14.8 9.3 19.5

92.7193

19.1

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SD

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--

21.02 28.752 27.916 28.52 25•89 24.09 23.67

5.7 1.5 1.6 0.7 5.2 4.9 4.5

27.397

3.4

Note. Numbers of cases used for each analysis are shown as subscripts. MMSE = Mini-Mental State Examination (Folstein, Folstein, & McHugh, 1975).

Mixed dementia. This group of 9 subjects consisted of 6 patients with confirmed diagnoses of Huntington's disease evaluated at The Johns Hopkins University Huntington's Disease Research Program and 3 patients seen at the West Los Angeles DVAMC Neuropsychologieal Assessment Laboratory. The latter included 1 patient with Parkinson's disease, 1 with a subcortical-type dementia syndrome of unknown etiology, and I with alcoholic dementia. Severely mentally ill. The 34 patients in this group were recruited from The Johns Hopkins Hospital Community Psychiatry Program. This community mental health center serves a poor, urban catchment

area in Baltimore, Maryland. These patients were diagnosed by an attending psychiatrist according to the criteria of DSM-III (third edition of the Diagnostic and Statistical Manual of Mental Disorders, American Psychiatric Association, 1980) or its revision, DSM-III-R (American Psychiatric Association, 1987) as suffering from schizophrenia (15), affective illness (9), alcohol hallucinosis (2), and other disorders (6). Normal control subjects. This group includes 27 community volunteers and university students from the Wiggins and Brandt (1988) study, 17 hospital employees serving as control subjects in other studies, and

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Figure 2. Scheff6 post hoc analyses of group differences in total number of items recalled after a 10-s exposure to the stimulus figure• (Vertical bars express standard errors of the means.)

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p(.01 p9 items is not exaggerating memory impairment. Using this cutoff, the Rey 15-Item Memory Test has a negative predictive value o f 62.4%. 3

Discussion This study revealed several limitations that warrant consideration when using Rey's 15-Item Memory Test to detect malingered amnesia. Most important, we found that many simulators and suspected malingerers recalled at least nine correct items or three complete rows. Further, many nonfaking patients--particularly those with severe mental illness, dementia, and genuine amnesia--scored well below normal control subjects, and many performed below the suggested cutoff scores. Ideally, a test designed to detect malingered amnesia should be sensitive to faking but insensitive to genuine memory disorders. However, the Rey 15-Item Memory Test falls short o f this ideal precisely because o f its sensitivity to genuine memory impairment.

Despite its demonstrated simplicity for normal adults, the Rey 15-Item Memory Test is less constrained by ceiling effects when applied to various clinical populations. Not only do patients with focal memory defects do poorly on this test, but those with more diffuse cognitive impairment perform poorly as well. Consistent with this, we found that the number of items recalled on the Rey 15-Item Memory Test correlated very highly with Mini-Mental State Examination scores (r = .81) and nearly as highly with IQ (r = .55). Goldberg and Miller 0986) also reported a significant positive correlation between IQ and Rey 15-Item Memory Test performance. Unfortunately, Bernard and Fowler (1990) did not report correlations, even though they obtained IQ and memory test data. A third finding o f this study was the heterogene'lty oI ~ e y 15-Item Memory Test performance by the three faking groups. Experimental subjects faking memory impairments obtained the best scores. In fact, none performed below the cutoffscores of nine items or three rows recalled, in spite of the fact that these subjects performed in the impaired range on other tests o f memory (Wiggins & Brandt, 1988). Subjects faking insanity obtained lower scores: 50% recalled fewer than three rows. Five of the 7 suspected malingerers recalled fewer than three rows, and 2 of these subjects were claiming to be not criminally re-

2 Positive predictive value equals the number of true positives divided by all positive test results. In this case 11/(I 1 + 40) = 0.216. 3 Negative predictive value equals the number of true negatives divided by all negative test results. In this case 108/(65 + 108) = 0.624.

672

SCHRETLEN, BRANDT, KRAFFT, AND VAN GORP Table 2 Sensitivity (or Specificity) o f Predictions Associated With Selected Cutoff Scores on Two Indexes o f Faking From the Rey 15-Item Memory Test Items recalled

Rows recalled

-4)

Simulators Suspected fakers All patients Normal subjects

69 7 148 80

12 43 (73) (100)

13 71 (64) (100)

41 100 (39) (91)

20 71 (62) (100)

41 85 (41 ) (97)

57 100 (22) (74)

Note. Sensitivity refers to the percentage of experimental or suspected fakers who score below the specified cutoff (i.e., the percentage of fakers correctly classified as faking). Specificity (given in parentheses) refers to the percentage of each nonfaking sample who score above the specified cutoff(i.e., the percentage of nonfakers correctly classified as nonfaking).

sponsible owing to mental impairment. These results support the hypothesis that subjects faking one disorder may demonstrate impairments in unrelated d o m a i n s of ability, presumably owing to their ignorance o f the clinical picture associated with a given form of psychopathology (Schretlen & Arkowitz, 1990). The question arises of whether, and under what circumstances, the Rey 15-Item M e m o r y Test may contribute to the clinical determination of malingering. The results o f this study suggest that patients with genuine amnesic disorders and those with severe cognitive i m p a i r m e n t caused by various neuropsychological conditions often perform very poorly on this test. Mild brain injuries, especially in persons whose premorbid IQ was at least borderline, on the other hand, are not likely to markedly impair performance on Rey's 15-Item M e m o r y Test. Thus, in the absence o f gross cognitive impairment, demonstrable neurologic disease, or severe psychiatric illness, persons with at least borderline intelligence should not recall fewer than nine items or three complete rows. Although the results of this study do not support the uncritical application of any given cutoff score for Rey's 15-Item Memory Test, the test can provide useful data concerning the probability o f malingering in some cases. References American Psychiatric Association. (1980). Diagnostic and statistical manual of mental disorders (3rd ed.). Washington, DC: Author. American Psychiatric Association. (1987). Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.).Washington, DC: Author. Bernard, L. C., & Fowler, W. (1990). Assessing the validity of memory complaints: Performance of brain-damaged and normal individuals on Rey's Task to detect malingering. Journal of Clinical Psychology, 46, 432-436. Brandt, J., Rubinsky, E., & Lassen, G. (1985). Uncovering malingered amnesia. Annals of the New York Academy of Sciences, 44, 502-503. Folstein, M. E, Folstein, S, E., & McHugh, P, R. (1975). "Mini-mental state": A practical method for grading the mental state of patients for the clinician. Journal of Psychiatric Research, 12, 189-198. Glaros, A. G., & Kline, R. B. (1988), Understanding the accuracy of tests with cutting scores: The sensitivity, specificity, and predictive value model. Journal of Clinical Psychology, 44, 1013-1023. Goldberg, J. O., & Miller, H, R. (1986). Performance of psychiatric inpatients and intellectually deficient individuals on a task that assesses the validity of memory complaints. JournalofClinicalPsychology, 42, 792-795.

Guthkeltch, A. N. (1980). Posttmumatic amnesia, post-concussional symptoms and accident neurosis. European Neurology, 19, 91-102. Lezak, M. (1983). Neuropsychological assessment (2rid ed.). New York: Oxford University Press. Miller, E. N., Selnes, O. A., McArthur, J. C., Satz, E, Becker, J. T., Cohen, B. A., Sheridan, K., Machado, A. M., Van Gorp, W G., & Visscher, B. (1990). Neuropsychological functioning in HIV-1 infected homosexual men: The multi-center cohort study (MACS). Neurology, 40, 197-203. Pankrantz, L. (1983). A new technique for the assessment and modification of feigned memory deficit. Perceptual and Motor Skills, 57, 367-372. Rey, A. (1964). I~xamen clinique en psychologic. Paris: Presses Universitaires de France. Rubinsky, E. W, & Brandt, J. (1986). Amnesia and criminal law: A clinical overview. Behavioral Sciences and the Law, 4, 27-46. Schachter, D. L. (1986). Amnesia and crime: How much do we really know? American Psychologist, 41, 286-295. Schretlen, D. (1988). The use of psychological tests to identify malingered symptoms of mental disorder. Clinical Psychology Review, 8, 451-476. Schretlen, D., & Arkowitz, H. (1990). A psychological test battery to detect prison inmates who fake insanity or mental retardation. Behavioral Sciences and the Law, 8, 75-84. Schretlen, D., Wilkins, S. S., Van Gorp, W G., & Bobholz, J. H. (in press). Cross-validation of a psychological test battery to detect faked insanity. Psychological Assessment: A Journal of Consulting and Clinical Psychology. Silverstein, A. B. (1982). Two- and four-subtest short forms of the Wechsler Adult Intelligence Scale-Revised. Journal of Consulting and Clinical Psychology, 50, 415-418. Teasdale, G., & Jennet, B. (1974). Assessment of coma and impaired consciousness. Lancet, 2, 81-84. Wechsler, D. (1981). Manual for the WechslerAdult Intelligence ScaleRevised. New York: Psychological Corporation. Wechsler, D. (1987). Manual for the Wechsler Memory Scale-Revised New York: Psychological Corporation. Wiggins, E. C., & Brandt, J. (1988). The detection of simulated amnesia. Law and Human Behavior, 12, 57-78. Zachary, R. A. (! 986). Shipley Institute of Living Scale revised manual Los Angeles: Western Psychological Services. Received October 11, 1990 Revision received February 13, 1991 Accepted March 4, 1991 •