- Email: [email protected]
Recommendation for test administration in litigation: Never administer the category test to a blindfolded subject
Pergamon
Archives of Clinical Neuropsychology, Vol. I1, No. 2, pp. 93-95, 1996 Copyright © 1996 National Academy of Neuropsychology Printed in the USA. All fights reserved 0887-6177/96 $15.00 + .00
0887-6177(95)00060-3
Recommendation for Test Administration in Litigation: Never Administer the Category Test to a Blindfolded Subject H. Daniel Blackwood Neuropsychology Associates, PC.
Fox (1994) purports to determine the appropriateness o f the normative data f o r the Logical Memory subtest of the Wechsler Memory Scale - - Revised for individuals in litigation and suggests that % . . many o f these people would have been incorrectly diagnosed as having a neuropsychological problem that did not exist." His data do not support such a conclusion, but rather appear simply to demonstrate that patients in litigation concerning potentially painful orthopedic and/or emotional injuries can, as a group, perform slightly below average levels on memory tests.
Consideration of the possible effects of financial and other incentives for impaired performance on neuropsychological tests has increased dramatically in recent years (e.g., Binder and Willis, 1991; Larrabee, 1990). Fox (1994) has recently purported to determine the appropriateness of the norms for the Logical Memory subtest of the Wechsler Memory Scale - - Revised (WMS-R) for individuals in litigation. He reported findings on 100 subjects who had claims of emotional and/or orthopedic problems in a workman's compensation setting and who were administered the Trail Making Test and the Logical Memory subtest of the Wechsler Memory Scale - - Revised (WMS-R), as well as the MMPI and other unspecified tests in a battery that is reported to require about 2 hours to complete. He reports that 62% of these subjects scored below the 30th percentile on Logical Memory I and that 49% did so on Logical Memory II. He further reports that about 30% of the subjects scored below the 20th percentile on each measure. The average percentage of initially produced material retained following a 30-min delay was reported as 88.3%. Fox (1994) makes a number of statements that are puzzling. For example, he suggests that the WMS-R norms as presented in the test manual (Wechsler, 1987) "overestimate the degree of memory impairment when applied to litigating clients." He further states that "this The author would like to thank Anne C. May, PhD, and the two anonymous reviewers for their comments concerning this manuscript. Address correspondence to: H. Daniel Blackwood, PhD, Neuropsychology Associates, P.C., 301 East Bethany Home Road, Suite A-125, Phoenix, AZ 85012. 93
94
H. D. Blackwood
sample of neuropsychologically normal claimants performed below normal on the memory measures." [Emphasis added.] As discussed below, inspection of the results he presents does not appear to support the first statement, and, with respect to the second statement, one might ask: How does the author define "normal"? Perhaps the pivotal statement of the article is: "Regardless of the precise factors involved, the practical consequence is that many of these people would have been incorrectly diagnosed as having a neuropsychological problem that did not exist." (Fox, 1994, p. 213) On what basis can such an impairment be said not to exist? If this is merely an assumption on the author's part, perhaps based upon the absence of documented acute structural cerebral lesions in this sample, this assumption would seem to imply that: (1) "neuropsychological problem" equals such acute structural cerebral lesions, and (2) subjects claiming only potentially painful orthopedic and/or emotional injuries do not have neuropsychological impairments, for example, memory problems. These implications are clearly contradicted in the literature, for example, Yozawitz's (1988) work describing the application of neuropsychological assessment to the rehabilitation of psychiatric patients, and the rationale presented by Tarter, Edwards, and Van Thiel (1988) for neuropsychological assessment of medical disease. On the other hand, Fox (1994) may be basing his assumption of no neuropsychological impairment on the test performance of his subjects. For example, he reports "completely normal scores on the Trail Making Test" [emphasis added] for his subjects and goes on to state that this indicates absence of "genuine neuropsychological impairment." While such scores may well contribute to such an ultimate diagnosis, making such an inference from any single test score would seem to be a serious distortion of the practice of clinical neuropsychology. Returning to the pivotal statement quoted above, specifically with respect to the contention that " . . . many of these people would have been incorrectly diagnosed . . . . " one might ask: So diagnosed by whom? The author's statement seems to imply that test scores themselves somehow effect a "diagnosis," but it is actually the application of scores by the clinician that results in a diagnostic conclusion. Considering the data presented by Fox (1994), no cut-off scores for the Logical Memory test that have been validated as separating any group of neurologically impaired subjects from nonimpaired subjects are provided. Neither are the results of any such classification of his subjects. Further, percentage of initially registered (or produced) material that is later recalled ("savings") has been shown to be a major measure of interest in documenting memory impairment in neurologically impaired subjects (e.g., Kopelman, 1992; Troster et al., 1993). In the Fox (1994) study, the average percentage of initially produced material recalled following a 30-rain delay was reported as 88.3%. According to recent data from the WMS-R normative group, produced by The Psychological Corporation (Prifitera and Ledbetter, 1992), for 35- to 45-year-old subjects this score falls between the 60th and 65th percentiles. This would seem to be a "respectable" mean score for the sample reported by Fox (1994). In addition, Fox (1994), again referring to savings scores, also alludes to "the usual 80% cut-off" for impairment on this measure and states that 32% of his subjects fall below this level. A reference providing the basis for the use of such a cut-off is not provided. Again, using the Psychological Corporation data from the WMS-R normative group (Prifitera and Ledbetter, 1992), 80.8% retention falls at the 40th percentile for 35- to 45-year-old subjects. In isolation, this would hardly seem to be an indication of "impairment." It is of interest that the sample reported by Fox (1994) performed, as a group, and on some measures below the average level of the normative group for the WMS-R. However, this finding presents no more of a "normative problem" for the WMS-R than an elevation on Scale 7 in a group of depressed subjects presents for the MMPI-2. Depressed patients can be anxious. As Fox (1994) has demonstrated, patients in litigation concerning potential-
Test Administration in Litigation
95
ly painful orthopedic and/or emotional injuries can, as a group, perform slightly below average normative levels on some memory measures. Further investigation as to the underlying cause of this finding should be encouraged and may provide valuable insights about these patients. However, whether this finding, in and of itself, would result in patients being incorrectly classified as brain-damaged or as having a neuropsychological problem "which does not exist" seems still to be an open question.
REFERENCES Binder, L. M., & Willis, S. C. (1991). Assessment of motivation after a financially compensable minor head trauma. Psychological Assessment: A Journal of Consulting and Clinical Psychology, 3, 175-181. Fox, D. D. (1994). Normative problems for the Wechsler Memory Scale - - Revised Logical Memory Test when used in litigation. Archives of Clinical Neuropsychology, 9, 211-214. Kopelman, M. D. (1992). The "new" and the "old": Components of the anterograde and retrograde memory loss in Korsakoff and Alzheimer patients. In L. R. Squire & N. Butters (Eds.), Neuropsychology of memory (2nd ed.). New York: The Guilford Press. Larrabee, G. J. (1990). Cautions in the use of neuropsychological evaluation in legal settings. Neuropsychology, 4, 239-247. Prifitera, A., & Ledbetter, M. (1992). Normative delayed recall rates based on the Wechsler Memory Scale - Revised standardization sample. Poster presentation at the 12th Annual Meeting of the National Academy of Neuropsychology, Pittsburgh, 1992. Tarter, R. E., Edwards, K. L., & Van Thiel, D. H. (1988). Perspective and rationale for neuropsychological assessment of medical disease. In R. E. Tarter, D. H. Van Thiel, & K. L. Edwards (Eds.), Medical neuropsychology: The impact of disease on behavior (pp. 1-10). New York: Plenum Press. Troster, A. I., Butters, N., Salmon, D. P., Cullum, C. M., Jacobs, D., Brandt, J, & White, R. E (1993). The diagnostic utility of savings scores: Differentiating Alzheimer's and Huntington's diseases with the Logical Memory and Visual Reproduction tests. Journal of Clinical and Experimental Neuropsychology, 15, 773-788. Wechsler, D. (1987). Wechsler Memory S c a l e - Revised manual. San Antonio: The Psychological Corporation. Yozawitz, A. (1988). Applied neuropsychology in a psychiatric setting. In I. Grant & K. M. Adams (Eds.), Neuropsychological assessment ofneuropsychiatric disorders. New York: Oxford University Press.
Archives of Clinical Neuropsychology, Vol. I1, No. 2, pp. 93-95, 1996 Copyright © 1996 National Academy of Neuropsychology Printed in the USA. All fights reserved 0887-6177/96 $15.00 + .00
0887-6177(95)00060-3
Recommendation for Test Administration in Litigation: Never Administer the Category Test to a Blindfolded Subject H. Daniel Blackwood Neuropsychology Associates, PC.
Fox (1994) purports to determine the appropriateness o f the normative data f o r the Logical Memory subtest of the Wechsler Memory Scale - - Revised for individuals in litigation and suggests that % . . many o f these people would have been incorrectly diagnosed as having a neuropsychological problem that did not exist." His data do not support such a conclusion, but rather appear simply to demonstrate that patients in litigation concerning potentially painful orthopedic and/or emotional injuries can, as a group, perform slightly below average levels on memory tests.
Consideration of the possible effects of financial and other incentives for impaired performance on neuropsychological tests has increased dramatically in recent years (e.g., Binder and Willis, 1991; Larrabee, 1990). Fox (1994) has recently purported to determine the appropriateness of the norms for the Logical Memory subtest of the Wechsler Memory Scale - - Revised (WMS-R) for individuals in litigation. He reported findings on 100 subjects who had claims of emotional and/or orthopedic problems in a workman's compensation setting and who were administered the Trail Making Test and the Logical Memory subtest of the Wechsler Memory Scale - - Revised (WMS-R), as well as the MMPI and other unspecified tests in a battery that is reported to require about 2 hours to complete. He reports that 62% of these subjects scored below the 30th percentile on Logical Memory I and that 49% did so on Logical Memory II. He further reports that about 30% of the subjects scored below the 20th percentile on each measure. The average percentage of initially produced material retained following a 30-min delay was reported as 88.3%. Fox (1994) makes a number of statements that are puzzling. For example, he suggests that the WMS-R norms as presented in the test manual (Wechsler, 1987) "overestimate the degree of memory impairment when applied to litigating clients." He further states that "this The author would like to thank Anne C. May, PhD, and the two anonymous reviewers for their comments concerning this manuscript. Address correspondence to: H. Daniel Blackwood, PhD, Neuropsychology Associates, P.C., 301 East Bethany Home Road, Suite A-125, Phoenix, AZ 85012. 93
94
H. D. Blackwood
sample of neuropsychologically normal claimants performed below normal on the memory measures." [Emphasis added.] As discussed below, inspection of the results he presents does not appear to support the first statement, and, with respect to the second statement, one might ask: How does the author define "normal"? Perhaps the pivotal statement of the article is: "Regardless of the precise factors involved, the practical consequence is that many of these people would have been incorrectly diagnosed as having a neuropsychological problem that did not exist." (Fox, 1994, p. 213) On what basis can such an impairment be said not to exist? If this is merely an assumption on the author's part, perhaps based upon the absence of documented acute structural cerebral lesions in this sample, this assumption would seem to imply that: (1) "neuropsychological problem" equals such acute structural cerebral lesions, and (2) subjects claiming only potentially painful orthopedic and/or emotional injuries do not have neuropsychological impairments, for example, memory problems. These implications are clearly contradicted in the literature, for example, Yozawitz's (1988) work describing the application of neuropsychological assessment to the rehabilitation of psychiatric patients, and the rationale presented by Tarter, Edwards, and Van Thiel (1988) for neuropsychological assessment of medical disease. On the other hand, Fox (1994) may be basing his assumption of no neuropsychological impairment on the test performance of his subjects. For example, he reports "completely normal scores on the Trail Making Test" [emphasis added] for his subjects and goes on to state that this indicates absence of "genuine neuropsychological impairment." While such scores may well contribute to such an ultimate diagnosis, making such an inference from any single test score would seem to be a serious distortion of the practice of clinical neuropsychology. Returning to the pivotal statement quoted above, specifically with respect to the contention that " . . . many of these people would have been incorrectly diagnosed . . . . " one might ask: So diagnosed by whom? The author's statement seems to imply that test scores themselves somehow effect a "diagnosis," but it is actually the application of scores by the clinician that results in a diagnostic conclusion. Considering the data presented by Fox (1994), no cut-off scores for the Logical Memory test that have been validated as separating any group of neurologically impaired subjects from nonimpaired subjects are provided. Neither are the results of any such classification of his subjects. Further, percentage of initially registered (or produced) material that is later recalled ("savings") has been shown to be a major measure of interest in documenting memory impairment in neurologically impaired subjects (e.g., Kopelman, 1992; Troster et al., 1993). In the Fox (1994) study, the average percentage of initially produced material recalled following a 30-rain delay was reported as 88.3%. According to recent data from the WMS-R normative group, produced by The Psychological Corporation (Prifitera and Ledbetter, 1992), for 35- to 45-year-old subjects this score falls between the 60th and 65th percentiles. This would seem to be a "respectable" mean score for the sample reported by Fox (1994). In addition, Fox (1994), again referring to savings scores, also alludes to "the usual 80% cut-off" for impairment on this measure and states that 32% of his subjects fall below this level. A reference providing the basis for the use of such a cut-off is not provided. Again, using the Psychological Corporation data from the WMS-R normative group (Prifitera and Ledbetter, 1992), 80.8% retention falls at the 40th percentile for 35- to 45-year-old subjects. In isolation, this would hardly seem to be an indication of "impairment." It is of interest that the sample reported by Fox (1994) performed, as a group, and on some measures below the average level of the normative group for the WMS-R. However, this finding presents no more of a "normative problem" for the WMS-R than an elevation on Scale 7 in a group of depressed subjects presents for the MMPI-2. Depressed patients can be anxious. As Fox (1994) has demonstrated, patients in litigation concerning potential-
Test Administration in Litigation
95
ly painful orthopedic and/or emotional injuries can, as a group, perform slightly below average normative levels on some memory measures. Further investigation as to the underlying cause of this finding should be encouraged and may provide valuable insights about these patients. However, whether this finding, in and of itself, would result in patients being incorrectly classified as brain-damaged or as having a neuropsychological problem "which does not exist" seems still to be an open question.
REFERENCES Binder, L. M., & Willis, S. C. (1991). Assessment of motivation after a financially compensable minor head trauma. Psychological Assessment: A Journal of Consulting and Clinical Psychology, 3, 175-181. Fox, D. D. (1994). Normative problems for the Wechsler Memory Scale - - Revised Logical Memory Test when used in litigation. Archives of Clinical Neuropsychology, 9, 211-214. Kopelman, M. D. (1992). The "new" and the "old": Components of the anterograde and retrograde memory loss in Korsakoff and Alzheimer patients. In L. R. Squire & N. Butters (Eds.), Neuropsychology of memory (2nd ed.). New York: The Guilford Press. Larrabee, G. J. (1990). Cautions in the use of neuropsychological evaluation in legal settings. Neuropsychology, 4, 239-247. Prifitera, A., & Ledbetter, M. (1992). Normative delayed recall rates based on the Wechsler Memory Scale - Revised standardization sample. Poster presentation at the 12th Annual Meeting of the National Academy of Neuropsychology, Pittsburgh, 1992. Tarter, R. E., Edwards, K. L., & Van Thiel, D. H. (1988). Perspective and rationale for neuropsychological assessment of medical disease. In R. E. Tarter, D. H. Van Thiel, & K. L. Edwards (Eds.), Medical neuropsychology: The impact of disease on behavior (pp. 1-10). New York: Plenum Press. Troster, A. I., Butters, N., Salmon, D. P., Cullum, C. M., Jacobs, D., Brandt, J, & White, R. E (1993). The diagnostic utility of savings scores: Differentiating Alzheimer's and Huntington's diseases with the Logical Memory and Visual Reproduction tests. Journal of Clinical and Experimental Neuropsychology, 15, 773-788. Wechsler, D. (1987). Wechsler Memory S c a l e - Revised manual. San Antonio: The Psychological Corporation. Yozawitz, A. (1988). Applied neuropsychology in a psychiatric setting. In I. Grant & K. M. Adams (Eds.), Neuropsychological assessment ofneuropsychiatric disorders. New York: Oxford University Press.