Concordance between the CVLT and the WMS-III word lists test

Archives of Clinical Neuropsychology 19 (2004) 319–324 Short communication Concordance between the CVLT and the WMS-III word lists test Bradley D. McDowell a,∗ , John D. Bayless a , David J. Moser a , John E. Meyers b , Jane S. Paulsen c a Department of Psychiatry, Psychiatry Research, 1-287 Medical Education Bldg., University of Iowa, Iowa City, IA 52242-1000, USA b Mercy Rehabilitation Clinic, Sioux City, IA, USA c Departments of Psychiatry and Neurology, University of Iowa, Iowa City, IA, USA Accepted 23 January 2003 Abstract The California Verbal Learning Test (CVLT) and the Word Lists Test (WLT) from the Wechsler Memory Scale-III are widely used tests of verbal learning and memory. To examine concordance between these popular tests, we administered both to a diagnostically diverse group of 25 patients. As expected, measures from the two tests were highly correlated, although level of concordance was not as high as might be expected. When diagnostic outcomes were discordant for free recall measures, the CVLT indicated impairment more often than did the WLT. © 2003 National Academy of Neuropsychology. Published by Elsevier Science Ltd. All rights reserved. Keywords: CVLT; WMS-III; Memory assessment; Neuropsychology; Test concordance The California Verbal Learning Test (CVLT; Delis, Kramer, Kaplan, & Ober, 1987) and the Word Lists Test (WLT) from the Wechsler Memory Scale, 3rd Edition (Wechsler, 1997), are commonly used tests of verbal memory. Each test involves free recall of lists of words over trials, followed by short- and long-delayed recall. Recognition testing is also performed. Given the widespread popularity of these two tests, it is useful to examine the extent to which they may lead to differing conclusions about a patient’s memory functioning. There are differences between these tests that may affect performance. For instance, words from the CVLT fall into semantic categories, whereas words from the WLT are unrelated to each other. ∗ Corresponding author. Tel.: +1-319-353-3282; fax: +1-319-353-3003. E-mail address: (B.D. McDowell). 0887-6177/$ – see front matter © 2003 National Academy of Neuropsychology. doi:10.1016/S0887-6177(03)00023-4 320 B.D. McDowell et al. / Archives of Clinical Neuropsychology 19 (2004) 319–324 The subject is informed about the delayed-recall trials for the WLT, but not for the CVLT. The normative samples for the CVLT and WLT also vary. The goal of this paper is to examine the concordance between the WLT and the CVLT under general clinical conditions. Many researchers have found linear relationships between CVLT indices and those of other popular verbal memory tests (Crossen & Wiens, 1994; Kaltreider et al., 2000; Lacritz, Cullum, Weiner, & Rosenberg, 2001). Although such studies increase our confidence in comparing performances over tests, significant correlations do not guarantee that the tests will also be significantly concordant. Stallings, Boake, and Sherer (1995), for example, compared the scores from the AVLT (Lezak, 1983; Rey, 1958) and CVLT in 40 patients with closed head injuries and reported significant correlations (ranging from .49 to .83) among raw score performances. Despite such associations, they also found that standardized scores on the CVLT resulted in much higher rates of diagnosed memory impairments than scores on the AVLT. Eighty-five percent of the patients were considered impaired using the CVLT whereas impairment rates using three sets of different AVLT norms (Geffen, Moar, O’Hanlon, Clark, & Geffen, 1990; Savage & Gouvier, 1992; Wiens, Crossen, & McMinn, 1988) ranged from 35 to 68%. 1. Method 1.1. Subjects The CVLT and WLT were administered to 25 referrals to a university hospital neuropsychology service and a hospital-affiliated rehabilitation center. The sample was heterogeneous, with diagnoses from 11 categories of neurological and psychiatric disorders including head injury, attention deficit disorder, and cognitive disorder, NOS. The average age of the patients was 42.08 years (S.D. = 17.68), and the average level of education was 13.4 years (S.D. = 2.61). Thirty-six percent of the patients were female, and all were Caucasian. Patients were excluded from the study if they were aphasic, had active psychotic symptoms, or were involved in legal proceedings. 1.2. Procedure The CVLT and WLT were administered according to manual instructions. Order of test administration was counterbalanced so that 48% of the patients received the CVLT first. The time interval between the administrations of the two tests varied from 1 h to several days. Although 2 subjects did not complete the CVLT recognition test for reasons unrelated to their level of cognitive functioning, their free-recall data were retained for relevant analyses. 1.3. Impairment classifications To determine concordance between the two tests, separate impairment decisions were made on the basis of individual, normative memory scores. Consistent with a standard established in previous studies, “impairment” corresponded to a score that fell below one standard deviation B.D. McDowell et al. / Archives of Clinical Neuropsychology 19 (2004) 319–324 321 from the mean of the appropriate normative subgroup (Heaton, Grant, & Matthews, 1991; Norman, Evans, Miller, & Heaton, 2000). 2. Results Table 1 reports the descriptive statistics for the memory measures that are shared between the two tests and for which normative data are available: immediate total recall across learning trials, long-delay free recall, and recognition. For the CVLT, the discriminability index was used to indicate recognition memory performance. This index provides a measure of the subject’s ability to discriminate between the target items that were presented earlier and foil items that were not presented. Unlike the CVLT, the WLT has an equal number of targets and foils, and the number of correct responses on the WLT corresponds to a discrimination index. 2.1. Order effects The effects of order for CVLT total immediate recall, t(23) = −0.112; WLT total immediate recall, t(23) = 0.074; CVLT delayed recall, t(23) = −0.414; WLT delayed recall, t(23) = −0.009; CVLT recognition discriminability, t(21) = −1.226; and WLT recognition performance, t(23) = 0.451, were nonsignificant (all Ps > .20). The absence of order effects replicates findings from Crossen and Wiens (1994) and Stallings et al. (1995). The remaining analyses were performed without regard to order of test administration. 2.2. Test correlations between raw measures The raw scores of corresponding measures of the CVLT and WLT were significantly correlated (all Ps < .05; see Table 1 for correlation coefficients). 2.3. Test concordance First, concordance was evaluated using the originally published norms for both tests (Delis et al., 1987; Wechsler, 1997; see Table 2). Concordance for the total free-recall performances was significant (κ = 0.412, P < .05); the tests agreed for 17 of the 25 patients (68%). Table (...truncated)