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Alternate forms of the auditory-verbal learning test: issues of test comparability, longitudinal reliability, and moderating demographic variables
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Alternate Forms of the Auditory-Verbal Learning Test: Issues of Test Comparability, and Moderating Craig Lyons Uchiyama,
Longitudinal Demographic
Reliability, Variables
Louis F. D’Elia, Ann M. Dellinger,
James T. Becker, Ola A. Selnes, Jerry E. Wesch, Bai Bai Chen, Paul Satz, Wilfred van Gorp, and Eric N. Miller Multicenter
AIDS Cohort Study
The present investigation examines the alternate-form and longitudinal reliability of two versions of the Auditory-Verbal Learning Test (AVLT) on a large, multiregional, healthy male sample. Subjects included 2,059 bisexual and homosexual HIV-seronegative males recruited from the Multicenter AIDS Cohort Study from centers in Baltimore, Chicago, Los Angeles, and Pittsburgh. The findings revealed no significant differences between forms upon initial or l-year longitudinal administration, supporting the equivalence of the two versions. However; significant practice effects were noted longitudinally, arguing for the need of appropriate retest normative data. Furthermore, as age, ethnic&y, and education were found to significantly affect test performance, it is recommended that normative data be interpreted according to these variables. In addition to providing normative and
This study was supported by National Institutes of Health contracts NO1 AI 7263 1, AI 72634, AI 32535, AI 72676, and AI 72632. Address all correspondence to: Craig Lyons Uchiyama, PhD, UCSF Langley Porter Psychiatric Institute, 401 Pamassus, Box CPT, San Francisco, CA 94143-0984. Craig Lyons Uchiyama is affiliated with the UCSF Langley Porter Psychiatric Institute. Louis F. D’Elia, Paul Satz, Wilfred van Gorp, and Eric N. Miller are affiliated with the UCLA School of Medicine. Ann M. Dellinger is affiliated with the UCLA School of Public Health. James T. Becker is affiliated with the University of Pittsburgh Graduate School of Public Health and School of Medicine. Ola A. Selnes and Bai Bai Chen are affiliated with the Johns Hopkins University School of Hygiene and Public Health. Jerry E. Wesch is affiliated with the Howard Brown Memorial Clinic Northwestern University Medical School. 133
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et al.
longitudinal data, this investigafion presents information limitations of the alternate forms of the AVLT.
concerning
the use and
The Auditory-Verbal Learning Test (AVLT), initially developed by Rey (1964) and later revised for English usage (Lezak, 1983; Taylor, 1959), is a measure of rote verbal memory that assesses multiple memory domains, including immediate memory span, new learning, retroactive and proactive interference, and recognition (Lezak, 1983; Spreen & Strauss, 1991). Impaired performance on this test has been associated with such conditions as left temporal lobe dysfunction (Malec, Ivnik, & Hinkeldey, 1991), depression (Query & Megran, 1984), psychosis (Rosenberg, Ryan, & Prifitera, 1984) mild head injury (Lcininger, Gramling, Farrell, Kreutzer, & Peck, 1990), entrenched Alzheimer’s (Haddad & Nussbaum, 1989), and alcoholism (Query & Megran, 1984). Several alternate forms of the test have been developed for repeated administration (Crawford, Stewart, & Moore, 1989; Lezak, 1983; Shapiro & Harrison, 1990), as retest assessments often are clinically necessary to monitor the course of degenerative conditions or the recovery from cerebral trauma. Probably the most well known of these forms was developed by Taylor (1959). Although there has been limited support for the immediate-retest reliability of this version in male inpatients (Ryan & Geisser, 1986; Ryan, Geisser, Randall, & Georgemiller, 1986), the application of such findings to nonpatient populations has been questioned, given the very depressed scores of this sample’s subjects. In addition, the need to examine alternate forms longitudinally has been sup ported previously (Lezak, 1983) as significant practice effects have been noted for the original version over periods ranging from 6 months to 1 year on a small sample (n = 23) of young males. In another study, Lezak (1979) also reported that the percentage of 24 male head-trauma patients functioning within normal limits increased over a 3-year period. However, the findings of the latter study are difficult to interpret, as such elevations may reflect either recovery from the traumatic event or practice effects from repeated exposure (Franzen, 1989). The purpose of the present investigation is to examine longitudinally the alternate forms of the Rey Auditory-Verbal Learning Test on a large, healthy, multiregional male sample; assess the psychometric equivalence of the two forms across time; determine the effects of repeated administrations on AVLT test scores; and investigate the moderating effects of demographic variables on test performance.
METHOD Subjects
Subjects were participants of the Multicenter AIDS Cohort Study (MACS), and included 2,059 homosexual and bisexual HIV-seronegative males from
Alternate Forms of the Auditory-Verbal
135
Learning Test
sites in Baltimore, Chicago, Los Angeles, and Pittsburgh. The purpose of the MACS is to research longitudinally the neurological and neuropsychological functioning of HIV-l seropositive and seronegative persons. Subjects were excluded from the investigation if they demonstrated a history of learning disability, a prior loss of consciousness, or a primary language other than English. Sample demographics are presented in Table 1. For further information on subject recruitment procedures, the reader may refer to the previously published works by Miller et al. (1990) and Kaslow et al. (1987). Because the current sample was composed of seronegative, healthy gay and bisexual men, the possibility was raised that the validity and normative results of this investigation would not be reflective of the general male population. Therefore, the scores from Trial 5 of the present study were compared to those of previously reported normative studies of men. Normative studies were excluded from comparison that were not stratified by gender, by age, or that were based on patient populations. Of the two studies found to meet this criteria, the stratified age groups that overlapped with the present study were selected for comparison. The mean score from Trial 5 of the present study was found to be almost identical (differing by only .31 points) to that of Bleeker, Bolla-Wilson, Agnew, and Meyers (1988). Although slightly better performance (1.58 points) was noted in the present sample over another sample (Geffen, Moar, O’Hanlan, Clark, & Geffen, 1990), this difference was likely related to the very small sample size of the latter study (mean = 10.4 persons per cell), as well as the fact that the males in the Geffen et al. sample had less than a high school education (mean years of education = 11.34) compared to the Bleeker et al. sample (mean years of education = 13.52) and the present sample. These findings demonstrate the similarity of the present study with previously
Demographic
N Age Education Ethnicity Caucasian American Hispanic American African American Hispanic/African American Native American Asian American Other
TABLE 1 Means and Standard Deviations for Alternate Versions of the AVLT
Total Sample
Form 1 Normative Sample
Form 2 Normative Sample
2,059 36.55 (7.19) 15.94 (2.39)
1,818 36.54 (7.20) 15.95 (2.40)
241 37.63 (7.16) 15.80 (2.31)
88% 5% 5% < < < <
1% 1% 1% 1%
89% 5% 5% < < < <
1% 1% 1% 1%
82% 8% 8% < 1% < 1% 1% < 1%
Form 1 Longitudinal Sample
Form 2 Longitudinal Sample
::.69 (6.01) ::.46 (6.95) 16.47 (2.04) 16.03 (2.21) 94% 6%
84% 3% 11% 3%
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published works, and would indicate no reason that the current findings cannot be generalized to heterosexual males. It was found that 1,818 individuals received Form 1 on their first administration, and 241 subjects received Form 2. Demographic information for these samples are presented in Table 1. General linear model one-way analyses found no significant between-group differences for age (F = .03; p > .05) and level of education (F = .88; p > .05). However, significant Pearson chi-squares were found in ethnicity (p < .05) when this variable was dichotomized (Caucasian, non-Caucasian) for reasons of small cell size. How this variable was controlled in the analyses is described in the Results section. In the l-year longitudinal analyses, 47 persons were initially administered Form 1 in Wave 3, and participated in Waves 5,7, and 9 (each of which was 1 year apart). Thirty-seven persons were initially administered Form 2 and participated in Wave 4, which was 1 year after the initial administration. Demographic information for the longitudinal samples is presented in Table 1. Some of the subjects included in the longitudinal analyses received exposure to the alternate form midway between their exposure to the original form. However, as analyses revealed that these subjects demonstrated no significant differences in scores from persons not receiving such exposure, they were retained in the longitudinal analyses. The longitudinal groups showed no significant demographic differences in terms of age (F = .03; p > .05), education (F = .90; p > .05), or ethnicity (Pearson chi-square = 2.09; p > .05). Because more subjects were inducted into the study after Wave 3 from Pittsburgh and Los Angeles, the results from the l-year longitudinal analyses may be less generalizable in terms of geographic representation. Data from Waves 1 and 2 could not be used in the l-year longitudinal analyses, as Form 1 was administered in both these waves (which were 6 months apart). To include them in the analyses would introduce confounding factors of unequal time periods and differential test exposure. However, these waves were included in the 6-month retest reliability analyses. Procedure Subjects were tested over 12 data collection periods, or waves, that were each 6 months in length. Two forms of the Auditory-Verbal Learning Test (Rey, 1964; Taylor, 1959) were administered (actual items in lists are presented in Lezak, 1983). The first, which will subsequently be referred to as Form 1, consisted of a 15-item word list (List A) presented 5 times (Trials 1 to 5). In these trials, the subjects were instructed to recall as many words as they could in any order. Immediately after the fifth presentation, a 15item distractor list (List B) was presented (Trial 6) with a similar test of recall. Following the distractor task, the subjects were immediately asked to recall List A without the benefit of another presentation (Trial 7). After a 30-minute delay, the subjects
Alternate Forms of the Auditory-VerbalLearning Test
137
were presented both with a free recall (Trial 8) and a forced-choice recognition task (Trial 9) of List A. The second version, which will be referred to as Form 2, was identical to Form 1 with the exception that the words in List A (presented 5 times) were substituted with words from List C. The interference trial (List B) of Form 2 was identical to that of Form 1.
RESULTS
Normative Analyses The means and standard deviations from the normative analyses, which were stratified according to age and education, are presented for Forms 1 and 2 in Tables 2 and 3, respectively. The comparability of the two forms was analyzed using a four-way general linear model due to discrepant cell sizes which made such statistics as classical M A N O V A ' s inappropriate. In this analysis, the independent variables included test form, age, education, and ethnicity; and the dependent variables included the scores from Trials 1 to 9 and the total number of Intrusions from Trials 1 to 5. Because the two groups differed in terms of ethnicity, this variable was dichotomized (Caucasian, non-Caucasian) in the manner of an indicator variable, and entered into the analysis as an independent variable. This way, should significant main effects be found, an examination of the appropriate partial sums of squares would indicate the effects of test form without the influencing effects of ethnicity. The results of the normative analyses revealed no significant main effect for test form (F = .82; df = 13; p > .05), supporting the comparability of the two versions upon initial administration. In examining the learning curves for Trials 1 to 5, a repeated-measure, general linear model was again used for the previously cited rationale. In this model, test form and ethnicity were the independent variables; trial was the repeated measure independent variable; and scores from Trials 1 to 5 were the dependent variables. The results of these analyses indicated a significant trial by form interaction (F = 2.67; df = 4; p < .05), suggesting that the learning curve for the two forms was significantly different upon initial administration. As there was no trial by ethnicity interaction (F = .24; df = 1; p > .05), there is no reason to believe that ethnicity, the only demographic variable that was significantly different for the two groups, was differentially influencing the learning curves of the two forms. The effects that the demographic variables had on Trial 5 test scores were examined by a general linear multiple regression, with ethnicity again being entered as an indicator variable. The partial F ' s were significant for age (F = 51.90; df= 1; p < .05), ethnicity (F = 21.52; df= 1; p < .05), and education (F = 71.94; df= 1;p < .05), demonstrating the strong relationship of these variables with test scores, as well as the need for interpreting normative data
z 0
Trial 3 Trial 4 Trial 5 Intr.Trial Imm. Recall Del. Recall Del. Recog. Ink Errors (Trials l-5)
Trial2
Trial 1
Trial
~.
6.66 (1.81) 9.59 (2.15) 11.17 (2.19) 12.06 (2.00) 12.63 (1.89) 6.50 (2.07) 1I .05 (2.68) 10.87 (2.82) 14.19 (1.28) 3.04 (2.93)
...~
Total Sample (n = 1818)
- ..___-
11.32 (2.20) 12.38 (1.90) 12.84 (1.79) 6.85 (2.08) 11.39 (2.40) 11.27 (2.54) 14.36 (1.13) 3.05 (2.89)
9.82 (2.28)
6.86 (1.86)
20-29 (n = 333)
~.--
11.36 (2.21) 12.15 (1.97) 12.76 (1.91) 6.58 (2.05) 11.24 (2.73) 11.08 (2.82) 14.23 (1.23) 3.09 (3.00)
9.72 (2.21)
6.74 (1.83)
30-39 (n = 968)
10.82 (2.08) 1I.76 (2.09) 12.45 (1.84) 6.15 (2.04) 10.50 (2.60) 10.25 (2.84) 14.01 (1.42) 2.91 (2.88)
9.26 (1.88)
6.46 ( 1.68)
40-49 (n = 437)
10.15 (1.96) 11.34 (1.91) 12.03 (2.02) 6.16 (2.28) 10.20 (3.03) 9.87 (3.3 f) 13.89 (1.57) 2.91 (2.67)
8.88 (1.97)
5.80(1.73)
5Oandabove (n = 80)
-
_____.
10.67 (2.18) 11.66 (2.05) 12.34 (1.99) 6.13 (2.01) 10.78 (2.70) 10.53 (2.90) 14.11 (1.37) 3.14 (2.99)
9.14 (2.10)
6.31 (1.83)
_
c 16 Years (n = 662)
--____-
TABLE 2 Normative Means and Standard Deviations for the AYLT:Form 1 _._.. .-____1_____~.-_ A@
11.44 (2.09) 12.26 (1.94) 12.81 (1.83) 6.54 (2.07) 11.19 (2.58) t 1.04 (2.76) 14.27 (l-23) 2.95 (2.82)
9.77 (2.02)
6.84 (1.73)
(n = 495)
16 Years
Education __I~~
11.48 (2.19) 12.33 (1.94) 12.91 (1.78) 6.84 (2.07) 11.21 (2.70) 11.07 (2.78) 14.21 (1.22) 2.97 (2.96)
9.91 (2.23)
6.86 (1.81)
(n = 653) __
> 16 Years
Trial 3 Trial 4 Trial 5 Ink Trial Imm. Recall Del. Recall Del. Recog. Intr. Errors (Trials l-5)
Trial 21
6.41 8.94 10.70 11.61 12.20 6.29 10.11 9.75 13.34 4.42
(1.73) (2.21) (2.12) (2.06) (1.83) (2.12) (2.68) (2.98) (1.98) (3.81)
Total Sample (n = 241)
6.78 9.52 11.13 12.09 12.30 7.02 10.91 10.48 13.83 3.87
(1.80) (2.61) (2.24) (1.93) (2.00) (2.39) (2.66) (3.16) (1.69) (4.61)
20-29 (n = 46)
Normative
6.50 (1.78) 9.03 (2.09) 10.81 (1.95) 11.60(1.95) 12.38 (1.56) 6.15 (2.06) 10.09 (2.48) 9.71 (2.71) 13.47 (1.96) 4.77 (3.75)
30-39 (n = 118)
Age
6.11 8.48 10.29 11.42 11.94 6.23 9.82 9.48 12.82 4.23
(1.53) (2.10) (2.36) (2.26) (2.13) (2.03) (2.87) (3.18) (2.15) (3.31)
40-49 (n = 66) 5.64 8.18 10.09 10.91 11.45 5.27 8.82 8.73 13.18 4.09
(1.57) (1.72) (1.64) (2.30) (1.81) (1.49) (3.16) (3.52) (1.78) (3.62)
50 and above (n= 11) 6.36 8.84 10.38 11.35 12.03 6.24 9.78 9.52 13.24 4.53
(1.83) (2.11) (2.01) (1.92) (1.62) (2.21) (2.45) (2.58) (2.03) (4.20)
< 16 Years (n=91)
TABLE 3 Means and Standard Deviations for the AVLT: FORM 2
6.32 9.04 10.95 11.80 12.31 5.96 10.41 9.98 13.59 4.22
(1.58) (2.23) (2.04) (2.16) (2.00) (2.01) (2.80) (3.12) (1.80) (3.84)
16 Years (n=81)
Education
6.57 8.90 10.79 11.71 12.31 6.80 10.15 9.75 13.16 4.47
(1.76) (2.29) (2.35) (2.10) (1.92) (2.09) (2.84) (3.32) (2.11) (3.23)
> 16 Years (n = 68)
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in accordance with such variables. It was found that higher scores were associated with younger age and higher education. Longitudinal
Analyses
Normative information on the longitudinal samples may be found in Table 4. The longitudinal data were subjected to two sets of repeated measure MANOVA’s. As no statistical differences were found between the groups in terms of age, education, or ethnicity, these variables were not statistically controlled. The first MANOVA used test form, time, and trial as independent variables; and scores from Trials 1 to 9 and total Intrusions across the first two time periods were used as dependent variables. The variables of time and trial were treated as within-subject repeated measure variables. The results indicated no significant longitudinal effect for test form (F = .78; df= 1; p > .OS). In examining the practice effects across repeated exposure, the results were significant (F = 322.12; df= 1; p < .05), demonstrating that scores significantly increased at l-year repeated administration. As there was no significant interaction between test form and time (F = SO; df = 1; p > .05), these practice effects appear to be similar for the two forms. The second MANOVA examined the learning curves for Trials 1 to 5 between the two forms across time, and incorporated test form as the betweensubject independent variable, time and trial number as the within-subject independent variables, and scores from Trials 1 to 5 for both initial and l-year retest as the dependent variables. The results of this MANOVA revealed no significant interaction for test form by trial (F = .91; df = 4; p > .05), suggesting that longitudinally, the two forms evidence similar learning curves for Trials 1 to 5. Equivalent-Form
Reliability
The equivalent-form, long-term retest reliabilities comparing the retest periods for the two forms with the initial testing are presented in Table 5. The long-term reliabilities for the scores were all significant, except for the Form 1 Intrusion scores which were notably lower than the Intrusion scores of Form 2. In addition to the previously mentioned exception, the l-year reliability of the two forms appeared to be generally comparable, although Trial 1 and Delayed Recall scores for Form 1 were slightly less reliable than those of Form 2. The coefficients were lowest for both forms for Trial 1, and highest for Delayed Recall. Alternate-Form
Reliability
The alternate-form, found to be moderate
6-month reliability coefficients for the two forms were to moderately high, with the exception of Intrusions
5
Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Ink Trial Imm. Recall Del. Recall Del. Recog Intr. Errors (Trials 1-5)
Trial
6.89 9.98 11.32 12.15 12.64 6.74 11.26 10.98 13.64 2.40
(2.11) (2.44) (2.46) (2.29) (1.91) (2.18) (2.82) (3.10) (1.54) (1.73)
Time 1 0 Years (n = 47)
Longitudinal
(2.26) (2.43) (2.26) (2.17) (2.00) (2.17) (2.58) 11.49(2.79) 13:87 (1.62) 3.32 (3.14)
7.79 10.26 11.89 12.64 12.89 6.55 11.72
Time 2 1 Year (n = 47)
Form 1
Means and Standard
7.57 10.70 12.26 13.15 13.64 6.57 12.36 11.98 14.00 4.45
(2.54) (2.61) (2.08) (1.67) (1.48) (2.07) (2.57) (2.71) (1.35) (4.73)
Time 3 2 Years (II = 47) 7.79 10.83 12.51 13.32 13.89 6.81 12.49 12.47 14.06 4.83
(2.42) (2.27) (2.28) (1.68) (1.39) (2.37) (2.44) (2.39) (1.34) (4.89)
Time 4 3 Years (n = 47)
(1.65) (1.93) (1.83) (1.62) (1.96) (1.69) (2.59) (2.33) (1.73) (3.08)
Time 1 0 Years (n = 37) 6.78 9.22 10.84 11.65 12.05 6.60 10.32 10.24 13.95 4.51
TABLE 4 Deviations for the AVLT: Form 1 and Form 2 Form 2
7.19 10.19 11.84 12.35 12.46 6.60 10.89 10.60 13.97 3.60
(1.79) (2.05) (1.94) (2.21) (1.84) (1.77) (2.84) (3.24) (1.30) (4.19)
Time 2 1 Year (n = 37)
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C. L. Uchiyam
Equivalent-Form
et al.
TABLE 5 Retest Reliability Coeffkients Form
Trial Trial 1 Trial 5 Imm. Recall Del. Recall Del. Recog. Ink Errors (Trials 1-5) *p < .05 2-tailed significance;
scores. month Trial 5 Trial 9
of the AVLT
1
Form 2
6-Month (n = 322)
I-Year (n = 47)
2-Year (n = 47)
3-Year (n = 47)
l-Year (n = 37)
.344** .481**
.297* .600** .603** .655** .364* .176
.537** sOQ** ..571** .572** .644** ,041
.394** .531** .641** .783** .480** .114
.521** .596** .662** .808** .394* .562**
.280** .414
**p < .Ol 2-tailed significance.
All coefficients were significant at the p < .05 (Ztailed) level. The 6alternate-form reliabilities were .363 for Trial 1 (n = 890) .488 for (n = 890), 574 for Trial 7 (n = 659), .604 for Trial 8 (n = 662) .345 for (n = 888), and .285 for Intrusions (n = 890).
DISCUSSION The results of this investigation provide normative and longitudinal data for two forms of the Auditory-Verbal Learning Test on a large, multiregional, healthy male sample. The overall sample was relatively young and well-educated; however, normative scores were stratified by age and education so that the data may be interpreted across a range of demographic values. Although the current sample was composed of gay and bisexual men, there is no a priori reason to believe that these normative data would not be applicable to the general male population. This position was supported by the similarity of the current normative data and previously published studies. In the normative analyses, there were no differences between the two AVLT test forms, supporting their psychometric equivalence upon initial administration. The learning curves for Trials 1 to 5, however, were found to be significantly different between forms, a difference that did not appear to be affected by the slightly different racial makeup of the groups. Because of this reason, diagnoses and interpretations that are based on rates learning should be made on test-specific normative data, such as those reported herein. An examination of the association of age and test scores revealed significant regression coefficients, with higher scores being associated with younger age. These findings are generally consistent with the reported literature (Bishop, Knights, & Stoddart, 1990; Geffen et al., 1990; Mitrushina, Satz, Chervinsky, & D’Elia, 1991; Petersen, Smith, Kokmen, Ivnik, & Tangalos, 1992; Query & Berger, 1980) although such an association has not been uni-
Alternate Forms of the Auditory-Verbal
Learning Test
143
versally replicated (Bolla-Wilson & Bleecker, 1986). As the effect of age appears to be influenced by other moderating variables, such as diagnostic status (Query & Berger, 1980) and intelligence (Query & Megran, 1983), caution should be exercised when interpreting the effects of this variable. The significant effects of education demonstrated in this investigation are consistent with those of Query and Megran (1983), where education was found to be related to AVLT scores in male inpatients. Although these findings were not replicated in a developmental study of children (Forrester & Geffen, 1991), the discrepancy between these studies may be related to the pediatric nature of the latter sample. Despite the fact that a significant predictive relationship was noted for ethnicity and test score, this finding should be viewed with caution, given the small non-Caucasian sample size and the increased possibility of selection bias. It was for this reason that these data could not be presented normatively. However, it is recommended that this variable be investigated more closely in future research in conjunction with such variables as social economic status and cultural factors that could significantly moderate or explain the present findings. Whether the normative data provided herein can be used with women remains to be demonstrated. Although gender effects have not been found in children (Forrester & Geffen, 1991), adult females have been noted to score higher than males on the AVLT (Bolla-Wilson & Bleecker, 1986; Geffen et al., 1990). Therefore, as the present sample consisted of healthy males, it is recommended that the normative data provided not be used with females until further examination of this question can be undertaken. The longitudinal analyses did not demonstrate significant differences between forms at l-year retesting which, taken in conjunction with the normative analyses, support the long-term psychometric equivalence of the two versions. However, significant practice effects were found for the forms at l-year retesting, and these practice effects appeared to be similar for the two forms. These findings demonstrate the need for the use of appropriate longitudinal normative data in interpreting retest results. The scores of the two forms showed similar equivalent-form retest reliabilities, with the exception of Intrusion scores for Form 1, which were nonsignificant and notably smaller than that of Form 2. The fact that Form 1 Intrusion scores are poor predictors of future Intrusions limits their clinical utility when assessing errors in situations requiring multiple assessments, and should be interpreted discerningly given their longitudinal unreliability. The reason that Intrusion errors for Form 1 should evidence less covariance than those of Form 2 is unclear, and may be related to such factors as the mental salience of the words included in the lists or their associative links to other nonlist words. However, this finding is worthy of continued research. The results of this investigation support the comparability of the two AVLT versions both upon initial and long-term retest administration. Because the
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et al.
present analyses were based on a nonpatient sample, it is recommended that future research also focus on similar psychometric issues with clinical samples. In addition, the present research examined demographic characteristics that could potentially affect test scores, with significantly poorer performance associated with increasing age and lower education. Lastly, the study provides researchers and clinicians with information concerning the learning curves, longitudinal practice effects, and psychometric properties of the alternate versions of the AVLT, issues that have great potential impact on the understanding of this test of verbal learning.
REFERENCES Bishop, J., Knights, R. M., & Stoddart, C. (1990). Rey Auditory-Verbal Learning Test: Performance of English and French children aged 5 to 16. Bleeker, M. L., Bolla-Wilson, K., Agnew, J., & Meyers, D. A. (1988). Age-related sex differences in verbal memory. Journal ofClinical Psychology, 44.403-411. Bolla-Wilson, K., & Bleecker, M. L. (1986). Influence of verbal intelligence, sex, age, and education on the Rey Auditory-Verbal Learning Test. Developmental Neuropsychology, 2, 203-211. Crawford, J. R., Stewart, L. E., & Moore, .I. W. (1989). Demonstration of savings on the AVLT and development of a parallel form. Journal of Clinical and Experimental Neuropsychology, 11.975-981. Forrester, G., & Geffen, G. (1991). Performance measures of 7- to 15year-old children on the Auditory-Verbal Learning Test. Clinical Neuropsychologist, 5, 345-359. Franzen, M. D. (1989). Reliability and validity in neuropsychological assessment. New York: Plenum Press. Geffen, G., Moar, K. J., O’Hanlan, A. P., Clark, C. R., & Geffen, L. (1990). Performance measures of 16. to 86.year-old males and females on the Auditory Verbal Learning Test. Clinical Neuropsychologist, 4, 45-63. Haddad, L. B., & Nussbaum, P. (1989). Predictive utility of the Rey Auditory-Verbal Learning Test with Alzheimers patients. Clinical Gerontologist, 9,53-59. Kaslow, R. A., Ostrow, D. G., Detels, R., Phair, J. P, Polk, B. F., & Rinaldo, C. R. (1987). The Multicenter AIDS Cohort Study: Rationale, organization, and selected characteristics of the participants. American Journal ofEpidemiology, 126, 3 10-3 18. Leininger, B. E., Gramling, S. E., Farrell, A. D., Kreutzer, J. S., & Peck, E. A. (1990). Neuropsychological deficits in symptomatic minor head injury patients after concussion and mild concussion. Journal of Neurology, Neurosurgery and Psychiatry, 53.293-296. Lezak, M. D. (1979). Recovery of memory and learning functions following traumatic brain injury. Cortex, 15,63-72. Lezak, M. D. (1983). Neuropsychological ussessmenf (2nd ed.). New York: Oxford University Press. Malec, J. F., Ivnik, R. J., & Hinkeldey, N. S. (1991). Visual spatial learning test. Psychological Assessment, 3, 82-88. Miller, E. N., Seines, 0. A., McArthur, J. C., Satz, l?, Becker, J. T., Cohen, B. A., Sheridan, K., Machado, A. M., van Gorp, W. G., & Visscher, B. (1990). Neuropsychological performance in HIV-l-infected homosexual men: The Multicenter AIDS Cohort Study (MACS). Neurology, 40, 197-203. Mitrushina, M., Satz, I?, Chervinsky, A., & D’Elia, L. (1991). Performance of four age groups of normal elderly on the Rey Auditory-Verbal Learning Test. Journal of Clinical Psychology, 47, 35 l-357. Petersen, R. C., Smith, G., Kokmen, E., Ivnik, R. J., & Tangalos, E. G. (1992). Memory function in normal aging. Neurology, 42, 396-401.
Alternate Forms of the Auditory-Verbal
Learning
Test
I45
Query, W. T., & Berger, R. A. (1980). AVLT memory scores as a function of age amonggeneral medical, neurologic and alcoholic patients. Journal ofClinical Psychology, 36, 10091012. Query, W. T., & Megran, J. (1983). Age-related norms for AVLT in a male patient population. Journal of Clinical Psychology, 39, 136-138. Query, W. T., & Megran, J. (1984). Influence of depression and alcoholism on learning, recall, and recognition. Journal of Clinical Psychology, 40, 1097-l 100. Rey, A. (1964). L’Examen clinique en psycho/o&. Paris: Press Universitaire de France. Rosenberg, S. J., Ryan, J. J., & Prititera, A. (1984). Rey Auditory-Verbal Learning Test performance of patients with and without memory impairment. Journal of Clinical Psychology, 40, 785-781. Ryan, J. J., & Geisser, M. E. (1986). Validity and diagnostic accuracy of an alternate form of the Rey Auditory-Verbal Learning Test. Archives of Clinical Neuropsychology, 1.209217. Ryan, J. J., Geisser, M. E., Randall, D. M., & Georgemiller, R. J. (1986). Alternate form reliability and equivalency of the Rey Auditory-Verbal Learning Test. Journal of Clinical and Experimental Neuropsychology, 8,6 1l-6 16. Shapiro, D. M., & Harrison, D. W. (1990). Alternate forms of the AVLT: A procedure and test of form equivalency. Archives of Clinical Neuropsychology, 5.405-410. Spreen, O., & Strauss, E. (1991). A compendium of neuropsychological tests: Administration, norms, and commentary. New York: Oxford University Press. Taylor, E. M. (1959). The appraisal of children with cerebral dejicits. Cambridge, MA: Harvard University Press.
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Alternate Forms of the Auditory-Verbal Learning Test: Issues of Test Comparability, and Moderating Craig Lyons Uchiyama,
Longitudinal Demographic
Reliability, Variables
Louis F. D’Elia, Ann M. Dellinger,
James T. Becker, Ola A. Selnes, Jerry E. Wesch, Bai Bai Chen, Paul Satz, Wilfred van Gorp, and Eric N. Miller Multicenter
AIDS Cohort Study
The present investigation examines the alternate-form and longitudinal reliability of two versions of the Auditory-Verbal Learning Test (AVLT) on a large, multiregional, healthy male sample. Subjects included 2,059 bisexual and homosexual HIV-seronegative males recruited from the Multicenter AIDS Cohort Study from centers in Baltimore, Chicago, Los Angeles, and Pittsburgh. The findings revealed no significant differences between forms upon initial or l-year longitudinal administration, supporting the equivalence of the two versions. However; significant practice effects were noted longitudinally, arguing for the need of appropriate retest normative data. Furthermore, as age, ethnic&y, and education were found to significantly affect test performance, it is recommended that normative data be interpreted according to these variables. In addition to providing normative and
This study was supported by National Institutes of Health contracts NO1 AI 7263 1, AI 72634, AI 32535, AI 72676, and AI 72632. Address all correspondence to: Craig Lyons Uchiyama, PhD, UCSF Langley Porter Psychiatric Institute, 401 Pamassus, Box CPT, San Francisco, CA 94143-0984. Craig Lyons Uchiyama is affiliated with the UCSF Langley Porter Psychiatric Institute. Louis F. D’Elia, Paul Satz, Wilfred van Gorp, and Eric N. Miller are affiliated with the UCLA School of Medicine. Ann M. Dellinger is affiliated with the UCLA School of Public Health. James T. Becker is affiliated with the University of Pittsburgh Graduate School of Public Health and School of Medicine. Ola A. Selnes and Bai Bai Chen are affiliated with the Johns Hopkins University School of Hygiene and Public Health. Jerry E. Wesch is affiliated with the Howard Brown Memorial Clinic Northwestern University Medical School. 133
I34
C. L. Uchiyama
et al.
longitudinal data, this investigafion presents information limitations of the alternate forms of the AVLT.
concerning
the use and
The Auditory-Verbal Learning Test (AVLT), initially developed by Rey (1964) and later revised for English usage (Lezak, 1983; Taylor, 1959), is a measure of rote verbal memory that assesses multiple memory domains, including immediate memory span, new learning, retroactive and proactive interference, and recognition (Lezak, 1983; Spreen & Strauss, 1991). Impaired performance on this test has been associated with such conditions as left temporal lobe dysfunction (Malec, Ivnik, & Hinkeldey, 1991), depression (Query & Megran, 1984), psychosis (Rosenberg, Ryan, & Prifitera, 1984) mild head injury (Lcininger, Gramling, Farrell, Kreutzer, & Peck, 1990), entrenched Alzheimer’s (Haddad & Nussbaum, 1989), and alcoholism (Query & Megran, 1984). Several alternate forms of the test have been developed for repeated administration (Crawford, Stewart, & Moore, 1989; Lezak, 1983; Shapiro & Harrison, 1990), as retest assessments often are clinically necessary to monitor the course of degenerative conditions or the recovery from cerebral trauma. Probably the most well known of these forms was developed by Taylor (1959). Although there has been limited support for the immediate-retest reliability of this version in male inpatients (Ryan & Geisser, 1986; Ryan, Geisser, Randall, & Georgemiller, 1986), the application of such findings to nonpatient populations has been questioned, given the very depressed scores of this sample’s subjects. In addition, the need to examine alternate forms longitudinally has been sup ported previously (Lezak, 1983) as significant practice effects have been noted for the original version over periods ranging from 6 months to 1 year on a small sample (n = 23) of young males. In another study, Lezak (1979) also reported that the percentage of 24 male head-trauma patients functioning within normal limits increased over a 3-year period. However, the findings of the latter study are difficult to interpret, as such elevations may reflect either recovery from the traumatic event or practice effects from repeated exposure (Franzen, 1989). The purpose of the present investigation is to examine longitudinally the alternate forms of the Rey Auditory-Verbal Learning Test on a large, healthy, multiregional male sample; assess the psychometric equivalence of the two forms across time; determine the effects of repeated administrations on AVLT test scores; and investigate the moderating effects of demographic variables on test performance.
METHOD Subjects
Subjects were participants of the Multicenter AIDS Cohort Study (MACS), and included 2,059 homosexual and bisexual HIV-seronegative males from
Alternate Forms of the Auditory-Verbal
135
Learning Test
sites in Baltimore, Chicago, Los Angeles, and Pittsburgh. The purpose of the MACS is to research longitudinally the neurological and neuropsychological functioning of HIV-l seropositive and seronegative persons. Subjects were excluded from the investigation if they demonstrated a history of learning disability, a prior loss of consciousness, or a primary language other than English. Sample demographics are presented in Table 1. For further information on subject recruitment procedures, the reader may refer to the previously published works by Miller et al. (1990) and Kaslow et al. (1987). Because the current sample was composed of seronegative, healthy gay and bisexual men, the possibility was raised that the validity and normative results of this investigation would not be reflective of the general male population. Therefore, the scores from Trial 5 of the present study were compared to those of previously reported normative studies of men. Normative studies were excluded from comparison that were not stratified by gender, by age, or that were based on patient populations. Of the two studies found to meet this criteria, the stratified age groups that overlapped with the present study were selected for comparison. The mean score from Trial 5 of the present study was found to be almost identical (differing by only .31 points) to that of Bleeker, Bolla-Wilson, Agnew, and Meyers (1988). Although slightly better performance (1.58 points) was noted in the present sample over another sample (Geffen, Moar, O’Hanlan, Clark, & Geffen, 1990), this difference was likely related to the very small sample size of the latter study (mean = 10.4 persons per cell), as well as the fact that the males in the Geffen et al. sample had less than a high school education (mean years of education = 11.34) compared to the Bleeker et al. sample (mean years of education = 13.52) and the present sample. These findings demonstrate the similarity of the present study with previously
Demographic
N Age Education Ethnicity Caucasian American Hispanic American African American Hispanic/African American Native American Asian American Other
TABLE 1 Means and Standard Deviations for Alternate Versions of the AVLT
Total Sample
Form 1 Normative Sample
Form 2 Normative Sample
2,059 36.55 (7.19) 15.94 (2.39)
1,818 36.54 (7.20) 15.95 (2.40)
241 37.63 (7.16) 15.80 (2.31)
88% 5% 5% < < < <
1% 1% 1% 1%
89% 5% 5% < < < <
1% 1% 1% 1%
82% 8% 8% < 1% < 1% 1% < 1%
Form 1 Longitudinal Sample
Form 2 Longitudinal Sample
::.69 (6.01) ::.46 (6.95) 16.47 (2.04) 16.03 (2.21) 94% 6%
84% 3% 11% 3%
136
C. L. Uchiyam et al.
published works, and would indicate no reason that the current findings cannot be generalized to heterosexual males. It was found that 1,818 individuals received Form 1 on their first administration, and 241 subjects received Form 2. Demographic information for these samples are presented in Table 1. General linear model one-way analyses found no significant between-group differences for age (F = .03; p > .05) and level of education (F = .88; p > .05). However, significant Pearson chi-squares were found in ethnicity (p < .05) when this variable was dichotomized (Caucasian, non-Caucasian) for reasons of small cell size. How this variable was controlled in the analyses is described in the Results section. In the l-year longitudinal analyses, 47 persons were initially administered Form 1 in Wave 3, and participated in Waves 5,7, and 9 (each of which was 1 year apart). Thirty-seven persons were initially administered Form 2 and participated in Wave 4, which was 1 year after the initial administration. Demographic information for the longitudinal samples is presented in Table 1. Some of the subjects included in the longitudinal analyses received exposure to the alternate form midway between their exposure to the original form. However, as analyses revealed that these subjects demonstrated no significant differences in scores from persons not receiving such exposure, they were retained in the longitudinal analyses. The longitudinal groups showed no significant demographic differences in terms of age (F = .03; p > .05), education (F = .90; p > .05), or ethnicity (Pearson chi-square = 2.09; p > .05). Because more subjects were inducted into the study after Wave 3 from Pittsburgh and Los Angeles, the results from the l-year longitudinal analyses may be less generalizable in terms of geographic representation. Data from Waves 1 and 2 could not be used in the l-year longitudinal analyses, as Form 1 was administered in both these waves (which were 6 months apart). To include them in the analyses would introduce confounding factors of unequal time periods and differential test exposure. However, these waves were included in the 6-month retest reliability analyses. Procedure Subjects were tested over 12 data collection periods, or waves, that were each 6 months in length. Two forms of the Auditory-Verbal Learning Test (Rey, 1964; Taylor, 1959) were administered (actual items in lists are presented in Lezak, 1983). The first, which will subsequently be referred to as Form 1, consisted of a 15-item word list (List A) presented 5 times (Trials 1 to 5). In these trials, the subjects were instructed to recall as many words as they could in any order. Immediately after the fifth presentation, a 15item distractor list (List B) was presented (Trial 6) with a similar test of recall. Following the distractor task, the subjects were immediately asked to recall List A without the benefit of another presentation (Trial 7). After a 30-minute delay, the subjects
Alternate Forms of the Auditory-VerbalLearning Test
137
were presented both with a free recall (Trial 8) and a forced-choice recognition task (Trial 9) of List A. The second version, which will be referred to as Form 2, was identical to Form 1 with the exception that the words in List A (presented 5 times) were substituted with words from List C. The interference trial (List B) of Form 2 was identical to that of Form 1.
RESULTS
Normative Analyses The means and standard deviations from the normative analyses, which were stratified according to age and education, are presented for Forms 1 and 2 in Tables 2 and 3, respectively. The comparability of the two forms was analyzed using a four-way general linear model due to discrepant cell sizes which made such statistics as classical M A N O V A ' s inappropriate. In this analysis, the independent variables included test form, age, education, and ethnicity; and the dependent variables included the scores from Trials 1 to 9 and the total number of Intrusions from Trials 1 to 5. Because the two groups differed in terms of ethnicity, this variable was dichotomized (Caucasian, non-Caucasian) in the manner of an indicator variable, and entered into the analysis as an independent variable. This way, should significant main effects be found, an examination of the appropriate partial sums of squares would indicate the effects of test form without the influencing effects of ethnicity. The results of the normative analyses revealed no significant main effect for test form (F = .82; df = 13; p > .05), supporting the comparability of the two versions upon initial administration. In examining the learning curves for Trials 1 to 5, a repeated-measure, general linear model was again used for the previously cited rationale. In this model, test form and ethnicity were the independent variables; trial was the repeated measure independent variable; and scores from Trials 1 to 5 were the dependent variables. The results of these analyses indicated a significant trial by form interaction (F = 2.67; df = 4; p < .05), suggesting that the learning curve for the two forms was significantly different upon initial administration. As there was no trial by ethnicity interaction (F = .24; df = 1; p > .05), there is no reason to believe that ethnicity, the only demographic variable that was significantly different for the two groups, was differentially influencing the learning curves of the two forms. The effects that the demographic variables had on Trial 5 test scores were examined by a general linear multiple regression, with ethnicity again being entered as an indicator variable. The partial F ' s were significant for age (F = 51.90; df= 1; p < .05), ethnicity (F = 21.52; df= 1; p < .05), and education (F = 71.94; df= 1;p < .05), demonstrating the strong relationship of these variables with test scores, as well as the need for interpreting normative data
z 0
Trial 3 Trial 4 Trial 5 Intr.Trial Imm. Recall Del. Recall Del. Recog. Ink Errors (Trials l-5)
Trial2
Trial 1
Trial
~.
6.66 (1.81) 9.59 (2.15) 11.17 (2.19) 12.06 (2.00) 12.63 (1.89) 6.50 (2.07) 1I .05 (2.68) 10.87 (2.82) 14.19 (1.28) 3.04 (2.93)
...~
Total Sample (n = 1818)
- ..___-
11.32 (2.20) 12.38 (1.90) 12.84 (1.79) 6.85 (2.08) 11.39 (2.40) 11.27 (2.54) 14.36 (1.13) 3.05 (2.89)
9.82 (2.28)
6.86 (1.86)
20-29 (n = 333)
~.--
11.36 (2.21) 12.15 (1.97) 12.76 (1.91) 6.58 (2.05) 11.24 (2.73) 11.08 (2.82) 14.23 (1.23) 3.09 (3.00)
9.72 (2.21)
6.74 (1.83)
30-39 (n = 968)
10.82 (2.08) 1I.76 (2.09) 12.45 (1.84) 6.15 (2.04) 10.50 (2.60) 10.25 (2.84) 14.01 (1.42) 2.91 (2.88)
9.26 (1.88)
6.46 ( 1.68)
40-49 (n = 437)
10.15 (1.96) 11.34 (1.91) 12.03 (2.02) 6.16 (2.28) 10.20 (3.03) 9.87 (3.3 f) 13.89 (1.57) 2.91 (2.67)
8.88 (1.97)
5.80(1.73)
5Oandabove (n = 80)
-
_____.
10.67 (2.18) 11.66 (2.05) 12.34 (1.99) 6.13 (2.01) 10.78 (2.70) 10.53 (2.90) 14.11 (1.37) 3.14 (2.99)
9.14 (2.10)
6.31 (1.83)
_
c 16 Years (n = 662)
--____-
TABLE 2 Normative Means and Standard Deviations for the AYLT:Form 1 _._.. .-____1_____~.-_ A@
11.44 (2.09) 12.26 (1.94) 12.81 (1.83) 6.54 (2.07) 11.19 (2.58) t 1.04 (2.76) 14.27 (l-23) 2.95 (2.82)
9.77 (2.02)
6.84 (1.73)
(n = 495)
16 Years
Education __I~~
11.48 (2.19) 12.33 (1.94) 12.91 (1.78) 6.84 (2.07) 11.21 (2.70) 11.07 (2.78) 14.21 (1.22) 2.97 (2.96)
9.91 (2.23)
6.86 (1.81)
(n = 653) __
> 16 Years
Trial 3 Trial 4 Trial 5 Ink Trial Imm. Recall Del. Recall Del. Recog. Intr. Errors (Trials l-5)
Trial 21
6.41 8.94 10.70 11.61 12.20 6.29 10.11 9.75 13.34 4.42
(1.73) (2.21) (2.12) (2.06) (1.83) (2.12) (2.68) (2.98) (1.98) (3.81)
Total Sample (n = 241)
6.78 9.52 11.13 12.09 12.30 7.02 10.91 10.48 13.83 3.87
(1.80) (2.61) (2.24) (1.93) (2.00) (2.39) (2.66) (3.16) (1.69) (4.61)
20-29 (n = 46)
Normative
6.50 (1.78) 9.03 (2.09) 10.81 (1.95) 11.60(1.95) 12.38 (1.56) 6.15 (2.06) 10.09 (2.48) 9.71 (2.71) 13.47 (1.96) 4.77 (3.75)
30-39 (n = 118)
Age
6.11 8.48 10.29 11.42 11.94 6.23 9.82 9.48 12.82 4.23
(1.53) (2.10) (2.36) (2.26) (2.13) (2.03) (2.87) (3.18) (2.15) (3.31)
40-49 (n = 66) 5.64 8.18 10.09 10.91 11.45 5.27 8.82 8.73 13.18 4.09
(1.57) (1.72) (1.64) (2.30) (1.81) (1.49) (3.16) (3.52) (1.78) (3.62)
50 and above (n= 11) 6.36 8.84 10.38 11.35 12.03 6.24 9.78 9.52 13.24 4.53
(1.83) (2.11) (2.01) (1.92) (1.62) (2.21) (2.45) (2.58) (2.03) (4.20)
< 16 Years (n=91)
TABLE 3 Means and Standard Deviations for the AVLT: FORM 2
6.32 9.04 10.95 11.80 12.31 5.96 10.41 9.98 13.59 4.22
(1.58) (2.23) (2.04) (2.16) (2.00) (2.01) (2.80) (3.12) (1.80) (3.84)
16 Years (n=81)
Education
6.57 8.90 10.79 11.71 12.31 6.80 10.15 9.75 13.16 4.47
(1.76) (2.29) (2.35) (2.10) (1.92) (2.09) (2.84) (3.32) (2.11) (3.23)
> 16 Years (n = 68)
140
C. L. Uchiyama et al.
in accordance with such variables. It was found that higher scores were associated with younger age and higher education. Longitudinal
Analyses
Normative information on the longitudinal samples may be found in Table 4. The longitudinal data were subjected to two sets of repeated measure MANOVA’s. As no statistical differences were found between the groups in terms of age, education, or ethnicity, these variables were not statistically controlled. The first MANOVA used test form, time, and trial as independent variables; and scores from Trials 1 to 9 and total Intrusions across the first two time periods were used as dependent variables. The variables of time and trial were treated as within-subject repeated measure variables. The results indicated no significant longitudinal effect for test form (F = .78; df= 1; p > .OS). In examining the practice effects across repeated exposure, the results were significant (F = 322.12; df= 1; p < .05), demonstrating that scores significantly increased at l-year repeated administration. As there was no significant interaction between test form and time (F = SO; df = 1; p > .05), these practice effects appear to be similar for the two forms. The second MANOVA examined the learning curves for Trials 1 to 5 between the two forms across time, and incorporated test form as the betweensubject independent variable, time and trial number as the within-subject independent variables, and scores from Trials 1 to 5 for both initial and l-year retest as the dependent variables. The results of this MANOVA revealed no significant interaction for test form by trial (F = .91; df = 4; p > .05), suggesting that longitudinally, the two forms evidence similar learning curves for Trials 1 to 5. Equivalent-Form
Reliability
The equivalent-form, long-term retest reliabilities comparing the retest periods for the two forms with the initial testing are presented in Table 5. The long-term reliabilities for the scores were all significant, except for the Form 1 Intrusion scores which were notably lower than the Intrusion scores of Form 2. In addition to the previously mentioned exception, the l-year reliability of the two forms appeared to be generally comparable, although Trial 1 and Delayed Recall scores for Form 1 were slightly less reliable than those of Form 2. The coefficients were lowest for both forms for Trial 1, and highest for Delayed Recall. Alternate-Form
Reliability
The alternate-form, found to be moderate
6-month reliability coefficients for the two forms were to moderately high, with the exception of Intrusions
5
Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Ink Trial Imm. Recall Del. Recall Del. Recog Intr. Errors (Trials 1-5)
Trial
6.89 9.98 11.32 12.15 12.64 6.74 11.26 10.98 13.64 2.40
(2.11) (2.44) (2.46) (2.29) (1.91) (2.18) (2.82) (3.10) (1.54) (1.73)
Time 1 0 Years (n = 47)
Longitudinal
(2.26) (2.43) (2.26) (2.17) (2.00) (2.17) (2.58) 11.49(2.79) 13:87 (1.62) 3.32 (3.14)
7.79 10.26 11.89 12.64 12.89 6.55 11.72
Time 2 1 Year (n = 47)
Form 1
Means and Standard
7.57 10.70 12.26 13.15 13.64 6.57 12.36 11.98 14.00 4.45
(2.54) (2.61) (2.08) (1.67) (1.48) (2.07) (2.57) (2.71) (1.35) (4.73)
Time 3 2 Years (II = 47) 7.79 10.83 12.51 13.32 13.89 6.81 12.49 12.47 14.06 4.83
(2.42) (2.27) (2.28) (1.68) (1.39) (2.37) (2.44) (2.39) (1.34) (4.89)
Time 4 3 Years (n = 47)
(1.65) (1.93) (1.83) (1.62) (1.96) (1.69) (2.59) (2.33) (1.73) (3.08)
Time 1 0 Years (n = 37) 6.78 9.22 10.84 11.65 12.05 6.60 10.32 10.24 13.95 4.51
TABLE 4 Deviations for the AVLT: Form 1 and Form 2 Form 2
7.19 10.19 11.84 12.35 12.46 6.60 10.89 10.60 13.97 3.60
(1.79) (2.05) (1.94) (2.21) (1.84) (1.77) (2.84) (3.24) (1.30) (4.19)
Time 2 1 Year (n = 37)
142
C. L. Uchiyam
Equivalent-Form
et al.
TABLE 5 Retest Reliability Coeffkients Form
Trial Trial 1 Trial 5 Imm. Recall Del. Recall Del. Recog. Ink Errors (Trials 1-5) *p < .05 2-tailed significance;
scores. month Trial 5 Trial 9
of the AVLT
1
Form 2
6-Month (n = 322)
I-Year (n = 47)
2-Year (n = 47)
3-Year (n = 47)
l-Year (n = 37)
.344** .481**
.297* .600** .603** .655** .364* .176
.537** sOQ** ..571** .572** .644** ,041
.394** .531** .641** .783** .480** .114
.521** .596** .662** .808** .394* .562**
.280** .414
**p < .Ol 2-tailed significance.
All coefficients were significant at the p < .05 (Ztailed) level. The 6alternate-form reliabilities were .363 for Trial 1 (n = 890) .488 for (n = 890), 574 for Trial 7 (n = 659), .604 for Trial 8 (n = 662) .345 for (n = 888), and .285 for Intrusions (n = 890).
DISCUSSION The results of this investigation provide normative and longitudinal data for two forms of the Auditory-Verbal Learning Test on a large, multiregional, healthy male sample. The overall sample was relatively young and well-educated; however, normative scores were stratified by age and education so that the data may be interpreted across a range of demographic values. Although the current sample was composed of gay and bisexual men, there is no a priori reason to believe that these normative data would not be applicable to the general male population. This position was supported by the similarity of the current normative data and previously published studies. In the normative analyses, there were no differences between the two AVLT test forms, supporting their psychometric equivalence upon initial administration. The learning curves for Trials 1 to 5, however, were found to be significantly different between forms, a difference that did not appear to be affected by the slightly different racial makeup of the groups. Because of this reason, diagnoses and interpretations that are based on rates learning should be made on test-specific normative data, such as those reported herein. An examination of the association of age and test scores revealed significant regression coefficients, with higher scores being associated with younger age. These findings are generally consistent with the reported literature (Bishop, Knights, & Stoddart, 1990; Geffen et al., 1990; Mitrushina, Satz, Chervinsky, & D’Elia, 1991; Petersen, Smith, Kokmen, Ivnik, & Tangalos, 1992; Query & Berger, 1980) although such an association has not been uni-
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versally replicated (Bolla-Wilson & Bleecker, 1986). As the effect of age appears to be influenced by other moderating variables, such as diagnostic status (Query & Berger, 1980) and intelligence (Query & Megran, 1983), caution should be exercised when interpreting the effects of this variable. The significant effects of education demonstrated in this investigation are consistent with those of Query and Megran (1983), where education was found to be related to AVLT scores in male inpatients. Although these findings were not replicated in a developmental study of children (Forrester & Geffen, 1991), the discrepancy between these studies may be related to the pediatric nature of the latter sample. Despite the fact that a significant predictive relationship was noted for ethnicity and test score, this finding should be viewed with caution, given the small non-Caucasian sample size and the increased possibility of selection bias. It was for this reason that these data could not be presented normatively. However, it is recommended that this variable be investigated more closely in future research in conjunction with such variables as social economic status and cultural factors that could significantly moderate or explain the present findings. Whether the normative data provided herein can be used with women remains to be demonstrated. Although gender effects have not been found in children (Forrester & Geffen, 1991), adult females have been noted to score higher than males on the AVLT (Bolla-Wilson & Bleecker, 1986; Geffen et al., 1990). Therefore, as the present sample consisted of healthy males, it is recommended that the normative data provided not be used with females until further examination of this question can be undertaken. The longitudinal analyses did not demonstrate significant differences between forms at l-year retesting which, taken in conjunction with the normative analyses, support the long-term psychometric equivalence of the two versions. However, significant practice effects were found for the forms at l-year retesting, and these practice effects appeared to be similar for the two forms. These findings demonstrate the need for the use of appropriate longitudinal normative data in interpreting retest results. The scores of the two forms showed similar equivalent-form retest reliabilities, with the exception of Intrusion scores for Form 1, which were nonsignificant and notably smaller than that of Form 2. The fact that Form 1 Intrusion scores are poor predictors of future Intrusions limits their clinical utility when assessing errors in situations requiring multiple assessments, and should be interpreted discerningly given their longitudinal unreliability. The reason that Intrusion errors for Form 1 should evidence less covariance than those of Form 2 is unclear, and may be related to such factors as the mental salience of the words included in the lists or their associative links to other nonlist words. However, this finding is worthy of continued research. The results of this investigation support the comparability of the two AVLT versions both upon initial and long-term retest administration. Because the
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present analyses were based on a nonpatient sample, it is recommended that future research also focus on similar psychometric issues with clinical samples. In addition, the present research examined demographic characteristics that could potentially affect test scores, with significantly poorer performance associated with increasing age and lower education. Lastly, the study provides researchers and clinicians with information concerning the learning curves, longitudinal practice effects, and psychometric properties of the alternate versions of the AVLT, issues that have great potential impact on the understanding of this test of verbal learning.
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