Parallel-form reliability of the Wechsler Memory Scale in a geriatric population with suspected dementia

The present study examined parallel-form reliability of the Wechsler Memory Scale (WMS) in a population where such forms are particularly useful, that is, among patients who are suspected of having some type of dementing illness. Comparative analyses were made for total raw scores. Memory Quotient (MQ) scores, and individual subtest scores. Thirty geriatric patients originally referred for neuropsychological testing because of suspected dementia were given both Forms 1 and 2 of the WMS. The results yielded high overall reliability coefficients for MQ and total raw scores. Individual subtest scores also yielded rather high coefficients, and only one subtest (Associate Learning) had a significant mean difference. Apparently, the two forms have sufficient parallel-form reliability to be considered clinically interchangeable. Thus, the WMS may be a useful tool for repeat evaluations of memory functioning in a demented population.     

Abbreviated form of the Wechsler Memory Scale-III Faces subtest

A major criticism of the Wechsler Memory Scale-III Faces subtest is the number of items, which can be daunting and time-consuming for an impaired client or boring for a normal client. An analysis of several versions, with data from a sample of 50 clinical referrals, revealed that a 32-item subtest was best overall. Using this version, 100% (Faces I) and 94% (Faces II) of the predicted raw scores were less than 4 points away from the actual raw scores, whereas 66% (Faces I) and 70% (Faces II) were less than 2 points away. Limitations of this procedure are discussed.     

Correlations for Wechsler Intelligence Scale for Children--Revised and the Wechsler Preschool and Primary Scale of Intelligence for Iranian children.

This study focused on the relationship between the Wechsler Intelligence Scale for Children--Revised (WISC--R) and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) given to 40 6-yr.-old Iranian children. Pearson correlations between the WISC--R and the WPPSI IQs and between scaled scores on the corresponding subtests were significant. The comparison of mean IQs and scaled scores indicates that the WISC--R yielded a significantly higher Verbal IQ and higher scores on Information, Vocabulary, Comprehension, and Picture Completion than the WPPSI. The mean difference between corresponding Verbal and Full Scale IQs was not significant. These results suggest that scores on the two instruments correlated well for these 6-yr.-old Iranian children and the content on which IQs for the recently restandardized WISC--R and WPPSI are based are related.     

Parsimonious prediction of Wechsler Memory Scale--III memory indices

Equations for prorating the Wechsler Memory Scale--III (WMS-III) Index scores were derived and validated on a sample of 252 mixed clinical cases. Regression equations were performed using age-scaled scores as predictors and the sum of age-scaled scores for Immediate Memory (IM) and General Memory (GM) as the criteria. Including Logical Memory and Verbal Paired Associates with either Faces or Family Pictures resulted in estimated scores that accounted for 95% to 97% of the variance for IM and GM. Over 80% of these cases had estimated sum of scaled scores that fell within 3 points of actual sum of scaled scores, within 1 standard error of measurement. When only Logical Memory and Verbal Paired Associates were included, estimations accounted for only 87% of the variance, and only 60% of the estimated scores fell within 3 points of actual sum of scaled scores. The regression equations are presented, as are the confidence intervals derived from a bootstrapping procedure that created 15,000 different samples.     

Test-retest reliability and practice effects of the Wechsler Memory Scale-III

Although serial administration of cognitive tests is increasingly common, there is a paucity of research on test-retest reliabilities and practice effects, both of which are important for evaluating changes in functioning. Reliability is generally conceptualized as involving short-lasting changes in performance. However, when repeated testing occurs over a period of years, there will be some longer lasting effects. The implications of these longer lasting effects and practice effects on reliability were examined in the context of repeated administrations of the Wechsler Memory Scale-III in 339 community-dwelling women aged 40-79 years over 2 to 7 years. The results showed that Logical Memory and Verbal Paired Associates subtests were consistently the most reliable subtests across the age cohorts. The magnitude of practice effects varied as a function of subtests and age. The largest practice effects were found in the youngest age cohort, especially on the Faces, Logical Memory, and Verbal Paired Associates subtests.     

Developmental analysis of the effects of reward on selected Wechsler subscales

The authors recently proposed that adverse effects of material rewards on Wechsler subscale performance may be the result of a reward-produced developmental regression. The present study further explores that idea through an attempt to replicate earlier findings with adults and to extend the inquiry to children. Selected Wechsler subscales were administered to 32 subjects at each of three ages (5, 10, and 18 years) under either reward or nonreward conditions. Subscales were chosen to represent both algorithmic and heuristic types of tasks. Reward and nonreward groups (8 males and 8 females per group at each age) were matched initially on age and ability. For adults, consistent with earlier findings, reward had an adverse effect on performance on the heuristic subscales and tended to facilitate performance on the algorithmic subscales. However, rewards generally had no effect at the fourth-grade level and had a reverse effect at the nursery school level, i.e., rewards facilitated heuristic and hampered algorithmic performance. These findings appear to be more consistent with an explanation based on developmental regression than on any available alternative mechanism.     

Construct validity of the Bender-Gestalt II: comparison with Wechsler Intelligence Scale for Children-III

This study investigated the relationships of visuomotor constructs as measured by the Bender-Gestalt II with the subtests of the WISC-III. A factor analysis included the standardized Copy and Recall scores of the Bender-Gestalt II and subtest scores of the WISC-III. The Copy score was predicted to load on measures of visual and spatial thinking and the Recall score on a short-term memory factor. The results of a principal components analysis suggest a four-factor solution with the Bender-Gestalt II Copy score loading on a visual and spatial thinking factor primarily with WISC-III Perceptual Organization subtests. The Recall score loaded on a visual and spatial thinking factor as well as a short-term memory factor with the WISC-III Digit Span subtest. The results suggest the Bender-Gestalt II Copy subtest shared commonality with the visual and spatial tasks given the similarity in the visuomotor demands of each test and was less influenced by processing speed or cultural knowledge than other tests on the visual and spatial thinking factor. Also, results suggest Bender-Gestalt II Recall measures elements of both visual and spatial thinking as well as aspects of short-term memory and memory retrieval. Clinical guidelines for co-administration and underlying processing demands are discussed.     

Second-order confirmatory factor analysis of the WAIS-III. Wechsler Adult Intelligence Scale

According to Vernon's structure-of-intellect paradigm, abilities can be conceptualized as a hierarchy, with a factor of general intelligence at the top of the hierarchy, and successively more specific abilities toward the bottom. This paradigm has proven useful for interpreting a number of Wechsler intelligence scales. However, most of the research with this paradigm has used exploratory factor analysis, and the validity of the paradigm for the newest Wechsler Adult Intelligence Scale (WAIS-III) has yet to be evaluated. The present study examined the WAIS-III using second-order confirmatory factor analysis, which is a more appropriate analytic tool when specific hypotheses are tested. Using the standardization sample for the WAIS-III (N = 2,450), support was found for the hierarchical factor structure with a second-order factor of general intelligence and four first-order factors of Verbal Comprehension, Perceptual Organization, Working Memory, and Processing Speed.     

Orthogonal higher order structure of the Wechsler Intelligence Scale For Children--fourth edition

According to J. B. Carroll's (1993) 3-stratum theory, performance on any subtest reflects a mixture of both 2nd-order and 1st-order factors. To disentangle these influences, variance explained by the general factor should be extracted first. The 1st-order factors are then residualized, leaving them orthogonal to the general factor and each other. When these methods were applied to the WISC-IV standardization sample, the general factor accounted for the greatest amount of common (71.3%) and total (38.3%) variance. The largest contribution by a first-order factor was 6.5% of total variance. It was recommended that interpretation of the WISC-IV not discount the strong general factor.