Wechsler Memory Scale | Fourth Edition

On the Brief Cognitive Status Exam, Item 11 (Inhibition), the examiner is supposed to administer the sample item, and then tell the examinee to do the same thing for the actual item. After I demonstrate the entire row and tell them I want them to do the “same thing,” should the examinee redo the first row that I just showed them and continue on, or should they begin with Line 2 (and continue from where I left off)?

The examinee begins back at the first item of the first row. The maximum number of points for this item is 24, reflecting the 24 shapes in the item.

The verbal load on many of the Visual Memory and Visual Working Memory subtest instructions seems substantial. We are concerned that the difficulties a client may experience in understanding the directions may cloud the results of these Visual Memory subtests.

Working memory is presented for a visual modality in WMS–IV as the Visual Working Memory Index. This index is derived from the sum of scaled scores for Spatial Addition and Symbol Span. Construction of stimuli used for these subtests purposely minimized the degree to which the stimuli could be verbalized and, subsequently, invoking the verbal working memory system. VWMI correlates at .53 with Verbal Comprehension, similar to the correlation with Processing Speed (r = .51), but less than Perceptual Reasoning (r = .67) and Working Memory (r = .62). There is no evidence of a negative impact to VWMI relative to other skill areas in the clinical samples with significant language deficits. If you have a concern about a specific client not understanding the instructions, it is allowable to repeat the examples and directions until they understand the task.

Please explain why the Designs task is better than the Faces task. Besides the fact that it is more difficult to verbally mediate the Designs task, and that there may be other confounds on a face memory task, it seems that there are significant executive functioning demands with Designs and it appears to be an incredibly difficult task! (i.e., there are lots of distracters that have many similarities to the target stimuli; consequently, establishing relevant from irrelevant may be difficult).

Face memory is a specific type of memory function that is often impaired in clinical groups with known social perception deficits (e.g., Schizophrenia, Autism) and is sometimes sensitive to right–left differences in temporal lobe epilepsy. The WMS–III Faces subtest has a relatively high guess rate that lowers its reliability relative to other memory tasks. Faces generally has low communality with other memory measures. The Faces subtest is useful for specific types of memory evaluations, but results may not operate as expected as a general indicator of visual memory. The Designs subtest was developed specifically to measure spatial and detail segments of memory functioning, as well as the integration of these in recall. This follows the segmentation of the visual system that has a dorsal stream, which processes primarily visual-spatial aspects of memory and the ventral stream that processes visual details with the purpose of attaching verbal labels where possible. Most visual memory measures do not enable the examiner to differentiate the nature of the visual memory problem and, therefore, makes interpretation more difficult. As far as executive functioning or attention to detail is concerned, the Designs subtest is comparable to most visual memory measures in this respect. For example, in the Faces subtest, the distracter faces are similar to one of the target faces. Family Pictures (WMS–III) and Picture Memory (WRAML–II) require attention to details, as well as visual scanning and search abilities. Tests such as the Rey-Complex Figure are used to measure executive functioning (see Bernstein & Waber, 1996) and visual memory. The Designs subtest requires fewer demands on executive functioning than other commonly used visual memory measures.

What are Contrast Scores and how do I use them?

Contrast scores enable you to partition overlapping variance between related abilities or a precursor ability of the construct of interest. In the contrast score name, the first score is the control variable and the second score is the dependent measure. For example, in the Logical Memory Immediate Recall vs. Delayed Recall contrast scaled score, the Logical Memory I scaled score is the control variable and the Logical Memory II scaled score is the dependent measure.

Contrast scaled scores are scaled on a mean of 10 and a standard deviation of 3, but should not be considered a replacement for the standard age-adjusted scaled scores. Contrast scores supplement standard age-adjusted scores and answer specific questions regarding an examinee’s performance. They should not be reported or interpreted as being the examinee’s performance relative to same-age peers.

Continuing with the Logical Memory example, the standard age-adjusted scaled score answers the question, “Is the examinee’s Logical Memory Delayed Recall impaired?” while the contrast score answers the question, “Is the examinee’s Logical Memory Delayed Recall impaired given their initial encoding of the stories during Immediate Recall?” This contrast score reflects the examinee’s performance during delayed recall controlling for performance during immediate recall. In other words, the Logical Memory II scaled score is being adjusted for the Logical Memory I scaled score.

Using the contrast score to supplement the information provided by the standard age-adjusted score, the interpretation of the two scores may be, “Client A’s Logical Memory Delayed Recall is in the Borderline range of functioning in comparison to same age peers. However, given the amount of material initially encoded during Immediate Recall, Client A’s performance is within the Low Average range of functioning.”

Contrast scores between 8 and 12 indicate that performance on the control and dependent variables is not significantly different. For example, the examinee’s delayed recall is what you would expect given their initial encoding of the stories. Contrast scores greater than 12 suggest, for example, that delayed recall is better than expected given their initial encoding of the stories. Contrast scores less than 8 suggest delayed recall is worse than expected given the examinee’s initial encoding of the stories. For further case studies using Contrast scores, see the Contrast Scaled Scores presentation on the WMS–IV website.

Which medications were listed as acceptable and how did you decide they were? What medications were examinees taking, e.g., Aricept for Alzheimer’s?

The exclusion and inclusion criteria in the WMS–IV Technical and Interpretive Manual Table 2.1 and Appendix D, respectively, list medication guidelines used in the normative sample and special groups. Medications were designated as acceptable, provisionally acceptable, or excluded during standardization case collection. A key factor in deciding the acceptability of a medication was its impact on the examinee’s functioning during test administration. The Neppe Psychological Symptom Questionnaire (NPSQ) and NPSQ Acceptance Criteria Checklist were used in the initial screening to gather information on medication type, reason for taking it, dosage/frequency, and any side effects/symptoms within 2 days prior to testing. Cases that involved excluded medications or did not meet NPSQ criteria were excluded from the study. The WMS–IV development team made decisions on a case-by-case basis if medications were not included on one of the three lists or were excluded for other reasons (e.g., off-label medication use). A variety of medications were being taken by individuals in the normative and clinical groups. In all circumstances, allowed medications were not suspected of interfering with an examinee’s test performance. Examiners reported on whether they felt medication use affected examinee test performance.

Do you have more information about the clinical groups reported in the WMS–IV (e.g., TBI, ALZ)?

The WMS–IV Technical and Interpretive Manual lists the Exclusion criteria (Table 2.1) and the general and special group-specific inclusion criteria (Appendix D) reported. Where appropriate, DSM-IV-TR criteria and other well-established guidelines for diagnostic purposes were followed. When possible, information regarding premorbid functioning was gathered.

Why is there no opportunity to repeat the Joe Garcia story? Many clinicians like to evaluate if repeating the story benefits the examinee and if there is a difference in narrative recall for immediate and delayed recall for each of the stories.

The repetition of Joe Garcia was dropped because there is already a learning task on Verbal Paired Associates. If you repeat the Joe Garcia story, you cannot compare how well someone performs on delayed recall when they have the repetition versus when they do not. It was necessary to repeat a story for the older age group because there would be insufficient floor if it was not repeated.

Why is the WMS–IV devoid of human figures?

The decision was made to omit the Faces subtest from WMS–IV and include it in the Advanced Clinical Solutions for WAIS-IV and WMS–IV Social Cognition battery. The Faces subtest measures a very specific memory process that is not necessarily the best measure for routine neuropsychological evaluations. If you are assessing individuals with Schizophrenia or an Autism Spectrum disorder, you may find the ACS Social Perception subtest very beneficial. The subtest provides valuable information about facial processing without the memory component If you prefer to use Family Pictures or Faces, you may continue to use the WMS–III version. Remember that the norms only get softer, so if an individual is mildly impaired, the older norms may not detect the more subtle memory impairment.

The Spatial Addition task seems as if it would be too confusing for impaired or elderly patients. If you are testing patients with Alzheimer’s disease, can they understand the task and get a scoreable response?

The Spatial Addition task is for examinees, ages 16–69 years, who are taking the Adult Battery. Many of the examinees classified as Probable Dementia in the Alzheimer’s Type group were administered the Older Adult Battery and did not have the opportunity to take Spatial Addition. The Mild Cognitive Impairment group did not have difficulty understanding the task and producing scoreable responses. If an examinee is younger than age 65 and has difficulty understanding the task due to severe dementia, they most likely will have difficulty throughout much of the evaluation. In the moderate and mild intellectually disabled groups, the VWMI, which Spatial Addition contributes to, was consistent with their overall working memory abilities and General Ability.

Why does WMS–IV focus on Visual Working Memory with out Verbal Working Memory?

A development goal for the WMS–IV was to avoid overlapping modalities and constructs with the WAIS-IV. The working memory tasks in the WAIS-IV require greater verbal demand thus the WMS–IV working memory focuses on a visual modality.

I test low functioning individuals who appear to have difficulty completing the WMS–IV tasks. Is the WMS–IV appropriate for this population?

The WMS–IV showed good clinical utility, reliability, and concurrent validity during standardization, particularly in clinical groups. Although individuals express difficulty with these subtests, even moderately impaired individuals were able to complete some of the items, particularly on Designs. The Designs subtest is perceived by many individuals to be difficult specifically because the stimuli are difficult to verbalize. The language centers of the brain naturally want to name objects to ease encoding and thus invoke verbal memory processes to aid visual memory functioning. The Designs subtest has multiple items of varying difficulty subsequently it is not difficult for examinees to get some points. The examinee may need to be encouraged to try even though it seems difficult. Interestingly, the intellectually disabled (mild and moderate) had some of their best scores on the Designs subtest. On Spatial Addition we did not see very many 0 scores during standardization so even very impaired people were completing the task correctly on early items, they just tended to discontinue earlier.