The Wechsler Memory Scale

A Guide for Clinicians and Researchers

Phillip Kent

• Publisher: Routledge
• Year: 2020
• ISBN:
  9781000047158
• Edition: 1
• Topic: Psychology
• Subtopic: Neuropsychology
• Index: Psychology

The Wechsler Memory Scale (WMS) is one of the most popular memory scales in the United States and much of the English-speaking world. This is the first book to systematically trace the evolution of the instrument in terms of its content and structure, whilst providing a guide to clinical interpretation and discussing its many research uses.

The Wechsler Memory Scale: A Guide for Clinicians and Researchers provides a comprehensive review and synthesis of the literature on all the major editions and revisions of the WMS, including the Wechsler Memory Scale-I, Wechsler Memory Scale-Revised, Wechsler Memory Scale-III, and the Wechsler Memory Scale-IV. It discusses major factor analytic studies of each version of the test, clinical interpretation of each version including studies on malingering, uses of each version with special populations, and makes suggestions for the next revision (i.e, the WMS-V).

This book is designed to be a go-to source for all graduate students, clinicians and researchers who use the Wechsler Memory Scale, as well as to institutions offering formal training in adult clinical and neuropsychological assessment.

Chapter 1
Methodology

In conducting background research for this book, multiple literature searches were completed using APA PsychNET Gold for the following periods: 1945–1949, 1950–1959, 1960–1969, 1970–1979, 1980–1989, 1990–1999, 2000–2009, and 2010–2018. Three types of searches were conducted for each period. The first procedure was Wechsler Memory Scale: Any Field and Years; the second procedure was Wechsler Memory Scale: Abstract and Years; and the third procedure was Wechsler + Memory + Scale: Abstract and Years. The searches yielded the following results (see Table 1.1).

Table 1.1 Research Protocol

Years Surveyed	Procedure 1 WMS:Any Field & Years	Procedure 2 WMS: Abstract & Years	Procedure 3W+M+S: Abstract & Years
1945-1949	1 1	7	3
1950-1959	40	25	18
1960-1969	55	26	17
1970-1979	178	116	105
1980-1989	563	491	343
1990-1999	1,025	911	535
2000-2009	5,985	819	461
2010-2018	12,073	833	380
Total	19,930	3,228	1,862

As can be seen from Table 1.1, the correspondence is fairly close between the numbers of potential references identified using the first two procedures for the years 1945–1999. During this period, 1,872 potential references were identified using Procedure 1 versus 1,576 using Procedure 2. Once we get to the year 2000 and beyond, the relationship breaks down. For the years 2000–2009, 5,985 potential references were identified using Procedure 1 versus 819 using Procedure 2. And the difference for the years 2010–2018 was even greater: 12,073 potential references were identified using Procedure 1 versus 833 references using Procedure 2. The reasons for the dramatic differences in these literature searches are not clear, but may be partially due to the increase in neuroscience research during this period.

Procedure 2 identified fewer potential references than did Procedure 1 for each period, because with the latter, although the terms Wechsler Memory Scale needed to appear anywhere in the abstract, the term Wechsler could refer to any Wechsler test, memory to any type of memory, and scale could identify a particular test or method of analysis.

It is only with the use of Procedure 3 that the most pertinent results were obtained. However, this procedure has the potential for under-identifying potential references since the WMS may have been used as an investigatory tool not referenced in the abstract. In addition, Procedure 3 identified irrelevant potential references, such as in the situation where the author of the publication described a scale as “like the Wechsler Memory Scale” but did not actually use the WMS in the study.

All abstracts for all publications identified using all three procedures for the years 1945–1999 were read to identify pertinent references. A pertinent reference was defined as one in which the Wechsler Memory Scale was used in a study that was in accordance with the goals of the present project. If a potential reference was not available in English, the article was excluded from consideration. Articles were also excluded if they did not contain enough information from which conclusions could be drawn.

For the years 2000–2018, the author read all the abstracts of potential articles identified using Procedures 2 and 3 to ascertain which were relevant to the present project. It was not feasible to read abstracts of all potential references obtained by Procedure 1 due to the sheer volume of the publications identified (18,058). Using the results of Procedure 3 as a rough guide, the author estimated that over 95% of the articles identified using Procedure 1 would not be relevant to the current project.

About 100 additional references were obtained through Googling “Wechsler Memory Scale,” completing an additional APA PsychNET Gold search for the first six months of 2019, searching for pertinent references on the Research-Gate and Academia websites, and obtaining pertinent references cited in various publications.

Although the aforementioned procedures did not identify all published research papers that could be pertinent to the present endeavor, it is felt by the present writer that they identified a representative sample of them, as APA PsychNET is the premier database used by psychologists and other behavioral researchers. Although the methodology used to identify pertinent references for this book was not exhaustive, it was felt to be comprehensive enough to accomplish the goals of this book.

Chapter 2
A History of the Origins and Evolution of Wechsler’s Memory Scales

The purpose of this chapter is to provide an overview of the evolution of the content and structure of the Wechsler Memory Scale and a critique of each version. As we shall see, evolution has not always resulted in improvement. Since the purpose of this chapter is to provide a broad overview, it will not discuss the content of the subtests in detail.

Despite the fact that the Wechsler Memory Scale is presently in its fourth edition and the publisher is in the process of preparing a new edition, which is expected to be released in the next two to three years, all prior editions of the test remain in use. Because of this, it is important for the clinician and researcher to know how the version of interest relates to other versions, especially past versions. This is also important since the test publisher has often cited research on prior versions to support the validity of new revisions. In addition, in the real world, it is not uncommon for a clinician to have test results on a patient from a prior version of the test that have to be compared to test results from a more recent revision. Understanding the content and limitations of each test version and the continuities or discontinuities between test versions is important for valid assessment and making inferences about suspected changes in memory functioning.

Sound evidence-based psychological and neuropsychological assessment includes knowledge of the each test’s reliability, validity, and shortcomings (Bowden, 2017a; Matarazzo, 1990) and a working knowledge of the research regarding the test. In addition, it involves considering the quantitative and qualitative information regarding the subject at hand and having a good working knowledge of psychological measurement, neurology, neuropsychology, and general psychology (Ardila, 1992; Matarazzo, 1990; Wechsler, 1939). As many researchers have pointed out, test scores in themselves do not mean much. A specific configuration of scores on a test can imply vastly different clinical conditions, depending upon the background and presenting symptoms of the person being evaluated. For instance, on the Minnesota Multiphasic Personality Inventory, peak scores on scales 4 and 9 can be manifested by (1) a person with an antisocial personality; (2) a person with a mood disorder; (3) a person with a substance disorder; (4) a person with a head injury; or (5) a person with any combination of these disorders. Without knowledge of the background of the person taking the test, a computerized interpretation of this configuration may result in an invalid assessment, with all due respect to Meehl (1954). When assessing people, it is important to take into account quantitative and qualitative information, and sometimes the latter trumps the former (Wechsler, 1939).

The Wechsler Memory Scales I and II

Although the Wechsler Memory Scale-I was officially introduced to the profession in 1945, it has been in clinical use since 1940 (Wechsler, 1945). Since Wechsler reported that the WMS-I was the result of 10 years of experimentation, it can be assumed he began work on the scale in approximately 1930, about the same time he began work on the Wechsler Bellevue Intelligence Scale (Wechsler, 1939).

The Wechsler Memory Scale has been officially revised three times (Wechsler, 1987, 1997, 2009a). The original scale and all official revisions have remained in research and clinical use well into the second decade of the 21st century, although the first three versions of the test are not officially available from the publisher. Regardless of what one thinks about the original instrument and its revisions, this is a remarkable achievement and points to the perspicacity of Wechsler in identifying many of the fundamental elements needed to conduct a valid clinical assessment of memory.

Although the Wechsler Memory Scale-I (WMS-I) formally appeared in 1945, the origins of the scale can be traced back to 1917. In 1917, Wechsler published a paper based on his master’s thesis at Columbia University titled “A Study of Retention in Korsakoff Psychosis.” For this study, Wechsler developed a test battery to evaluate the nature of this disorder. According to Wasserman (2012), Wechsler patched together a clinical memory battery from existing published and unpublished tests, following a framework suggested by Whipple (1915). According to Boake (2002), some of the subtests were derived from the Cornell-Coxe Performance Ability Scale (Cornell & Coxe, 1934). The 1917 test battery contained (1) a screening questionnaire to assess personal and current information and orientation; (2) measures of auditory and visual-spatial attention; (3) a measure to assess the encoding and recall of easy and hard verbal word pairs; (4) a measure of the learning and recall of two lists of 10 unrelated words and two lists of 10 related words; and (5) measures of immediate and delayed recall ranging from 15 seconds to 10 minutes (Wechsler, 1917). Several components of this memory battery were incorporated into the WMS-I (Kent, 2013). Thus, as early as 1917, Wechsler realized the importance of screening for possible disorientation that would affect the validity of his assessment procedure; of assessing attention apart from learning; and of assessing immediate and delayed recall. It is significant to note that all versions of the WMS assess attention, learning (recall based on repeated trials), and memory (recall after a single presentation).

Some components of the WMS-I were also derived from a table that appeared in Wechsler’s original book on the Wechsler Bellevue Intelligence Scale (Wechsler, 1939). In this book, he presented a review of the literature summarizing how various diagnostic groups had performed on standard psychological tests then in use. As a result, the scale’s construction could be described as an early example of evidence-based practice.

The original publication describing the WMS-I (Wechsler, 1945) runs a scant nine pages and provides no information regarding the scale’s reliability and validity, nor does it provide detailed instructions on how to clinically interpret the test results. The original scale contains questions derived from standard mental status exams of the day that screened people for suspected aphasia, dementia, and disorientation (the Personal and Current Information and Orientation subtests). In addition, it has measures of attention and working memory (the Mental Control and Memory Span subtests), and encoding (the Visual Reproduction, Logical Memory, and Associate Learning sub...