ASSIGNMENT 2 – RIGHT HEMISPHERE STROKE

ANNOTATED LECTURE NOTES

What follows is a written version of the material presented in lectures and the residential schools designed to aid you in mastering this material.

Three types of information are presented: the introductory background material for the case; information regarding the tests that have been utilized in the assessment; and the testing results along with the standardization tables necessary to interpret them. I shall proceed in the order in which the information is presented in the assignment. The first thing we need to consider is the introduction to the assignment and what it reveals about this gentleman:

· He is a 56-year-old white male (at the time of the first testing).

· He is an architect (suggesting completion of 16 years of formal education).

Note that the assessments are conducted in the context of difficulties he has been experiencing since returning to work.

Regarding the injury:

· He suffered a cerberovascular accident (stroke)

· Stroke occluded the right middle cerebral artery.

· He had left sided immobility which has lessened to a weakness and “pins and needles” primarily in the left arm.

His colleagues report that he has problems with:

· Memory

· Drawing

The data for only two tests have been provided. This would constitute a poor assessment if these were the only tests administered but the data presented is sufficient to enable you to test the hypotheses generated and get a taste for the psychological assessment interpretative process.

The Wechsler Adult Intelligence Scale – 3^rd Edition (WAIS-III) and the Wechsler Memory Scale – 3^rd edition (WMS-III) have been administered and some of the test scores from the initial and follow-up assessments have been provided.

THE WTAR

Data has also been provided based on the Wechsler Test of Adult Reading which can be combined with demographic data to predict WAIS-III and WMS-III scores. Examination of this measure is not strictly necessary to complete the assignment (but the values it predicts certainly are), but this measure would be commonly employed in cases of this type to estimate premorbid or expected level of cognitive functioning.. The WTAR consists of progressively more difficult words which must be read aloud by the test-taker. Reading tests have been commonly employed to estimate IQ scores. As the words are roughly in order of reading grade level, those who have not been exposed to certain words will not know how to pronounce them. Thus performance on the test is a measure of the degree to which you have been exposed to infrequent or irregular words in the English language, something which is highly correlated with the number of years of formal education one has had. Some of the original studies with measures of this type have indicated that, perhaps with the exception of severe impairment, declines in cognitive functioning are NOT accompanied by declines in performance on reading tests. Many clinicians therefore use the measure as a way of examining word knowledge with the expectation that whatever problem you may have, has had little impact upon test performance. This is a round about way of saying that it is often used as an estimate of your abilities before you began suffering from your current difficulty. Individuals hypothesized to be currently experiencing a decline in cognitive functioning could be recognized as such by comparing where they should be based upon their WTAR + Demographic scores with where they are now! More about this later!

THE WAIS-III

The WAIS-III is a cognitive/intellectual battery of tests designed to assess a variety of cognitive domains. Most notable in the battery is the omission of tests that evaluate memory beyond that of short-term recall. The battery consists of 14 subtests only 13 of which are customarily administered. The Object Assembly subtest has been included in the third edition of the battery to maintain consistency with its predecessor (the WAIS-R) and to permit the substitution of this test for a spoiled Block Design performance. In the case that you will be analyzing no data for Object Assembly has been provided.

The nature of the subtests will be discussed shortly, but analysis of the WAIS-III focuses primarily around composite scores. Composite scores are combinations of subtests according to a particular theoretical framework. The two types of composites on the WAIS-III are IQ scores (which are based upon an historical framework) and Index scores (which are based upon an empirical framework). One of the things that can be somewhat confusing about the WAIS-III is that subtests are combined in ways that are similar but not identical for the two frameworks described. Let’s consider the IQ framework first.

David Wechsler, the developer of the Wechsler batteries conceived of his test as a measure of overall cognitive/intellectual ability in the form of a score that included all of the subtests on the battery, the Full Scale Intelligence Quotient (FSIQ). This FSIQ could be divided into two sub-categories, the Verbal Intelligence Quotient (VIQ) which encompassed those measures that were administered verbally and required verbal responses, and the Performance Intelligence Quotient (PIQ) which encompassed those measures that were administered visually and usually required a written, pointing, or object-manipulation response. So essentially, FSIQ represents an overall indication of performance and VIQ and PIQ are subdivisions that relate to the mode of input and output of information. This framework has been retained in the WAIS-III with IQ scores computed from the measures that have been traditionally used for this purpose.

Factor analysis of the WAIS-III, however, reveals that rather than a dichotomous verbal and visual structure to the battery, four abilities or constructs are actually measured by the test. This factor structure forms the basis of the four Index scores. The Verbal Comprehension Index (VCI) consists of those subtests that best measure verbal comprehension and expression. The Perceptual Organization Index (POI) consists of those subtests that best measure an individual’s ability to process complex visual information and solve problems – in some ways a non-verbal reasoning measure. The Working Memory Index (WMI) consists of those subtests that best measure attentional abilities and the degree to which an individual can efficiently perform mental operations. The Processing Speed Index (PSI) consists of the subtests that best measure speeded visual information processing - these measures all involve scanning of visual information and the rapid writing of responses on a page.

As you are well aware, the more items that are included on a scale the higher the reliability is likely to be. Examination of the numbers of subtests that are included in each of the IQ and Index scores (in the table below) would appropriately suggest that higher internal consistency is found in composites that contain more subtests. Our approach to analyzing psychological test data is to proceed in a hierarchical fashion from the most reliable measures and work our way down to the least reliable measures. This means beginning with FSIQ, proceeding to VIQ and PIQ, then to VCI, POI, WMI, and PSI, and finally to the individual subtest level should this prove necessary.

The following is a general description of each of the WAIS-III subtests:

Vocabulary

This subtest presents 33 words orally to the test-taker and requires them to supply a dictionary style definition. It is the most reliable subtest in the scale and is the best measure of g (69% of its variance). It contributes to FSIQ, VIQ, and VCI composites and is generally considered a measure of word knowledge. This measure is heavily influenced by formal education and literacy.

Similarities

This subtest consists of 19 word pairs. The test-taker’s task is to indicate how the two words are similar. More points are awarded for a more abstract relationship. It contributes to FSIQ, VIQ, and VCI composites and is generally considered to be a measure of relational word knowledge. This measure is strongly influenced by education and literacy.

STRUCTURE OF WAIS-III COMPOSITE SCORES

No. of Subtests: 14

VIQ Subtests: (Number of Items)

Information (28)

Digit Span (15)

Vocabulary (33)

Arithmetic (20)

Comprehension (18)

Similarities (19)

PIQ Subtests:

Picture Completion (25)

Picture Arrangement (11)

Block Design (14)

Digit Symbol-Coding (133)

Matrix Reasoning (26)

FSIQ = VIQ subtests + PIQ subtests

Factor Indices:

Verbal Comprehension

Information (28)

Vocabulary (33)

Similarities (19)

Perceptual Organisation

Picture Completion (25)

Block Design (14)

Matrix Reasoning (26)

Working Memory

Digit Span (15)

Arithmetic (20)

Letter-Number Sequencing (7)

Processing Speed

Digit Symbol-Coding (133)

Symbol Search (60)

Arithmetic

This subtest contains 20 items requiring progressively more demanding mental arithmetic. Factor analytic studies indicate that despite the arithmetic content that this is most commonly a measure of attention or working memory. This does not mean that people with dyscalculia or specific learning disability in arithmetic will not perform poorly on this measure. The content of the subtest requires mastery of relatively simple mathematical procedures such as percentages, averages, and probability. Consequently the influence of education on this subtest is greater than for the other measures that contribute to the Working Memory Index. This measure is included in the computation of FSIQ, VIQ, and WMI composites.

Digit Span

This subtest also contributes to FSIQ, VIQ and WMI composites. The Digit Span task is the prototypical immediate memory or attentional task. On Digits Forwards, test-takers are required to repeat up to eight-digit sequences back in correct order as they were presented. The Digits Backwards task requires the digit sequences to be repeated back in reverse order. It is this second task that is, perhaps, more appropriately termed working memory as mental juggling of the number sequence is required to successfully complete the task. Characteristically, individuals recall on average 2 nire digits forwards than backwards. Less than 4% of the standardization sample recalled more digits backwards than forwards.

Information

This 28 item subtest measures general knowledge through a broad range of questions about science, literature, geography, and historical events. This measure is highly correlated with educational achievement. This subtest contributes to FSIQ, VIQ, and VCI.

Comprehension

This 18 item subtest asks questions about social knowledge and awareness of socially appropriate behaviours and responses. A critical issue with this test is that it does not ask what you would do in a particular situation but rather what should you do. Similarly it asks not why you think something is so, but what we are taught are the reasons behind issues such as taxation, or the importance of a free-press. This subtest contributes to FSIQ, and VIQ. It does not contribute to any factor indices

Letter-Number Sequencing

This subtest contains seven items with three trials for each item. In some ways it is similar to Digits Forwards from the Digit Span subtest. In each trial the examinee is read a series of number and letters that have been placed in a random order. The examinee is required to reorder the numbers and letters and repeat them back in the correct ascending sequence with numbers first followed by letters. This subtest contributes only to the WMI composite. It does not contribute to any IQ scores.

Picture Completion

This subtest consists of 25 colour drawings of objects, people, and scenes where an important element is missing. The examinee is required to indicate what important element is missing from the picture. This subtest contributes to FSIQ, PIQ, and POI composites.

Digit Symbol-Coding

This subtest consists of a maximum of 133 items. The examinee is presented with a table containing the numbers 1 through 9 and symbols (simple line drawings) that are associated with each number. A template which contains 133 numbers (1 through 9) in a random sequence where the numbers are presented but the associated symbols have been omitted is presented to the examinee. Beginning with the first item, the examinee must fill-in as many symbols that go with each number in sequence in a two minute period. This subtest contributes to FSIQ, PIQ, and PSI composites.

Block Design

This subtest utilizes up to 9 blocks each with 2 red surfaces, 2 white surfaces, and 2 half red/half white surfaces. These blocks are employed by the examinee to replicate a design presented as a two-dimensional picture. Examinees manipulate the blocks and put them together in such a way so as to produce the same design with the top surfaces. The designs become progressively more complex and go from requiring 4 blocks to all 9 blocks in order to replicate the design.This subtest contributes to FSIQ, PIQ, and POI composites.

Picture Arrangement

This subtest consists of 11 series of line drawings that when placed in the correct order tell a story (allegedly humorous, but clients seldom laugh). The drawings are laid out in front of the examinee in an incorrect order and the examinees task is to reorder them in the correct arrangement. This subtest contributes to FSIQ, and PIQ composites. It does not contribute to any factor indices.

Symbol Search

This subtest was taken directly from the WISC-III and requires the examinee to look at two symbols and determine whether either symbol is present in a sequence of five symbols. There are 60 items each with two target and five test symbols. The examinee is required to verify the presence or absence of the symbols in as many items as they can in two minutes. This subtest contributes only to the PSI composite. It does not contribute to any IQ scores.

BACK TO THE CASE

When interpreting WAIS-III, WMS-III, or any psychological test data for that matter we proceed from the most reliable to the least reliable measures. This approach protects the clinician from being biased by an interesting, unusual, abnormal BUT unreliable finding. The most reliable measures are less prone to random variations and our decisions are more likely to be accurate if we base our interpretations on them. Now it’s time for me to get on to my soapbox. I will make a statement now that will seem radical but is eminently defensible through logic and basic psychometric principles. Measures of intelligence have no meaning in a clinical evaluation. This is not because the construct of intelligence does not exist (although I have seen little evidence to support it in my career) but rather that the measurement of intelligence necessarily presupposes that the individual being assessed is normal! Said another way, when you know that someone is normal then a test of intelligence may indicate that individual’s ranking relative to other normal individuals. This is not, however, the case when we use these tests in the clinical setting. Clinically, the Wechsler scales utilize tests of different cognitive abilities that are of interest to the clinician. In this context, scores such as Full Scale Intelligence Quotient (FSIQ), Verbal IQ (VIQ), and Performance IQ (PIQ) cannot be construed as measuring intelligence in any way. To believe so would be to infer that a blind person is of low intelligence (VIQ = 100, PIQ = 47, FSIQ =74) (when it’s just that they can’t see any of the Performance subtests), a deaf person is of low intelligence (VIQ=48, PIQ= 100, FSIQ = 68) (when it’s just that they can’t hear the Verbal subtests), and a dead person is just profoundly intellectually impaired (VIQ = 48, PIQ = 47, FSIQ = 45). This last little gem is a consequence of the fact that despite the fact that the dead individual makes no responses to any of the questions receiving a raw score of 0 on every subtest, the scaled score associated with a raw score of 0 is 1 (surprisingly not 0). With 11 subtests constituting FSIQ, a dead person (or any inanimate object for that matter) receives a sum of scaled scores of 11 which corresponds to a FSIQ of 45.

So, having convinced you of the evils of the pragmatics of intelligence theory, what do FSIQ, VIQ, and PIQ mean? Good question. In the context of clinical assessment FSIQ represents overall performance on the majority of subtests. It functions essentially as a grand mean. It is of value to us because it has the highest reliability and has the potential for representing overall performance on the test. However, just as a grand mean may not actually be representative, we look to sub-grouping of tests to determine whether the FSIQ is representative or not. VIQ and PIQ divide the subtests into two groupings based upon their input and output modalities. VIQ subtests are all administered verbally by the tester and answered verbally by the test-taker. PIQ subtests are all administered using visual stimuli and the test-taker can respond by pointing, writing, or manipulating objects. Two PIQ subtests may also involve giving verbal responses (Picture Completion and Picture Arrangement) but the scoring of each of these tests does not rely on a verbal response. These sub-groupings are historical rather than empirical. By this I mean that the existence of VIQ and PIQ as scores was based upon David Wechsler’s belief that these divisions would be meaningful and not based upon research findings that support this distinction. Empirical studies (factor analyses) of the WAIS-III in fact support four composites or indices and these form the true basis of interpreting the WAIS-III in the clinical setting. What is lucky for us is that the four constructs, in principle, reflect a sub-grouping of each of VIQ and PIQ into two smaller divisions. I say, in principle, because in each case one of the subtests omitted from the IQ score is included in an index score. Letter Number Sequencing is omitted from VIQ but is part of WMI, and Symbol Search is omitted from PIQ but is part of PSI. In turn, while Comprehension and Picture Arrangement are included in VIQ and PIQ respectively, they are not utilized in any of the index scores.

So in proceeding from the most reliable to the least reliable measures we begin with FSIQ, proceed to VIQ and PIQ, and then to the Index scores VCI, POI, WMI, and PSI. After, and only after, that you can proceed to consider individual subtests if they address relevant hypotheses or in order to examine the integrity of index scores.

Enough chatting, let’s begin looking at the table below. The primary purpose here is to teach you how to read the information in the tables. Consistent with the approach described above let’s start with FSIQ. Mr. Adams obtained a FSIQ Standard Score (SS) of 106. The next column, headed %ile, indicates the relative ranking of this score in the standardization sample. Standard scores have a mean of 100 and a standard deviation of 15, so this score is under half a standard deviation above the mean which corresponds to the 66^th percentile. How would we say this in language understandable to more people than just myself and any other unfortunate soul who lives and breathes psychometrics? Standard scores are all age-adjusted so we could describe this as “Mr. Adams’ overall level of cognitive functioning is estimated to fall within the Average range and is as good as or better than 66 percent of people of his age.” Where did I get the “Average” statement from? The table titled “WAIS-III QUALITATIVE DESCRIPTIONS FOR IQ SCORE RANGES” in “TABLES TO ASSIST IN ANALYSING TEST DATA FOR THIS CASE” which accompanies the assignment.

The next two columns contain information regarding the 90% confidence interval at the time of testing. There are two numbers the low end of the range (Lo) and the high end of the range (Hi). These numbers tell us the range in which we can be 90 percent sure that this person’s true ability lies. Remember that the score you compute on a psychological test is just an observation. We need to determine the range in which the underlying ability we are trying to measure is likely to truly fall. This is never one score but a range of scores. So while Mr. Adams obtained a FSIQ of 106, these two columns tell me that I can be 90% sure that the score of 106 reflects an ability somewhere between 102 and 109.

The last two columns contain the 90% confidence interval for a score on that measure at retest. The Lo and Hi columns indicate the lower and upper limits of the range. So we can be 90% sure that because Mr. Adams got a FSIQ of 106 at his initial testing that when we retest him it should fall somewhere between 101 and 111. The implication of this is that if we tested Mr. Adams some time later and he got a FSIQ of 101 or less or 111or more we would have direct evidence that his score has changed (declined if 101 or less, or improved if 111 or more). As you can see these last two columns would only be used if a second testing had been performed – more on this later!

Test – 90%CI Retest – 90%CI

IQs SS %ile Lo Hi Lo Hi

Verbal 115 84 110 119 109 121

Performance 94 34 89 100 86 103

Full Scale 106 66 102 109 101 111

Test – 90%CI Retest – 90%CI

Indices SS %ile Lo Hi Lo Hi

VCI 112 79 107 116 105 118

POI 95 37 89 101 86 104

WMI 104 61 98 109 95 112

PSI 88 21 82 97 78 101

So, with the information above we can describe Mr. Adams’ performances on the three IQ measures and four index scores of the WAIS-III indicated in the table above. Remember that only other psychologists are going to know all this jargon, so rather than referring to VCI you would talk about a measure of his verbal comprehensive and expressive abilities. Rather than WMI you would say something like a measure of attention, concentration, and the ability to efficiently perform mental operations.

Now the next topic relates to the detection of abnormality in the profile of scores and uses the two tables below. We have already discussed the idea of FSIQ reflecting Mr. Adams’ overall level of functioning. To test this idea we need to consider that FSIQ may not be made up of 11 homogeneous test scores but rather systematic differences that average out to the FSIQ score. The first way of addressing this is to examine the subsets of FSIQ, VIQ and PIQ. If VIQ and PIQ differ significantly, then FSIQ does not represent a homogeneous level of functioning. VIQ for Mr. Adams is 115, and PIQ is 94. The difference between these two measures is (115-94) 21. If we consult the table of significant differences between WAIS-III composite scores for Mr. Adams’s age group we find that a 7.90 difference would be significant at p=.05. The 21 point difference is greater than this so we can assert that VIQ and PIQ differ significantly.

Differences Between WAIS-III IQ Scores and Between Index Scores Required for Statistical Significance at the .05 Level for the 55 to 64 Age Group

	VIQ – PIQ	VCI – POI	VCI – WMI	POI – PSI	VCI – PSI	POI – WMI	WMI – PSI
p=.05	7.90	8.54	9.08	11.53	10.91	9.81	11.93

But what does this mean? A test of significance is testing the likelihood that the two scores came from the same distribution. Do not be swayed by the apparent size of the difference. Just looking at the significance table for the different WAIS-III composites shows differing values from 7.90 to 11.93. These values are different because of the differences in reliability of the measures involved. The more reliable and the more inter-correlated two measures are, then the less a difference needed for significance. Just remember that good reliability results in things being more easily detected and poor reliability results in things being much harder to detect. Back to our original question here, what does it mean that VIQ and PIQ are significantly different? The easiest way to understand this is to turn it around. What is the null hypothesis? That VIQ and PIQ are identical (no difference between them). A significant difference means we reject the null hypothesis and infer that the two numbers are not the same. Nothing more, nothing less. Knowing that VIQ is significantly different from PIQ means that we can infer that Mr. Adams has different verbal and visual/graphomotor abilities (remember VIQ and PIQ reflect the modalities of the tests). We can say one more thing – knowing that VIQ and PIQ are significantly different and that VIQ is the bigger number (115), we can say that Mr. Adams’ verbal abilities are better than his visual abilities.

Disappointed? Hoping for more? What you really probably wanted to know was whether or not the difference is clinically meaningful! This is not addressed by significance (although this is not always true) but rather by abnormality. We address abnormality by doing a “head-count”. This is the testing equivalent of asking “OK! Hands up all those people who did …”. How common is a 21 point difference between VIQ and PIQ in a person who has a FSIQ in the Average range. That question can be answered by the table below – 2.9% of the standardization sample.

One-Tailed Frequencies of Differences Between WAIS-III IQ and Index Scores for Individuals with FSIQ of 90 to 109

	Difference	Frequency
VIQ – PIQ	21	2.9%
VCI – POI	17	9.1%
VCI – WMI	8	27.9%
POI – PSI	7	31.4%
VCI – PSI	24	5.6%
POI – WMI	-9	24.5%
WMI - PSI	16	13.7%

This raises the next big question – how rare is rare? All clinicians who use psychological tests have to ultimately make a decision about this. I can tell you what I recommend here and why. Other decisions are not wrong but like anything else in life there are consequences to what we decide. For tests of significance I use p<.05 as the standard for a statistically significant difference with a two-tailed test. For abnormality, I recommend that you consider that anything that occurs with a frequency of 1 in 10 or less (10%) is sufficiently rare to call the behaviour abnormal. Personally I use a more strict criterion of (5%, 1 in 20) but the assignment has been put together based upon an abnormality criterion of 10%. One other comment here, abnormality refers only to infrequency or rarity of the behaviour, it does not tell you whether or not the behaviour is impaired. For example, an accountant is likely to be highly skilled at mental arithmetic so his score on the WAIS-III Arithmetic subtest is likely to be abnormally higher than other scores. This abnormality will be detected during data analysis, but does not signal impairment. Some abnormalities are good – we call them skills, some abnormalities are bad - we call them deficits. You will need to determine when an abnormality is signaling skill versus impairment. The final criterion is the confidence interval applied to test scores. I use 90% confidence because I am happy to have an error rate of 5% at either end of the distribution. Too lax a criterion (68%) will result in too narrow a band of scores while too strict a criterion (99%) will result in a band that is too wide to be of use (i.e. I can be 100% sure that the FSIQ score you got on the test was somewhere between 45 and 155! Well, duh!).

A second point. Some people (not me, but you know, “other people”) might ask: If we care about abnormality so much, why don’t we go straight to those tables and leave out the test of significance? Ahhhh, the impetuosity of youth! Remember, the score we obtain on the test is only a sample of behaviour from the individual. It is no more necessarily characteristic of that individual than your blood pressure at midday is representative of your blood pressure overall. There will certainly be a relationship, but this is why we have confidence intervals – to tell us the likely range in which a person’s score is likely to fall when we have only one observation. So when we ask if a VIQ of 115 and a PIQ of 94 are significantly different we are implicitly taking into account the less than perfect reliability of our measurement. Although this does not make it easier, it is understandable if we stop talking about scores as if they are real things. The question we are really asking is: How likely is it that a VIQ which I am 90% sure falls somewhere between 110 and 119 is the same level of performance as a PIQ which I am 90% sure falls somewhere between 89 and 100? Since the 21 point difference is greater than that necessary to meet our criterion of significance we reject the null and assert the two scores are different. However, if the difference had not been significant we would have accepted the null and asserted that for all intents and purposes the difference is 0 (i.e. we cannot reject the null hypothesis). So what does this have to do with the point? When we look up how frequent a difference is (like 21) it is based upon the assumption that 21 is the right number to reflect the difference! The significance test, in this case for VIQ and PIQ, tells us that 21 is the best estimate of the difference between the two measures. If it had not been significant then 0 would be the best estimate of the difference. Consequently when the test of significance indicates a non-significant finding you do not know what difference value to look up – it certainly is not 21 and probably should be 0! When we do find a significant difference as with VIQ and PIQ in the case of Mr. Adams then the 21 point difference (which exceeds the critical difference of 7.90 necessary for significance) is assumed to be the best estimate of the difference between these two measures, and we happily look up the frequency of a difference of 21 between VIQ and PIQ and find that it is rare – 2.9%! What this all leads to a simple rule: If the difference is significant then look up the frequency of the difference! If the difference is not significant DO NOT look up the frequency of the difference – it is not abnormal! You will note that despite this rule I have still supplied you with the frequencies for all differences – this is a trap and is designed to prevent you from assuming that the only information I provide is meaningful!

We now repeat this process for the Index scores of the WAIS-III. Six comparisons can be made: VCI with POI, VCI with WMI, VCI with PSI, POI with WMI, POI with PSI, and WMI with PSI. Essentially we are looking for significant differences to indicate where performance levels differ and then for those, AND ONLY THOSE, statistically significant differences we then examine the frequency of the difference in order to detect abnormal differences. Note that many of the comparisons are statistically significant, indicating that this individual has distinctly different performance levels for each of the cognitive domains assessed on the WAIS-III: verbal comprehension, visual organization, attention/concentration, and speed of information processing. Notice also that some of the comparisons with VCI are associated with frequencies of less than 10% in the standardization sample. This is revealing a consistent pattern – Mr. Adams’s visual organizational abilities (POI) and processing speed (PSI) are abnormally lower than his verbal abilities (VCI).

The next table, below, can be used to examine the individual subtests for relative strengths and weaknesses. The reasoning behind this analysis goes as follows. A relative strength is a performance on a subtest that is comparatively higher than other subtests. Similarly a relative weakness can be seen on those measures that are comparatively lower relative to other measures. Each subtest is usually compared to the mean of subtests. The question is how do we compute the mean? This goes back to the discussion regarding the representativeness of FSIQ. Simply put, if there is no difference between VIQ and PIQ then the average of all the subtests administered can be used and comparisons are made with the rightmost columns (All Subtests). If there is a difference between VIQ and PIQ (as in this case) then separate means are computed for verbal and performance subtests and separate comparisons are made for verbal and performance subtests (Leftmost and middle columns). Please note that this table differs slightly from the one included with your assignment. Your assignment table lists the abnormality criterion for 5%. The table below provides the frequency of differences found in 10% of the population as this is the criterion we are using in this assignment.

The mean for the seven verbal subtests is 11.9. We now compare each verbal subtest with this mean. Subtracting the mean from each of the subtests yields a pattern of positive and negative difference scores. A positive value means that the subtest is above that individual’s mean score, while a negative value indicates a lower performance. Comparison of these differences with those in the table above indicate which subtests are significantly different from their respective means. Note that the leftmost ands middle columns are used in this case because VIQ and PIQ differ significantly. The first thing you are looking for is whether or not each number differs significantly from it’s mean, indicated by an absolute difference greater than or equal to the cut-scores indicated in the table (in this case because they are verbal tests, column 2). For those measures that are significantly different from their respective means, those that are positive are “relative strengths (S)” and those that are negative are “relative weaknesses (W)”. These findings can be used to describe where Mr. Adams’ strengths and weaknesses lie in terms of the behaviours assessed by each subtest. Only one measure differs significantly from its verbal mean, Letter Number Sequencing which falls 3.9 points below the verbal mean. This difference exceeds the critical value for this subtest of 3.16. For this reason we refer to Mr. Adams’ ability to retain and manipulate sequences of numbers and letters as a relative weakness.

Differences Between Single Subtest Scaled Scores and Mean Scaled Score at the .05 Level of Statistical Significance and Magnitude of Difference Found in 5% of the Standardisation Sample

	Verbal	Subtests	Performance	Subtests	All	Subtests
Subtest	p<.05	10%	p<.05	10%	p<.05	10%
VO	2.10	2.43			2.30	2.77
SI	2.77	2.79			3.12	2.96
AR	2.63	3.00			2.95	3.27
DS	2.40	3.71			2.67	3.85
IN	2.34	2.71			2.59	3.04
CO	2.96	2.86			3.35	3.15
LNS	3.16	3.43			3.60	3.62
PC			3.16	3.14	3.46	3.69
CD			3.04	3.57	3.31	3.88
BD			2.94	3.00	3.19	3.38
MR			2.60	3.14	2.75	3.23
PA			3.75	3.43	4.19	3.77
SS			3.54	3.14	3.93	3.46

You can also refer to column 3 to see how unusual or infrequent a significant difference is. For example the significant weakness in Letter-Number Sequencing of 3.9 points exceeds the score associated with 10% of the population (3.43) and thus we can infer that not only is this subtests a weakness for Mr. Adams but it is an abnormally large discrepancy and does not reflect normal range variation. Note also that Mr. Adams has a significant and abnormal strength in Matrix Reasoning when looking at his performance subtests.

The table below shows the working for the subtest comparisons:

Verbal Mean (Vm) =11.9				Performance Mean (Pm) = 8.8
Verbal Subtests	SS	SS-Vm	S/W	Performance Subtests	SS	SS-Pm	S/W
Vocabulary	12	0.1		Picture Completion	8	-0.8
Similarities	11	-0.9		Digit Symbol-Coding	9	0.2
Arithmetic	13	1.1		Block Design	7	-1.8
Digit Span	11	-0.9		Matrix Reasoning	13	4.2	S
Information	14	2.1		Picture Arrangement	9	0.2
Comprehension	14	2.1		Symbol Search	7	-1.8
Lett.-Num. Seq.	8	-3.9	W

A note about the subtest scores. The table below reproduces the subtest scores provided for Mr. Adams. Each subtest is named and two numbers are provided. In the first column of numbers the acronym SS in this case stands for Scaled Score. Scaled scores have a mean of 10 and a standard deviation of 3 and are adjusted for the age of the individual (usually termed age scaled scores). The second column of numbers indicates the percentile rank of the scaled score. For example, Mr. Adams’s score on the Vocabulary subtest was 12 which indicates that his knowledge of the meaning of words is as good as or better than 75% of people of his age.

Subtest SS %ile Subtest SS %ile

Vocabulary 12 75 Picture Completion 8 25

Similarities 11 63 Digit Symbol-Coding 9 37

Arithmetic 13 84 Block Design 7 16

Digit Span 11 63 Matrix Reasoning 13 84

Information 14 91 Picture Arrangement 9 37

Comprehension 14 91 Symbol Search 7 16

Lett.-Num. Seq. 8 25

The next table asks about the status of Mr. Adams’s WAIS-III scores in a different way. While the previous analyses have focused on the level of performance amongst his cognitive abilities, the next analyses ask the question “Based on what we know about you, where should your scores lie?” Based on certain types of information, the clinician attempts to construct a pattern of hypothetical scores which represent what the person would look like if they had no disorder or condition, or in other words what the person would have looked like before the accident. You should immediately recognize that if Mr. Adams had been tested on the WAIS-III and WMS-III before his accident we would not need to do this at all. We would compare directly his current scores with the earlier testing. Unfortunately for psychologists, people do not routinely engage in psychological testing just in case they may have an accident (although the idea certainly has some merit!). Such circumstances are viewed as “pure gold” or “mana from heaven” when they occur, but in the vast majority of cases we are forced to estimate what a person’s scores would likely have been before the accident. This is called estimating premorbid levels of functioning.

I have tested the client and need a value from his past that will accurately tell me what he was like before his difficulties. There are a number of ways of getting such values. The first is to use information that is not related to the pathology such as demographic characteristics of the individual. Such an approach asks the question “What should your FSIQ be given that you are a male in your 50’s who has completed a university degree. This approach estimates premorbid functioning using demographic variables alone.

A second approach, the one used in this case, combines demographics with a test that we believe is unlikely to be affected by whatever is wrong with Mr. Adams. Although this is a current measure we are using it to “guesstimate” what he would have looked like before his difficulties. For this approach we use the Wechsler Test of Adult Reading (WTAR) along with demographic variables to estimate Mr. Adams’ WAIS-III performance (and later his WMS-III performance). So, for example, Mr. Adams’ score on the WTAR along with his ethnicity, gender, age, and educational level estimate that his VIQ should be 116. His obtained score of 115 does not differ significantly from this estimate (for a difference to be significant it would have to be 7.2 or larger) indicating that his current VIQ falls where we would expect it to. Remember you don’t need to look up frequencies for non-significant differences. In contrast his PIQ of 94 can be compared with his expected level of 111. This 17 point difference is significant and rare occurring in only 2-4% of the population. With this analysis we can see that Mr. Adams’ PIQ, FSIQ, POI, and PSI are all abnormally lower than would be expected based upon this gentleman’s reading ability and demographic characteristics.

Premorbid Estimates of WAIS-III Composites Using WTAR + Demographic Data

Actual Predicted

Composites SS SS Diff (p=.05) Freq.

Verbal 115 116 -1 7.2 50-74%

Performance 94 111 -17 7.8 2-4%

Full Scale 106 116 -10 6.9 5-9%

Verbal Comprehension 112 115 -3 7.9 25-49%

Perceptual Organisation 95 111 -16 7.9 2-4%

Working Memory 104 113 -9 8.3 10-24%

Processing Speed 88 107 -19 9.9 5-9%

Okay, before we go on to the memory testing let’s take stock. Ask yourself the following questions (and answer them!):

· What range of cognitive/intellectual functioning best represents Mr. Adams’ current abilities on the WAIS-III?

· Does this level suggest impairment?

· Were there any abnormalities detected in the WAIS-III scores?

· What cognitive domains were these abnormalities related to?

· Do these abnormalities reflect skills or impairments?

· Is there evidence at this point for deterioration in Mr. Adams’ cognitive/intellectual functioning from an estimated premorbid state?

And now? On to the WMS-III!

STRUCTURE OF THE WMS-III

The third edition of the Wechsler Memory Scale contains a number of subtests designed to assess both short-term and long-term memory functioning. The nomenclature of measures on this test can be confusing and mixes term from classical and modern memory theory. Unlike the WAIS-III there is no one overall measure comparable to FSIQ although there are measures similar to VIQ and PIQ. In this description of the test I will only focus on those measures necessary to generate the respective Index scores and will not include the optional subtests.

The WMS-III essentially measures three abilities: the ability to recall information shortly after its presentation (Immediate Memory), the ability to recall this same information after a 20 to 30 minute delay (General Memory), and the ability to attend and concentrate (Working Memory). Within each of the first two measures (Immediate and General Memory) there are subdivisions that are based upon whether or not the test is verbally or visually administered and whether or not the examinee had to recall or only recognize the information that was presented. In the case of this assignment these subdivisions are not relevant to either the analysis or interpretation. They will be discussed here for the sake of thoroughness.

The Immediate Memory Index consists of two verbal subtests (comprising Auditory Immediate) and two visual subtests (comprising Visual Immediate). The first verbal subtest, Logical Memory, involves the presentation of two stories which are then to be repeated back by the examinee in as much detail as possible. The second story is presented twice and recall is tested to get a gross measure of learning. The second verbal subtest, Verbal Paired Associates, presents 8 pairs of words which are read aloud to the examinee. Each word pair is an uncommon pairing of words (such as flower-paperclip) and recall is tested by the examiner supplying the first word of the pair (flower) and the examinee must supply the second word of the pair (paperclip). Four trials are administered with the examiner rereading the list of word pairs each time and testing cued recall.

The two visual subtests are Faces and Family Pictures. In Faces, the examinee views 24 photographs of faces and is then asked to determine which 24 out of a further 48 faces they have seen before. The Family Pictures subtest introduces the examinee to seven characters (Grandmother, grandfather, father, mother, son, daughter, and dog – I know, I know, blatant discrimination against cat people!). The examinee is then shown four scenes in which different family members are doing different things in different parts of the picture (Maybe this is why they didn’t use a cat – the cat would be doing the same thing in all four pictures – nothing!). After seeing all four scenes, the examinee is required to indicate who was in each picture, their location, and what they were doing.

The General Memory Index consists of the delayed recall trials (administered approximately 20 to 30 minutes after the immediate recall) of these same subtests. Auditory Delayed consists of delayed recall of the Logical Memory stories and the Verbal Paired Associates. Visual Delayed consists of the delayed trials of the Faces and Family Pictures tests. A third measure Auditory Recognition Delayed consists of the recognition trials of Logical Memory and Verbal Paired Associates that are presented after their delayed recall. General Memory Index is therefore made up of Auditory Delayed, Visual Delayed, and Auditory Recognition Delayed measures.

The Working Memory Index consists of the Letter-Number Sequencing subtest of the WAIS-III and a visual span task called Spatial Span. This task is very much like digit span except that rather than repeating forwards or backwards number sequences read by the examiner, the examinee taps out (forwards or backwards) a series of patterns tapped out by the examiner on a board with ten blocks in various positions. One thing to note is that the Letter-Number Sequencing score used in this Working Memory Index is not from a second administration of the test but rather is exactly the same number as was used in the WAIS-III. I know it seems insane, the reasons are too complicated to discuss here – sufficient to say that the WMI on the WAIS-III and the WMI on the WMS-III are far from independent assessments of the same construct.

BACK TO THE CASE

Let’s now look at Mr. Adams’s scores on memory testing. Remembering our interpretative principle of examining the most reliable information first, our analysis will begin with the Immediate Memory, General Memory, and Working Memory indices. All of the other indices listed in the assignment are subsets of the first two indices that relate to visually and verbally administered tests.

Mr. Adams’s scores on the WMS-III were 96 for the immediate recall of information, 96 for the recall of information after a 20 to 30 minute time delay, and 79 for his ability to attend and concentrate. These performances were as good as or better than 39%, 39%, and 8% of people of his age and corresponded to performances in the Average, Average, and Below Average ranges respectively.

Wechsler Memory Scale-Third Edition

Test – 90%CI Retest – 90%CI

Indices SS %ile Lo Hi Lo Hi

Auditory Immediate 108 70 102 113 98 116

Visual Immediate 84 14 78 95 73 101

Immediate Memory 96 39 90 103 86 107

Auditory Delayed 105 63 97 112 92 116

Visual Delayed 78 7 73 90 68 95

Aud. Rec. Delayed 115 84 102 120 95 128

General Memory 96 39 90 103 86 107

Working Memory 79 8 74 90 69 94

Letter-Number Seq. 8 25

Spatial Span 4 2

There are three comparisons that can be made here, the most important of which is the IM comparison with GM. This addresses the issue of whether or not Mr. Adams’s memory performances are detrimentally affected by increasing the delay between presentation and recall. There is a 0 point difference between Mr. Adams’ immediate (IM) and delayed (GM) recall. This difference is not significant indicating that his abilities to recall information immediately and after a time delay are equivalent. The comparisons of IM and GM with Working Memory (WM) indicate significant differences - for IM:WM (17 points) and GM:WM (17 points). These differences while significant are not considered abnormal as such discrepancies are found in 15.5% and 14.6% of the population respectively.

Differences Between WMS-III Primary Index Scores for Statistical Significance at the .05 Level for the 55 to 64 Age Group

	AI – VI	AI – AD	VI – VD	AD – ARD	AD – VD	IM - GM	IM – WM	GM – WM
p=.05	15.0	13.8	18.1	19.7	17.1	12.8	13.8	14.1

One-Tailed Frequencies of Differences Between WMS-III Primary Index Scores

Comparison	Test Difference	Frequency
AI – VI	24	7.8%
AI – AD	3	38.9%
VI – VD	6	27.6%
AD – ARD	-10	22.1%
AD – VD	27	4.0%
IM – GM	0	50.0%
IM – WM	17	15.5%
GM – WM	17	14.6%

Now let’s consider the indices that make up IM and GM. Immediate Memory is made up of Auditory Immediate (AI = 108) and Visual Immediate (VI = 84). The 24 point difference between these two measures is significant and abnormal occurring in only 7.8% of the population. This indicates that Mr. Adams recall of visual information is abnormally lower than his ability to recall auditory information.

General Memory is made up of Auditory Delayed (AD = 105), Auditory Recognition Delayed (ARD = 115), and Visual Delayed (VD = 78). Two comparisons make sense here: comparing AD with VD, and AD with ARD (comparing recall and recognition of the same material). The 27 point difference between AD and VD is significant and abnormal (4.0% of the population) again illustrating that Mr. Adams’ recall of visual information 30 minutes later is abnormally lower than his recall of auditory information. The 10 point difference between AD and ARD is not statistically significant and indicates that his recognition of auditory information thirty minutes after its presentation is comparable to his ability to recall it.

There is a third set of comparisons that make sense at this point. We know that Mr. Adams has problems recalling visual information when compared to his auditory recall. We need to also consider whether the 30-minute delay generates difficulties within these indices. Thus we can compare immediate and delayed measures within each modality, i.e. AI:AD and VI:VD. The 3 point difference between AI and AD is not significant indicating that what Mr. Adams learns immediately he retains thirty minutes later. The 6 point difference between VI and VD is also not significant and indicates that even though his visual memory is bad (indicated by the earlier analyses) he retains as much information thirty minutes later as he did immediately.

We can clearly see that Mr. Adams has difficulties with recall of visual information. What we don’t know at this point is whether or not these memory performances are where we would expect them to be. We can examine this in two ways. The first is by comparing his WMS-III scores with his WAIS-III scores. This asks whether or not Mr. Adams’s WMS-III scores are normal for a man with his intellectual abilities (as indicated by his FSIQ).

Using the table below based upon Mr. Adams’s FSIQ of 106 we would expect that his predicted IM, GM, and WM scores would all be 103, 104, and 104 respectively. He actually obtained 96, 96, and 79 for these measures yielding differences of 7, 8, and 25 between estimated and obtained scores respectively. Only the WM difference is significant and indicate an abnormally low score on WMS-III WM (frequency of <1%). We will come back to this later. The findings for IM and GM would indicate that Mr. Adams’ memory abilities fall in the range we expect of a man of his intellectual abilities. Or do they? Remember that we have already found that the Average range IM hides Average AI and Low Average VI. Similarly, the Average range GM hides an Average AD, High Average ARD, and Below Average VD. So let’s check these composites out as well!

AI is predicted to be 104 and Mr. Adams actually obtains 108. That these numbers do not differ significantly indicates that is immediate auditory memory is where we would expect it to be. This applies to his delayed recall of auditory information as well (Predicted AD = 103, AD = 105). ARD is of interest. His predicted ARD score is 103 while he actually obtained a score of 115. This 12 point difference is significant indicating that he recognizes the auditory information thirty minutes later to a degree better than was expected. Notice the frequency estimate for this comparison is N/A. This means Not Available and is a quirk of the normative data provided for this test. The reasoning is that only memory scores lower than expected indicate pathology. So while a person can score significantly and abnormally better than is expected no population data for comparisons in that direction have been provided. So while this difference is significant we cannot determine how unusual it is. Regardless it does not reflect the presence of memory impairment.

Comparing VI and VD with their respective premorbid estimates reveals differences that are both significant and abnormal. VI (84) is 18 points below its predicted level (102) and this difference occurs in only 10% of the population. Similarly, the 25 point difference between VD (78) and its premorbid estimate (103) is significant and abnormal (3%). This indicates that while IM and GM do not appear to be lower than expected, they actually hide abnormally low VI and VD scores. This indicates that Mr. Adams’ visual memory abilities are impaired relative not only to his auditory memory but also his other intellectual abilities as well.

Comparisons of WAIS-III and WMS-III Composites Using Predicted Difference Method (Based Upon a FSIQ of 106).

WMS-III Index	Predicted	Obtained	Difference	p=.05	Frequency
Auditory Immediate	104	108	-4	16.9	N/A
Visual Immediate	102	84	18	16.9	10%
Immediate Memory	103	96	7	17.1	>25%
Auditory Delayed	103	105	-2	13.7	N/A
Visual Delayed	103	78	25	16.1	3%
Aud. Rec. Delayed	103	115	-12	10.9	N/A
General Memory	104	96	8	15.2	25%
Working Memory	104	79	25	12.0	<1%

The second approach uses the WTAR+demographics to predict expected WMS-III scores. Based upon his WTAR, age, gender, and education we expect him to have an IM score of 104, GM score of 106, and WM score of 110. Comparison with his actual scores of 96, 96, and 79 yield differences of –8, -10, and –31 respectively. IM does not differ significantly from premorbid estimates. GM does differ significantly but does not occur with sufficient infrequency to be called abnormal. WM however falls significantly and abnormally below (<1%) expected premorbid levels.

Premorbid Estimates of WMS-III Composites Using WTAR + Demographic Data

Actual Predicted

Composites SS SS Diff (p=.05) Freq.

Immediate Memory 96 104 -8 10.1 10-24%

General Memory 96 106 -10 9.5 10-24%

Working Memory 79 110 -31 11.2 <1%

Notice that there are no premorbid estimates for Auditory or Visual Memory measures. Because the WTAR does not generate these indices we are blind to the relationship of these measures to premorbid levels. This is an important lesson – analyses can only address the issues for which they are appropriate. The premorbid analysis would suggest that Mr. Adams’ memory is fine and consistent with what would be expected. But this applies to only the Immediate and General memory Composites which we have already found are masking or hiding abnormal differences between auditory and visual memory.

Before we leave the memory section there is an anomaly we need to address. The WMS-III analyses have indicated that Working Memory on the WMS-III is abnormally low compared to his memory scores, premorbid estimates, and other intellectual abilities. Under most circumstances this would suggest that Mr. Adams has difficulties with attention and concentration. However, on the WAIS-III there were no such indications of difficulties with working memory. I will not provide the answer here but will tell you that the answer lies in looking at how these two supposedly related constructs are made up on the two test batteries.

Let’s consider those questions again with respect to the WMS-III:

· What range of memory functioning best represents Mr. Adams current abilities on the WMS-III?

· Does this level suggest impairment?

· Were there any abnormalities detected in the WMS-III scores?

· What abilities were these abnormalities related to?

· Do these abnormalities reflect skills or impairments?

· Is there evidence at this point for deterioration in Mr. Adams’s memory functioning relative to his other cognitive/intellectual functioning indicated on the WAIS-III and/or compared to his expected level of performance?

Hang in there! Almost done!

Retest Data:

We can now look at the testing from eighteen months later. This analysis is the most straightforward but it requires you to again work with information from multiple tables. Now this is where those retest confidence intervals from the first testing come into the analysis. The retest confidence interval allows us to determine whether or not scores on the second testing have deteriorated, stayed the same, or improved.

WAIS-III WMS-III

Composites SS %ile Indices SS %ile

Verbal 117 87 Auditory Immediate 111 77

Performance 105 63 Visual Immediate 88 21

Full Scale 112 79 Immediate Memory 100 50

VCI 116 86 Auditory Delayed 108 70

POI 105 63 Visual Delayed 88 21

WMI 108 70 Aud. Rec. Delayed 120 91

PSI 96 39 General Memory 104 6

Working Memory 96 39

We will now generate a table that combines the information from our first testing and second testing. We need the 90% RETEST confidence bands from the FIRST testing, the actual scores from the SECOND testing and then consideration of where these scores fall relative to the retest bands. Scores that fall within the retest band are unchanged. Those below it, have declined, those above it have improved.

This analysis indicates that PIQ, FSIQ, Perceptual Organisation, on the WAIS-III and Working Memory on the WMS-III have improved to a degree where it cannot be attributed to random variation in test scores. Thus it would appear that in the areas of processing speed and visual memory, Mr. Adams’ scores have not significantly improved.

	90% RETEST CI		Retest
WAIS-III/WMS-III Measures	Lo	Hi	Score	Status
Verbal IQ	109	121	117	Unchanged
Performance IQ	86	103	105	Improved
Full Scale IQ	101	111	112	Improved
VCI	105	118	116	Unchanged
POI	86	104	105	Improved
WMI	95	112	108	Unchanged
PSI	78	101	96	Unchanged
Auditory Immediate	98	116	111	Unchanged
Visual Immediate	73	101	88	Unchanged
Immediate Memory	86	107	100	Unchanged
Auditory Delayed	92	116	108	Unchanged
Aud. Recognition Delayed	95	128	120	Unchanged
Visual Delayed	68	95	88	Unchanged
General Memory	86	107	104	Unchanged
Working Memory	69	94	96	Improved

To better understand the implications of these changes, let’s take a look at the retest WAIS-III and WMS-III data.

IQs SS %ile Indices SS %ile

Verbal 117 87 VCI 116 86

Performance 105 63 POI 105 63

Full Scale 112 79 WMI 108 70

PSI 96 39

VIQ for Mr. Adams on retest is 117, and PIQ is 105. The difference between these two measures is (117-105) 12. The table of significant differences below indicates that a 7.90 difference would be significant at p=.05. As the 12 point difference is greater than this, we can assert that VIQ and PIQ continue to differ significantly.

Differences Between WAIS-III IQ Scores and Between Index Scores Required for Statistical Significance at the .05 Level for the 55 to 64 Age Group

	VIQ – PIQ	VCI – POI	VCI – WMI	POI – PSI	VCI – PSI	POI – WMI	WMI – PSI
p=.05	7.90	8.54	9.08	11.53	10.91	9.81	11.93

One-Tailed Frequencies of Differences Between WAIS-III IQ and Index Scores for Individuals with FSIQ of 110 to 119

	Difference	Frequency
VIQ – PIQ	12	16.2%
VCI – POI	11	22.7%
VCI – WMI	8	28.7%
POI – PSI	9	29.0%
VCI – PSI	20	11.2%
POI – WMI	-3	43.6%
WMI - PSI	12	22.2%

What about the Index Scores?

	Difference	Frequency
VCI – POI	11 (sig)	22.7%
VCI – WMI	8 (ns)	28.7%
POI – PSI	9 (ns)	29.0%
VCI – PSI	20 (sig)	11.2%
POI – WMI	-3 (ns)	43.6%
WMI - PSI	12 (sig)	22.2%

Notice how the areas of deficit which were present in the initial testing are still present as significant differences but are no longer abnormal.

WMS-III

Indices SS %ile

Auditory Immediate 111 77

Visual Immediate 88 21

Immediate Memory 100 50

Auditory Delayed 108 70

Visual Delayed 88 21

Aud. Rec. Delayed 120 91

General Memory 104 6

Working Memory 96 39

Differences Between WMS-III Primary Index Scores for Statistical Significance at the .05 Level for the 55 to 64 Age Group

	AI – VI	AI – AD	VI – VD	AD – ARD	AD – VD	IM - GM	IM – WM	GM – WM
p=.05	15.0	13.8	18.1	19.7	17.1	12.8	13.8	14.1

One-Tailed Frequencies of Differences Between Retest WMS-III

Primary Index Scores

Comparison	Retest Difference	Frequency
AI – VI	23 (sig)	9.5%
AI – AD	3 (ns)	38.9%
VI – VD	0 (ns)	50.0%
AD – ARD	-12 (ns)	17.8%
AD – VD	20 (sig)	11.7%
IM – GM	-4 (ns)	30.7%
IM – WM	12 (ns)	24.4%
GM – WM	8 (ns)	31.1%

As with the WAIS-III data the pattern of difficulty remains with significant differences between auditory and visual recall in both immediate and delayed recall. The significant and abnormal differences between Immediate/General memory and Working Memory has disappeared consistent with the noted improvement in WMS-III Working Memory.

To understand how his memory now is relative to his intellectual abilities we need to compare IQ with memory scores. Note that because Mr. Adams’ FSIQ has gone up from 106 to 112 we must now use a different normative table:

Comparisons of WAIS-III and WMS-III Composites Using Predicted Difference Method (Based Upon a FSIQ of 112).

WMS-III Index	Predicted	Obtained	Difference	p=.05	Frequency
Auditory Immediate	107	111	-4	16.9	N/A
Visual Immediate	104	88	16	16.9	10-15%
Immediate Memory	107	100	7	17.1	>25%
Auditory Delayed	107	108	-1	13.7	N/A
Visual Delayed	105	88	17	16.1	10%
Aud. Rec. Delayed	106	120	-14	10.9	N/A
General Memory	107	104	3	15.2	>25%
Working Memory	108	96	12	12.0	10-15%

Notice how, although IM and GM do not indicate a significant difference from predictions based upon FSIQ, visual immediate and visual delayed continue to be significantly lower than expected, and for visual delayed abnormally so. This indicates that while there have been improvements in the areas of visual perception and organization on the WAIS-III, visual recall is still a problematic area for this gentleman.

All that is left now is to write an interpretation of this data. Unfortunately, since this is what the assignment is about I cannot help you further. In thinking about the data and Mr. Adams’ plight, consider what sort of question each analysis is capable of addressing:

· The percentiles of each of the subtests and indices permit you to describe Mr. Adams’s current level of functioning.

· The WAIS-III subtest analysis permits you to detect abilities or performances which are particularly strong or weak for Mr. Adams.

· The analysis of WAIS-III indices permits you to determine whether or not his cognitive abilities are related in the way that they are in most people, or whether there is something unusual about his pattern of abilities.

· The analysis of WMS-III indices asks the same of the memory indices – “Are they put together in the way that they are for most people?”

· The analysis comparing WAIS-III with WMS-III permits you to determine whether or not Mr. Adams’s memory abilities are consistent with his other intellectual abilities.

· The analyses involving the WTAR + demographics permits you to answer the question “Where should Mr. Adams’s scores be?” Comparison of these values with those he actually obtained provides insight as to which abilities may have been detrimentally impacted upon by his injuries.

· The Retest Confidence Intervals permit you to examine which measures have changed over the eighteen month interval between tests.

· The integration of all of these analyses will assist in constructing a picture of not only what Mr. Adams’ cognitive abilities were like four months after his stroke and again eighteen months later, but also how these abilities may have changed over time. Recognition of these strengths and weaknesses will be critical in advising Mr. Adams on the types of duties he is best equipped to perform in the workplace.

This is a demanding assignment because it asks you to grasp a lot of information to which you have not been formerly exposed. However, this is a good model of how 21^st century assessors go about analysing and interpreting psychological test data. Before you feel too hard done by, consider the small number of variables that you have to consider in this case from only two tests. In a routine assessment in my own clinical practice more than twenty tests are customarily administered each with many scales and subscales. The process you have learned here is essentially the same as that applied to analyse twenty tests or two hundred variables, it just becomes progressively more complicated with the addition of more measures. The other warning I should give is that this case has been structured and simplified to illustrate certain principles. Most psychological assessments are highly complex and full closure is seldom achieved. The process is the same as in this case, but the outcome is rarely as neat.

This concludes the ancillary materials provided to assist you in completing assignment 2. Enjoy!

Dr. Graeme Senior

Senior Lecturer

Department of Psychology

University of Southern Queensland