El discurso pedagógico

4.1.1. Design Aspects

In order to maximise the chance of the new version being a good Alternative Form to the Visual Reproduction subtest of the Wechsler Memory Scale – Revised, the development of the designs had to be comparable. As such, four designs were developed in this study to match the four design structure of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised.

Careful consideration was given to the structure and the features of the Alternative Designs. The Alternative Designs of the Alternative Form were carefully developed not to constitute a part of or be closely related to a primary element from another design, so to limit the potential for overlap or confusion between designs.

Each alternative design was individually matched to correspond as closely as possible to the features, size and level of difficulty to the designs of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised. Design A of the Alternative Form consisted of lines and squares as its main features as did Card A of the Visual Reproduction subtest. Design A was developed to be more spatially demanding than Design B. Design B of the Alternative Form used a single regular shape to represent the design as did Card B of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised. Design A and Design B of the Alternative Form were developed to be simpler in structure than Designs C and D. Design C was developed to be easier than Design D with only one large key figure, like that of Card C of the Visual Reproduction subtest. Design C had greater availability to verbal encoding than Design A, Design B and Design D, such that it resembled a pizza. Design D had the most number of spatial elements than Design A, Design B and Design C. Design D represented the same component structure as Card D of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised, with the use of three primary figures.

4.1.2. Administration Procedures

The administration procedure of the Alternative Form was exactly the same to the administration protocol of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised described in the manual (Wechsler, 1987). Specifically, each design was presented for 10 seconds followed by immediate recall of each design. A delayed free recall procedure was administered 25 – 35 minutes after the initial presentation.

4.1.3. Design Comparison of the Alternative Form and the Visual Reproduction subtest

Due to variability of other factors that could potentially influence test performance, the Visual Reproduction subtest of the Wechsler Memory Scale – Revised and the Alternative Form were administered on two separate sessions. This was done to reduce interference and confusion of the two forms and not overload memory. The administration of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised and the Alternative Form occurred over two sessions scheduled 7-10 days apart. The timeline of approximately one week between the administration of the Visual Reproduction subtest and the Alternative Form was considered sufficient not to cause interference effects, with no participants substituting the designs between sessions.

The Visual Reproduction subtest and the Alternative Form were administered to participants in a serial counterbalanced order. This was done so the potential gain in scores from familiarity with the assessment process would be counteracted and test order effects minimised.

Furthermore, the Visual Reproduction subtest and the Alternative Form were administered amongst other cognitive tests commonly used in clinical neuropsychological assessments. That is, the two versions were alternated with other verbal and non-verbal tasks (Logical Memory, Rey Auditory Verbal Learning Test, Rey Complex Figure Test) and a measure of intelligence (Wechsler Adult Intelligence Scale – Revised). This was done to not overload one cognitive domain and to maintain participant interest and motivation.

4.1.4. Controlling for Unknown Factors

To limit the influence of unknown factors such as stress and anxiety on test performance, the stability of performances between Session One and Session Two was evaluated using the Symbol Search and the Speed and Comprehension of Language Processing test. The speed of processing score in Session One set the benchmark in order for second session to proceed, which was met by all participants.

Due to the well documented effects of depression on cognitive functioning, all participants were screened for depression using the Beck Depression Inventory – Second Edition. The Beck Depression Inventory – Second Edition was administered at the end of the second session so questions that could potentially trigger an emotional response did not contaminate test performance. Only one participant was excluded from this study on the basis of a mood disorder.

4.1.5. The Relationship between the Alternative Form and the Visual Reproduction subtest of the Wechsler Memory Scale – Revised

In order for the Alternative Form and the Visual Reproduction subtest of the Wechsler Memory Scale – Revised to be equivalent, a moderate to high correlation between the two versions would be expected. The hypothesis that the Alternative Form would have a moderate-high positive correlation with the Visual Reproduction subtest of the Wechsler Memory Scale – Revised was supported.

The relationship between the Alternative Form and the Visual Reproduction subtest revealed a moderate association on immediate recall (r = .51; rs = .45) and delayed recall (r = .43; rs = .37).

To evaluate the robustness of the correlation between the two forms, the stability coefficient for immediate and delayed recall on the Visual Reproduction subtest would set the benchmark to make comparisons. On the Visual Reproduction subtest of the

Wechsler Memory Scale – Revised for participants aged 20 – 64 the stability coefficients ranged from .56 to .80, with an average of .68 on the immediate recall, and a range of .58 to .68 with an average of .63 on delayed recall for a 4 – 6 week test-retest period (Wechsler, 1987). Taking into consideration the stability coefficient of the Visual Reproduction subtest of the Wechsler Memory Scale – Revised, the correlation between the Alternative Scoring System and the Original Scoring System suggests a high association between the Alternative Form and the Visual Reproduction subtest was demonstrated. Therefore, the results of this study indicated that the Alternative Form and the Visual Reproduction subtest of the Wechsler Memory Scale – Revised were highly comparable.

The common variance shared between the Alternative Form and the Visual Reproduction subtest of the Wechsler Memory Scale – Revised for Total Immediate Recall and Total Delayed Recall was 26% and 18% respectively. Furthermore, the Alternative Form predicted 20% and 17% in the variance of scores on the Visual Reproduction subtest of the Wechsler Memory Scale – Revised. However, given the small sample size (n = 44) and the truncated IQ range (89 – 141) in this study, the true correlation between the Alternative Form and the Visual Reproduction subtest of the Wechsler Memory Scale – Revised may be higher if a wider IQ range and larger sample size was obtained, potentially making the two versions even more equivalent.

4.2. The Advantages of the Alternative Scoring System