Abstract
Introduction: :
Standardized tests for isolated visual memory are often confounded by non–visual cues and requisite visual–motor coordination to recreate learned geometric figures. The widely used Benton Visual Retention Test (BVRT) has these limitations, using figures that may be verbalized and also recalled by their spatial organization. The Shum Visual Learning Test (SVLT), which requires matching of unknown Chinese characters, is less likely to be confounded by verbal and visual–spatial clues. However its administration via an automated computer program requires motor coordination and generates anxiety as testing is performed within a limited time period.
Purpose: :
To determine whether a modified SVLT provides comparable scoring and distribution to the BVRT in a group of normal controls.
Methods: :
Visual memory in 32 normal subjects (64 eyes) was tested by the BVRT and modified SVLT. Subjects underwent testing of individual right and left eyes. In both the BRVT and the SVLT, test plates were presented for 10 seconds. The ten plates of figures in the BVRT, were given both absolute scores (1 point for correct, or 0 for incorrect) and relative scores as outlined in the administration manual). In the modified SVLT, test plates of a single Chinese character were presented during the learning period, and then paired with a slightly dissimilar character. The subject was asked to choose the figure previously learned. Scoring was absolute, either correct (one point) or incorrect (zero points) for each of ten plates. Scores were compared to published norms.
Results: :
Both the BVRT (mean 5.85, standard deviation 2.15) and the modified SLVT (mean 6.88, standard deviation 1.85) revealed a normal distribution of scores. As expected, when stratified by age, the older age group (> 50 years) scored significantly lower in both examinations than the 18–49 age group (BVRT mean 5.24 v. 6.57, SVLT mean 6.74 v.7.82).
Conclusions: :
The BVRT and modified SVLT visual memory tests provide normal distribution curves and expected stratification based on age. The modified SVLT offers several advantages: isolation of visual memory from verbal and visual–spatial cues; simplified (absolute) scoring; and the elimination of essential visual–motor coordination (handwritten reproduction of images).
Keywords: clinical research methodology • learning • scene perception