Measuring memory in large group settings using a continuous recognition test.

Memory function generally deteriorates with age, and memory impairments are a common symptom of serious illness such as dementia. Although screening tests are widely used throughout Medicine, they are not yet commonly used to detect memory impairments. The objective of this study was to characterize an audience-based memory test suitable for administration to a large number of individuals simultaneously. A continuous recognition test was developed to assess memory function in audiences using a slide-show in which 50 images were presented, of which 25 were repeated. Audience members responded by recording if an image was a repetition. The test was administered to a total of 1018 participants at 25 sites with an average audience size of 41 individuals (range = 9-142). A total of 868 individuals aged 40-97 y completed the test appropriately and provided their age, education level, and gender. Recognition memory as measured by discriminability (d') showed a significant decline with age (40-49 y old, d' = 3.51; 90-99 y old, d' = 1.95, p < 0.001) together with a greater than three-fold increase in variability. Individuals with less than 13 y of education had lower scores than those with more education (d' = 2.13 vs. 2.88, respectively, p < 0.001). These results are consistent with the known effects of age and education on memory. There were no significant effects of gender on test performance. Such memory tests represent a practical and novel approach to screen for the signs of early dementia.