Normative data on the CERAD Word List in a robustly intact sample of older adults
Abstract
Background
List learning and memory tests are frequently used to evaluate older adults for late life cognitive disorders, such as Alzheimer’s disease. The Word List subtest of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychological battery has been widely-used in clinical research, including clinical trials, to identify and track such disorders. It is also freely-available, as it is in the public domain. However, normative data, especially in robustly intact older adults, is lacking.
Method
CERAD Word List data from 897 older adults (age in years: M = 81.1, SD = 8.1, range 55-100; 67% women; education in years: M = 14.8, SD = 2.8, range = 7-24) deemed to be cognitively intact at two annual visits in a longitudinal observational study from the Uniform Data Set of the National Alzheimer’s Coordinating Center were used to generate predicted Word List scores based on age, sex, and education. Predicted scores were compared to observed scores to preliminarily validate these normative values.
Result
For six primary scores from the Word List subtest (Trial 1, Trial 2, Trial 3, Total Acquisition, Delay Recall, Recognition Total Correct), the three demographic variables significantly predicted test scores, with R2s ranging from 0.03 – 0.18 (p-values<0.001). When these predicted scores were compared to observed scores, there were no significant differences (p-values>0.40), indicating preliminary support for these prediction scores.
Conclusion
Although further validation is needed in independent intact and impaired samples, the current demographically-based prediction scores provide normative data for the CERAD Word List subtest for older adults being evaluated for cognitive complaints. The inclusion of additional variables needs to be examined to improve the accuracy of these prediction scores. Nonetheless, normative data allows providers and researchers to be confident in using this learning and memory test in clinics and clinical trials.
