Adapted from "Researchers Develop Simple Tools to Predict Cognitive Decline in Aging" by Lauren Gold, Cornell Chronicle, 1/26/10.
For most people, misplacing the car keys or forgetting a name is an occasional annoyance of normal aging. But sometimes forgetfulness can signal the beginning of deterioration in language, attention, reasoning, judgment or memory. With large numbers of aging baby boomers, the need for simple, accurate clinical tools that identify memory changes associated with cognitive impairment is increasingly important.
In a collaboration between Weill Cornell Medical College in New York City and Cornell's Ithaca campus, Charles Brainerd and Valerie Reyna, professors of Human Development and of Psychology, have teamed up with Dr. Cary Reid, Weill Cornell geriatrician and investigator with CITRA, on a project that will improve tools for predicting and diagnosing memory loss.
The Cornell Institute for Translational Research on Aging (CITRA), brings together community based organizations, social scientists, and medical researchers to address pressing problems in the field of aging. The contribution of CITRA's expertise and infrastructure was pivotal in securing national support.
Now, with a two-year grant from the American Recovery and Reinvestment Act via the National Institutes of Health, the team is investigating whether a decline in a particular type of memory, called reconstructive memory, predicts cognitive impairment in the elderly. If the hypothesis bears out, it could lead to a breakthrough in our ability to detect cognitive decline years before the onset of major symptoms.
According to data from other studies, healthy elderly adults become mildly cognitively impaired at a rate of about 10 percent per year after age 70. Clinicians use a variety of neuropsychological tests to predict and diagnose the condition. However, the most reliable single test -- a basic verbal recall task in which a subject hears a sequence of words and then is asked to recall them – does not accurately predict future impairment.
That could be because people use three distinct strategies -- verbatim recall, reconstruction and familiarity judgment -- to retrieve information from memory. Earlier studies by Brainerd and Reyna have shown that verbatim recall, in which subjects mentally picture or hear the actual word, declines with age. To compensate, older adults use reconstruction, in which they remember something about the word (it was an animal, for example; or it started with the letter "p"), and then familiarity judgment, in which they sift through possible candidate words until they identify the right one. Since reconstructive memory relies on associations and experiences, which can be accessed through multiple pathways and networks in the brain, it is more robust and usually spared in healthy aging, Brainerd said.
But a decline in reconstructive memory could be an important and more accurate indicator of the extensive deterioration throughout the brain that causes cognitive impairment. To test the hypothesis, Brainerd and Reyna developed a mathematical model that analyzes data from verbal recall tests and estimates the amount a subject relies on each of the three memory processes.
In the first phase of the study, the researchers are using the model to analyze data from more than 800 previously tested adults -- some healthy and others already diagnosed with cognitive impairment -- and examining whether a decline in reconstructive memory is more closely linked with cognitive impairment among groups of people.
In the second phase, the researchers are testing and tracking 200 older adults over 18 months to see if performance in reconstructive memory predicts later emergence of impairment on an individual level. Recruitment and testing of study participants is now underway at sites in Ithaca and New York City and will gain momentum this summer as undergraduate and graduate students join the project. Dr. Reid is facilitating recruitment of study participants through the Irving Sherwood Wright Center on Aging in New York City and has been very helpful in advancing the project, said Reyna.
The findings could improve testing and treatment for impairment dramatically, Brainerd said. "Like any disease, the sooner you can identify it the better."
"The project is a model for integrating teaching and research and demonstrates the critical role of research-community infrastructure to facilitate and inform the research."