Cornell University researchers have developed a reliable method to distinguish memory declines associated with healthy aging from the more-serious memory disorders years before obvious symptoms emerge. The method also allows research to accurately predict who is more likely to develop cognitive impairment without expensive tests or invasive procedures.
Their results hold promise for detecting cognitive impairment early and monitoring treatment, but also have implications for healthy adults, said Charles Brainerd, professor of human development and the study's lead co-author with Valerie Reyna, director of the Institute for Human Neuroscience and professor of human development, both in Cornell's College of Human Ecology.
Their research, "Dual-retrieval models and neurocognitive impairment," appears online in the Journal of Experimental Psychology: Learning, Memory and Cognition, Aug. 26 (http://bit.ly/13GTlxl).
The memory abilities affected by cognitive impairment differ from those affected by healthy aging, the authors say, resulting in unique error patterns on neuropsychological tests of memory. Their theory-driven mathematical model detects these patterns by analyzing performance on such tests and measuring the separate memory processes used.
"With 10 or 15 minute recall tests already in common use worldwide, we can distinguish individuals who have or are at risk for developing cognitive impairment from healthy adults, and we can do so with better accuracy than any existing tools," said Brainerd.
The notion that memory declines continuously throughout adulthood appears to be incorrect, they say. "When we separated out the cognitively impaired individuals, we found no evidence of further memory declines after the age of 69 in samples of nationally representative older adults and highly educated older adults," said Reyna.
To develop their models, the team used data from two longitudinal studies of older adults - a nationally representative sample of older adults, the Aging, Demographics and Memory Study, and the Alzheimer's Disease Neuroimaging Initiative - that include brain and behavioral measures as well as diagnoses for cognitive impairment and dementia.