Published in the April issue of the Archives of General Psychiatry, the study offers a greater understanding of how different types and varying degrees of memory complaints may relate to brain function decline, a finding that may lead to early treatment interventions for people who could develop Alzheimer's disease.
"There's a lot of confusion about memory complaints and whether they should be taken seriously or not," said Dr. Linda Ercoli, lead study author and assistant clinical professor at the UCLA Semel Institute for Neuroscience and Human Behavior. "The study is one of the first to show an association between memory complaints and underlying brain function decline and although not every complaint will lead to Alzheimer's disease, it's important to listen when patients talk about their memory concerns."
The UCLA team tested 30 adults, age 50-82, with memory complaints. Half of the participants carried the apolipoprotein E-4 allele or APOE-4, a gene associated with Alzheimer's disease. All participants did not have other conditions such as depression and anxiety that can also affect memory.
Volunteers were given a questionnaire at the start of the study to gauge the frequency, seriousness and type of memory complaints. Researchers measured brain function at both the beginning and end of the two-year study using positron emission tomography (PET). PET scans measure brain activity by revealing the amount of glucose metabolized by the brain as fuel. Researchers then measured how complaints were related to decline in brain activity over two years.
The study found that for all participants, greater complaints of frequent forgetting were associated with a global brain decline over two years, which appears to be part of the normal aging process, according to researchers.
However, study participants with the Alzhiemer's disease genetic risk factor, APOE-4, who reported more frequent use of strategies such as lists and calendars to compensate for memory difficulties, showed a greater brain function decline in the temporal regions of the brain that are involved with memory functions, compared to participants without the genetic risk.
The relationship between greater use of memory compensation strategies and declines in brain function in the temporal regions may be indicative of early developments associated with Alzheimer's disease, according to researchers.
"These findings may eventually help us identify which patients may benefit from clinical monitoring and early interventions to prevent or delay the onset of Alzheimer's disease," said Dr. Gary Small, principal investigator, professor at the Semel Institute and Parlow-Solomon Professor on Aging.
The study was funded by the Larry L. Hillblom Foundation, the National Institute of Mental Health and the Ahmanson Foundation.
Other study authors include Prabha Siddarth, Ph.D., S.C. Huang, Ph.D., Karen Miller, Ph.D., Dr. Susan Y. Bookheimer, Dr. Benjamin C. Wright, and Michael Phelps, Ph.D.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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