November 11, 2014
People who worry that their memory is slipping are more likely than their peers without memory concerns to develop Alzheimer’s disease years later, a new study found. The findings confirm earlier reports that subjective memory complaints may predict a future dementia diagnosis. They also show that memory concerns may arise 10 years or more before a formal diagnosis of Alzheimer’s or mild cognitive impairment (MCI), a form of memory loss that can progress to dementia.
For the study, researchers at the University of Kentucky studied 531 older men and women, average age 73, who were initially free from serious memory problems. All were part of the Biologically Resilient Adults in Neurological Studies, or BRAINS, an ongoing study of memory in volunteers aged 60 and older.
Every year during medical follow-ups, the study participants were asked whether they were concerned about memory lapses since their last visit. More than half, or 55 percent, reported that they were. They were also given annual tests of memory and thinking skills, over an average period of 10 years.
During the study period, those with self-declared memory concerns were nearly three times more likely to receive a diagnosis of mild cognitive impairment or dementia than those without memory worries. MCI developed, on average, eight to nine years after the start of the study at an average age of 81, while dementia (usually Alzheimer’s) was diagnosed on average 12 years later.
“What’s notable about our study is the time it took for this transition to dementia or clinical impairment to occur — about 12 years for dementia and nine years for clinical impairment —after the memory complaints began,” said study author Richard J. Kryscio, with the University of Kentucky in Lexington. “These findings suggest that there may be a window for intervention before a diagnosable problem shows up.”
Those with subjective memory complaints who carried the APOE-E4 gene, which raises the risk of Alzheimer’s disease, were particularly likely to go on to develop mild cognitive impairment or dementia. Those who smoked also progressed to serious memory complaints faster than nonsmokers. The findings appeared in Neurology, the medical journal of the American Academy of Neurology.
The researchers also examined the brains of the more than 40 percent of the study volunteers who died during the study. Even if someone was not given a diagnosis of MCI or dementia, those who complained about memory lapses were more likely to have brain changes, including the accumulation of beta-amyloid plaque, a hallmark of Alzheimer’s, than those without memory worries.
“Our study adds strong evidence to the idea that memory complaints are common among older adults and are sometimes indicators of future memory and thinking problems. Doctors should not minimize these complaints and should take them seriously,” said Dr. Kryscio. “However, memory complaints are not a cause for immediate alarm, since impairment could be many years away.”
Anyone concerned about memory should talk to their doctor about their concerns. Stress, depression, medications, aging and other factors can all impair memory, and steps such as adjusting medications can be taken to restore memory in many seniors who are having problems.
In addition, it’s important to note that having memory problems does not mean that Alzheimer’s or other forms of dementia will eventually develop. Many of those who were worried about memory lapses did not go on to develop clinical dementia.
Source: Richard J. Kryscio, PhD, Erin L. Abner, PhD, Gregory E. Cooper, MD, PhD, et al: “Self-Reported Memory Complaints: Implications from a Longitudinal Cohort With Autopsies.” Neurology Vol. 83, pages 1359-1365, Sept. 2014