Cognitive complaints in the elderly are often dementia harbingersOctober 3, 2014
Sometimes a missing set of keys is just that - an inconvenience borne of lapsed attention. But a new study suggests that when seniors report they are plagued by missing keys, forgotten appointments, words that can't be retrieved and names that don't come, those complaints should not be lightly dismissed.
New research finds that after the age of 60, "cognitive complainers" - people who say they have noticed mental slippage - are more likely than those who do not complain of such changes to develop mild cognitive impairment, and to have Alzheimer's-like plaques and tangles in their brains upon death even when dementia was never diagnosed.
In a study published Wednesday in the journal Neurology, researchers in Kentucky tracked 531 people with an average age of 73 and no signs of dementia for 10 years. The researchers asked participants yearly if they noticed memory changes and administered a battery of cognitive tests.
Cognitive complaints were hardly rare: fully 56% of the participants reported changes in their memory, at an average age of 82. But people who reported memory complaints were nearly three times more likely to develop clinically-significant memory and thinking problems, the researchers found.
About 1 in 6 participants developed dementia during the study, and 80% of those first reported memory changes.
The study offers an important look at the length of time it takes from the point at which a senior acknowledges memory slippage and the time when symptoms satisfy the clinical criteria for diagnosis of mild cognitive impairment or dementia. On average, it took 9.2 years for seniors complaining of memory problems to satisfy the diagnostic definition of mild cognitive impairment (with former smokers getting to that point 2.8 years faster). For those who would go on to meet the criteria for diagnosis of Alzheimer's disease, it took an average of 2.9 years to do so.
Participants who carried the genetic variant APOE 4, which predisposes one to develop Alzheimer's, were more than twice as likely either to die or to develop dementia during the study.
Some 14% of participants went from cognitive complaints to full-blown dementia in just over six years: those rapid decliners tended to be women and people with high blood pressure. And women who had taken hormone replacement therapy were slightly slower to make that transition: it took them close to 10 years, on average, to go from complaints of memory problems to a diagnosis of dementia.
Study participants agreed to allow researchers to autopsy the brains of those who died during the study, and patterns emerged among those who had complained of mental slippage during life. Even where no diagnosis of dementia or Alzheimer's disease had been made, those who complained of memory problems were far more likely than those who did not to have signs of Alzheimer's-related abnormalities in their post-mortem brains.
Lead author Richard J. Kryscio, with the University of Kentucky in Lexington, said that seniors' complaints of memory slippage should not be dismissed, but might rather be seen as "a window for intervention before a diagnosable problem shows up.”
With no effective Alzheimer's therapies on hand, however, time itself may offer some small consolation. The relatively slow rate at which cognitive complaints turn into dementia diagnoses may mean that some older seniors will die of something else before they get a diagnosis. But younger cognitive complainers have more to worry about: they are more likely to live long enough for their complaints to become a diagnosis of dementia.