A woman suffering from Alzheimer's disease holds the hand of a relative. (Sebastien Bozon / AFP/Getty…)
Elderly people who suffer from a marked decline in memory function that falls short of dementia are more than twice as likely to die within five years than are those with normal cognition, researchers told the Alzheimer's Assn. International Conference meeting this week in Vancouver, Canada.
The latest study focuses on people older than 70 years of age who have "mild cognitive impairment" -- a condition in which mental decline is greater than is considered normal but does not satisfy a definition of Alzheimer's disease. Having mild cognitive impairment that affects memory was found to increase a patient's likelihood of dying in the near term. But mild cognitive impairment that results in diminished reasoning faculties, poor judgment or organizational difficulties did not bring with it a higher risk of impending death, the study found.
Older patients diagnosed with mild cognitive impairment are more likely than those who have normal mental function to go on to develop Alzheimer's disease. But predictions about which patients do so remain highly uncertain. Scientists are increasingly focusing on those with mild cognitive impairment who later are diagnosed with Alzheimer's disease: Such studies, they believe, will reveal what Alzheimer's disease in its earliest stages looks like. That, in turn, may point the way to earlier treatments that could halt or reverse a patient's progression to full-blown dementia.
In other research presented in Vancouver, researchers suggested that changes in gait and walking speed, which are common in people as they age, could be a sign of developing dementia. A second study tracked 1,153 participants with an average age of 77 as they walked along a 10-meter walkway studded with electronic sensors.
The participants--who ranged from cognitively healthy to those with mild cognitive impairment to those with severe Alzheimer's disease--navigated the walkway while also performing another mental task, such as naming animals or counting backward out loud. While virtually all participants slowed or varied their pace while multitasking, those with mild cognitive impairment slowed or varied their gait more noticeably than did healthy participants. The changes were even more pronounced among those who had been diagnosed with Alzheimer's disease.
The researchers from Basel, Switzerland, suggested that changes in gait might appear even earlier than symptoms of memory loss or mental decline, and could be more readily detected, even by a busy physician.
In the first study linking memory status to death, three other factors pushed an older adult's risk of dying in the near term even higher: suffering from depression; suffering from other illnesses, and carrying the variant of the APOE-4 gene that confers a higher probability of developing Alzheimer's disease.
Those patterns were gleaned by a study that tracked 733 residents of the Bronx in New York City for an average of five years each. The population studied was comprised of people over 70 who were enrolled in the Einstein Aging Study--so-called because it was conducted by researchers from Yeshiva University's Albert Einstein College of Medicine and Montefiore Medical Center.
The study builds on what is known about the longevity of people once they are diagnosed with Alzheimer's disease. Compared with elders with normal cognitive function, such patients are more than three times likelier to die of any cause within a five-year period. But much less is known about patients diagnosed with mild cognitive impairment.