Nov. 25, 2003 -- When memory starts to decline, figuring out the difference between the normal aging process and early signs of Alzheimer's disease has mystified scientists. But now an MRI brain scan has for the first time identified subtle brain changes that can help predict who is likely to develop Alzheimer's disease.
These brain changes occur several years before the memory problems of early Alzheimer's, according to researchers. The finding could lead to early testing of those most at risk -- and tactics to prevent onset of the disease.
The study, appearing in the journal Radiology, is the first to document these subtle changes that are caused by loss of brain cells, writes lead researcher Henry Rusinek, PhD, a professor of radiology at New York University School of Medicine in New York City.
The researchers say that other studies have pointed to the medial temporal lobe, a small section of the brain, as being very vulnerable to the aging process. These studies show that these changes are also seen in the early stages of Alzheimer's disease.
Does this mean looking for these brain changes could help pinpoint who is likely to go on to develop Alzheimer's disease?
This transition from normal aging to more serious memory problems is largely uncharted, according to Rusinek.
Brain Imaging Shows Changes
The 45 men and women in this study -- all over 60 years old -- took tests at the outset that showed they had no signs of memory or concentration lapses.
Every two years, for a total of six years, they took tests to document changes in memory and other brain functions. Among the tests: recalling paragraphs, pairing words and images, a vocabulary test, and a shopping list. They also had a series of magnetic resonance imaging (MRI) tests of the brain.
Six years later, 32 of these elderly people showed no brain function decline, but 13 were diagnosed as having early signs of memory decline or Alzheimer's disease.
In analyzing the data, Rusinek and colleagues found that those with brain function decline were about five years older than the others. Indeed, the frequency of Alzheimer's disease is very age-related -- with risk increasing steadily between ages 60 and 90.
Of those people who had brain impairment, the MRI was 89% effective at predicting further memory decline as evidenced by brain cell death on their MRI brain scan. That brain cell death was the most significant predictor of imminent brain decline, writes Rusinek.
"I do not believe that serious memory loss is a natural consequence of aging," says Rusinek in a news release. "A vast majority of elderly we see are very sharp and creative."
He anticipates a day when early testing for these brain cell changes could lead to treatment. In the meantime, he advises those at risk for memory decline to exercise the brain as well as the body.