The battle against Alzheimer's is moving forward on many fronts, with new blood tests, new treatments using light therapy, new warnings about links between Alzheimer's and diabetes, and new imaging techniques to provide earlier detection.
Now a new study suggests symptoms signaling possible Alzheimer's disease can be detected by memory and cognitive tests as long as 18 years before a diagnosis is clinically confirmed, researchers say.
In a study conducted in Chicago, 2,125 people with an average age of 73 and without Alzheimer's disease were administered tests of memory and cognitive skills every 3 years for 18 years.
Analyzing the numbers of people in the study group who eventually developed Alzheimer's showed that those who scored lower overall on the tests had an increased risk of developing the disease, researchers reported in the journal Neurology.
"The changes in thinking and memory that precede obvious symptoms of Alzheimer's disease begin decades before," says study lead author Kumar B. Rajan in the Department of Internal Medicine at Chicago's Rush University.
The study involved both African-American and European-American participants; 61 percent were women.
During the 18-year study follow-up period, 23 percent of African-American participants and 17 percent of European-American participants developed Alzheimer's disease.
In the study's first year, participants who scored lower on the tests were about 10 times more likely to be later diagnosed with Alzheimer's disease than people with higher scores, the researchers found.
The study, supported by the National Institute on Aging and the International Alzheimer's Association, suggests that even "subtle declines in cognitive function affect future risk," Rajan says.
"A general current concept is that in development of Alzheimer's disease, certain physical and biologic changes precede memory and thinking impairment," Rajan says.
If that's the case, he suggests, those processes might take a very long time to show themselves, but could manifest and be detectable much earlier than previously thought.
Any efforts to prevent Alzheimer's and its dementia may need a fuller understanding of those processes as early as middle age, he says.
Other researchers are coming at Alzheimer's from different directions in an attempt to diagnose and possibly treat the condition.
Scientists in Great Britain have identified a blood protein that can predict the future likelihood of a person developing Alzheimer's. Levels of a protein known as MAPKAPK5 were lower in the blood of participants who experienced a significant decline in their cognitive ability in a 10-year period, they found.
In the U.S., researchers report being able to restore "lost memories" in the brains of mice simply by stimulating neurons in their brains with pulses of light.
This suggests memories lost to certain kinds of amnesia, and possibly Alzheimer's, are not erased entirely but somehow remain, hidden and just out of reach, they say.
And Italian researchers have discovered degeneration of white matter in the brain, which shows up in specialized MRI scans, may be an early sign of specific forms of Alzheimer's disease, including so-called early-onset Alzheimer's.
And, finally, researchers have found that people with diabetes may face a significantly higher risk for developing Alzheimer's, based on the affect uncontrolled blood sugar can have on the brain.
