PARIS, France - People at risk for Alzheimer's are twice as likely to fall as healthy people, and the disease may also be visible in scans of the eye, researchers said on Sunday.
The studies, presented at the Alzheimer's Association International Conference in Paris, are part of a widespread search for ways to detect Alzheimer's before memory problems begin, when drugs and treatments have a better chance of a difference.
"I don't think we can wait until people develop Alzheimer's disease or mild Alzheimer's. I think we need to act before that," Dr. William Klunk of the Alzheimer Disease Research Center at the University of Pittsburgh Medical Center said at the conference.
Brain scans and spinal fluid tests are used by researchers to detect Alzheimer's-related changes, but they are expensive and impractical for widespread screening, and none of them have been approved for routine use.
So teams are looking for other early changes that offer evidence the disease is developing before symptoms occur.
Susan Stark of Washington University in St. Louis looked to see whether frequent falls may be an early warning sign of Alzheimer's disease.
Her team studied 125 people who had brain scans and contributed samples of their spinal fluid. Each study participant kept a journal of how many times they fell over an 8-month period.
The researchers found that people whose brain scans detected pre-symptomatic Alzheimer's disease were twice as likely to fall as those who had normal scans.
"This is really the first study that tests for falls in the preclinical phases of Alzheimer's disease," Stark said.
"It suggests that higher rates of falls can occur very early in the disease process."
Eye test for Alzheimer's
In a separate study, Shaun Frost, a researcher from the Commonwealth Scientific and Industrial Research Organization, Australia's national science agency, looked to see whether changes in the retina at the back of the eye -- which is closely related to the brain -- could be used to detect early Alzheimer's disease.
"It is much easier for us to image the retina than it is for us to do a brain scan," Frost told the meeting.
Frost's team found the width of certain blood vessels were significantly different in people with early signs of Alzheimer's disease compared with healthy people.
People in the small study who had abnormal blood vessels in their eye also had plaque deposits of an Alzheimer's-related protein known as beta amyloid on positron emission tomography, or PET brain scans.
"These findings are indicating a relationship between changes in the retina and the plaque burden in the brain," Frost said.
He said the study suggested it might be possible to use retina tests along with other biomarker tests to detect Alzheimer's early.
The study needs to be confirmed by larger studies, but it shows one of the ways in which researchers are trying to find ways of diagnosing Alzheimer's early.
Even though there are no treatments that can halt or delay the disease, scientists say knowing how to diagnose Alzheimer's before symptoms occur will be important when new drugs become available.