Slips of memory once thought to be a normal part of aging may be the result of early-stage Alzheimer's disease, scientists are beginning to find.

Five studies presented at the Alzheimer's Association International Conference in Boston on Wednesday found that people who were clinically healthy but expressed concern regarding memory lapses were significantly more prone to develop more severe issues in the future, multiple news sources report.

One study, according to The Telegraph, found that elderly individuals with concerns about their memory had significantly greater levels of plaque, which accumulates in the brains of those with Alzheimer's.

Another study, conducted by the University of Kentucky, found that those who reported changes in their memory were twice as likely to be diagnosed with dementia or mild cognitive impairment within the next 10 years.

For years people have complained about slips in memory -- complaints that have universally gone ignored by doctors who believed it was nothing serious.

This, said Creighton Phelps, the acting director of the dementias of aging branch at the National Institute on Aging, is starting to change.

"The hardest part is deciding what is normal aging and what's abnormal," Phelps told Bloomberg.com. "We all lose our car keys. We've been doing that all our lives. If you forget how to use a key or you find it in a refrigerator, that should make you and stop and think."

To deal with this problem, an international group of experts, led by Frank Jesses from the University of Bonn in Germany, have devised a framework for future research with guidelines that lay out terms and methods for coordinating efforts around the world and determining whether an individual's complaints should be addressed.

The last 12 months have not been good for those hoping for a treatment for Alzheimer's, with several high-profile clinical trials failing to show any benefit. Many scientists speculate that this may be because drugs are being introduced too late into the progression of the disease after too many brain cells have been killed off.

For this reason, earlier and earlier diagnosis may not only help individuals with the disease prepare for the future but, scientists hope, help advance medical treatment as well.