By Chris Adams

In the last two decades, scientists have learned a great deal about Alzheimer’s disease and dementia, and they’ve boosted their ability to predict which people might experience it. But what they haven’t been able to do with any great success is treat it.

In a session with National Press Foundation fellows, Dr. R. Scott Turner of Georgetown University detailed the latest scientific understanding of Alzheimer’s disease, as well as the broader category of all dementias.

Alzheimer’s sneaks up on people, starting with what he called a “silent phase” of brain changes without measurable symptoms. During that phase, people may notice changes even if they aren’t detectable on tests.

Up next is mild cognitive impairment, in which changes are noticeable to friends and family members but a person is still able to maintain their regular life. After that is dementia – mild, moderate, moderately severe and severe – that limits everyday abilities.

Scientists have made significant strides understanding the disease but they’ve been increasingly frustrated by the failure of large clinical trials that could help treat it; in one high-profile case, a hoped-for drug cure instead made memory worse.

“We have not come up with a successful treatment,” Turner said. “It has been a very, very tough year in Alzheimer’s trials.”

Turner detailed the latest clinical trials for Alzheimer’s disease, including which biomarkers – or measurable physical indications – can predict it. There are also drugs on the market to treat Alzheimer’s disease, and they have been available for two decades. But all they can do is slightly mitigate the onset of more severe forms of the disease.

Scientists have also learned what might lessen a person’s risk for getting Alzheimer’s disease, including proper diet (Turner’s lab recommends the Mediterranean diet) and regular exercise. But there is still a lot to learn, with 100 clinical trials underway or planned.