would reduce your risk for developing symptoms and keep you normal as long as possible. reporter: currently in the u.s., 5.2 million people suffer from alzheimer s. that number is expected to triple by 2050. this year, the direct cost for caring for them will top $320 billion, including more than $100 billion to medicare. everything reporter: a predictive test that could allow early intervention could be ground breaking says dr. william hu, an alzheimer s specialist at the emory clinic. if we can delay alzheimer s by five years, we can reduce the prevalence by about half and half the people who have alzheimer s disease now essentially cured. reporter: one problem, there are no drugs at present that effectively treat the plaques and tangles although new ones are in the pipelines and would allow doctors to use other therapy. exercise, diet and brain training to keep the mind as healthy as possible until