By Kay Lazar Globe Staff

If all goes according to plan, 1,000 older people who have no symptoms of Alzheimer’s disease, but who have an abnormal protein in their brains believed to be a hallmark of the illness, will be selected to test whether drugs can hold off the disease in a first of its kind study to be led by Boston scientists.

The proposed study, detailed Tuesday at the Alzheimer’s Association International Conference in Vancouver, received a preliminary thumbs up earlier this month from the National Institutes of Health, but the project’s leaders are awaiting a final decision on funding the project, expected in September.

“In this tough time of federal funding, we are keeping our fingers very tightly crossed,” lead researcher Dr. Reisa Sperling, an Alzheimer’s specialist at Brigham and Women’s Hospital, said in a phone interview.

Recent drug trials aimed at clearing the abnormal amyloid proteins in the brains of Alzheimer’s patients have produced disappointing results, with no apparent easing of symptoms, and researchers think that’s because the drugs were used too late.

Scientists believe that more than 50 percent of certain critical brain cells are already lost by the time a patient displays even mild cognitive impairment. There is no known cure for Alzheimer’s disease.

Sperling’s study would enroll 1,000 adults over age 70 who have amyloid plaques revealed by brain scans and who are exhibiting very subtle cognitive problems that are typically reported in people years before they are diagnosed with Alzheimer’s.

“They can come in and say, ‘my memory is not as good as it used to be’ because we have some data that suggests complaining about your memory is more likely to be seen in people who have amyloid in their brain, but are still normal,” Sperling said.