A combination of genetic testing and sophisticated imaging techniques can detect brain damage caused by Alzheimer’s disease 20 years before obvious symptoms of the disease appear, according to researchers.
Such an early diagnosis, they say, could open the door to treatments that would prevent further deterioration of the brain, staving off the onset of the disease for years or even decades.
Dr. Gary W. Small of the University of California, Los Angeles, and his colleagues report in today’s Journal of the American Medical Association that, in people who have a gene called ApoE4, the early stages of Alzheimer’s can be detected by an imaging technique called PET scanning.
“The search for an early and accurate diagnostic tool for Alzheimer’s is a critical step in the development of preventative strategies,” said Dr. Zaven Khachaturian, director of Alzheimer’s research at the National Institute on Aging. “This is a major step forward.”
Scientists currently have only one drug for treating Alzheimer’s, and it is effective in only some patients. But a variety of other promising medications are nearing or beginning human trials.
Each of these would be most effective in the very earliest stages of the disease, which affects as many as 4 million Americans over the age of 65.
“It doesn’t make sense to treat somebody late in the course of the disease because all the brain cells are already dead,” Khachaturian said.
The study provides the first direct evidence the brain damage produced in Alzheimer’s accumulates over a long period of time before symptoms become evident, which should provide insights into the mechanisms of the disease, said Sheryl Williams, vice president of medical affairs at the Alzheimer’s Association.