英语科普：老年人健忘的原因

New research links 'silent strokes,' or small spots of dead brain cells, found in about one out of four older adults to memory loss in the elderly. The study is published in the January 3, 2012, print issue of Neurology®, the medical journal of the American Academy of Neurology. "The new aspect of this study of memory loss in the elderly is that it examines silent strokes and hippocampal（海马的） shrinkage simultaneously," said study author Adam M. Brickman, PhD, of the Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center in New York.

For the study, a group of 658 people ages 65 and older and free of dementia（痴呆） were given MRI brain scans. Participants also underwent tests that measured their memory, language, speed at processing information and visual perception. A total of 174 of the participants had silent strokes.

The study found people with silent strokes scored somewhat worse on memory tests than those without silent strokes. This was true whether or not people had a small hippocampus（海马） , which is the memory center of the brain.

"Given that conditions like Alzheimer's disease are defined mainly by memory problems, our results may lead to further insight into what causes symptoms and the development of new interventions¹ for prevention. Since silent strokes and the volume of the hippocampus appeared to be associated with memory loss separately in our study, our results also support stroke prevention as a means for staving off memory problems," said Brickman.