A new study due out next week suggests that a phenomenon called “silent strokes” make explain memory loss in up to 25 percent of older adults who experience memory problems.
A silent stroke is often found after-the-fact by an MRI of a person’s brain.
“When patients are asked whether they remember having a stroke, they are often surprised and cannot recall feeling any symptoms of stroke at any point in their lives,” says Jose Vega M.D., Ph.D., who was not involved in the study. He also noted that a previous study “showed that by the age of 69, approximately 11 percent of people who consider themselves stroke-free have suffered at least one stroke that can be seen on MRI.”
The new study finds that number may be much higher. The result of a silent stroke are small spots of dead brain cells.
“The new aspect of this study of memory loss in the elderly is that it examines silent strokes and hippocampal 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.
For the study, a group of 658 people ages 65 and older and free of dementia 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 — just over 25 percent of the people in the study.
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, 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 interventions 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.
The study is published in the January 3, 2012 edition in the journal Neurology.
Source: American Academy of Neurology