MONDAY, April 10, 2006 (HealthDay News) -- Stroke may harm memory without necessarily causing dementia or other cognitive impairment, researchers report.
Columbia University researchers in New York performed an initial assessment of nearly 1,300 people, averaging just over 76 years of age, with no cognitive impairment or dementia. The evaluations were done between January 1992 and December 1994, and the study volunteers were then re-examined at 18-month intervals until November 1999.
Close to 8 percent of the study participants had a history of stroke. While all the participants experienced some memory decline over the course of the study, the decline was more rapid in people who had a history of stroke, the researchers reported in the April issue of the journal Archives of Neurology.
The association between stroke and memory decline was strongest in men and in people with a type of gene called apoE4 allele, which has long been linked to Alzheimer's disease. The study also identified a decline in abstract/visuospatial abilities among men and people without the apoE4 variant who also had a history of stroke.
"The mechanisms by which stroke increases the risk of cognitive decline are not clear," the study authors wrote.
They suggested that stroke may cause memory problems by damaging or destroying certain areas of the brain or by triggering the deposit of materials that form brain plaques associated with Alzheimer's disease.
"It is also possible that the occurrence of stroke adds cognitive deficits in persons with subclinical Alzheimer's disease that brings them over the diagnostic threshold and that stroke does not have a direct specific effect on Alzheimer's disease," the authors noted.
More information
The American Academy of Family Physicians has more about memory and age.
