The amount of blood flowing into the brain may play a larger role in the development of dementia than previously believed, according to a study in the September issue of the journal Radiology.
Researchers from Leiden University Medical Center in the Netherlands used magnetic resonance imaging (MRI) to examine the brains of elderly patients with and without dementia related to Alzheimer's or Parkinson's disease. As expected, MR images showed that the patients with late-onset dementia had more brain damage compared with young adults and with seniors who had optimal cognitive function. But researchers found that the late-onset dementia group also had a much lower rate of blood flow to the brain than the other two groups.
"Our findings not only support the hypothesis that vascular factors contribute to dementia in the elderly, they are highly suggestive that a diminished cerebral blood flow indeed causes brain damage," said Aart Spilt, M.D., a Leiden radiology resident and lead author of the study. "This gives us a clue to the genesis of dementia."
Dementia is a loss of cognitive functions, such as thinking, remembering and reasoning, that interferes with normal activities. Although many conditions can produce these symptoms, Alzheimer's disease is the most common cause of dementia. Some patients with Parkinson's disease also develop dementia.
In the Dutch study, researchers examined 17 patients with late-onset dementia (dementia occurring after age 75), another 16 seniors of the same age with optimal cognitive function and 15 healthy younger individuals. Researchers used MRI to measure cerebral blood flow and the extent of structural brain damage in each person and then compared the results of the three groups.