EMBARGOED FOR RELEASE UNTIL MONDAY, DECEMBER 21, 1998 For more information contact: Sarah Parsons (651) 695-2732 [email protected]
Healthy Aging Brains DonÃt Shrink Faster
ST. PAUL, MN (December 21, 1998) ñ Healthy 85-year-olds donÃt lose brain tissue any faster than healthy 65-year-olds, contrary to popular belief, according to a study in the December issue of Neurology, the scientific journal of the American Academy of Neurology.
ìPeople assume that we lose brain tissue faster as we get older, but this study shows thatÃs not the case for those in good health,î said neurologist Jeffrey Kaye, MD, director of the Aging and AlzheimerÃs Center at Oregon Health Sciences University and the Portland Veterans Affairs Medical Center.
Kaye and his colleagues initially tested healthy people ages 65 to 95. Those showing signs of AlzheimerÃs disease or other dementia were excluded from the study because these disorders cause the brain to shrink. The study also excluded those with a history of diseases that might affect the brain, such as diabetes, hypertension and stroke. Researchers performed ongoing cognitive tests, and those who developed signs of dementia were excluded from the study. The remaining 46 participants were followed for an average of five years.
Changes in brain volume over time were measured with magnetic resonance imaging (MRI) scans.
The common perception that cell loss accelerates with age may be due to problems with previous studies, Kaye said. Studies showing large differences in brain volumes in younger elderly people and the older elderly may have included many people who were destined to develop AlzheimerÃs disease.
ìThey may have already had significant losses in brain volume, even though no one would have detected yet that they had the disease,î he said.
For the healthy people in KayeÃs study, the rate of brain tissue loss was small ñ one percent or less per year.
ìThis study implies that brain health continues well into the extremes of our current age span,î Kaye said. ìIt suggests that we can age normally forever. On the other side of the coin, these people are still at risk of developing dementia.î
Kaye said understanding how the healthy brain ages helps researchers understand how diseases affect the brain. ìFor example, if people have an accelerated rate of tissue loss in the brain, that may tell us they are going to develop dementia,î he said. ìThis could help us identify people to participate in studies to determine whether new treatments are having an effect on the brain. Right now, claims that a drug is preventing the progression of the disease in the brain canÃt be substantiated.î
The study measured changes in total brain volume. ìMore research is needed to determine whether the loss of volume is due to loss of neurons, the nerve cells that most people think of as ëbrain cells,à or to loss of glial cells, the supporting tissue in the brain,î Kaye said.
This study is part of a larger study on brain aging and cognition supported by the federal Department of Veterans Affairs, the National Institute on Aging and the Alzheimer Research Alliance of Oregon.
The American Academy of Neurology is an association of more than 15,000 neurologists and neuroscience professionals dedicated to improving care for patients through education and research.
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