Scientists have for the first time identified a rare group of people whose brains appear to defy the laws of aging.
Researchers are baffled by the "SuperAgers" because this elite group of elderly individuals aged 80 and older have memories as sharp as people 20 to 30 years younger than them.
The brains of these SuperAgers also appear to have retained its middle-age youthfulness with one region even being larger than their middle-age counterparts, according to a study published in the Journal of the International Neuropsychological Society.
The study included 12 SuperAger participants, 10 normally aging elderly participants with an average age of 83.1 and 14 middle-aged participants with an average age of 57.9. All participants were from the Chicago area.
Lead researcher Emily Rogalski of Northwestern University Feinberg School of Medicine was amazed by the vitality of the SuperAgers' cortex, the brain's outer layer responsible for memory, attention and other thinking abilities.
Rogalski looked at 3-D MRI scans and found the SuperAger cortex was significantly thicker than in normal people aged 80 and over whose brains showed significant thinning, and closely resembled the cortex size of middle-aged participants between the ages of 50 and 65.
"These findings are remarkable given the fact that grey matter or brain cell loss is a common part of normal aging," Rogalski said in a statement.
Rogalski and her team had estimated the number of brain cells left in the participants' brains by measuring the thickness of the cortex.
"We can't actually count them, but the thickness of the outer cortex of the brain provides an indirect measure of the health of the brain," Rogalski said. "A thicker cortex, suggests a greater number of neurons."
The team also found that a region deep in the brain called the anterior cingulate was actually thicker in the brains of SuperAgers than in normal 50 to 65 year olds.
"This is pretty incredible," Rogalski said. "This region is important for attention. Attention supports memory. Perhaps the SuperAgers have really keen attention and that supports their exceptional memories."
Researchers hope that unlocking the secrets of the youthful brains of the elderly who seem to be remarkably protected from the effects of aging like memory decline and brain cell atrophy will lead to new treatments to fight memory loss and Alzheimer's disease.
"By looking at a really healthy older brain, we can start to deduce how SuperAgers are able to maintain their good memory," Rogalski said.
"Many scientists study what's wrong with the brain, but maybe we can ultimately help Alzheimer's patients by figuring out what goes right in the brain of SuperAgers. What we learn from these healthy brains may inform our strategies for improving quality of life for the elderly and for combatting Alzheimer's disease," she added.
Of all the participants in the study, only about 10 percent of the people who "thought they had outstanding memories" met the criteria to be defined as a SuperAger, which meant that they scored at or above the average of the 50 to 65 year olds on memory test.
"These are a special group of people," Rogalski said. They aren't growing on trees."
Researchers noted that most of the SuperAger participants plan to donate their brains for scientific research.
"By studying their brains we can link the attributes of the living person to the underlying cellular features," Rogalski said.