Older Brains Become Less Coordinated: U.S. Study

Communications problems between different regions of the brain may be to blame.

ByABC News
February 18, 2009, 2:48 PM

— -- CHICAGO, Dec 5 (Reuters) - Forgot where you put your keys?Or your car?

If you are over 60, it may just be a normal part of aging,U.S. researchers said on Wednesday in a study that suggestsbrain structures deteriorate with age in otherwise healthypeople.

The study, published in the journal Neuron, is part of aneffort by researchers at Harvard University to understand thedifference between normal, age-related declines and clinicalimpairment.

"We're trying to understand the edge of that boundarybetween normal aging and Alzheimer's disease," said RandyBuckner, a Harvard professor and Howard Hughes MedicalInstitute researcher who worked on the study.

Buckner and colleagues took brain scans of 55 adults ages60 and over, and 38 younger adults ages 35 and younger. Theyused an imaging technique called PET to detect the presence ofamyloid, a chemical typically associated with Alzheimer'sdisease, to rule out those whose memory declines weredisease-related.

What they found is that some brain systems become lesscoordinated with age. "It looks like it is an effect of normalaging independent of Alzheimer's disease," Buckner said in atelephone interview.

They found brain structures called white matter tracks,which carry information between different regions of the brain,were deteriorating only in the older group.

"In young adults, the front of the brain was pretty well insync with the back of the brain," Jessica Andrews-Hanna, agraduate student in Buckner's lab, said in a statement. "Inolder adults this was not the case. The regions became out ofsync and they were less correlated with each other."

Buckner said the study suggests the cognitive decline inaging may be linked to communication problems between regionsof the brain.

"We are talking about an effect that is progressing in thelate decades of our lives," he said.

Not everyone was impaired to the same degree. This may helpexplain why some people who develop Alzheimer's disease succumbquickly and others decline more slowly.