Chemical changes in brains may predict risk for Alzheimer's

A new study has identified biochemical changes in the brains of normal people who might be at risk for Alzheimer’s disease.

The study of 311 people in their 70s and 80s with no cognitive problems used an advanced brain imaging technique called proton MR spectroscopy to see if they had abnormalities in several brain metabolites that may be biomarkers for Alzheimer’s disease.

They also had PET scans to assess the level of amyloid—beta deposits, or plaques, in the brain that are one of the first signs of changes in the brain due to Alzheimer’s disease. The participants were also given tests of memory, language and other skills.

The study found that 33 percent of the participants had significantly high levels of amyloid—beta deposits in their brains. Those with high levels of amyloid—beta deposits also tended to have high levels of the brain metabolites myoinositol/creatine and choline/creatine.

People with high levels of choline/creatine were more likely to have lower scores on several of the cognitive tests, regardless of the amount of amyloid—beta deposits in their brains.

"This relationship between amyloid—beta deposits and these metabolic changes in the brain are evidence that some of these people may be in the earliest stages of the disease,” said study author Kejal Kantarci, MD, MSc, of the Mayo Clinic in Rochester, Minn., and a member of the American Academy of Neurology. The study was published in the August 24, 2011, online issue of Neurology, the medical journal of the American Academy of Neurology.