As people with Down Syndrome age, they show signs of dementia that resemble Alzheimer’s disease. That’s probably because their brains undergo similar changes, a study in the July issue of Archives of Neurology suggests. Autopsies of individuals with Down Syndrome have revealed amyloid protein plaques and tau tangles in their brains, just like the brains of Alzheimer’s patients, but scientists didn’t know whether these neurological characteristics resulted in similar cognitive deficits in living patients. Now, researchers at the University of California, Los Angeles, used positron emission tomography to compare the levels of amyloid and tau in 19 Down Syndrome and 10 Alzheimer’s patients, and found that the subjects had similar overall levels of the compounds in their brain, though there were some differences in distribution. In the brains of Down Syndrome patients, the researchers saw higher levels of the proteins in the parietal and frontal lobe, key brain regions for behavior and reasoning, which could explain why patients with Down Syndrome show personality changes earlier in life.