News Review From Harvard Medical School -- Changes Seen Long
before Early Alzheimer's Changes in the brain and the fluid
around it may occur as much as 25 years before symptoms of
early-onset Alzheimer's disease, a new study finds. The study
focused on 128 people. All had a family history of early
Alzheimer's caused by a gene inherited from one parent. Symptoms
start in the 30s, 40s or 50s. About half of those in the study
carried the gene. Researchers gave everyone several tests. They
determined when symptoms would be expected to start based on the
parent's age at diagnosis. About 25 years before symptoms were
expected, those with the gene showed a drop in beta-amyloid in
the fluid around the brain. This is a key component of
Alzheimer's plaques inside the brain. About 15 years before
symptoms were expected, people with the gene had smaller brains,
and plaques had appeared. Fluid around the brain also had more
tau protein. This is another sign of Alzheimer's. About 10 years
ahead of symptoms, people's brains