MRIs, Formula Could Help Detect Alzheimer's Early

NEW YORK -- Taking a look at brain size might help doctors detect Alzheimer's disease before it starts.

Researchers in New York are examining changes in brain structure and metabolism associated with early Alzheimer's disease, in hopes of detecting symptoms before they emerge.

The researchers at the New York University's School of Medicine are using a new technique to measure the volume of the brain. In doing so, the researchers identified healthy people at risk of developing memory impairment, a symptom associated with a high risk for future Alzheimer's disease.

Over six years, Dr. Henry Rusinek followed 45 healthy volunteers over the age of 60. Researchers used the magnetic resonance imaging scans of the volunteers to measure their medial-temporal lobes of the brain. That part of the brain contains the hippocampus and the entorhinal cortex which are key structures allied with learning and memory.

In addition to the MRI scans, the researchers used a formula to measure the medial-temporal lobes.

At the beginning of the study, everyone was within the normal range on a battery of tests typically used to detect early loss of memory and other mental deficits. Each person received a baseline MRI scan, which was repeated two years later.

Researchers found that, each year, this region of the brain shrank considerably more in people who developed memory problems compared with people who didn't.

"With our findings, we now know that the normal healthy brain undergoes a predictable shrinkage that can be used to help recognize Alzheimer's several years before clinical symptoms emerge," Rusinek said.

Rusinek said the technique was about 90 percent accurate and predicted memory problems.

But the researchers said future studies are necessary to determine whether the technique would be as accurate in a much larger pool of subjects. Additionally, the researchers said it's unclear as to whether other neurodegenerative diseases that affect the aging brain could also be accurately identified with this technique.

Alzheimer's disease is a progressive illness that kills neurons in the brain, causes memory loss and leads to dementia, according to the Alzheimer's Association. It afflicts an estimated 4 million older adults in the United States. Currently, the disease can be diagnosed definitively only after a person dies, by an autopsy showing certain brain abnormalities.

Despite the promise of the MRI studies, researchers said the hippocampus region of the brain is difficult to measure. They said that area is shaped like a sea horse and is only about 4 cm long.

The study is published in the December issue of the journal Radiology.