Fluorodeoxyglucose positron emission tomography to help determine whether cognitive impairment will lead to Alzheimer's

With nearly 10 million baby boomers at risk for developing Alzheimer's disease, researchers are taking a closer look at a condition known as mild cognitive impairment.

This is a state between the normal forgetfulness that comes with aging and the more pronounced thinking deficits of dementia. Mild cognitive impairment often progresses to Alzheimer's disease, but some people remain stable and others recover. New technology is improving the ability to determine who might fall into each category, reports the April 2008 issue of the Harvard Mental Health Letter. These developments are promising because they are occurring just as the first disease-modifying drugs for Alzheimer's have reached late-stage clinical testing.

One technology, fluorodeoxyglucose positron emission tomography (FDG-PET), measures blood glucose metabolism in the cerebral cortex. Diminished glucose uptake suggests that neurons are not as active. Clinicians can also measure brain volume changes with volumetric MRI to detect shrinkage, which is typical in Alzheimer's. These techniques are likely to prove most useful when combined with detection of newly discovered proteins believed to be the first signs of Alzheimer's.

If one of these technologies—or a combination—can reliably predict which people with cognitive impairment are likely to progress to Alzheimer's, scientists might be able to determine who should get the disease-modifying medications now in development. And they might be able to predict which healthy people are most likely to get mild cognitive impairment, and try to prevent it.

The technologies and medications needed to predict and prevent mild cognitive impairment and Alzheimer's are still in the early stages of development, but the Harvard Mental Health Letter says that this research will almost certainly lead to better treatments.

Also in this issue:

•  Preschoolers with psychiatric disorders
• Post-combat mental health help
• Asthma and anxiety, depression
• Metformin plus lifestyle changes help people with schizophrenia lose weight
• Antidepressant effectiveness

The Harvard Mental Health Letter is available from Harvard Health Publications, the publishing division of Harvard Medical School, for $59 per year.